Physiology 2 (pt 2)

  1. Gland
    May consist of one cell or group or highly specialized epithelial cells that secrete substances into ducts, onto surface or into blood
  2. Exocrine glands
    • Secrete their products into ducts (tubes) that empty onto the body's surface or into a body cavity i.e salivary glands into oral cavity
    • Secretions include mucus, perspiration, oil, wax, saliva, and digestive enzymes
  3. Endocrine glands
    • Ductless
    • Their secretions enter the extracellular fluid and diffuse into the blood
    • Secretions are always hormones
  4. Example of endocrine glands
    • Pituitary
    • Thyroid
    • Adrenal 
    • Parathyroid
    • Pineal 
    • Thymus
  5. Endocrine organs
    • Can secrete hormones and do other functions like secrete enzymes
    • Hypothalamus
    • Pancreas
    • Ovaries
    • Testes
  6. Autocrine Factors
    Chemicals released in the body which affect the same cell; includes some interleukins
  7. Interleukins
    • Chemicals released by helper T cells to stimulate the helper T cell to proliferate (make more of themselves) and activate other T cells-- this begins your entire immune response
    • Ex: when you don't have an infection, you want your WBC count to be low so they don't attack your own tissue.
  8. Paracrine factors
    • Chemicals that are released in the body and affect nearby cells and are destroyed rapidly
    • Never enter the blood stream
    • Examples: histamine and platelet derived growth factor (PDGF)
  9. Histamine
    • Released into the stomach
    • Acts on stomach lining to influence digestive processes to produce acid
    • People that have too much will take a histamine reducing (H2 blocker) to release less acid
  10. Platelet derived growth factor (PDGF)
    • Released by platelets to stimulate smooth muscle and fibroblasts to divide and rebuild the vessel wall during clotting
    • Helping to repair an injured site
  11. Hormones
    Chemicals released into the extracellular tissue which diffuse into the blood stream and affect distant cells
  12. Hormone function
    • Regulate composition and volume of extracellular fluid
    • Regulate metabolism and energy balance
    • Regulate contraction of smooth and cardiac muscle
    • Regulate homeostatic responses to emergency (maintains homeostasis); wound healing
    • Regulates immune system
    • Role in growth and development
    • Contribute to processes of reproduction
  13. 3 classes of hormones
    • Lipid derivatives
    • Amino acid derivatives
    • Peptides and proteins
  14. Steroid hormones
    • A lipid with ring-like structure
    • Primarily produced in the adrenal cortex and gonads
    • Derived from cholesterol
    • Fat soluble; allow these to be intracellular
  15. Amine hormones
    • Simplest hormone
    • All derived from the amino acid tyrosine
    • Very small 
    • Water soluble; keeps these in plasma membrane
  16. Biogenic amines/catecholamines
    • The technical terms for amine hormones
    • Ex: epi, norepi, and thyroid hormones
  17. Peptide hormones
    • Consist of a chain of 3-200 amino acids (the size of a protein)
    • Most hormones fall into this classification
    • Very large
    • Usually water soluble; keeps them out of the cell
  18. What must hormones do to be effective
    Have to bind to receptors in either cell membrane or in cytoplasm
  19. Target cell
    • Only certain cells have receptors for certain hormones
    • Hormones only influence its target cells
    • Typically alter the rate of function
  20. Solubility
    The main factor when noting if a hormone can enter the cell or must remain outside
  21. Lipid soluble
    • Hormones can diffuse through the phospholipid bilayer of the plasma membrane to get inside the cell
