Vert phys lab midterm

Card Set Information

Author:
cfalgo1
ID:
139373
Filename:
Vert phys lab midterm
Updated:
2012-05-02 09:07:20
Tags:
Vert Phys Lab Midterm
Folders:

Description:
Vert Phys Lab Midterm
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user cfalgo1 on FreezingBlue Flashcards. What would you like to do?


  1. What will you explore in this lab
    basic techniques in physiology research including the proper handling of live animal tissues acquisition of experimental data using real world methods analysis and presentation of theresulting data, report writing and critical thinking
  2. keys to success
    • read lab manual before lab
    • make sure you understand basic physiology involved in lab
    • think about what paper should look like before lab
    • be prepared for a heavier than average workload
    • use instructers
  3. Instructors and their email
    • Christine Savolainen--> LSB 228--> LSAVOL1@LSU.edu
    • Charles brown--> LSB 228--> CBROW87@lsu.edu
  4. Point layout of lab
    • 2 small papers- 25 points each (50 points)
    • 3 full papers- 50 points each (150 points)
    • 2 exams- 75 points each (150 points)
    • 3 hypotheses- 5 points each (15 points)
    • total= 365 points
    • 5 bonus points
  5. Grading Scale
    • A - 90-100
    • B- 80-89.99
    • C- 70-79.99
    • D- 60-69.99
    • F- 60 and lower
  6. what are grounds to miss lab
    • post graduate interviews
    • conferences
    • family emergencies
  7. what is the penalty for late papers
    5 points per day (weekends count as one day)

    • late means submitted more than 10 minutes after the start of lab and one late day ccumulates at that time each subsequent day
    • no papers will be accepted more than one week late
  8. Parts of the lab report
    • abstract
    • introduction
    • materials and methods
    • results
    • discussion
    • references
  9. examples of journals
    • American Journal of Physiology
    • Journal of Experimental Biology
    • Journal of Comparative Physiology
    • Journal of Physiology
  10. Title
    • 2 points
    • provide one single descriptive statement which by itself can give a good sense of what the paper is about
  11. Abstract
    • 6 points
    • brief summary of the paper that should be treated as separate entity from the rest of the paper
    • 1-1 and a half pages double spaced
  12. what to include in the abstract
    • what did you do- description of experiments
    • why did you do it-- statement of purpose
    • what are your major findings-- sumarize results
    • what do your results mean-- statement of general conclusions
  13. statement of purpose
    why did you perform the experiment
  14. introduction
    background information relevance of the experiments, why do we care about this
  15. what should be in your introduction
    • 10 points
    • background information to understand the experiments
    • define specific scientific terms
    • state problems specific questions that you are adressing
    • cite original literature
    • can be divided into subsections with separate headings
    • provide clear objectives and hypothesis statements at end of introduction
  16. Materials and Methods
    • 6 points
    • provide one brief statement citing your lab manual
    • citation must be included in the reference section
    • when testing your own hypothesis you must make your own method
  17. what should be in the methods and materials section
    • purpose of section is to allow the reader to understand your experimental design and recreate your experiments and achieve similar results
    • should be writte as a narrative in past tense not as a list o recipe
    • should include chemical concentration
  18. results
    • 14 points- 7 points for narrative, 7 points for figures
    • has two parts
    • written narrative
    • graphical or tabular representations
    • outlines major findings from research which is ultimatley one of the main reasons we partake in scientific writing
  19. written narrative
    • should take the reader by the hand and lead them through your findings
    • should cite any figures
  20. Figures or Tables
    graphical representations of the data which help to illustrate all the data in a concise format
  21. characteristics of figures or tables
    • figure caption
    • axes which utilize an appropriate scale and meaningful units
    • clearly label each treatment using a legend
    • can be drawn by hand or by computer
    • quantify your data
  22. more notes on results section
    • do not report raw data (can only be in the appendix)
    • if multiple measurements use the mean and standard deviation
    • refer reader explicityly to your figures as you write about your findings
    • should reference your own data in past berb tense
  23. Discussion
    • for discussing your data
    • almost everything you say should start with your results
  24. what to include in your discussion section
    • did you see what you expected to see
    • was your hypothesis correct
    • wha physiological mechanism might underlie your findings
    • what do your results mean in terms of functioning organisms
    • how do your findings compare with those of others
    • what are some future experiments you could perform to get a broader understanding of the problem
    • it is important to cite your own figures when mentioning data and cite references when discussing other results
  25. references
    • must have at least 2 references
    • used to back up any general statements made
    • cite references where appropriate in text using format
    • references should be alphabetized according to first authors last name and should follow consistent format
    • include page numbers when referencing text books or lab manual
  26. final writing tips about the lab reports
    • double space
    • use scientific name of animal (title, abstract, introduction)
    • italicize scientific names and journal titles
    • proofread
  27. how to cite references in the paper
    • 1 and 2 authors
    • sentence (Authors, years)

