Physiology 2

  1. Sleep
    • A state of changed consciousness or partial consciousness which can be aroused by stimulation
    • Defined by EEG
  2. EEG
    • The printout of an electronic device that uses scalp electrodes to monitor the internal neural activity in the brain
    • Record from the parietal or occipital lobes of an awake person
  3. EEG paterns
    • Undergo characteristic shifts in a sleeping person
    • Reflect stages of sleep; duration of the series is typically ~90 minutes and pattern cycles 4 to 8 times per night
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  4. Alpha waves
    • 8-13 Hz
    • Decreased amplitude, slow waves, calm, relaxed, awake, eyes closed
  5. Beta Waves
    • 14-25 Hz
    • Higher frequency, lower amplitude, a bit irregular, awake, alert, concentrating hard on something
    • Aka EEG arousal
  6. EEG arousal
    • Normal to have beta waves during sleep cycle, but too much can cause not restful sleep
    • Ex: sleep apnea can be a result of this
  7. Theta Waves
    • 4-8 Hz
    • Early stage and REM sleep
    • Abnormal in awake adults
    • Higher amplitude, low frequency waves
    • Seen in narcolepsy
  8. Delta Waves
    • <4 Hz
    • Increased amplitude, further decreased frequency
    • Ex: deep sleep (dreamless) and anesthesia
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    • Beta
    • Alpha
    • Theta
    • Delta
  10. Sleep and brain stem activity
    Sleep produces depressed cortical activity, but brain stem function continues (respiration, heart rate, blood pressure)
  11. RAS
    • Brain stem white matter, keeps you alert
    • May regulate sleep; causing shifts in states of consciousness
  12. Hypothalmus regulation
    • Levels of wakefulness, using histamine as excitatory neurotransmitter and by inhibiting GABA and light dark cycles
    • Stimulating release of melatonin from pineal gland
    • More promoting of sleep during night time
  13. Melatonin secretion
    Starts naturally around 9:00pm and ends round 7:30am
  14. Purpose of sleep
    • Has a restorative function
    • Gives the brain the opportunity to mentally sort through the days events
  15. Quantity of sleep
    • Daily requirements of sleep decline with age:
    • Infants-16 hours
    • Adults- 7 hours
    • Elderly- <7 hours
  16. What age group does not require stage 4 sleep?
    >60 years
  17. What percentage of sleep is REM in infants? in adults?
    • 50% in infants
    • 25% in adults
  18. Types of sleep
    • Defined in terms of EEG patterns
    • NREM (non rapid eye movement): initial phase of sleep that has 4 stages
    • REM (rapid eye movement): no individual stages
  19. NREM Sleep or slow wave sleep
    • Each stage gets slower in frequency and higher in amplitude
    • Progression takes between 30-45 minutes
    • Serotonin levels rise (promote sleep) and norepinephrine levels decline (NE maintains alertness)
  20. Normal NREM sleep cycle and time
    • 1-> 2-> 3-> 2-> 1-> REM 
    • Takes 90-120 mins
  21. Stage 1 sleep
    • Light sleep
    • Eyes are closed; drowsiness and sleep begin
    • Thoughts flit in and out and drifting sensation occurs
    • Vitals are normal
    • Increased frequency and decreased amplitude in waves

    Alpha waves predominate and arousal is immediate; muscle jerks
  22. Stage 2 sleep
    • EEG patter becomes more irregular, arousal is more difficult
    • More stable sleep begin

    Transition to theta waves
  23. Stage 3 and 4
    • Sleep deepens
    • Frequency of EEG drops and the amplitude increases
    • Vitals begin to decline and muscles are relaxed
    • Dreaming is common
    • Growth hormone is released during this stage

    More theta and delta waves
  24. Slow wave sleep
    • Deep sleep progresses into this becasue the EEG patter in dominated by delta (1-4 Hz) now. 