    • Include thyroxine and some steroids
  22. Where do lipid soluble hormones bind?
    • Receptors in cytoplasm and/or nucleus
    • Usually acts as a transcription factor that changes the genetic activity of the target cell in a specific manner
    • It turns on protein production or tells a gene to turn on and work faster
  23. Lipid soluble hormones binds to a DNA-associated receptor protein
    • This turns on the gene and prompts transcription of DNA to produce mRNA
    • This is then translated into ribosomes which creates proteins or enzymes
  24. Water-soluble hormones
    • Peptide and protein hormones
    • Not lipid soluble and cannot diffuse across the plasma membrane
    • The receptors are plasma membrane proteins which trigger enzymes (G-proteins) which triggers a 2nd messenger inside the cell to carry the response
    • Ex: cAMP, DAG, and inositol triphosphate
  25. Steps of a second messenger
    • Binding of hormone to the protein receptor in a target cell
    • Activates a specific enzyme called G protein to form secondary messenger
    • Cyclic AMP is converted from ATP to cAMP by G enzyme
    • cAMP as a secondary messenger then activates cytoplasmic enzymes called protein kinases or increase the Ca concentration
    • This results in changing the metabolic activity of the target cell in a specific manner
  26. Alternative second messengers
    • Dicylglycerol 
    • Inositol triphosphate
    • Used by some hormones like epinephrine
  27. Hypophysis
    • Pituitary gland 
    • Lies in a pocket of the sphenoid bone (sella turcica) at the base of the brain, just below the hypothalamus
    • Connected to hypothalamus by infundibulum
    • Composed of two adjacent lobes
    • Master endocrine gland
  28. Posterior Pituitary gland
    • Neurohypophysis
    • Stores and releases two hormones that are produced in the hypothalamus
  29. Anterior Pituitary Gland
    • Adenohypophysis
    • Releases hormones that regulate a whole range of body activities from growth to reproduction
    • Some influence other endocrine glands and are called tropic hormones; regulated by hypothalamus
  30. Releasing hormones
    • Produced by the hypothalamus 
    • Stimulate the production and release of other hormones, specifically those of the anterior pituitary
  31. Inhibitory hormones
    • Chemicals inhibit the production and release of anterior pituitary hormones
    • Most often negative feedback mechanisms maintain the homeostasis
  32. Hypothalamo-pituitary portal vessels
    • There is an unusual blood vessel connection between the hypothalamus and the anterior pituitary
    • The capillaries at the base of the hypothalamus called the median eminence recombine to form this
    • Allows for rapid response and reduced synth of hypothalmic hormins bc there is direct blood flow
  33. Pituitary gland
    • Master endocrine gland
    • Regulates many body activities
    • Small, round structure that is attached to the hypothalamus of the brain by a stalklike structure called the infundibulum
  34. Posterior Pituitary gland
    Doesn't produce hormone

    ADH and OT are released
  35. Tropic hormones
    Influence the release of hormones of other endocrine glands
  36. Pineal gland
    • A pine-cone shaped gland found near the thalamus in the core of the brain, within the epithalamus
    • Melatonin
  37. Thyroid gland
    • Small gland located just below larynx in front of trachea
    • Consists of two lobes connected by a mass of tissue
  38. Cause of Hypothyroidism
    • Iodine deficiency
    • Damage to thyroid gland such as neck radiation or autoimmune disease (hashimoto's disease)
    • Lack of THS 
    • Lack of receptors for T3 and T4
  39. Results of hypothyroidism
    • Decreased thyroid hormone releases causes:
    • Decreased metabolic activity
    • Myxedemia (nonpitting edema causing puffiness around eyes, hands, feet)
    • Enlargement of the tongue
    • Bradycardia
    • Decreased mental concentration
    • Cold sensitivity
    • Coma and death (extreme)
  40. Cause of Hyperthyroidism
    • Grave's disease-- toxic diffuse goiter
    • Due to production of antibodies that stimulate the TSH receptors on the thyroid gland causing increased thyroxine activity
  41. Hyperthyroidism result
    • Increases cellular metabolism causing sudden weight loss
    • Tachycardia
    • Insomnia
    • Diarrhea
    • Exophtalmia i.e protrusion of eyeballs
    • Goiter is formed due to increased size of thyroid
  42. Parathyroid gland
    • Attached to posterior surfaces of the thyroid gland
    • Shaped like small round masses
    • Typically 2 attached to each lobe of thyroid
  43. Osteoperosis
    • Seen in older women because there is lower estrogen which prevents the reabsorption of calcium from the digestive tract
    • Linked with parathyroid hormone (PTH)
  44. Adrenal glands
    • Two of these, each located superior to each kidney
    • Composed of two regions: outer adrenal cortex and the inner adrenal medulla
  45. Cushing's Disease
    Protein wasting that you see if you have too much cortisol or not enough sugar
  46. Gluconeogenesis
    Glucagon promotes the conversion of nutrients, the aa and lactic acid, into glucose
  47. Glycogenolysis
    • Converting fats and proteins, glucagon, accelerates the conversion of glycogen into glucose
    • Stimulates the release from the liver into the blood
  48. Diabetes mellitus
    • Insulin-related disorder of glucose metabolism in which there is both hyperglycemia and
    • disturbances of lipid metabolism
    • Incidence of diabetes in the US is about 2.3% of the population with higher
    • incidence in females and nonwhites
    • Due to lack of insulin or insulin activity
    • Increased tendency for platelets to aggregate
  49. Type I diabetes
    • Due to destruction of the beta cells of the islets of langerhans usually due to an autoimmune response
    • Requires person to take insulin injections
    • Called Insulin Dependent Diabetes Mellitus (IDDM)
    • Usually occurs in children and used to be called juvenile diabetes
  50. Type II diabetes
    • Usually due to resistance to insulin activity and typically doesn't require insulin injections
    • Called non-insulin dependent diabetes mellitus (NIDDM) 
    • Usually occurs in older obese adults
  51. Problem w/sugar in bloodstream
    • Too much irritates the blood vessels
    • Eventually they start to thicken to protect from the irritation which cuts short the amount of blood that can go through
  52. Acute and chronic complications of Diabetes
    • Injury of capillaries of the retina
    • Increased formation of sorbitol (sugar alcohol)