    • 3 or more authors
    • sentence (author 1 et al, Year)
  28. how to reference reference
    • Savolainen, LC, Brown, C, Moore, D, and Galvez, F (2012).
    • Autonomic physiology and control of smooth muscle. Biol 4161 Vert Phys Handout
  29. bar graph
    may be appropriate choice for comparing different trials or different experimental groups
  30. time series
    may be an appropriate choice if independent variable is time and dependent variable is numerical
  31. scatter plot
    may be an appropriate choice is you are trying to show a relationship between your two variables
  32. neurons
    cells that are specialized for recieving and transmitting electrical impulses
  33. what makes up a typical nerve cell
    • cell body (soma)
    • dendrites
    • axon
  34. dendrites
    recieve electrical impulses and carry them towards the soma
  35. axon
    carries the impulses away from the soma
  36. what determines the membrane potential at any time
    • relative concentration of ions in and around the neuron
    • relative permeability of membrane for these ions
  37. what describes the membrane potential mathmatically
    Goldman Hodgkin Katz equation
  38. what channels propagate and create an action potential
    voltage gated Sodium and Potassium channels
  39. what must happen for an action potential to be created
    membrane potential must suprass some threshold value (usually 15-30 mV above resting potential)
  40. what does the hitting threshold cause
    voltage gated sodium channels open and moves membrane towards equilibrium poteintal for sodium generating the upstrock of the action potential, at the same time voltage gated potassium channels are opening, as sodium channels begin to close the membrane potential moves back towards equilibrium potential for K+, the increased K+ permeability causes membrane to overshoot the resting membrane potential generating hyperpolarization. when the voltage gated k+ channels close the axon returns to resting potential
  41. an action potential is a ______________ event
    • all or none
    • does not vary size of AP but does vary the frequency of action potentials
  42. temporal summation
    when two or more local potentials occur in quick succession in an excitable membrane they can summate arithmetically
  43. compund nerve
    composed of fibers of differing diameters
  44. what happens in a compoud nerve
    small stimulus applied to a nerve will depolarize the larger fibers enough to create action potential but will only set up a transient local potential in smaller fibers
  45. absolute refractory period
    • sodium channels inactivate and undergo a period of time where they can not be reactivated
    • causes the propagation to take place in a backward direction
    • also sets a uper limit as to where the neuron can generate action potentials
  46. relative refractory period
    • follows the absolute refractory period
    • some but not all sodium channels have reset and can be reexcited but it requires a greater voltage stimulus to activate enough sodium channels to initiate another action potential
  47. refractory period in nerves
    • each individual neuron can be in a different refractory state
    • responses observed are the average responses from the nerve
  48. what refractory period can be measured
    the shortest absolute refractory period due to the absolut and relative refractory period not the same in all axons
  49. differential recording
    • when two recording electrodes are placed near an active nerve
    • what is reported is the difference between two electrodes (active electrode - indifferent electrode)
  50. what causes the electrical potential at the site of the electrode to change
    currents set up in the extracellular fluid by the action potentials of the active fivers
  51. compound action potential
    • extracellular potential change due to currents in the extracellular fluid caused by AP of active fibers
    • travels down nerve influencing electrodes
  52. during set up where are the active and indifferent recording electrodes
    active electrode is first
  53. biphasic appearane on oscilloscope
    when the active electrode records first a negative then a positive poteintial the AP has biphasic appearance
  54. monophasic appearance on oscilloscope
    if ony one electrode "sees" the AP
  55. two groups of motor nerves
    somatic (visceral)

    autonomic
  56. somatic motor nerves
    those that control the contractile responses in skeletal muscle

    control what we consider voluntary movements of our daily lives
  57. autonomic motor nerves
    • responsible for altering the activity of the viscera or internal organs
    • many of its actions are exerted on smooth muscle of these organs
    • the organs usually show endogenous activity in the absence of autonomic stimulation but this activity is either enhanved or suppressed through autonomic nervous system
  58. the autonomic nervous system is separated into two groups
    sympathetic

