Biology Systems

  1. Endocrine System
    • means of internalcommunication, coordinating the activities of the organ systems
    • synthesize and secrete chemical substances: Hormones
  2. Exocrine Glands
    substances that are transported by ducts
  3. Adrenal Glands
    on top of the kidneys and consists of adrenal cortex and adrenal medulla
  4. Adrenal Cortex
    • in response to stress,adrenocorticotropic hormone (ACTH) produced by anterior pituitary stimulates the adrenal cortex to produce more than two dozen different steroid hormones, collectively known adrenocortical steroid or corticosteroids
    • in blood streams, bound to transcortins
    • Glucocorticoids
    • Mineralocorticoids
    • Cortical Sex Hormones
  5. Glucocorticoids
    • cortisol and cortison
    • glucose regulation and protein metabolism
    • raise blood glucose levels by promoting protein breakdown and gluconeogenesis and decreasing protein synthesis
    • increase plasma glucose levels and antagonistic to effects of insulin
    • release amino acids from skeletal muscles
    • release lipids from adipose tissue
    • promote peripheral use of lipids
    • anti-inflammatory effects
  6. Mineralocortiocoids
    • aldosterone
    • regulate plasma levels of sodium and potassium and total extracellular water volume
    • aldosterone causes active reabsorption of sodium and passive reabsorption of water in the nephron
    • increase in both blood volume and blood pressure
    • excess aldosteron, excess retention of water and hypertension
    • stimulated by angiotensin II and inhibited by ANP
  7. Cortical Sex Hormones
    • adrenal cortex secreted small amounts of androgens like androstenedione and dehydroepiandrosteron in both men and women
    • over production in femal, have masculine effects
  8. Adrenal medulla
    produces epinephrine and norepinephrine----catecholamines
  9. Epinephrine
    • increases conversion of glycogen to glucose in liver and muscle tissue, causing increase in blood glucose levels and an increase in the basal metabolic rate
    • Both increase rate and strength of the heartbeat and dilate and constrict blood vessels, as to increase the blood sypply to skeletal muscles, the heart, and the brain and decrease blood supply to the kidneys, skin and digestive tract
    • both also promote release of lipids by adipose tissue
    • fight or flight response
    • by sympathetic nervous stimulation in response to stress
  10. Pituitary Gland
    • small,tri-lobed gland in the base of the brain
    • two main lobes: anterior and posterior
    • hands below the hypothalamus
  11. Anterior Pituitary Gland
    • synthesized both direct homrones
    • directly stimulate their target organs and tropic hormones which stimulate other endocrine glands to release hormones
    • hormonal secretions of the anterior pituitary are regulated by hypothalamic secretions called releasing/inhibiting hormones or factors
  12. Direct Hormones
    • Growth Hormone
    • Prolactin
  13. Growth Hormone
    • somatotrophin
    • bone and muscle growth
    • protein synthesis
    • lipid mobilization
    • catabolism
  14. Prolactin
    milk production and secretion in female mammary glands
  15. Tropic Hormones
    • ACTH
    • TSH
    • LH
    • FSH
    • MSH
  16. Adrenocorticotropic Hormone (ACTH)
    • synthesize and secrete glucocorticoids
    • regulated by releasing hormone corticotrophin releasing factor
  17. TSH
    • Thyroid Stimulating Hormone
    • Thyroid gland to synthesize and rlease thyroid hormones including thyroxin
  18. LH
    • Lutenizing Hormone
    • ovulation and formation of corpus luteum
    • regulating progesterone secretion
    • stimulates interstitial cells for men to produce testosterone
  19. FSH
    • follicle stimulating hormone
    • causes maturation of ovarian follicles that begin secreting estrogen
    • in men, maturation of seminiferous tubules and sperm production
  20. MSH
    • melanocyte stimulating hormone
    • secreted by the intermediate lobe of the pituitary
    • in frogs, causing skin darkening
  21. Posterior Pituitary
    • not make homrones
    • stores and release the peptide hormones: oxytocin and ADH
    • produced by neurosecretory cells of the hypothalamus
  22. Oxytocin
    • secreted during childbirth
    • increases the strength and frequency of uterine muscle contractions
    • stimulates milk secretion in the mammary glands
  23. Antidiuretic Hormone
    • ADH, Vasopressin
    • increases the permeability of the nephron's collecting duct to water
    • promote water reabsorption and increaing blood volume which increases blood pressure
    • ADH secreted when plasma osmolarity increases as senssed by osmoreceptors in the hypothalamus or when blood volume decreases as sensed by baroreceptors in the circulatory system
  24. Hypothalamus
    • part of the forebrain
    • directly above the pituitary gland
    • receives neural transmissions from other parts of the brain and from peripheral nerves that trigger specific responses from its neurosecretory cells
  25. Neurosecretory Cells
    regulate pituitary gland secretions via negative fveedback mechanism and through the actions of inhibiting and releasing hormones
  26. Interactions with Anterior Pituitary
    • Hypothalamic releasing hormones that stimulate or inhibit the secretions of the anterior pituitary
    • Releasing Hormones: secreted into hypothalamic hypophyseal portal system
    • Blood from capillary bed---portal vein---anterior pituitary---second capillary network
  27. Interactions of Posterior Pituitary
    Neurosecretory cells in the hypothalamus synthesize both oxytocin and ADH and transport them via their axons into the posterior pituitary for storage and secretion
  28. Thyroid
    • affect function of nearly every organ
    • essential for growth and development in children
    • essential for maintenance of metabolic stability in adults
    • thyroxine from thyroglobulin;
    • and triiodothyronine
    • Trioodothyronine five times more potent than thyroxine
    • Transported in the blood by proteins
    • Only unbound hormone is able to enter a cell and elicit a cellular response
    • thyroxine: formed and secreted by thyroid gland
  29. Thyroid Hormones
    • derived from iodination of the amino acid tyrosine
    • increase rate of metabolism
    • Hypothyroidism: undersecreted or not secreted at all; slowed heart rate, fatigue, cold intolerance, and weight gain; in new borns: cretinism---mental retardation and short stature
    • Hyperthyroidism: overstimulated, increased metabolic rate, profuse sweating, weight loss and protruding eyes
  30. Calcitonin
    • decreases plams Ca2+ concentration by inhibiting the release of Ca2+ from bone
    • secretion is regulated by plasma Ca2+
    • antagonistic to the parathyroid
  31. Pancreas
    • Both an exocrine organ and endocrine organ
    • Exocrine Function: secreted digestive enzymesinto small intestine via a series of duct
    • Endocrine Function: performed by small glandular structures called islets of langerhans, composed of aplha and beta cells
  32. Alpha Cells
    produce and secrete glucagon
  33. Beta Cells
    produce and secrete insulin
  34. Glucagon
    • stimulates protein and fat degradation
    • conversion of glycogen to glucose
    • gluconeogenesis
    • serve to increase blood glucose levels
    • antagonistic to insuline
  35. Insulin
    • protein hormone secreted in response to high blood glucose concentration
    • stimulates uptake of glucose by muscle and adipose cells and storage of glucose as glycogen in muscle and liver cells, lowering blood glucose levels
    • stimulates making of fats from glucose and uptake of amino acids
    • underproduction: diabtes mellitus, hyperglycemia
  36. Parathyroid Glands
    • four small pea shaped structures embedded to the posterior surface of the thyroid
    • make and secrete parathyroid hormone
    • regulate Ca2+ concentration
    • raises Ca concentration in blood by releasing Ca from the bone and decreasing Ca excretion in the kidneys
    • calcium in bone is bonded to phosphates and breakdown of the bone releases phosphate as well as calcium
  37. Kidneys
    • When blood volume falls, kidneys produce renin
    • produce erythropoietin,
  38. Renin
    • Enzyme that converts the plasma protein angiotensinogen to angiotensin I
    • Angiotensin I converted to angiotensin II, stimulates adrenal cortex to secrete aldosterone
  39. Aldosterone
    • helps to restore blood volume by increasing sodium reabsorption at the kidney, leading to an increase in water
    • removes intial stimulus for renin production
  40. erythropoietin
    • glycoprotein, stimulates red blood cell proliferation
    • stimulation of stem cells to differentiate into rubriblasts (least mature erythrocyte)
    • increased rate of mitosis
    • increased release of reticulocytes from the bone marrow
    • increases hemoglobin formation, allows critical concentration necessary for maturation to be reached at a more rapid rate
  41. Gastrin
    • Stomach releases when food ingested
    • carried to the gastric glands and stimulates them to secrete HCl in response to food in stomach