    • Atherosclerosis at younger age
    • Increased triglycerides and cholesterol
    • Coronary artery disease, lightheadedness, fainting
    • UTI
    • Injury to nerve fibers, diminished sensation in extremeties
    • Decreased sweat
    • Skin lesions
    • GI symptoms
  53. Follicle
    Sac in ovary that matures the egg
  54. Corpus luteum
    Used to be follicle but turns into this gland after ovulation of the ovary
  55. Endometrium
    • Feed fedus before creation of amniotic sac
    • Progesterone increases vascular supply to this
  56. Interstitial cells of the testes
    • Called interstitial cells of leydig
    • primarily produce androgens
  57. What are the functions of the cardiovascular system?
    • Generate blood pressure
    • Transport blood
    • Exchange of nutrients and wastes at the capillaries
    • Regulate blood flow as needed
  58. Blood
    • Only fluid tissue in the body
    • Connective tissue that has formed elements, or living blood cells, suspended in a nonliving fluid matrix, plasma
  59. Functions of blood
    • Transportation (carries blood gases, nutrients)
    • Regulation (regulates blood pH, adjusts body temp)
    • Protection (clotting mechanism prevents blood loss)
  60. Blood can be separated into
    Formed elements and plasma
  61. Formed elements
    • Living component
    • RBC (erythrocytes)
    • WBC (leukocytes)
    • Platelets (thrombocytes)
  62. Plasma
    • Non-living component
    • Contains 90% water
    • Contains fibrous proteins that become visible when clotting occurs
    • Contain antibodies, some gases, nutrients, some lipid
    • approximately 55-60% of blood volume is this
  63. How much blood volume is erythrocytes
    • 45%
    • Also called hematocrit
  64. Buffy coat
    • Leukocytes and platelets 
    • <1% of whole blood
    • In between plasma and erythrocytes when blood is centrifuged
  65. Erythrocytes
    • RBC
    • Functions to transport oxygen and CO2
  66. Leukocytes
    • WBC
    • Defense against disease
    • Not restricted to the blood stream
    • Able to reproduce rapidly when deeded, WBC of over 11,000 cells per cc is indication of infection
  67. Thrombocytes
    Platelets are instrumental in blood clotting
  68. Color of pulmonary artery
    Blue bc it carries unoxygenated blood
  69. Four chambers of the heart
    • 2 Atria
    • 2 ventricles
  70. Atria
    • Receives blood
    • Small, thin-walled chambers
  71. Ventricles
    • Pumping chambers
    • Larger muscular walls than the atria
    • Makes up most of the heart mass bc they have to pump blood all over the body
    • Contributes to BP
    • Left is much thicker bc it has to pump blood to entire body
  72. Arteries
    • Carry blood away from the heart 
    • Very muscular
    • Can constrict or dilate
    • Aterioles are the smallest branches of the arteries and deliver blood to capillaries
  73. Veins
    • Carry blood toward the heart
    • Collapsed, thin walled
    • Have valves (keep blood going in one direction)
    • Large lumen (opening)
    • Venules are the smallest veins, converge toward heart and receive blood from capillaries
    • Typically oxygen deprived blood
  74. Which veins carry oxygen rich blood
    Pulmonary or umbilical veins
  75. Capillaries
    • Smallest blood vessel
    • Supplies actual tissue
    • Sites of gas exchange
    • One cell thick
    • Typically colored purple bc of the gas exchange
  76. Image Upload 1 Image Upload 2
  77. Superior vena cava
    Returns unoxygenated blood from body regions which are superior to the diaphragm to right atria
  78. Inferior vena cava
    Returns blood from the body inferior to diaphragm
  79. Pulmonary artery
    Carries unoxygenated blood from right ventricle to lungs
  80. Pulmonary veins
    (4) carries oxygenated blood from the lungs to left atria
  81. Aorta
    • Largest artery in the body
    • Carries oxygenated blood from the left ventricle to the rest of the body
  82. Aortic branches
    • Left subclavian artery: oxygenated blood to left upper limbs
    • Left common carotid artery: oxygenated blood to left cranium and left brain
    • Brachiocephalic trunk: branches into right subclavian and right common carotid; to supply right upper limb and head
  83. Heart valves
    Four one way valves that enable blood flow in one direction
  84. Atrioventricular (AV) valves
    • Prevent backflow into atria when ventricles are contracting
    • Right- tricuspid
    • Left- bicuspid or mitral valve
    • Both contract forcefully during contraction at the same time
  85. Cordae tendinae
    • Connective tissues (collagen) attached to the AV valves
