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Human Phys II Exam 2
| Question | Answer |
|---|---|
| absolute refractory period | ~period where second action potetial can't be triggered for about 2 msec no matter how long the stimulus of AP ~will not open for any amount of depolarization |
| action potential | ~AP is sequence of charge in membrane potential due to increase in ion permeabilities and returning potential to resting potential ~large constant strength depolarization that can travel for long distance through neuron without losing strength |
| conduction | ~high speed movement of AP through axon |
| frequency coding of action potential | ~encodes the intensity of stimulus ~changes in intensity are represented as varying AP frequency, CNS regulates AP frequency to produce variable contraction |
| motor unit | ~group of skeletal muscle fibers and somatic motor neuron that controls them. It is the basic unit of contraction in skeletal muscle ~receive from just one motor unit |
| relative refractory period | ~stronger than normal depolarizing graded potential is needed to bring cell up to threshold and AP will smaller than normal ~requires higher depolarization to initiate increased NA+ permeability to generate AP b/c the threshold is increased |
| alpha motor neuron | ~neurons that innervate extrafusal muscle fibers and cause contractions |
| central pattern generator | ~networks of CNS neurons that function spontaneously to control certain rhythmic muscle movements |
| extrafusal | ~the normal contractile fibers of muscle |
| gamma motor neuron | ~small neuron that innervates intrafusal fibers within the muscle spindle |
| flexion reflex | ~A polysynaptic reflex that causes arm and leg to be pulled away from painful simulus |
| Golgi Tendon Organ (GTO) | ~receptors are found at the junction of tnedon and muscle fibers that respond to both stretch and contraction of muscle |
| intrafusal | ~modified muscle fibers of muscle spindle that lack myofibrils in their central portion |
| kinesthetic sensation | ~"movement" sensing ~awareness of body position in space and of the relative location of body parts to each other |
| length control reflex | ~increased strength->increased spindle afferent AP frequency ~monosynaptic excitatory ending stimulate alpha motor neurons of stretched muscle->increased contraction->decreased length ~negative feedback |
| proprioception | ~awareness of body position in space and of the relative location of body parts to each other ~GTO |
| statokinetic | ~regulation of body position and simple locomotion organized by spinal cord and brain stem |
| stretch reflex | ~reflex pathway in which muscle stretch initiates contraction response |
| telokinetic | ~goal-directed movement(voluntary) organized by primary motor cortex(or pyramidal system) |
| tension control reflex | ~tactile and other types of senstaion may be involved in long reflex that extend from periploy->primary sensory cortex->spinal cord->extrafusal motor unit ~provides sensitive regulation of tension |
| Babinski sign | ~abnormal extensor response of the foot (spread and flexed toes) |
| paradoxial reversal phenomenon | ~indicate special nature of pyramidal pathway ~stimulate just few cortical neurons in primary motor cortex ~stimulus->coordinate hand and arm movement ~movement from same stimulus reverse depending on starting position |
| primary motor area (pyramidal system) | ~thin strip of cortex, neighboring primary sensory area ~have orderly "maps" of body surface so that stimulation to: motor map->coordinated movement sensory map->preseption of surface stimulation |
| servomechanism | ~self regulation feedback system or mecahnism |
| vestibular nuclei | ~where the synapse of the vestibular nerve takes place |
| vestibular apparatus | ~portion of inner ear that contains sensory receptor for balance and equilibrium |
| active hyperemia | ~increase in blood flow that accompanies increase in metabolism |
| chronotopic action of NE,E,Ach | ~effect of regulation by autonomic nervous system on heart rate |
| end diastolic volume (EDV) | ~the maximum volume of bllod that ventricles hold during cardiac cycle |
| end systolic volume (ESV) | ~amount of blood left in ventricle at end of contraction |
| intropic action of NE,E | increase amount of Ca2+ available-> increase force of contraction |
| myogenic autoregulation | ~homeostatic regulation of blood flow through arterioles that automatically adjusts to changes in blood pressure without changes in nervous system regulation or local changes in tissue activity |
| Parkinson's disease | ~substantis nigra, dopamine is reduced in brain |
| reactive hyperemia | ~increase in tissue blood flow collowing period of low perfusion |
| Renaud's phenomenon | ~chronic elevation of BP that is caused indirectly by another condition (often hormonal abnormalities) |
| ventricular fibrillation | ~prolonged conduction time of activity in ventricular myocardium, so that the refractory period ends too early in region, leading to contraction out of normal sequence, and disorganized contraction of myocardium |
| baroreceptor reflex | primary reflex pathway for homeostatic control of BP |
| baroreceptors | stretch-sensitive mechanoreceptors that respond to change in pressure |
| orthostatic (postural) reflexes | ~reflexes that help maintain body position |
| hydrostatic pressure | the pressure exerted by a stationary column of fluid in a tube |
| mitral stenosis | ~key valve (mitral valve) for heart function -left AV valve -normally closed during systole, prevent backflow of blood into L atrium ~w/ age or damage, valve becomesstiffened & cannot close ~effect-> decreased SV&CO |
| aneurism | ~erosion of vessel wall ~effect of atherosclerosis |
| atherosclerosis | ~pathological condition in which lipids and calcium deposit beneath vascular endothelium |
| primary hypertension | ~cause is unknown ~arterial BP increase ~chronic= >130 systolis and >85 diastolic ~allosteric change occur in hypertension to adjust abrreceptor activity and responsiveness of vascular smoth muscle to various stimuli |
| secondary hypertension | ~cause by abnormal hormone secretion (renal cause) -vascular obstruction to kidneys -renal disease -abnormality of descending aorta hormonal pregnancy |
Created by:
Sparkleflutist22
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