  42. Secretin
    • released by small intestine when acidic food enters from stomach
    • stimulates secretion of alkaline bicarbonate solution from the pancreas that neutralizes acidity of the chyme
  43. Cholecystokinin
    • released from small intestine in response to presence of fats
    • causes contraction of the gallbladder
    • release of bile into small intestine
  44. Pineal Gland
    • tiny structure at base of the brain
    • secretes melatonin
    • in regulation of circadian rhythms-physiological cycles lasting 24 hours
    • regulated by light and dark cycles in surroundings
    • melatonin antagonist to MSH
  45. Hormones
    • Classifed : Peptide or Steroid
    • Via extracellular or intracellular
  46. Peptides
    • act as first messengers
    • binding to specific receptors on surface of target cells triggers enzymatic reactions within each cell, first of which may be conversion of ATP to cyclic adenosine monophosphate
  47. Cyclic AMP
    • acts as second messenger
    • relaying messages from extracellular hormone to cytoplasmic enzymes and initiating reactions
    • cascade effect: each step hormone action amplified
    • inactivated by enzyme phosphodiesterase
  48. Steroids
    • estrogen and alsosterone
    • lipid derived molecules with ring structure
    • lipid soluble
    • enter target cells directly and bind to specific receptor proteins in the cytoplasm
    • receptor-hormone complex enters the nucleus and directly activates the expression of specific genes by binding to receptors on the chromatin
    • induces change in mRNA transcription and protein synthesis
  49. Meristematic Tissue
    • actively growing parts of the plant
    • in the apical region (apical meristem)
  50. Auxins
    • plant hormones associates with several types of growth patterns
    • reponsible for phototropism
    • geotropism
    • produced in terminal bud of a plant's growing tip move downward in the shoot and inhibit development of lateral buds
    • initiate formation of lateral roots while they inhibit root elongation
  51. Phototropism
    • tendency of the shoots of plants to bend towards ligh sources (particularly the sun)
    • when light strikes the tip of a plant from one side, the auxin supply on the side is reduced
    • The illuminated side of plant gows more slowly than the shaded side, asymmetrical growth in the cells of the stem causes the plant to bend towards the lgiht side
    • Indole-acetic acid is one of the auxins associated with phototropism
  52. Geotropism
    • growth of portions of plants toward or away from gravity
    • Negative Geotropism
    • Positive Geotropism
  53. Negative Geotropism
    • causes shoots to grow upward, away from the acceleration of gravity
    • if plant turned on side, then shoot will turn upward again
    • gravity increases concentration of auxin on lower side of horizontal plant, concentration on upper side decreases
    • unequal distribution of auxins stimulates cells on the lower side to elongate faster than cells on the upper side, causing plant to grow vertically
  54. Positive Geotropism
    • Causes roots to grow towards the pull of gravity
    • horizontal roots have same auxin distribution as horizontal stems, but effect on root cells is opposite
    • cells exposed to higher concentration of auxin, are inhibited from growing, whereas cells on upperside continue to grow,causes root to turn downwards
  55. Gibberellins
    • stimulate rapid stem elongation particularly in plants that do not grow tall
    • inhibit formation of new roots and stimulate production of new phloem cells by the cambium (auxins stimulate production of new xylem cells)
    • terminate the dormancy of seeds and buds
    • induces some biennial plants to flower during their first year of growth
  56. Kinins
    • promote cell division
    • kinetin: type of cytokinin
    • ratio of kinetic to auxinis of particular importance indertmination of the timing of the differentiation of new cells
    • action of kinetin is enhanced when auxin is present
  57. Ethylene
    • stimulates fruit ripening
    • induces senescenceor aging
  58. Inhibitors
    • block cell division
    • growth regulation
    • maintenance of dormancy in the lateral buds and seeds of plants during autumn and winter
    • break down gradually with time (and in some cases are destroyed by cold) so buds and seeds can become active in the next growing season
    • abscistic acid
  59. Antiauxins
    • regulate activity of auxins
    • increase concentration of indole acetic acid, increase amount of indole acetic acid oxidase produced
  60. Nervous System
    • includes all of the neural tissues in the body
    • Central Nervous System and Peripheral Nervous System
    • enables organisms to receive and respond to stimuli from their external and internal environments
    • responds to stimuli more rapidly than endocrine system
  61. Neurons
    • Functional units of nervous system
    • converts stimuli into electrochemical signals that are conducted through the nervous system
    • elongated cell consisting of dendrites, cell body, and a single axon
  62. Dendrites
    cytoplasmic extension that receive information and transmit it toward the cell body
  63. Cell Body
    Soma contains nucleus and controls metabolic activity of the neuron
  64. Axon
    • long cellular process that transmits impulses away from the cell body
    • most sheathed by an myelin, insulating substance
  65. Myelin
    • Allows axons to conduct impulses faster
    • insulating substance
    • produced by glial cells
    • membrane permeable to ions only in nodes of ranvier, action potential jumps from node to node
  66. Oligodendrocytes
    produce myelin in central nervous system
  67. Schwann Cells
    produce myelin in peripheral nervous system
  68. Nodes of Ranvier
    Gaps between segments of myelin
  69. Synaptic Terminals
    • Axons end as swellings
    • synaptic buttons or knobs
  70. Synapse
    • Neurotransmitters released from here
    • synaptic cleft
    • gap between axon terminal of one cell (presynaptic neuron) and the dendrite of the next cell (postsynaptic neuron)
    • When action potential arrives nerveterminal deporlarizes it, synaptic vesicles fuse with the presynaptic membrane and release neurotransmitter into the synapse
    • neurotransmitter diffuse across synapse and acts on receptor proteins embedded in the postsynaptic membrane
    • neurotransmitter lead to depolarization of the postsynaptic cell and consequent firing of an action potential
    • neurotransmitter removed from the synapse in many ways, take back up into the nerve terminal (via enzymes located in the synapse)
    • ex. acetylcholinesterase inactivates the neurotransmitter acetylcholine, may simply diffuse out of the synapse
    • when reach neuromuscular junction, acetylcholine released from nerve terminal into synaptic cleft
    • action potential spreads over nerve termina, calcium channels open that allows large quantities of calcium to diffuse into interior of the terminal
    • calcium ions exert attractive forces on acetylcholine vesicles and draw them to neural membrane
    • some of the vesicles will fuse with neural membrane, empty acetylcholine into synaptic cleft by exocytosis
    • sodium responsible in propagation of action potential but not release of acetylcholine into synaptic cleft
  71. Effector Cells
    neurons may also communicate with postsynaptic cells other than neurons, such as cells in glands
  72. Neurotransmitters
    chemical messengers in membrane bound vesicles in nerve terminals
  73. Cells in Central Nervous System
    • Astrocytes
    • Oligodendrocytes
    • Microglia
    • Ependymal cells
  74. Astrocytes
    • maintain integrity of the blood brain barrier
    • regulate nutrient and dissolved gas concentration
    • absorb and recycle neurotransmitters
  75. Microglia
    Remove cellular debris and pathogens
  76. Ependymal Cells
    • Line the brain ventricles
    • aid in the production, circulation, and monitoring of cerebral spinal fluid
  77. Satellite Cells
    Surround the neuron cell bodies in the ganglia
  78. Production of Neurotransmitters in Nervous Systems, ex. norepinephrin and acetylcholine
    • When norepinephrin made, immediate precursor is dopamine; made in axoplasm of endings of adrenergic fibers; completed inside vesicles of these fibers
    • 1. Tyrosine converted to DOPA through hydroxylation
    • 2. DOPA undergoes decarboxylation to become Dopamine
    • 3. Dopamine transported into vesicle of adrenergic fibers
    • 4. Hydroxylation to become norepinephrine
    • 5. In adrenal medulla, converted to epinephrine, through methylation
    • 6. Choline combined with Acetyl-CoA to become acetylcholine
  79. Action Potentials
    • Impulses that travel the length of axo and invade nerver terminal, cause release of neurotransmitter into synapse
    • when neuron at rest, potential difference between the extracellular space and intracellular space is called the resting potential
    • becomes sufficiently exicted or depolarized, action potential generated