    parasympathetic
  59. sympathetic motor nerves
    • emerge from ventral roots of spinal cord
    • reffered to as fight or flight system because it generally prepares body for physical activicty associated with stressful situations
  60. parasympathetic motor nerves
    • leave central nervous system from cranial and sacral regions
    • associated with vegetative or digestive activites associated with relaxation and little physical exertion
  61. orientation of somatic nerves
    • cell bodies within the CNS
    • axons exten all way from CNS to the skeletal muscle
  62. autonomic nerve orientation
    • synapse in ganglia in peripheral nervous system
    • post gangleonic nerve goes to target organ
  63. sympathetic motor neuron orientation
    • pre ganglionic nerve is short synapsing in vertebral chain of ganglia
    • post ganglionic nerve is long
  64. parasympathetic motor nerve orientation
    pre ganglionic nerves are long and travel almost all the way to the effector organ befor synapsing
  65. which type of muscle generate spontaneous contractions in absense of external input and why
    • smooth muscles (expecially in GI tract)
    • due to leaky ion channels and electrogenic ion pumps in the membrane
    • as membrane poteintial rises bursts of action potentials are triggered
    • this increases intracellular calcium (from extra and intracelllular sources) resulting in contraction whose strength and duration dpend upon time course of Calcium changes
  66. how do NT, modulators and hormones affect processes
    can change in frequency or amplitude of contractions in the baseline tension in muscles or some combination of these
  67. acetylcholine
    the NT released by preganglionic neurons in both the sympathetic and parasympathetic systems
  68. how does acetylcholine effect post gangleonic cells
    post gangleonic cells are depolarized when nicotinic acetylcholine receptors on cells bind acetylcholine
  69. how do autonomic nerves synapse
    make connections to effector organs through numerous diffuse swellings or varicosities instead of at discrete synapses
  70. what is the post ganglionic transmitter released by the parasympathetic nervous system
    • acetylocholine
    • can have inhibitory and excitatory effects
  71. what does post gangleonic acetylcholine bind to
    muscarinic acetylocholine receptors
  72. eserine
    • (phosostigmine)
    • parasymypathomimetic
    • interferes with metabolism of ecetylcholine
    • acts to inhibit acetylcholinesterase
  73. acetylcholinesterase
    • enzyme responsible for breakdown of acetylcholine
    • indirectly stimulating both nicotinic and muscarinic receptors
  74. atropine
    competitive antagonist for muscarinic acetylcholine receptors causing decrease in activity of parasympathetic nervous system
  75. norepinephrine
    released by the sympathetic post ganglionic neurons
  76. alpha adrenergic receptors
    generally cuase smooth muscle to contract in the sympathetic nervous system
  77. beta adrenergic receptors
    generally cause smooth muscles to relax
  78. epinephrine
    • very closely related to norepinephrine that is released in conjunction with norepinephrine from the adrenal medula
    • also acts as hormones
    • has opposite effects as norepinephrine
  79. skeletal muscle
    largest tissue in the verterade body and its contraction provides voluntary movement
  80. muscle fibers
    contain myofibrils and are cylindrical cells that make up muscle
  81. myofibrils
    cylindrical structers about 1-2 micrometers in diameter containing many groups of interdigitating thick and thin filaments (myosin and actin)
  82. sarcomere
    contractile unit of skeletal muscle and many individual sarcomeres are lined up in series within each myofibirl
  83. sarcoplasmic reticulium
    • surrounds myofibrils
    • modified endoplasmic reticulium that stores calcium ions
  84. transverse tubules
    • T tubules
    • lead from suface of muscle fiber and serve as the functional link between the muscle fiber membrane (sarcolemma)
  85. neuromuscular junction
    synapse between neuron and a muscle
  86. action potentials in muscle
    • AP travel down motor axon to neuromuscular junction
    • depolarization causes neurotransmitter acetylcholine to be released into synaptic cleft
    • ACh interacts with nicotinic ACh receptors on sarcolemma and causes depolarization
    • AP generated in muscle travels down sarcolemma down T tubules and stimulates SR to release Calcium into sarcoplasm
  87. what does calcium in the sarcoplasm trigger
    a biochemical cascade leading to contraction
  88. how does muscle relax
    when Ca pumps actively sequester the cytoplasmic Ca within the sarcoplasmic reticulum
  89. motor unit
    • a muscle fiber and its motor neuron that it is innervated by
    • motor neurons can innervate mulitple muscle fibers
  90. precise movement
    • the fewer muscle fibers will be in each motor unit
    • and muscle will have large number of motor units
  91. large powerful muscles
    few motor units but each unit has a large number of muscle fibers
  92. specific physiological properties of skeletal muscle
    • slow twitch oxidative fibers
    • fast twitch glycolytic fibers
  93. how do you acheive graded contraction
    • vary the number of motor units contracting at a given time
    • \smaller motor units with small motor neurons are activated first followed by motor units of increasing size and strength
  94. slow twitch fibers
    smaller motor units
  95. fast twitch fibers
    large motor units
  96. muscle summation
    • if a motor unit is stimulated to contract before the fiber has had time to completely relax then tension will be maintained
    • first twitch expends energy in stretching part of muscle ( slack)
    • second twtch applied before fiber can relax will lead to greater stretch
  97. tetanus
    if compund action potentials reach muscle with high enough frequency to cause steady contraction without returning to resting tension
  98. the length tension curve
    • shows relationship between muscle structure and function
    • shows that maximum tension corresponds to the intermediate sarcomere lenghts where myosin and actin overlapped maximally
  99. fasicles
    bundles of numerous muscle fibers within a muscle encased by connective tissue, blood vessels and nerves
  100. what skeletal muscle was studied
    gastrocnemious muscle
  101. 2 types of tissue of the vertebrate heart
    • contractile tissue
    • conductive cardiac tissue
  102. conductive cardiac tissue includes
    • specialized areas of cardiac tissue called pacemakers that are capable of generating spontaneous depolarizations and action potentials
    • interconnecting cardiac fiber networks that are used to conduct these myogenic action potentials over the entire surface of the heart
  103. how is the autonomic nervous system related to the heart
    the rate of firing action potentials by the pacemakers is modulated by activity of the autonomic nervous system
  104. the cardiac cycle
    • rhythmic excitation of the primary pacemaker (sino-atrial node)
    • action potential moves from SA node through the internodal fibers and then through junctional fibers to the secondary pacemaker the atrio-ventricular node (AV node)
    • at same time potentials are sent throughtout atria throuigh interatrial fibers
    • potentials then enter the bundle of his
    • then the purkinje fiber system where they are carried along septum between ventricles
  105. what electrical connections between myocardial cells ensure
    • remaining blood in the two atria is forced simultaneously into the two ventricles to finish priming them before theventricular contractions
    • up to 70% of blood enters the ventricles passively before the atrial contractions
  106. how long are action potentials SA node stalled
    110 ms as the signal pass from the internodal fibers through the junctional fibers at the AV node
  107. is there a difference in conductioin velocities of different fibers of the heart
    junctional fibers conduct messages more slowly than internodal fibers
  108. what is the role of the av delay in the heart
    slowing the signal long enough to allow the atria to prime the ventricles before ventricular contraction
  109. what is the conduction velocity as ap spread over ventricles
    • 4m/s
    • 6times faster than usual cardiac muscle
  110. sympathetic innervation of the heart
    atria and ventricles
  111. what types of synapses does the sympathetic nervous system use in the heart
    adrenergic