    • Vitals are at their lowest
    • Skeletal muscles relax and sleeper turns every 20 mins
    • Arousal is difficult and sleepwalking occur in this stage
  25. REM sleep
    • EEG patterns reverts through the NREM stages to stage 1 patterns, vitals increase, oxygen use is greater that awake (seems to be awake;not restful)
    • Eyes move rapidly under lid but most other skeletal muscles are temporarily paralyzed
    • Most dreaming occurs during this stage
    • Most difficult to arouse but may wake spontaneously
    • REM periods get longer during the night from 5 to 50 mins
  26. Dreams in REM sleep
    • NE and Ach levels rise causing this
    • Occur later in the night/morning because REM gets longer as the night progresses
    • Are a mental processing throughout the day
  27. Learning
    Acquisition and storage of information as a consequence of experience
  28. Memory
    • Relatively permanent storage and retrieval of previous experience. It is the ability to recall learned information
    • Essential for learning and incorporating our experiences into behavior; part of our consciousness
  29. Memory encoding
    Neural processes that change an experience into a memory of that experience- the physiologic events that lead to memory formation
  30. Three characteristics of memory
    • Memory storage occurs in stages and is continually changing; relatively permanent
    • Hippocampus and surrounding structures have major roles in processing
    • Memory traces (chemical or structural changes that encode memories) are found widely distributed in the brain (synapses form as you form memories)
  31. Two types of memory and brain areas involved
    • Declarative memory-- hippocampus, amygdale and diencephalon
    • Procedural memory-- sensory-motor cortex, the basal nuclei and the cerebellum
  32. Declarative memory
    • Retention and recall of conscious experiences that there be put into words (declared)
    • Names, facts, and events
    • Fact memory
  33. Procedural Memory
    • Memory of how to do things
    • For skilled behaviors independent of conscious understanding like riding a bike
    • Also involves learned emotional responses like fear of spiders
    • Length of minutes to years
    • Nondeclarative
    • Skill memory
  34. Episodic memory
    • Explicit and declarative
    • Length of minutes to years
    • More situational like remembering what you had for breakfast and what vacation you took
  35. Semantic memory
    • Explicit, declarative
    • Length of minutes to years
    • Knowing facts such as your mother's maiden name
  36. Long-term memory
    • Limitless capacity
    • Scores of phone numbers
    • The ability to store and retrieve decreases with age
  37. Working memory
    • Length of seconds to minutes
    • Short-term memory
    • Words and numbers like a new phone number that needs to be written down or dialed
    • 7-8 chunks of information such as a long sentence or a telephone number
    • Quickly forgotten
  38. Consolidation from STM to LTM depends on:
    • Emotional state: learn best when alert--motivated, focused; NE released when we are excited or stressed out (endorphins interfere w/ learning or memory)
    • Rehearsal: repetition
    • Association: new info tacked onto old info thats already stored in LTM
    • Automatic memory: not consciously formed (remember situations)
  39. Crucial structures for incorporating and storing sensory perception are the:
    • Hippocampus- limbic system
    • Amygdala- limbic system
    • Thalamus- diencephalon
    • Hypothalamus- diencephalon
    • Association areas (areas that surround and are associated with your senses)
  40. Hippocampus
    Oversees learning circuits and remembering spatial relationships
  41. Amygdala
    • Gatekeeper of memories
    • Widespread connections with all cortical sensory areas, thalamus, emotional centers of the hypothalamus
    • Crucial: Helps transfer fact memory to LTM
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    • Frontal lobe
    • Stores semantic and episodic memories
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    • Motor cortex
    • Involved in storing procedural memories
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    • Cerebellum
    • Plays an important role in the storage of procedural memories
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    • Hippocampus
    • Pivotal role in the formation of new long-term semantic and episodic memories
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    • Amygdala
    • Vital to the formation of new emotional memories
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    • Temporal lobe
    • Formation and storage of long-term semantic and episodic memories and contributes to the processing of new material in short-term memory
    • Musical memory
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    • Prefrontal cortex
    • Storage of short-term memories
    • Behavioral center
  49. Transport of sensory inputs in the brain
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  50. Amnesia
    • Damage to either hippocampus or amygdala 
    • Results in only slight memory loss