    • minimum threshold membrane potential is the level at which an action potential is initiated
    • all or none response
    • impulse propagation: from dendrite to synaptic terminal, one way; synapses in one way and refractory period make backwards impossible
    • different speeds, greater diameter of axon, more heavily myelinated, faster impulses
  80. Resting Potential
    • At rest, neuron is polarized
    • Potential Difference = Between inside and outside of cells
    • typical resting = -70 millivolts, inside of neuron is more negative than outside; selective ion permeability of neuronal cell membrane and maintained by active transport by the Na+/K+ pump
  81. Na+/K+ ATPase
    • Concentration of K+ higher inside
    • Concentration of Na+ higher outside
    • Negatively charged proteins are trapped inside
    • Resting potential created because neuron is selectively permeable to K+, so K+ diffuses down its concentration gradient, leaving negative charge inside
    • Neurons impermeable to Na+, so cells polarized
    • restores gradients after action potentials
    • 3 Na+ out
    • 2 K+ in
  82. Voltage Gated Ion Channels
    • Ion channels located in nerve cell membrane open in response to changes in voltage
    • Action Potential Begins when voltage-gated Na+ channels open in response to depolarization, allowing Na+ to rush down the electrochemical gradient into the cell, causing rapid further depolarization of cell
    • then channels close,
    • Voltage Gated K+ channels open, allowing K+ to rush out down its gradient, more negative potential, repolarization
    • may even experience hyperpolarization, more negative inside than normal
    • immediately after action potential, may be very difficult or impossible to initiate another action potential, period of time: refractory period
  83. Effects of Drugs
    • Curare
    • Botulism toxin
    • Anticholinesterases
  84. Curare
    • blocks the post-synaptic acetylcholine receptors so that acetylcholine is unable to interact with the receptor
    • leads to paralysis by blocking nerve impulses to muscles
  85. Botulism Toxin
    prevents the release of acetylcholine from the pre-synaptic membrane and also results in paralysis
  86. Anticholinesterase
    • used in nerve gas and in the insecticide parathion
    • inhibits the activity of acetylcholinesterase enzyme
    • acetylcholine is not degraded in the synapse and ocntinues to affect post synaptic membrane
    • no coordinated muscular contractions can take place
  87. Protozoa
    • Unicellular organisms have no organized nervous system
    • may respond to stimuli such as touch, heat, light, and chemicals
  88. Cnidaria
    • simple nervous system: nerve net
    • limited centralization
  89. Annelida
    • primitive central nervous system consisting of a defined ventral nerve cord and an anterior brain of fused ganglia
    • pathways from receptors to effectors
  90. Arthropoda
    specialized sense organs present
  91. Afferent Neurons
    neurons that carry sensory information about the external or internal environment to the brain or spinal cord
  92. Efferent Neurons
    Neurons carry motor commands from brain or spinal cord to various parts of the body
  93. Interneurons
    participate only in local circuits, linking sensory and moto neurons in brain and spinal cord, their cell bodies and their nerve terminals are in the same location
  94. Plexus
    • network of nerve fibers
    • nerves are bundle of axons covered with connective tissue
  95. Ganglia
    • Neuronal cell bodies often cluster together, in periphery
    • in central nervous system, nuclei
  96. Central Nervous System
    • Brain
    • Spinal Cord
  97. Brain
    • mass of neurons
    • interpreting sensory information
    • forming motor plans
    • Cognitive Function
    • Outer Portion: Gray Matter (Cell bodies)
    • Inner: White Matter (Myelinated Axons)
    • Brain: Prosencephalon, Mesencephalon, and Rhombencephalon
  98. Prosencephalon
    Forebrain contains: Telecephalon and Diencephalon
  99. Telencephalon
    • major part:cerebral cortex
    • Olfactory Bulb
  100. Cerebral Cortex
    • Highly convoluted gray matter that can be seen on surface of the brain
    • Processes and integrates sensory input and moto responses and is important for memory and creative thought
  101. Olfactory bulb
    center for reception and integration of olfactory input
  102. Diencephalon
    contains: thalamus and hypothalamus
  103. Thalamus
    Relay and integraton center for the spinal cord and cerebral cortex
  104. Hypothalamus
    • Controls visceral functions such as hunger, thirst, sex drive, water balance, blood pressure and temperature regulation
    • control endocrine system
  105. Mesencephalon
    • Midbrain
    • Relay center for visual and auditory impulses
    • role in motor control
  106. Rhombencephalon
    • Hindbrain
    • Cerebellum
    • Pons
    • Medulla
    • Brainstem
  107. Hindbrain
    Posterior part of the brain and consists of the cerebellum, pons and medulla
  108. Cerebellum
    modulate motor impulses initiated by the cerebral cortex and important in the maintenance of balance, hand-eye coordination, and the timing of rapid movement
  109. Pons
    relay center to allow the cortex to communicate with the cerebellum
  110. Medulla
    controls many vital functions such as breathing, heart rate, and gastrointestinal activity
  111. Brainstem
    Midbrain, Pons, and Medulla
  112. Spinal Cord
    • Elongated extension of the brain which acts as conduit for sensory information to the brain and motor information from the brain
    • integrate simple motor responses by itself
    • outer white matter: motor and sensory axons
    • inner gray matter: nerve cell bodies
  113. Dorsal Horn
    • Sensory information enters the spinal cord
    • cell bodies of these sensory neurons located in dorsal root ganglia
  114. Ventral Horn
    • Motor information exits spinal cord
    • simple reflexes like the knee-jerk reflex, sensory fibers (entering through the dorsal root ganglia) synapse directly on ventral horn motor fibers
  115. PNS
    • Nerves and Ganglia
    • sensory nerves enter the CNS
    • Motor nerves leave CNA
    • PNS: somatic and autonomic
  116. Somatic Nervous System
    innervates skeletal muscle and voluntary movement
  117. Autonomic
    • involuntary nervous system
    • without aid of conscious control
    • snesory and motor fibers
    • cardiac and smooth muscles
    • sympathethic and parasympathetic
  118. Sympathetic
    • flight or fight
    • increases blood pressure and heart rate
    • increase blood flow to skeletal muscles
    • decreases gut motility
    • dilates bronchioles to increase gas exchange
    • norepinephrine: neurotransmitter
  119. Parasympathetic
    • conserve energy
    • restore body to resting activity after exertion (rest and digest)
    • lower heart rate
    • increase gut motility
    • vagus nerve: in thoracic and abdominal viscera
    • Acetylcholine: Neurotransmitter
  120. EYE
    • detects light energy and transmits information about intensity, color, and shape to the brain
    • Sclera: covers eyeball, thick and opaque layer
    • Choroid: beneath sclera, supply retina with blood; dark, pigmented area that reduces reflection in eye
    • Retina: Innermost layer; contains photoreceptors that snese light
    • Cornea: front of the eye bends and focuses light rays
    • Ray then travel to pupil, diameter controlled by pigmented, muscular iris
    • iris responds to intensity of light in the surroudings (light makes pupil constrict)
    • light through lens
    • lens, shape and focal length controlled by ciliary muscle, fouces image onto retina
  121. Photoreceptors
    • transduce light into action potentials
    • two types: cones and rods
  122. Cones
    • high intensity illumination
    • sensitive to color
    • three pigments: red, green and blue wavelengths
  123. Rods
    • low intensity illumination
    • nigh vision
  124. Rhodopsin
    • absorbs single wavelength
    • phtorecepot cells synapse onto bipolar cells, which in turn synapse onto ganglion cells
    • Axons of ganglion cells bundle to form optic nerves
    • optic nerves conduct visudal info to the brain
    • point at which optiv nerve exits the eye: blind spot; no photoreceptors there
    • fovea: small area of reitna, densely packed with cones and high acuity vision
  125. Vitreous Humor
    • jellylike material
    • maintain shapes and optical properities
  126. Aqueous Humor
    • formed by eye
    • and exits through ducts to join venous blood
  127. Myopia
    • nearsightedness
    • image on front of retina
  128. Hyperopia
    • Farsightedness
    • Behind the retina
  129. Astigmatism
    caused by irregular shaped cornea
  130. cataracts
    • lens become opaque
    • light cannot enter eye and blindness results
  131. glaucoma
    • increase pressure of eye
    • blocking of outflow of aqueous humor
  132. Ear
    transduces sound energy into impulse perceive by brain as sound
  133. Sound Process
    • sound waves pass through three regions
    • 1. enter outer ear: consist of auricle (external ear), and auditory canal