    norepinephrine
  112. how does activating the sympathetic nervous system affect the heart
    release of NE accelerates heart rate and strengthens ventricular contractions
  113. parasympathetic innervation of the heart
    • atria and ventricles using the two branches of the vagus nerve
    • very little effect on junction or ventricles
  114. crainial nerve X
    vagus nerve
  115. what types of synapses does the parasympathetic nervous system use in the heart
    release acetylcholine to decrease the rate and strength of ventricular contraction
  116. sympathetic tone
    under basal resting conditions low frequency of sympathetic discharge tends to modulate inherent rhythm of SA node
  117. vagal tone
    low frequency discharges from vagus nerve also regulate heart under basal resting conditions
  118. which system dominates baseling activity of the heart
    parasympathetic
  119. pressoreceptors or baroreceptors
    • stretch receptros located in walls of carotid and aortic sinuses
    • project to cardivascular control centers in medulla of brainstem and the frequency of AP is affected by blood pressure
  120. what happens if there is a sudden drop in blood pressure
    • rate of firing of pressoreceptros is reduced and autonomic system responds by increasing sympathetic tone and reducing vagal tone of the heart
    • increased sympathetic activity increases heart rate and strength of ventricular contractions
  121. what happens if sudden increase in blood pressure
    • pressoreceptro firing rates increase
    • cardivascular center decreases sympathetic tone and reducing vagal tone of heart to bring blood pressure back to normal
  122. where are the chemoreceptors found
    • in hypothalmus that monitor blood oxygen and carbon dioxide levels
    • send input to cardivascular reflex center in brainstem to aid control of heart rate
  123. difference between frog and mammal hearts
    • three chambered pump (2 atria and 1 ventricle)
    • mygenic cells in sinus venosus act as principle pacemaker
  124. why do we study heart using frog hearts
    since frog is ectotherm metabolic demands on heart are much lower than in a mammal