    • Destruction to both results in widespread amnesia
  51. Anterograde amnesia
    • Consolidated memories not lost
    • New sensory inputs can't be associated w/old
    • Keeps long term memories but no new ones-- can be from severe damage to amygdala and hippocampus
  52. Retrograde amnesia
    • Loss of memories formed in the distant past but can make new memories
    • Ability to consolidate is there
    • Amygdala may be damaged
  53. Left cerebral hemisphere
    • Deals with somatosensory and motor functions of the right side of the body and vice versa
    • In 90% of the population, the left is specialized to produce language i.e. thinking about what to say or write, motor skills to speak or write and understanding written and spoken word
    • Same with sign language 

    Absolutely no language on right brain (including reading and writing)
  54. Language
    • A complex code that includes the acts of listening, seeing, reading, and speaking
    • Major centers are found in the temporal, parietal and frontal cortex and cerebellum

    Males and females use slightly different brain areas for language processing
  55. Wernicke's Area
    • Temporal and parietal region on the left side that controls language comprehension, the individual's ability to understand written and spoken language
    • Not the motor skills of speech but knowing what you and others are saying

  56. Broca's Area
    • Language area in the frontal cortex of the left side
    • Responsible for articulation of speech, respiratory and oral musculature for speaking words
    • Not involved in the comprehension, just the physical act of speaking
  57. Damage to left hemisphere in early infancy or childhood
    • Assignment of language function to a hemisphere of the brain can be changed if damage occurs in this stage of life
    • Once the hemisphere has been decided (usually left determined at birth), damage to this hemisphere would cause permanent language deficits
  58. Critical period for language development
    • End of puberty or earlier
    • This when exposure to language is essential, puberty is when the brain attains its structural, biochemical and functional maturity
    • Talk to toddlers like people bc this is when language is truly developing
  59. Memories/emotions storage
    • Verbal memories are more apt to be associated with the left side
    • Nonverbal memories like visual patterns, emotions in speech, sensations are associated w/ right side but same area
  60. What happens if there is damage on the right side of the brain
    • The person may not be able to understand what is meant by a text 
    • Differentiate between inflection tone i.e happy vs sad speech
  61. Functions of the skeletal muscles
    • Support body by allowing use to stay upright
    • Allow for movement by attaching to skeleton
    • Help maintain a constant body temp (shivering when cold)
    • Assist in movement in the cardiovascular and lymphatic vessels
    • Protect internal organs and stabilize joints
  62. Muscle fibers
    • Thousands of cells that make up skeletal muscles
    • Elongated cells
    • Have striated appearance and many nuclei per cell
    • Filled w/lots of mitochondria and endoplasmic reticulum
  63. Muscle
    Refers to a number of muscle fibers bound together by connective tissue
  64. Endomysium
    Wraps each muscle fiber
  65. Perimysium
    Wraps each fascile (several muscle fibers bundled together
  66. Epimysium
    Wraps entire muscle
  67. Tendon
    • Connects muscle to bone
    • Epimysium extending beyone muscle to interweave into periosteum
  68. Insertion
    Attachment on the moveable bone; pull insertion closer to the origin
  69. Origin
    Attachment on the immoveable bone
  70. Ligament
    Bone to bone, extensions of the connective tissue coverings found in muscle
  71. Smooth muscle
    • Involuntary in hollow organs and vessels
    • Narrow cylindrical fibers
    • Nonstriated
    • Uninucleate
  72. Cardiac muscle
    • Involuntary found in the heart
    • Striated
    • Branched
    • Generally uninucleate fibers
  73. Skeletal muscle
    • Voluntary muscle that is attached to the skeleton
    • Very striated
    • Tubular
    • Multi nucleated fibers
  74. Sarcolemma
    • Muscle plasma membrane covering the skeletal muscle
    • Na on outside; K inside
    • Membrane is polarized at rest (-70mv); needs to be depolarized to activate the cell to contract
  75. Sarcoplasm
    • Cytoplasm of the muscle cell
    • Large amounts of myoglobin
  76. Myoglobin
    • A red pigment that stores oxygen to let you exercise longer
    • What changes when increasing endurance; more myoglobin=less you compensate by breathing bc cells hold more oxygen
    • Red meat has more myoglobin compared to chicken
  77. Sarcoplasmic reticulum
    • Modified endoplasmic reticulum
    • Regulates intracellular levels of Ca
    • Stores and releases Ca2+
    • Wraps each myofibril like a shirt sleeve
  78. Image Upload 11
    Yellow tube and blue tube
    • Yellow: t-tubule runs up and down and is connected to the plasma membrane or sarcolemma
    • AP is conducted into the muscle through this into the SR.