    • 2. At end of auditory canal, tympanic membrane, (eardrum) of the middle ear, which vibrates at same frequency as incoming sound
    • 3. three bones, ossicles (malleus, incus, stapes) amplify stimulus and through oval window which lead to fluid filled inner ear
    • 4.consist fo cochlea and vestibular apparatus: INNER EAR
    • 5. Vestibular Apparatus: Maintaining equilibrium
    • 6. Vibration of ossicles exerts pressure on fluid in cochlea, stimulating hair cells in basilar membrane to transduce pressure into action potentials
    • 7. travel via the auditory (cochlear) never to the brain for processing
  134. External Respiration
    referes to the entrance of air into lungs and the gas exchange between the alveoli and the blood
  135. Internal Respiration
    exchange of gas between the blood and the cells and the intracellular processes of respiration
  136. Photosynthesis
    converts the energy of the sun into chemical energy of bonds in compounds such as glucose
  137. Respiration
    • involves the conversion of the chemical energy in these bonds into usable energy needed to drive the processses of living cells
    • High energy atoms are removed from organic molecules- Dehydogenation and oxidation reaction
    • Subsequenct acceptance of hydrogen by hydrogen acceptor (oxygen in the final step) reduction component of the redox reaction
    • Energy released by this reduction is used to form a high energy phosphate bond in ATP
    • Net result of redox reaction is energy production
    • Reductions occur in steps of Electron Transport Chain
  138. Fuel Molecules
    • Carbohydrates and Fats
    • C-H bond rich
    • capable of releasing highest energy
    • CO2 - little usable every; stable energy exhausted end product
  139. Glucose Catabolism
    degradative oxidation of glucose occurs in two stages: Glycosis and Cellular Respiration
  140. Glycolysis
    • lead to oxidative breakdown into two molecules of pyruvate (ionized form of pyruvic acid) and production of ATP and the reduction of NAD+ to NADH
    • occur in cytoplasm
    • concomitant production of ATP
    • Two molecules of PGAL are used per molecule of glucose
    • and all steps occur twice for each glucose molecule

    • 1. Glucose Reacts with Hexokinase to form Glucose-6-Phosphate
    • 2. Interacts with Phosphoglucose Isomerase, fructose-6-Phosphate is formed
    • 3. Interacted with enzyme Phosphofructokinase to form compound fructose 1, 6,-biphosphate
    • 4. When interacted with aldolase, glyceraldehyde 3 Phosphate is formed
    • 5. After reactions, Phosphoenolpyruvate is formed
    • 6. When acted upon with pyruvate kinase, pyruvate is formed and complete
  141. Glycolytic Pathway
    Image Upload 1
  142. Glycolysis: Starting and Ending
    • 2 molecule of Pyruvate
    • 2 ATP used
    • 4 ATP generated
    • 2 ATP net per glucose molecule
    • Substrate Level Phosphorylation: ATP synthesis directly coupled with degradation of glucose without the participation of an intermediate molecule such as NAD+
    • 1 NADH made per PGAL
    • 2 NADH per glucose
    • 2 Pi used
    • 2 H+ made
    • 2H20 made

    Pyruvate Degradation in Two Ways: Anaerobically (Fermentation) and Aerobically (cell respiration in mitochondria)
  143. Fermentation
    • NAD+ regenerated for glycolysis to continue in absence of O2
    • Reducing pyruvate to ethanol or lactic acid
    • 2 ATP produced per glucose molecule
    • Alcohol and Lactic Acid
  144. Alcohol Fermentation
    • in yeast and some bacteria
    • converted to ethanol
    • NAD+ regenerated and glycolysis continues
  145. Lactic Acid Fermentation
    • in fungi and bacteria and human cells during streneous activity
    • Oxygen supply to muscle cells lag, pyruvate generated is reduced to lactic acid
    • NAD+ regenerated when pyruvate is reduced
  146. Cellular Respiration
    • Most efficient Catabolic Pathway used to harvest energy and store glucose
    • Can yield 36-38 ATP
    • Aerobic
    • Oxygen - Final Acceptor of electrons that are passed from carrier to carrier to final stage of glucose oxidation
    • into three stages: Pyruvate Decarboxylation, Citric Acid Cycle, and Electron Transport Chain
  147. Pyruvate Decarboxylation
    • Transported from cytoplasm to mitochondrial matrix, decarboxylated
    • Loses Co2
    • Acetyl Group transferred to CoA, to form Acetyl CoA
    • NAD+ reduced to NADH
  148. Citric Acid Cycle
    • Krebs Cycle
    • 1. 2 Carbon Acetyl group from Acetyl CoA combines with oxaloacetate, to form the six carbon citrate
    • 2. Oxaloacetate regenerated after series of reactions for use in another turn of the cycle
    • 3. For each turn:
    • 1 ATP made by substrate level phosphorylation via GTP
    • Electrons transferred to NAD+ and FAD, generate, NADH and FADH2
    • Then transported to electron transport chain, where more ATP is produced via oxidative phosphorylation
  149. Citric Acid: Starting and Ending
    • 2 pyruvates decarboxylated and channeled into citric acid cycle
    • Starting: 2 Acetyl CoA Ending: 4CO2
    • 6 NAD+ 6 NADH
    • 2 FAD 2 FADH
    • 2 GDP 2 ATP
    • 2 Pi, 4 H20 4 H+, 2 CoA
  150. Electron Transport Chain
    • Located inside of the inner mitochondrial membrane
    • Oxidative Phosphorylation: ATP produced when high energy potential electrons transferred from NADH and FADH2 to oxygen
    • As electrons transferred, free energy is released, the used to form ATP
    • Most molecules, are cytochromes: electron carriers that resemble hemoglobin in structure of active site
    • Functional unit of cytochrome: Iron atom, can undergo reversible redox reaction, and be reduced and oxidized
    • Each Carrier reduced as it accepts and electron and then oxidized when passes it on to the next carrier
    • Last Carrier: passes its electron to final electron acceptor, O2
    • O2 picks up pair of hygrogen ion from medium forming water
  151. Substrate level phosphorylation: ATP calculation
    • Degradation of One glucose: 2 ATP from glycolysis
    • 1 ATP for each turn of citric acid cycle
    • TOTAL: 4 ATP via Substrate level phosphorylation
  152. Oxidative Phosphorylation
    • greater than 90% ATP used by cells in our body
    • Major process in electron transport chain
    • Along Electron Transport Chain, Respiratory Enzyme continually pump hydrogen ions from matrix of mitochondria to inter membrane space, creates large concentration gradient
    • As hydrogen passes from concentration gradient, energy created is used to convert ADP to ATP
    • Two Pyruvate Decarboxylation = 1 NADH each for a total fo 2 NADH
    • Each turn of citric Acid cycle: 3 NADH and 1 FADH2 for a total of 6 NADH and 2 FADH2 per glucose molecule
    • FADH2 = 2 ATP
    • NADH = 3 ATP except for the two NADH during glycolysis
    • So the NADH in Glycolysis, generate 2 ATP per glycolysis = 4 ATP
    • 32 ATP from Oxidative Phosphorylation
    • Total of 36
    • Prokaryotes: 38, 2 NADH of glycolysis don't have any membranes to cross and don't lose energy
  153. Alternate Energy Sources
    • When glucose runs low, body uses other energy sources
    • Other Carbohydrates, Fats, and Proteins
    • First converted to either glucose or glucose intermediate, which can then be degradedinthe glycolytic pathway and the citric acid cycle
  154. Carbohydrates
    • Disaccharides hydrolyzed into monosaccharides
    • Converted into glucose or glycolytic intermediate
    • Glycogen stored in liver can be converted when needed into a glycolytic intermediate
  155. Fats
    • Stored in adipose tissue in the form of triglyceride
    • When needed, hydrolyzed by lipases to fatty acids and glycerol and are carried by the blood to other tissues for oxidation
    • Glycerol can be converted to PGAL, a glycolytic intermediate
    • A fatty acid must first be activated in the cytoplasm
    • Process requires 2 ATP
    • Once activated, fatty acid transporated into mitochondrion and taken through a series of beta-oxidation cycles that convert it into two carbon fragments, converted to Acetyl CoA, Acetyl CoA then enters the TCA cycle
    • With each round of b-oxidation of a saturated fatty acid, 1 NADH and 1 FADH2 generated
    • Yield the greatest number of ATP per gram
  156. Proteins
    • Body degrades proteins only where not enough carbohydrate or fat available
    • Undergo transamination reaction, in which they lose an amino group to form an a-keto acid
    • Carbon Atoms of most amino acids are converted into acetyl CoA, pyruvate, or one of the intermediates of the citric acid cycle
    • Intermediates enter their respective metabolic pathways allowing cells to produce fatty acids, glucose, or energy in the form of ATP
    • Oxidative Deamination: Removes an ammonia molecule directly from the amino acid
    • Ammonia: toxic substance in vertebrates, fish can excrete ammonia, whereas insects and birds convert it to uric acid, mammals converts it urea for excretion
  157. Protozoa and Hydra
    Contact with the external environment and respiratory gases can be exchanged between the cell and the environment by simple diffusion through the cell membrane
  158. Annelids