    • Anchor cusps to the papillary muscles in the ventricles
  86. Semilunar valves
    • Prevent backflow from the aorta and pulmonary trunk into the ventricles
    • Each has 3 pocket-like cups that tend to fill w/blood which helps them close
    • When ventricles contract, the pressure forces the semilunar valves open and to flatten against arterial walls
    • As ventricles relax, blood begins to recoil back to the ventricles
    • Blood fills the cups and closes them
  87. Pulmonary circuit
    • Blood is pumped from the right ventricle through the lungs and then to the left atrium (blood becomes fully oxygenated)
    • Very short
  88. Systemic Circuit
    • Blood is pumped through the left ventricles to all the organs and tissues of the body except the lungs and then back to the right atrium
    • Loss of oxygen
  89. Diastole
    • Heart relaxation
    • Chambers are filling w/blood
    • Low pressure
  90. Systole
    • Heart contraction
    • Blood is expelled from the chambers
    • High pressure bc contraction
  91. Cardiac cycle
    • Includes all events associated w/flow of blood through the heart during one complete heartbeat
    • Avg 72 bpm and each cardiac cycle lasts about 0.8 secs
    • Marked by pressure/volume changes and openings
  92. Atrial diastole and ventricular diastole (heart is relaxed)
    • Pressure in the heart is low
    • Blood flowing passively into the atria and passively through the open AV valves into the ventricles
    • 80% of ventricular filling occurs before atrial contraction
    • Semilunar valves are closed
    • Pressure is 70-80mmHg
  93. Atrial systole/Contraction
    • Depolarization then contraction (P wave)
    • Blood is compressed in atrial chamber
    • Increased atrial pressure
    • Actively propels last 20% of blood into ventricular chamber through the open AV valve
    • Atria relax as ventricles depolarize
  94. End-diastolic volume
    Amt of blood in the ventricles at the end of ventricular diastole, due to atrial contraction
  95. Ventricular systole
    • Ventricles contract, blood is compressed
    • Ventricular pressure rises suddenly and sharply, closing AV valves (lub)
    • All closed chambers for short time= isovolumetric ventricular contraction
  96. Isovolumetric contraction phase
    • Pressure continues to increase
    • When pressure is higher in ventricle than in aortic or pulmonary arteries, then this forces SL valves to open expelling blood into those arteries
  97. Ventricular ejection phase
    Pressure is about 120 mmHg when blood is ejected
  98. Stroke volume
    • The amt of blood ejected
    • = end-diastolic volume (EDV)- end-systolic volume (ESV)
    • What you started with in the ventricles minus what doesnt get pumped out after ejection
  99. Ventricular diastole (early)
    • Ventricles relax, pressure drops
    • Backflow of blood closes SL valves (dub)
    • During time of ventricular systole, atria have been in diastole, filling, isovolumetric ventricular relaxation
    • Passive ventricular filling begins and cycle begins again
  100. Blood flows from higher to lower pressure
    • Causes opening and closing of valves
    • Keeps flow in one direction
  101. When AV valves close
    • Onset of ventricular systle
    • Louder and stronger sound than second sound (lub)
  102. Semilunar valves close
    • Onset of ventricular diastole
    • Short, sharp sound (dub)
  103. Heart murmur
    • Sounds other than normal lub dub
    • Can be sign of heart disease
    • Can be produced by heart effects that cause blood flow to be turbulent
    • Normal blood flow is laminar (smooth) but blood flowing rapidly through an abnormally narrowed valve (stenosis) or by blood flowing backward through a leaky valve (insufficiency) or in an abnormal direction, like between two atria (septal defect) can cause abnormal heart sounds
    • Some may require medication or surgery
  104. Ability of cardiac muscle to contract
    • Intrinsic; it is a property of the heart muscle itself and does not depend on the nervous system
    • Heart beats rhythmically without any nervous intervention
  105. Autorhythmic
    • Self excitation
    • All cardiac muscle cells are capable of this
  106. ANS on the heart
    • Acts like brakes and accelerator of HR
    • Sympathetic turns it up
    • Parasympathetic turns it down
  107. Cardiac conduction system
    Intrinsic method of nodes to maintain rhythm
  108. Node
    • Specialized tissue-- combination of nervous and muscle (only in heart)
    • Causes muscle depolarization in one direction
    • Cells initiate then spread to depolarization or AP 
    • Contract on their own