    Blue: SR; runs horizontally and is connected to the t-tubules at the triads (where there is a t-tubule in between 2 blue tubes
  79. Myofibrils
    • Modified organelle of a muscle cell
    • Contractile elements in muscle and run in parallel fashion
    • Makes up about 80% of cell volume
  80. Sarcomere
    • A chain of these contractile units make up each myofibril
    • Arrangement of dark and light bands within this is responsible for striations
  81. Dark Bands
    • A bands
    • Each A band has a lighter midsection called H zone (only in relaxed state)
  82. Light Bands
    • I bands
    • Each I band has a darker midsection called Z line
    • Sarcomeres run Z line to Z line
  83. Myofilaments
    • Proteins that cause the banding pattern; even smaller structures within sarcomeres
    • Thick and thin myofilaments are made of Actin and Myosin
  84. Thick myofilament
    • Composed of a protein called myosin
    • Contain crossbridges (globular portion) which link thick and thin myofilaments during contraction
    • This means the thick myosin heads attach to the thin filaments called a crosbridge to allow for contraction or shortening of the sarcomere
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  85. Thin myofilaments
    • Composed primarily of Actin proteins-- looks like two strands of pearls twisted together
    • Tropomyosin and troponin (regulatory proteins) are present on this
  86. Tropomyosin
    Protein strands on actin that block active sites on actin so myosin cannot bind to actin in a relaxed muscle
  87. Troponin
    Ca binds, changes structure, and causes tropomyosin to slide and expose myosin binding sites on tropomyosin
  88. T-tubles
    • At each junction between A and I bands
    • Runs between the terminal cisterna or lateral sacs so triads are formed
    • Conduct impulses to deepest regions of the muscle cell
    • Where the Calcium is stored and released from
  89. Sliding filament mechanism
    • Thin filaments slide past the thick ones for an overall shortening of the fiber
    • When muscle is stimulated to contract, the cross bridges attach to active sites on actin thin filament
    • Crossbridge generates tension and pull the thin filament towards center of the sarcomere
    • Muscle cell then shortens
    • Requires calcium for myosin to attach to actin
  90. Neuromuscular Junction
    • Stimulation of a specific nerve to that specific muscle causes an AP to travel down nerve fibers resulting in release of Ach from axon terminal or boutons; exocytosis into synaptic cleft
    • Ach diffuses across synapse and bind to nicotinic receptors located on motor end of plate
    • Sodium ion gates open in motor end plate in response to Ach forming positive graded potential (End plate potential, EPP)
    • If EPP is large enough, it will cause sodium voltage gates to open along the sarcolemma
  91. Motor end plate
    Trough-like part of the sarcolemma that helps to form neuromuscular junction, is highly folded to increase surface area which allows for more receptors
  92. Motor Unit
    • All of the muscle fibers supplied by a single neuron, many units per muscle
    • Each can contract as a unit or group
    • More that activate, stronger the force (recruitment)
  93. Muscle twitch
    • Brief contraction of all muscle fibers in a motor unit in response to a single AP in a motor neuron
    • Simplest type of recordable muscle contraction
  94. Components of muscle twitch
    • Latent period
    • Contraction
    • Relaxation
    • Refractory
  95. Latent Period
    • Brief period between stimulus applied and contraction
    • Ca+ is released from the SR and myosin head begins during latent period
  96. Contraction period
    • Muscle is contracting 
    • Time depends on slow vs fast twitch
  97. Relaxation period
    Muscle fibers are returning to their uncontracted states, repolarizing
  98. Refractory period
    • After depolarization, a skeletal muscle fiber cannot be depolarized again for about 0.005 sec.