    • Mucus secreted by cells on the external surface of the earthworm's body provides a moist surface for gaseous exchange by diffusion
    • Circulatory system brings O2 to the cells and waste products such as CO2 back to the skin for excretion
  159. Arthropod Phylum
    • Consists: Of series of respiratory tubules called trancheae, whose branches reach every cell
    • Tubes open to surface in opennings called spriracles
    • System permites intake, distribution and removal of respiratory gases directly between the air and the body cells by diffusion
    • No carrier of oxygen is needed and efficiency of this system allows insects to have a relatively inefficienct open circulatory system
  160. Respiration in Humans
    • Air enters lungs after traveling through series of respiratory airways
    • Air passages consists of the nose, pharynx (throat), larynx, trachea, bronchi, bronchioles, and the alveoli
    • Gas Exchange between the lungs and the circulatory system occurs across the very thin walls of the alveoli which are air filled sacs at the terminals of the airway branches
    • After gas exchange, air rushes back through the respiratory pathway and is exhaled

    • Functions: Provide the necessary energy for growth, maintenance of homeostasis, defense mechanisms, repair and reproduction of cells in the body
    • Protect agains infection dehydration, and temperature changes, moving air over the vocal cords for the production of sound and assisting in the regulation of body pH by regulating rate of carbon dioxide removal from the blood
  161. Ventilation
    • Process by which air is inhaled and exhaled
    • Purpose of ventilation to take in oxygen from the atmosphere and eliminate carbon dioxide from the body
  162. Inhalation
    • diaphragm contracts and flattens
    • external intercostal muscles contract, pushing the rib cage and chest wall up and out
    • causes thoracic cavity to increase in volume
    • volume increase in turn, reduces the pressure, causing the lungs to expand and fill with air
  163. Exhalation
    • generally a passive process
    • lungs and chest wall are highly elastic and ten to recoil to their original positions after inhalation
    • diaphragm and external intercostal muscles relax and chest wall pushes inward
    • consequent decrease in thoracic cavity volume causes the air pressure to increase, the causes the lungs to deflate, forcing air out of the alveoli
  164. Control of Ventilation
    • Ventilation is regulated by neurons (referred to as respiratory centers) located in the medulla oblongata, whose rhythmic discharges stimulate the intercostal muscles or the diaphragm to contract
    • When partial pressure of CO2 rises, medulla oblongata stimulates an increase in the rate of ventilation
    • Primary Goal of Respiration: Maintain Proper Concentratioin of Oxygen, carbon dioxide, and hydrogen ions in tissues
    • Respiratory Activity: highly responsive to changes in the blood levels of these compounds
    • Excessive Carbon Dioxide and Hydrogen Ions are the primary stimulus for respiration
    • When carbon dioxide and hydrogen ion levels, increase, respiratory center stimulates both the inspiratory and expiratory muscles of the lungs,
    • Oxygen Blood Levels do no have significant effect on respiratory center
    • Oxygen Blood levels are monitored by peripheral chemoreceptors which indirectly stimulate respiratory center
  165. Pulmonary Capillaries
    • Dense network of minute blood vessels surrouonds the alveoli
    • Gas exchange occurs by diffusion across the capillary walls and those of the alveoli, gases move from regions of higher partial pressure to regions of lower partial pressure
    • Oxygen diffuses from the alveolar air into the blood while carbon dioxide diffuses from the blood into the lungs to be exhaled
  166. Respiration in Plants
    • Respiration is continuous
    • Photosynthesis only takes place during the day
    • Photosynthesis produces glucose and gives off oxygen whereas respiration requires oxygen to degrade glucose
    • Bonds of glucose are broken in glycolysis to produce 2 ATP and pyruvic acid
    • Gases diffuse into air space entering (or leaving) through the stomatas of the leaf or the lenticels (opening) of woody stems, 36 ATP molecules are produces per molecule of glucose
    • Anaerobic respiration takes place in simple plants when molecular oxygen is lacking
  167. Autotroph
    Any organism that manufactures its own organic molecules (glucose, amino acids, and fats) from inorganic molecules (CO2, H2O, and mineral salts)
  168. Photosynthesis
    • Harness energy of sunlight to form these chemical bonds
    • Occurs in algae and multicellular green plants
    • Others use chemosynthesis to obtain energy
    • Metabolic Process where solar energy is trapped, converted to chemical energy, and then stored in bonds of plant organic nutrient molecules
    • All green plants use photosynthesis to convert carbon dioxide and water into glucose and oxygen
    • Glucose can be stored as starch or used as energy source
    • Takes place in specialized organelle - Chlroroplast
  169. Chloroplast
    • Photosyntheis takes place here
    • Highly organized plastid containing chlorophyll pigment
    • bounded by two membranes and contains network of membranes called thylakoid membranes
  170. Chlorophyll
    • Within the thylakoid membranes
    • Complexed with metal magnesium
    • When absorbs photons of light, electrons in the ground state are boosted to an excited state and can be harnessed to drive the reactions of photosynthesis
    • Absorbs light in the red and blue wavelengts giving it a green appearance
    • Chlorophyll a and Chlorophyll b
    • Part of two photosystems
  171. Grana
    • Sing, granium
    • Thylakoid Sacs are stacked into columns
  172. Stroma
    fluid matrix of the chloroplast
  173. Photosystem
    • light capturing unit of thylakoid membrane
    • Composed of a number of chlorophyll molecules
    • In center, single chlorophyll molecule coupled to other proteins that excited by absorbed photon
    • In photosystem I: chlorophyll a molecule is called p700 and absorbs at 700 nm
    • In photosystem II: chlorophyll molecule is called p680, and absorbs at 680 nm
  174. Overview of Photosynthesis Reactions
    • Involves reduction of CO2 to carbohydrate accompanied by release of oxygen from water
    • Net reaction: Reverse of Respiration, reduction occurs
    • Two distinct reactions, Light and Dark Reactions
  175. Light Reactions
    • Convert solar energy into chemical energy in the form of ATP (by photophosphorylation) and NADPH
    • Must take place in the light
    • Photolysis Reactions, begin with absorption of a photon of light by chlorophyll molecule
    • When light strikes special chlorophyll a P700 molecule in photosystem I, excites electrons to a higher energy level
    • High energy electrons can flow along two pathways giving cyclic electron flow or noncyclic electron flow
  176. Cyclic Electron Flow
    • Excited Electrons of P700 move along a chain of electron carriers
    • Redox Reactions returns the electrons to P700
    • Produce ATP from ADP and Pi = Photophosphorylation
    • Coenzyme Ferrodoxin: one of the early electron carrier in electron transport chain
  177. Noncyclic electron Flow
    • Key pathway of the light reaction
    • Involves reactions of both photosystems
    • photons of light excite electrons in P700 in photosystem I
    • High energy electrons are transferred to the electron acceptor NADP+
    • NADP+ accepts high energy electrons and forms NADPH
    • P700 is left with electron holes and is oxidizing agent
    • When light excites P680 in photosystem II, electrons are excited
    • Electrons travel down same chain until they reach P700 and fill the electron holes
    • Cascade Produces ATP by noncyclic photophosphorylation
    • P680 has electron holes, strong enough oxidizing agent to oxidize water and fill its holes
    • Water is split into two hydrogen ions and an oxygen atom and the electrons produced reduce P680
    • Oxygen Atoms combine to form O2
    • Net Result: NADPH and ATP and the photolysis of water
  178. Dark Reactions
    • Coupled to the light reaction
    • Incorporate CO2 into organic molecules in a process called carbon fixation
    • Reduction Synthesis because carbohydrates are produced by reducing CO2
    • Reaction in Chloroplasts
    • Use ATP and NADPH produced by light reactions to reduce CO2 to carbohydrates, primarily glucose
    • Not require direct light, only occur during day when light reaction replenishing supply of ATP and NADPH
    • Carbon fixation or reduction synthesis
    • CO2 is the source of carbohydrate production in Calvin Cycle
    • Produce is 3 carbon PGAL
    • Cycle must occur 3 times
    • 1. Add CO2 to ribulose bisphosphate to produce 6 carbon intermediate that splits into two 3 carbon 3-phosphoglyceric acid
    • 2. Acid phosphorylated by ATP and reduced by NADPH to give PGAL
    • 3. Two molecules of PGAL converted to glucose then be oxidized to provide usable energy
  179. Photoionization
    escape of high energy electrons from chlorophyll molecules
  180. Calvin Cycle