  109. Intrinsic conduction system
    • The heart's in-house conduction system
    • Controls the independent but coordinated activity of the heart
    • Consists of contractile cardiac cells (autorhythmic) that specialize to initiate and distribute impulses throughout the heart, influence other cells to contract
    • Depolarization and contraction then occurs in an orderly, sequential manner called rhythmic contractions
  110. Conduction pathway
    • Nodal tissue located in SA node, AV node, AV bundle of HIS, right and left bundle branches, purkinje fibers
    • Image Upload 3
  111. Sinatrial Node (SA node)
    • Located in the superior region of the right atrium and is the usual site of initial depolarization of the heart
    • Normally has the fastest depolarization rate (75bpm) of any other region of the conduction system 
    • Pacemaker: determines normal sinus rhythm
  112. AV (atrioventricular) node
    • Located in the inferior portion of the inter-atrial septum
    • As the impulse spreads out of the SA node it can spread through the atria by passing directly from atrial cell (across gap junctions)
    • Impulse is slightly delayed to allow it to spread throughout both atria before going into ventricles
  113. AV bundle (Bundle of HIS)
    • From AV node, impulse spreads down to here
    • Divides into a right and left bundle branch which runs down the respective side of the inter ventricular septum, just beneath the endocardium (toward the apex of the heart)
  114. Purkinje fibers
    • Impulse spreads from the bundle of HIS into this which radiate upward from the apex throughout the ventricles
    • Ventricular contraction immediately follows depolarization
  115. Rates of spontaneous depolarization
    • While the SA node "drives" the heart at about 75 bpm, the AV node depolarized at a rate of 50 bpm and AV bundle and purkinje fibers depolarize at about 30 pbm
    • If the SA node is dysfunctional, the AV node can become pacemaker but slower; if AV fails then bundle fibers can take over but even slower
  116. How fast does the SA node depolarize then the parasympathetic "brakes" are not on?
    100 bpm
  117. Electrocardiograph (EKG or ECG)
    • Electrical currents generated and transmitted through the heart also spread throughout the body can be monitored with this instrument
    • Graphic recordings of electrical changes during heart activity
  118. Leads
    • Used to record in ECG by placing on the skin in specific sites
    • 12 leads typically used which give cardiologists knowledge of different regions of the heart
  119. Deflection waves
    • Typical EKG consists of a series of these 3 distinguishable waves
    • P-Wave
    • QRS complex
    • T wave
    • Image Upload 4
  120. P wave
    Results from depolarization from the SA node through the atria, then atria contracts
  121. QRS complex
    Results from ventricular depolarization and precedes ventricular contraction, it contracts
  122. T wave
    • Caused by ventricular repolarization
    • Slower than depolarization, so T wave is more spread out (atrial repolarization is masked by the QRS complex)
    • Electrical chang as Na and K get pumped to the correct side to repeat the project
  123. ST segment
    • Usually flat and is the baseline between the S and T
    • Elevated ST segment suggests ischemia (lack of oxygen supply) May also see an inverted T following this
  124. PR interval
    • The time between the beginning of the P wave and the beginning of the QRS complex.
    • An extended PR is a sign of an abnormally long delay of the AP at the AV node-- known as first degree heart block
  125. QT intervel
    • The first time from the beginning of the Q wave through the end of the T wave
    • Short QT wave suggests hypercalcemia; too much calcium can be too excitatory
    • Long QT suggests hypocalcemia and the heart is not contracting as quickly or effeciently.
  126. Deep Q waves
    Can suggest a previous infarction or heart attack
  127. Healthy heart
    • The size, duration, and timing of the deflection waves tend to be consistent
    • Any changes in pattern or timing may reveal disease or damage to the heart
  128. Tachycardia
    • An increase in the heart rate above normal
    • Is serious because cardiac output decreases and could lead to ventricular fibrillation
  129. Bradycardia
    • Slowing of the HR below 50 bpm
    • Could possibly be due to SA node dysfunction or heart block when some P waves are not conducted through the AV node
  130. Ventricular Fibrillation
    • Chaotic
    • Grossly irregular
    • Seen in acute heart attack and electrical shock
Card Set
Physiology 2 (pt 2)