    easier preparation (robust)
  125. Frank-Starling effect
    observation that increased filling of the ventricle (from increased venous pressure) results in stronger mechanical force produced during systole
  126. effects stretching have on heart
    increases strenght on contraction force
  127. effects of epinephrine on the heart
    increased contraction force
  128. acetylcholine effects on the heart
    decreased contraction force of the heart
  129. eserine effects on heart
    increased the contraction force
  130. atropine effects on the heart
    increase on contraction force of the heart
  131. nicotines effect on the heart
    increased the contraction of the heart
  132. pathway of blood through the heart
    blood returning from body arrives at right side of heartand is pumped through the lungs, oxygen picked up and carbon dioxide is release, oxygenated blood then arrives at left side of heart from where it is pumped back to body
  133. sinoatrial node
    group of specialized cardiac muscle fibers acts as pacemaker fro heart

    rhythmically produce action potentials that spread through muscle fibers of atria
  134. atrioventricular node
    • only electrical connection between atria and ventricles
    • AP spread slowly through AV node allowing atrial contractions to contribute to ventricular filling and then rapidly through AV bundle and purkinje fivers to excite both ventricles
  135. components of ECG
    • P wave
    • QRS complex
    • T wave
  136. P wave
    • produced by atrial depolarization
    • small increase in potential
  137. QRS complex
    • produced by ventricular depolarization
    • atrial repolarization also occurs during this time