    • Similar to Krebs cycle
    • 1. Carbon Dioxide is fed into the cycle; in krebs, produced and released
    • 2. Reducing Power is used during the cycle, NADPH; NaDH removed
    • 3. Energy is used in cycle for conversion of ATP to ADP; Energy was produced when ATP was formed from ADP and inorganic phosphate
  181. Summary of Calvin Cycle
    • carbon dioxide is fixed to RBP
    • Splits to form 2 molecules of PGA
    • PGA phosphorylated and reduced by ATP And NADPH to form PGAL
    • PGAL recycled to RBP
    • In Six turns,12 PGAL from 6 carbon dioxide and 6 RBP
    • The 12 PGAL recombine to form 6 RBP and 1 Molecule of glucose, net product
    • PGAL - Prime Endproduct of photosynthesis
  182. Plant Structure
    • The Leaf
    • The Root
  183. The leaf
    • Waxy Cuticle
    • Palisade
    • Spongy layer
    • Guard
  184. Waxy Cuticle
    • reduce transpiration and conserve water;
    • no openings on their upper surface
  185. Palisade
    • elongated chloroplast containing cells spread over a large surface area
    • directly under the upper epidermis and are well exposed to light
  186. Spongy Layer
    • stomata open into air spaces that contact an internal moist surface of loosely packed spongy layer cells
    • Moist surface is necessary for diffusion of gases into and out of cells for both photosynthesis and respiration
    • Air spaces increase surface area available for gas diffusion by the cells
    • Contain chloroplasts
  187. Guard
    cells surround each of the stomata on the lower surface of the leaves
  188. Stomata
    • Openings in the lower epidermis of the leaf that permit diffusion of carbon dioxide, water vapor and oxygen between leaf and atmosphere
    • Size is regulated by guard cells; open stomata during day to admit CO2 for photosynthesis and close them at night to limit loss of water vapor (transpiration)
    • During the day, guard cells contain chloroplasts and produce glucose
    • High Glucose, causes them to swell; since wall is thick, produces curvature of opening between guard cells and stomata opening then increases
    • At night, photosynthesis stops, cell turgor decreases, and stomata closes
    • Photosynthesis stop when no CO2
  189. Vescular Bundles
    Veins containing xylem and phloem bring water to the leaf from roots (xylem) and carry manufactured food out of the leaf (phloem)
  190. The Root
    • Specialized epidermal cells with thin walled root hair are found in root
    • Provide increased surface for absorption of water and minerals by diffusion and active transport
  191. Chemosynthesis
    • Some bacteria form carbohydrates by use of chemical energy rather than by using radiant energy of the sun
    • Bacteria oxidize compounds of nitrogen, sulfur, or iron
    • Small energy released by oxidation is sufficient for formation of glucose
    • Energy produced is sufficient to support the vital functions of these nitrogen, sulfur, and iron bacteria
    • Nitrifying Bacteria: Oxidize ammonia and nitrites to nitrates; plants use nitrates to make proteins; Bacteria use energy to make glucose
  192. Unicellular Locomotion
    • Beating cilia or flagella
    • Cylindrical Stalk of 11 microtubules and 9 paired arragned in a circlewith 2 single
    • power stroke, thrusting movement by sliding action of microtubules
    • Return of cilia or flagellum to its original position - recovery stroke
  193. Invertebrate Locomotion
    • Hydrostatic Skeletons
    • Flatworms
    • Annelids
  194. Flatworms
    • Two Antagonistic Layers: Longitudinal and Circular
    • Muscle contract against the resistance of the incompressible fluid within the animal's tissue (hydrostatic skeleton)
    • Contraction of the circular layer of muscles causes incompressible fluid to flow longitudinally, lengthening animal
    • Contraction of longitudinal layer of muscles, shortes the animal
    • Same type of skeleton assists in locomotion of annelids
  195. Segmented Worms
    • Earthworms advance principally by action of muscles on hydrostatic skeleton
    • Bristles in lower part of each segment, called setae, anchor the earthworm temporarily in the earth while muscles push it ahead
  196. Exoskeleton
    • hard skeleton that covers all muscles and organs of some invertebrates
    • in arthropods
    • composed of chitin
    • composed of noncellular material secreted by epidermis
    • impose limitations on growth
    • periodic molding and deposition new skeleton necessary for growth
  197. Vertebrate Skeleton
    • Endoskeleton
    • Cartilage
    • Bone
    • Osteocytes
    • Bone formation
  198. Endoskeleton
    • muscles attached to bones, permitting movement
    • provides protection by surrounding delicate vital organs in bone
    • rib cage protects the thoracic organ whereas skull and column protect brain and spinal cord
  199. Cartilage
    • type of connective tissue that is softer and more flexible than bone
    • for firmness and flexibility
  200. Bone
    • specialized type of mineralized connective tissue
    • body support, hard, strong, elastic, and lightweight
    • Two types: Compact Bone and Spongy Bone
  201. Compact Bone
    • dense bone
    • not appear to have any cavities when observed with the naked eye
    • bony matrix is deposited in structural units called osteons (Haversian Systems)
    • Each osteon consists of a central microscopic channel called Haversian Canal surrounded by a number of concentric circles of bony matrix (calcium phosphate) called lamellae
  202. Spongy Bone
    • less dense
    • consists of interconnecting lattice of bony spicules (trabeculae): cavities in between the spicules are filled with yellor or red bone marrow
    • Yellow Marrow: Inactive and infiltrated by adipose tissue
    • Red Marrow: Involved in blood cell formation
  203. Osteocytes
    • Osteoblasts: Synthesize and Secrete organic constituents of bone matrix; once become surrounded by matrix and mature to osteocytes
    • Osteoclasts: Large Multinucleated cells involved in bone reabsorption
  204. Bone Formation
    occur by either endochondral ossification or by intramembranous ossification
  205. Endochondral Ossification
    • existing cartilage is replace by bone
    • Long bones arise primarily through endochondral ossification
  206. Intermembranous Ossification
    mesenchymal (embryonic or undifferentiated) connective tissue is transformed into, and replaced by bone
  207. Axial Skeleton
    Basic Framework of the body, consisting of the skull, vertebral column, and the rib cage
  208. Appendicular skeleton
    Bones of appendages and the pectoral and pelvic girdles
  209. Sutures and Immovable Joints
    Hold the bones of the skull together
  210. Movable Joints
    • Bone that do move relative to one another are held together
    • additionally supported and strengthed by ligaments
  211. Ligaments
    bone to bone connectors
  212. Tendons
    Attach skeletal muscle to bones and bend the skeleton at the movable joints
  213. Origin
    point of attachment of a muscle to a stationary bone(proximal end in limb muscles)
  214. Insertion
    Point of attachment of a muscle to the bone that moves (distal end in limb muscles)
  215. Extension
    indicates a straigthening of a joint
  216. Flexion
    bending of a joint
  217. Muscular System
    • bundles of specialized contractile fibers held together by connective tissue
    • Skeletal, Smooth and Cardiac
    • Pyramidal System: able to provide rapid commands to skeletal muscles
    • Red Nucleus: located in mesencephalon, component of extrapyramidal system
  218. Skeletal Muscle
    • Voluntary Movementsand is innervated by somatic nervous system
    • Each fiber is multinucleated cell created fusion of several mononucleated embryonic cells
    • Embedded in fibers are filament called myofibrils, which are further divided into contractile unit called sarcomeres
    • Myofibrils enveloped by a modified endoplasmic reticulum that stores calcium ions and is called sarcoplasmic reticulum
    • cytoplasm of muscle fiber: sarcoplasm
    • Cell membrane: Sarcolemma; capable of propagating an action potential and connectedto asystem of transverse tubules (T system) oriented perpendicularly to the myofibrils
    • T system: provides channels for ion flow throughout the muscle fibers, and can also propagate an action potential
    • Mitochondria very abundant
    • Striations of light and dark bands
  219. Sarcomere
    • composed of thin and thick filaments
    • thin: actin molecule
    • thick: myosin
    • Z lines: boundaries of single sarcomere
    • M lines: runs down the center of the sarcomere
    • I band: region containing thin filaments only
    • H zone: region containing thick filaments only
    • A band: spans entire length of thick filaments and any overlapping portions of thin filaments
    • During contraction, A band not reduced, H zone and I band are
  220. Contraction
    • Muscle contraction stimulated by message from somatic nervous system via motor neuron
    • Link between nerve terminal and sarcolemma: Neuromuscular Junction
    • The space between the two: Synapse or Synaptic cleft
    • Depolarization of motor neuron