    • Absolute refractory: muscle cannot contract even if stimulated; needs to be at least 1/3 complete
    • Relative refractory: from the end of the absolute period to the start of a new depolarization
  99. Skeletal muscle vs Cardiac muscle refractory period
    • Skeletal= short
    • Cardiac= long
  100. Atonic contraction
    • When you are sending constant stream of AP to muscle when you are flexing and holding it
    • Allows you to contract continually
    • Don't want heart to contract for sustained period of time bc it needs to remain a pump
  101. Wave summation
    Tension achieved under rapid repeated stimuli is greater than the tension of a single muscle twitch
  102. Incomplete tetanus
    When periods of stimulation occur but some relaxation occurs between contractions
  103. Complete tetanus
    Periods of stimulation occur w/no relaxation between stimuli, a sustained contraction results
  104. ATP
    • Immediate source for muscle contraction
    • Only enough on hand for 5-6 seconds of contraction
  105. Creatine Phosphate
    • High-energy molecule which can be used to produce more ATP quickly during prolonged exercise
    • Released energy is used to convert ADP to ATP so the muscle can use it as an energy source for contraction
    • Provides energy for about 15 secs
  106. Glucose
    • Muscles use this for energy during prolonged exercise
    • Stored as glycogen and is converted back to glucose which is then further broken down by glycolysis into: 2 molecules of pyruvic acid and 2 molecules of ATP
  107. Glycolysis
    • Anaerobic process; does not utilize oxygen
    • Quick, little energy, therefore must switch to oxidative phosphorylation i.e Krebs
  108. Krebs cycle
    • Further breaks down sugar into much more energy
    • Pyruvic acid enters the mitochondria, where it is completely broken down into CO2 and water
    • Requires oxygen; aerobic respiration/cellular respiration/oxidative phosphorylation
    • 2 molecules of pyruvic acid generate 36 ATP
  109. Oxygen deficiency
    If oxidative phosphorylation cannot take place after glycolysis, the pyruvic acid is converted to lactic acid-- some of which will diffuse out of muscle fiber into the blood stream
  110. Lactic acid diffusion
    • Typically takes 30 mins after exercise ends
    • Contributes to muscle fatigue and pain
  111. Oxygen Debt
    • The amount of oxygen needed to be taken into the system after exercise to metabolize the lactic acid, restore the creatine phosphate supply and re-oxygenate the myoglobin in the muscle tissue
    • When you start to breathe heavy, you have surpassed myoglobin stores
  112. Lactic acid build-up triggers
    • Respiratory centers of the brain to begin rapid deep breathing to replace oxygen and rid the muscle tissue of lactic acid
    • More exercise= increased aerobic respiration= decrease in oxygen debt
  113. Muscle fatigue
    • The inability of the muscle to maintain its strength of contraction after prolonged use due to lack of energy
    • Happens when a muscle is repeatedly stimulated
    • May be a response to lowering of the pH from lactic acid buildup or low stores of myoglobin
  114. Myoglobin
    Oxygen-binding protein that increases the rate of oxygen diffusion into a muscle fiber and provides a small store of oxygen within the fiber
  115. Fast skeletal muscles
    • Type II fibers that contain the high ATP-ase activity or fibers that can split ATP at a faster rate of cross bridge cycling and therefore 4x faster shortening velocities
    • Doesn't burn oxygen to create energy
  116. Fast oxidative skeletal muscles
    • Have numerous mitochondria and have the high capacity for oxidative phosphorylation (make lots of ATP)
    • Typically have more blood flow and contain large amounts of myoglobin to provide oxygen for the process
    • "pink" muscle
  117. Fast glycolytic muscle
    • Have fewer mitochondria but more glycogen stores
    • Have less blood vessels supplying them, and less myoglobin 
    • Aka white muscle fibers
  118. Slow muscle
    • Fibers containing myosin with lower ATPase activity are called these 
    • Type I fibers
    • 4x slower than fast muscles but have same force production
    • Typically have high oxidative capacity; efficient at using oxygen