    large narrow spike
  138. T wave
    • produced by ventricular repolarization
    • longer increase in potential
  139. three phases of cardiac action
    • rapid depolarization
    • plateau depolarization (very obvious in ventricular fibers) and repolarization back to resting membrane potential
  140. heart sounds
    made by closure of the two valves of the heart that give rise to audible vibrations
  141. atrioventricular valves (AV)
    between atrium and ventricle on each side of heart prevents backflow from ventricle to atria
  142. semilinear valves
    located between ventricle and artery on each side of heart and prevent backflow of blood from aorta and pulmonary artery into each ventricle
  143. lub dub sound of heart
    • created by closure of the heart
    • lower pitched lub--> during early phase of ventricular contraction produced by closing AV (mitrial and tricuspid) valves
    • higher pitched dub-->? closing of semilunar valves (aortic and pulmonary) close when blood pressure drops below artery
  144. AV valves
    • mitral
    • tricuspid
  145. semilunar valves
    aortic and pulmonary
  146. Parts of the cardiac cycle
    • Ventricular diastole
    • atrial systole
    • isovolumic ventricular contraction
    • ventricular systole
  147. Ventrcular diastole
    • blood returns to heart
    • deoxygentated blood enters right atria and enters the right ventricle through the open atrioventricular valve
    • oxygenated blood from the lungs enters the left atrium and flows to the left ventricle through the open AV valve
  148. atrial systole
    • filling of the ventricle is completed when the atria contract
    • in resting state atrial systole accounts for 20% of the atrial filling
  149. ventricular systole
    • atrial contraction is followed by contraction of the ventricles
    • as ventricles contract the pressure rises in them and exceeds that in atria closing the AV valve
    • until the pressure in left ventrcle exceeds the pressure of the aorta and right ventricle P exceeds pulmonary artery P the volume will not change
  150. isovolumic phase of ventricular contraction
    • the pressure in left ventricle exceeds P in aorta and the pressure in the right P exceeds P in the pulmonary artries
    • the pulmonary and aortic valves open and blood is ejected into aorta and pulmonary arteries
    • as ventricular muscles relax pressure in venticles fall below those in aorta and pulmonary artery and the aortic and pulmonary valves close
    • venticular pressure continues to fall and once it is below the atria the AV valves open and filling begains again
  151. how to connect ECG
    • remove jewlery from hands arms and right leg
    • use ball point pen to mark small corsses on skin
    • place one on each forarm and 1 on the right ankle
    • abrade skin with abrasive gel or pad (reduce skin resistance) then clean area with alcohol swab to remove dead skin. let skin dry and stick electrodes onto skin
  152. why should you not place ECG electrodes over major muscles
    because muscle activity interferes with the signal recorded from the heart
  153. how to find heart rate using ECG machine
    • find duration of contraction
    • divide 60 by the time interval (seconds)
  154. when is blood pressure at its highest
    immediately after the ventricle contracts (systolic pressure)
  155. when is blood pressure at its highest
    immediatly prior to the pumping of blood into the arteries (diastolic pressure)
  156. invasive way to measure systolic and diastolic blood pressure
    inserting small catheter into artery and attaching caterte to pressure gauge
  157. mercury sphygmomanometer
    • Scipione Riva-Rocci
    • estimated using stethoscope and blood pressure cuff connected to mercury sphygmomanometer
    • cuff placed on upper arm and inflated to stop arterial blood flow to arm from brachial artery
    • pressure is released slowly when cuff falls below systolic pressure in arter the blood begins to flow to arm (turbulent flow)
    • turbulent flow generates sound called the Korotkoff sounds (systolic pressure)
    • as cuff pressure decreases the sound disapeers and this is the diastolic pressure
  158. finding blood pressure with the computer
    • place a finger pulse transducer and conect it to computer
    • cuff is inflated to a pressure the obliterates finger pulse
    • as pressure is released the finger pulse returns and pressure at which it repeasers is a measure of systolic
  159. why do we care about placement of cuff compared to heart
    • there are differences in pressure with arm held in different positions
    • difference in 1 meter of height is a pressure difference of 10.3 kPa or 777mmHg
    • due to hydrostatic pressure of column of blood any measurments below the heart will be increased in pressure and any made above theheard will be decreased in pressure relative to the heart level
  160. how far do you inflate the pressure cuff when taking blood pressure
    180mmHg
  161. how fast do you release pressure in blood pressure cuff
    1 to 2 mmHg per second
  162. how long should a person recover before taking blood pressure again
    at least 2 minutes
  163. what finger do yo place the Finger Pulse Transducer for blood pressure
    tip of the middle finger
  164. where should the persons hand be when recording blood pressure with the computer
    • in their lap and have the leg suppor the wrist allowing fingers to hang freely
    • do not move during recording
  165. skeletal and striated muscles are connected to bones by
    tendons or directly
  166. tendons
    strong bundles of collagen fibers
  167. skeletal muscle is composed of
    long multinucleate cells called fibers grouped into fascicles
  168. two or muscles work
    • antagonistically
    • a contraction of one muscle stretches or elongates the other
  169. each muscle fiber is innervated by a branch
    of a motor axon
  170. motor unit
    a single motor neuron and all the muscle fibers that it innervates
  171. activation of a muscle
    • initiation of an action potential
    • conduction of action potential down nerve fiber
    • release of neurotransmitter acetylcholine into neuromuscular junction and depolarization of the muscle membrane with resultant contraction of the muscle fibers
    • muscle action potential causes increase in calcium intracellular that activates contracile molecular machinery inside fiber
    • use of intracellular supplies of adenosine triphosphate as energy
    • brief contraction or twitch
  172. recruitment
    controlling the number of twitching muscle fibers
  173. two types of ways the nervous system controls muscle
    • recruitment
    • vary the frequency of action potentials in motor axons
  174. at what frequencies do separate twitches occur
    • 200 ms
    • calcium restored to baseline levels between action potentials
  175. at what frequencies does summation occure
    • 200 to 75 ms
    • calcium in muscle is still above baseline when next ap arrives
    • muscle has not completly relaxed and next contraction is stronger
  176. what frequencies do tetanus occur
    • higher than 75ms
    • muscle has no time to relax between successive stimuli
    • smooth contraction many times stronger than a single twitch called tetanic contractin
  177. what was used to measure muscle fatigue
    hand dynamometer

What would you like to do?

Home > Flashcards > Print Preview