    • release of neurotransmitter, acetylcholine from nerve terminal
    • neurotransmitter diffuses across synaptic cleft and binds to special recepto site on sarcolemma
    • If enough receptors stimulated, permeability of sarcolemma is altered and action potential is generated
    • Action potential along sarcolemma, and T system an into interior of muscle fiber
    • Sarcoplasmic Reticulum to release calcium ions into sarcoplasm
    • Calcium ions initiate contraction of sarcomere
    • Actin and Myosin slide past each other
  221. Rigor Mortis
    • Muscles contract and Become rigid even without action potentials
    • Rigidity: caused by an absence of adenosine triphosphate which is required for the myosin heads to be released from actin filaments
    • Muscles rigid for 12-24 hourse until proteins destroyed
  222. Isotonic Contraction
    occurs when a muscle shortens agains a fixed load while tension othe muscle remains constant
  223. Concentric Contraction
    type of dynamic contraction where muscle fibers shorten and tensionon muscle increases
  224. Dynamic Contraction
    • both concentric and eccentric
    • changein length of muscle with corresponding change in tension on that muscle
  225. Eccentric Contraction
    dynamic contraction where muscle fiber lengthens and tension on muscle increases
  226. Isometric Contractions
    both ends of the muscle are fixed and no change in length occurs during the contraction but the tension increases
  227. Stimulus and Muscle Response
    • Strength of contraction of the entire muscle can be increased by recruiting more muscle fibers
    • A simple twitch: response of a single muscle fiber, consists a latent period, contraction period, and a relaxation period;
    • Latent Period: time between stimulation and onset of contraction
    • Action potential sarcolemma and Ca2+ ions are released
    • After contraction period, there is a relaxation period which muscle is unresponsive to a stimulus; period known as refractory period

    • When fiber exposed to frequent stimuli, muscle cannot fully relax
    • contractions begin to combine, stronger and more prolonged
    • temporal summation; contractions become continuous when stimuli are so frequent that muscle cannot relax
    • tetanus: contraction, stonger than simple twitch
    • If tetanus maintained, muscle will fatigue and contraction will weaken
  228. Tonus
    • state of partial contraction
    • muscles never completely relaxed and maintain a partially contracted state all time
  229. Cori Cycle
    • Lactic acid generated when pyruvic acid reacted with lactate dehyrdogenase
    • during strenuous activity
    • lactic acid in liver to glucose for discharge into bloodstream
    • once in blood, rebuild glycogen reserves
  230. Smooth Muscle
    • involuntary
    • autonomic nerous system
    • one centrally located nucleus
    • lack striations
  231. Cardiac Muscle
    • of heart
    • both skeletal and smooth
    • actin and myosin filaments in sarcomeres, giving striated
    • one or two centrally located nuclei
  232. ATP
    • primary source of for muscle contractions
    • very little stored in muscles
  233. Creatine Phosphate and Arginine Phosphate
    can be temporarily stored in high energy compound
  234. Myoglobin
    • hemoglobin like protein found in muscle tissue
    • has high oxygen affinity and maintains oxygen sypply in muscles by binding oxygen tightly
  235. Heterotrophic
    Unable to synthesize their own nutrients
  236. Digestion
    degradation of large molecules into smaller molecules that can be absorbed inot the bloodstream and used directly by cells
  237. Intracellular Digestion
    within the cell, usually in membrane bound vesicles
  238. Extracellular Digestion
    Digestive process that occurs outside of the cell within a lumen or tract
  239. Digestion in Unicellular Organisms
    • Food capture is effected by phagocytosis
    • Food vacuoles form
    • Amoeba: pseudopod surround and engulf food and enclose it in food vacuoles
    • Lysosomes: fuse with the food vacuole and release their digestive enzymmes that act upon the nutrients
    • Resulting simpler molecules diffuse into cytoplasm
    • Unusable end products eliminated from vacuoles
    • Paramecium: cilia sweep food into oral groove and cytopharynx
    • Food vacuole forms around food at lower end of the cytopharynx
    • Vacuole Breaks off into cytoplasm and progresses toward the anterior end of the cell
    • Enzymes secretedinto vacuole and products diffuse into cytoplasm
    • Solid Wastes expelled at anal pore
  240. Digestion In Invertebrates
    • Physical breakdown: by cutting and grinding in the mouth and churning in the digestive tract
    • Molecular Composition is unchanged
    • Surface area of substrates where the enzymes act on is increased
    • Chemical Breakdown: accomplished by enzymatic hydrolysis
    • Smaller digested nutrients pass through the semipermeable plasma membrane of the gut cells to be further metabolized or transported
    • Cnidarians
    • Annelids
    • Arthropods
  241. Cnidarians
    • uses intracellular and extracellular digestion
    • Tentacles: bring food to mouth and release particle into cup like sac
    • Endodermal Cell lingin gastrovascular cavity, secrete enzymes into cavity
    • Digestion occurs outside the cell
    • Once food is reduced smaller, gastrodermal cells engulf nutrients and digestion is complete intracellularly
    • Undigested food is expelled through mouth
    • Every cell exposed to extracellular environment, facilitating intracellular digestion
  242. Annelids
    • one way digestive tract with both a mouth and anus
    • allows specialization of different parts of digestive tract for different functions
    • parts: mouth, pharynx, esophagus, crop (store food), gizzard (grind food), intestine (large dorsal fold typholosole, to provide increased surface area for digestion and absorption) and anus
    • Soluble food passes by diffusion through walls from small intestine to blood
  243. Arthropods
    jaws for chewing and salivary glands which improve food digestion
  244. Human Digestive Tract
    • Oral Cavity
    • Pharynx
    • Esophagus
    • Stomach
    • Small Intestine
    • Large Intestine
    • Anus
    • There are accessory organs
  245. Oral Cavity
    • Mechanical and Chemical Digestion of food begins
    • Mechanical Digestion: Breakdown of large food particles into smaller particles through the biting and chewing action of teeth
    • Chemical Digestion: Enzymatic breakdown of macromolecules into smaller molecules and begins in mouth when salivary glands secrete saliva
    • Saliva Lubricates food to help swallowing and provides solvent for food particles
    • Saliva secreted in response to nervous reflex triggered by presence of food
    • Saliva: Salivary Amylase, hydrolizes starch to maltose
  246. Esophagus
    • Muscular Tube leading from the mouth to the stomach
    • Food moved down by peristalsis
    • In negative thoracic cavity, and abdominal cavity has positive pressure gradient
    • Without defense mechanism, pressure gradients favor continual reflux of materials into esophagus
    • GERD: condition
  247. Stomach
    • large muscular organ in upper abdomen
    • stores and partially digests food
    • walls of stomach are lined by thick gastric mucosa, contains glands
    • glands secrete muchs, protects stomach lining from harshly acidic juises pH = 2, in stomach
    • Secrete pepsin which is a protein-hydrolyzing enzyme, and hydrochloric acid kills bacteria dissolve intercellular glue holding food tissues together, and activates certain proteins
    • Churning of stomach produces an acidic, semifluid mixture of partially digested food known as chyme
    • Chyme passes into first segment of small intestine, the duodenu through pyloric sphincter
  248. Small Intestine
    • chemical digestion completed
    • divided into three sections: duodenum, jejunum, ileum
    • adapted to absorption
    • Long and coiled
    • Villi Extend and contain capillaries and lacteals (surface area)
    • Amino Acids and monosaccharides through capillaries
    • Large Fatty Acids and glycerol through lacteals and then reconverted
  249. Duodenum
    • Most digestion
    • Secretions of intestinal glands, pancreas, liver and gall bladder mix together with acidic chyme entering from stomach
    • Intestinal Mucosa: secretes lipases, aminopeptidases, and disaccharides
    • Dissachridase lactase breaks down lactose, many lack that are lactose intolerant
    • Lactose in small intestine cannot be digested and metabolized by bacteria, producing intestinal discomfort
  250. Parietal Cells
    secretes: Intrinsic Factor and Hydrochloric Acid
  251. Gastrin
    • Produced in G cells of duodenum
    • functions to stimulate hydrochloric acid, histamine, and pepsinogen secretion as well as increase gastric blood flow
    • stimulates parietal cells to produce HCl that denatures proteins and activates digestive enzymess
  252. Hydrochloric acid
    denature proteins and activates digestive enzymes
  253. Intrinsic factor
    secretion of parietal cells that helps in absorption of vitmain B12 across lining
