neuromuscular junction Flashcards
what is a refactory period
its a time during which an organ or cell is incapable of repeating a particular action
absolute refractory cooresponds refers to
depolarization and repolarization
relative refractory periods refer to
hyperpolarization
what is twitch
this is a single rapid contraction and relaxation of a muscle fiber or a group of muscle fibers due to a sigle action potential of the motor neuron
what happens in the latent period
this is the period btw when the stimulus is applied and when the first sign of the muscle contraction
at what period does the excitation - contraction coupling takes place
latent
what happens in the contraction period
this si the period btw the onset of the contractiona nd the endind of the contraction in which the peach tension occurs
what happens in the relaxation period
period btw the time of the peak tension to the point when tension returns to baseline
what are the other actions that takes place in the relaxation period
ca2 is being pumped back into the sacroplasmic reticulum
cross-bridge cycle stops
muscle is stretching back to its original length
does a muscle contraction curve have a refractory period
NO
what is excitation-contraction coupling
this is when an action potential causes depolarization in the myocyte membrane
a partial state of contraction of a skeletal muscle to maintain its optimal length during resting condition, even when a force isapplied to elongate the muscle is what
muscle tone
clinically muscle tone can be described as what
as the resistance, felt by the examiner during
passive stretching of a joint when the muscles are at rest
features of the muscle tone
Essential for maintaining body posture.
Reflect a state of preparedness to a movement
Prevents hypermobility of joints
Declines during REM.
types of hypertonia
spasticity
rigidity
spasm
classification of muscle tone
postural and phasic
truths about postural muscle tone
seen in axial muscles
gravity is an important factor
results from a steady stretch on the muscles
manifests as prolonged muscle contraction
truths about the phasic tone
assesed clinically as a rapid and short duration
results from a rapd stretch of tendon
muscle tone is regulated by what
spinal mechansim and supraspinal mechanisim
spinal mechanism is dependent on the interaction betw what
muscle spindle
spinal cord
interneurons
supraspinal is regulated by
facilatatory and inhibitory long tracts and cerebelum
sudden rapid stretch of a muscle stimulates what
nuclear bag fibers and 1a afferents
rapid stretch is the clinical bases of what
deep tendon reflex
sustained stretch stimulates what
nuclear chaon fibers and type 2 a
static stretch response is the physiological basis of what
maintainng muscle tone
supraspinal control consist of
supraspinal control through descendong long tracts
and cerebellum
role of cerebellum
medaila part of the anterior lobe activates medullary reticular formation and inhibits muscle tone
lateral part activates pontine reticular formation and facilitates muscle tone indirectly
cerebellar lesions produce hypotonia
hypertonic constsit of what
spasticity
dystonia and rigidity
the involuntary muscle hyperactivity consists of what
spasticity sensus strictu
rigidity
dystonia
spasms
postive consequences of spasticity
helps in standing and walking
reduces edema
delays muscle atrophy
prevent osteoporosis
aids in breathing
A muscle with a shorter length and reduced cross-section produces what
less force