    • Best for long distance w/ great myoglobin stores
    • Slow glycolytic not found
  119. Cerebral Motor Cortex
    Cortical areas controlling motor functions lie in the posterior part of frontal lobes
  120. Sensorimotor cortex
    • All the areas of the cerebral cortex that control muscle movement
    • Include: 
    • Primary motor cortex
    • Premotor cortex
    • Brocas areas
  121. Primary motor cortex
    • Large neurons called pyramidal cells allow us to consciously control muscle movements
    • Long axons form massive tracts called pyramidal or corticospinal tracts
    • Located on precentral gyri
    • Control is contralateral; right controls left and vise versa
  122. Premotor Cortex
    • Anterior to primary motor cortex
    • Controls learned motor skills or a repetitive nature (musical instruments, typing)
    • Supplies 15% of the pyramidal tract fibers
    • Sends coordinated impulses to the primary motor area
  123. Brocas areas
    • Anterior/inferior to premotor
    • Located only in the left hemisphere
    • Responsible for motor coordination of speech (articulation)
    • Muscles to tongue, throat, and lips
  124. Basal nuclei
    • Gray matter deep within the cerebral white matter 
    • Receives inputs from the entire cerebral cortex and projects to premotor cortex, so influences movement directed by primary motor cortex
    • Plays a role in sorting, stopping and monitoring movement, regulates intensity of movement and inhibits unnecessary movement
    • Impairment results in poor posture and muscle tone, tremors at rest, and abnormal slowness of movement (bradykinesia)
  125. Parkinson's Disease
    • Characterized by resting tremor
    • Slowed/absent movement (hypokinesia)
    • Rigidity of the extremities and neck 
    • Reduced facial expressiveness
    • Caused by the loss of dopamine in the substantia nigra as a part of the basal nuclei
  126. How to treat Parkinson's
  127. Cerebellum
    • Processes inputs received from cerebral motor cortex, brain stem nuclei
    • Sensory receptors from muscle fibers, eyes, and vestibular apparatus (equilibrium) and proprioreceptors 
    • Modifies movement to provide precise timing and pattern for smooth coordinated movement
    • Subconscious control
  128. Cerebellar disease
    • Intention tremor
    • Tremors that are absent at rest, appears when person attempts voluntary movement
    • Esp pronounced as movement reaches final destination
    • People cannot start/stop movement well; lack of corrdination
    • Have poor posture and unstable gait; cannot stand on one foot w/ eyes closed
  129. Signs of cerebellar damage
    • Vertigo
    • Ataxia
    • Nystagmus
    • Intentional tremor
    • Slurred speech
    • Hypotonia
    • Exaggerated broad based gait
    • Disdiadochokinesia: inability to perform rapid repeating alternating movement
  130. Descending pathways
    • Descending tracts that deliver efferent impulses from the brain to spinal cord
    • 2 types: corticospinal or pyramidal tracts and the brainstem pathways
  131. Pyramidal tracts
    • Major motor pathways concerned with voluntary movement (especiallly precise or skilled movement
    • Axons descend without synapsing from primary motor cortex all the way to spinal cord
    • Crossover in the medulla oblongata for contralateral innervation
  132. Brainstem pathways or extrapyramidal nuclei
    • Descending pathways that don't pass through the pyramids
    • Originate in the brain stem
    • Concerned w/postural control, balance and walking
    • Most do not cross to other side
  133. CN III
    • Oculomotor
    • Eye movement
  134. CN IV
    • Trochlear
    • Eye movement
  135. CN V
    • Chewing or mastication
    • Cornea movement
  136. VI
    • Abducens
    • Eye movement
  137. CN VII
    • Facial 
    • Facial expression
    • Cornea movement
  138. CN IX
    • Glossopharyngeal
    • Tongue
  139. CN X
    • Vagus
    • Heart rate, breathing, digestive
  140. CN XI
    • Accessory 
    • Movement of head and neck
  141. CN XII
    • Hypoglossal
    • Chewing, swallowing, speech
  142. Cranial nerves only sensory
    • I olfactory
    • II optic
    • VIII vestibulocochlear
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Physiology 2