  254. Cholecystokinin
    • produced and stored in the I cells of the duodenal and jejunal muscose
    • stimulation of pancreatic enzymes and somatostatin secretion as well as gallbladder contraction
  255. Secretin
    • made and stored in the S cells of the upper intestine
    • stimulates secretion ofbicarbonate containing substances from pancreas and inhibits gastric emptying and gastric acid production
  256. Liver
    produces bile that is stored in the gall bladder before release into small intestine
  257. Bile
    • No enzymes
    • emulsifies fats, breaking down large globule into small droplets
    • if not there, then fats cannot be digested
  258. Emulsification
    of fats exposes a greater surface area of the fat to the action of pancreatic lipase
  259. Pancreas
    • Produces enzymes such as amylase for carbohydrate digestion
    • Trypsin: protein degradation
    • Lipase: Fat Degradation
    • secretes a bicarbonate that neutralizes acidic chyme arriving from stomach, operate optimally at higher pH
  260. Large Intestine
    • functions in absorption of salts and any water not already absorbed by small intestine
    • rectum: transient storage of feces before elimination through anus
  261. Intracellular Digestion
    • Plants stores insolubles in cells
    • Principle Storage Food: starch found in large amounts in seeds, stems and roots
    • When nutrients required, storage polymers broken down to cimpler molecules by hydrolysis
    • simple product can be used in storage cell itself or transported by diffusion to other cells
  262. Extracellular Digestion
    • Must obtain nutrients from environment,
    • Enzymes secreted, hydrolyzing complex nutrients, into simpler molecules which are then absorbed
    • once inside, simpler molecules can be used for energy or to make larger molecules
  263. Excretion
    • removal of metabolic wastes produced in the body
    • Distinguised from elimination, removal of indigestible material
  264. Deamination
    • amino acids in liver leads to the production of nitrogenous wastes
    • All metabolic processes lead to production of mineral salts that must be excreted by the kidneys
  265. Excretion in Protozoans and Cnidarians
    • All cells are in contact with the external, aqueous environment
    • Water soluble wastes can exit the cells by simple diffusion through the cell membrane
    • Passive Excretion
    • Possess a contractile vacuole: organelle specialized for water exretion by active transport
    • Excess water diffused and maintains its volume and pressure
  266. Excretion in Annelids
    • carbon dioxide excretio occurs directly through the moist skin
    • Two pairs of nephridia in each body segment excrete water, mineral salts, and nitrogenous wastes in the form of urea
  267. Excretion in Arthropods
    • carbon dioxide released from tissues into tracheae conitnuous with spiracles
    • nitrogenous wastes exreted in form of solid uric crystals
    • Mineral salts and uric acid accumulate in the Malphigian tubules and then moved to intestine and expelled
  268. Excretion in Humans
    • Lungs
    • liver
    • Skin
    • kidney
  269. Lungs
    carbon dioxide and water vapor diffuse from blood and exhaled
  270. skin
    • sweat glands excrete water and dissolved salts
    • perspiration serves to regulate body temperature
  271. Liver
    • processes nitrogenous wastes, blood pigment wastes and other chemicals for excretion
    • Ureas produced by deamination of amino acids in the liver and diffuses into blood fro ultimate excretion in the kidneys
    • bile salts and red blood pigments are excreted as bile and pass out with the feces
    • Kidneys: maintain the osmolarity of the blood, excrete numerous waste products and toxic chemicals and conserve glucose, salt and water
  272. Kidneys
    • regulate the concentration of salt and water in the blood through the formation and excretionof urin
    • bean shaped
    • behind stomach and liver
    • each is composed of one miillion nephrons
  273. Structure of Kidney
    into three regions: outer cortex, inner medulla, and renal pelvis
  274. Nephron
    • consists of a bulb called bowman's capsule, which embraces a special capillary bed called a glomerulus
    • positioned such that loop of Henle runs through the medulla, while convoluted tubules and bowman's capsule are in the cortex
    • concentrated urine in the collecting tubules flows into pelvis of the kidney, funnel like region that opens directly into the ureter
    • Reabsorbs nutrients, salts, and water from the filtrate and returns them to the body, maintaining bloodsteams solute concentration
    • Clean blood plasma of unwanted substances as is passes through kidney
    • Blood plasma: both wanted and unwanted substances; nephron selectively absorbs wanted substances and remaining exreted
    • Primary Site of Reabsorption: Proximal Convoluted Tubule
  275. Primary Sites of regulating water, sodium and potassium loss in nephron
    • Ascending Loop of Henle
    • Collecting Duct
    • Descending loop of Henle
  276. Distal Convoluted tubule
    primary site for secretion of substances into the filtrate
  277. Bowman's Capsule
    • leads into a long coiled tubule that is divided into functionally distinct units:
    • Proximal Convoluted Tubule
    • Loop of Henle
    • Distal Convoluted Tubule
    • Collecting Duct
  278. Ureter
    • from each kidney empty into the urinary bladder, where urine collects until expelled via the urethra
    • Most of the nephron is surrounded by a complex peritubular capillary network to help reabsorption of amino acids, glucose, salts, and water
  279. Urine Formation
    • Filtration
    • Secretion
    • Reabsorption
  280. Filtration
    • Blood pressure forces 20% of blood plasma entering glomerulus through capillary walls and into surrounding Bowman's Capsule
    • Fluid and small solutes entering the nephron are called filtrate
    • Filtrate: Isotonic with blood plasma; Particles too large to filter through the glomerulus, such as blood cells and albumin, remain inthe circulatory system
    • Filtration: passive process driven by the hydrostatic pressure of the blood
  281. Secretion
    • Nephron secretes substance such as acids, bases and ions like potassium and phosphate from the interstitial fluid into the filtrate by both passive and active transport
    • Materials secreted from peritubular capillaries into the nephron tubules
  282. Acid base Disorders
    • Respiratory: effect blood acidity by causing PCO2
    • Metabolic: efffect the blood acidity by causing HCO3-
  283. Reabsorption
    • Essential substances and water are reabsorbed from the filtrate and returned to the blood
    • occurs primarily in the proximal convoluted tubule and is an active process
    • movement accompanied by passive movement of water
    • formation of concentrated urine which is hypertonic to the blood
  284. Aldosterone
    • hormone that causes an increased exchange transport of sodium and potassium ions along the distal convoluted tubule, collecting tubule and the collecting duct resulting in a decreased excretion of sodium ions in the urine and increased potassium excretion in the urine
    • not effect renal blood flow
  285. Antidiuretic Hormone
    responsible for the creation of a more concentrated urine or a more dilute urine
  286. Osmolarity Gradient
    • selective permeability establishes in surrounding interstitial fluid
    • tissue osmolarity increasing from cortex to inner medulla
    • solutes that contribute: urea and salt
    • osmolarity of urine: established in collecting tubule by means of counter current multiplier system
  287. counter current multiplier system
    • anatomic arrangement of the loop of henle within the kidney permits the establishment of the concentration gradient that permits reabsorption of 99% ofthe filtrate in the collecting tubules
    • production of concentrated urine is possible
  288. Concentration of Urine
    • counter current system causes medium in the medulla of kidney to be hyperosmolar with respect to the dilute filtrate flowing in the collecting tubule
    • as filtrate flowing in the collecting tubules passes through this region of the kidney, on its way to pelvis and ureter, water flows out of the collecting tubules by osmosis
    • water removed by capiillaries
    • reabsorption of water in this zone, permits concentration of urine, depends on permeability of the collecting tubules to water
    • regulation of permeability of collecting tubule in water is accomplished by hormone ADH vasopressin
    • increases permeability of the collecting duct to water, allowing more water to be reabsorbed and more concentrated urine to be formed
  289. Excretion in Plants
    • able to use many of these waste products
    • products used as simple precursors in the synthesis of complex molecules
    • any excess carbon dioxide as well as waste oxygen and water vapor
    • leaves the plant by diffusion through stomata and lenticels
    • exit of water vapor through leaf stomates : transpiration
Card Set
Biology Systems
BIology section of PCAT systems