Module11 Skeletal Muscle Flashcards
List 3types of muscles
cardiac, skeletal, smooth muscle
basic characteristics of muscles
excitability -produce electrical impulses
contractility- able to shorten in length,
extensibility and elasticity
state the mechanism of skeletal muscle excitation and how it terminated
neuromuscular transmission and terminated by breakdown of Ach by acetycholinesterase
can skeletal muscle contract without nervous stimulation ?
nope, UNLESS it is stimulated by neurons then only it contracts (voluntary)
why we feel ‘hot’ after having heavy meal ?
muscles start working and need more effort to digest food it is called exothermic reaction
connective tissue that covered whole muscle is known as ?
epimysium
perimysium -surrond muscle fibers
endomysium - surround myofibrils
thin myofilaments made up of ?
actin, troponin, tropomyosin
explain the mechanism of muscle contraction
1) propagation of action potential into T tubule
2) action potential triggers ca release from terminal cisternae of SR
3) ca binds to troponin and activate tropomyosin to expose binding site for myosin head
4) cross bridge is form and myosin head binds to new position on actin
5) muscle start to contract
muscle needs ATP in order to contract, how can ATP regenerate ?
1) interaction of ADP with creatine phosphate
2) anerobic glycolysis (2ATP)
3) aerobic respiration (36 ATP)
where creatine phosphate comes from and how it generate ATP for skeletal muscle contraction?
it is synthesized in liver from ornithine, glycine, arginine
In skeletal muscles it is phosphorylated to form creatine phosphate in a reaction catalyzed by CREATINE KINASE.
reduce affinity of myosin for actin causes the myosin to unbind from the actin filament and muscle relaxation
the statement is true or false ?
true!when ATP bind to myosin it reduces it affinity and muscle relax
list types of muscle fibers
aerobic (type 1) (s) -high endurance
intermediate (type 2A) (FR)-high oxidative fast twitch
anaerobic (type 2b) (FF) - little endurance easily fatigue
3types of muscles unit ?
1) slow (s)motor unit -maintain upright posture
2) fast fatigable (FF) motor unit - sprinting, jumping
3) fast fatigue resistance(FR) motor unit - marathon
describe :
1) spatial summation -
2) temporal summation -
1) increasing the number of motor units contracting at one time
2) increasing the frequency of contractions of individual muscle contraction (contraction isnt completely over and cause continuous of contraction)
torn of ligament is called sPrain
torn/stretch of muscle or Tendon is sTrain
yas its a true statement
Differentiate hypertrophy and atrophy.
hyperthropy - increase power&muscle mass
atrophy - muscle is not used in long time/only used in weak contraction.
what gives anaerobic type 2b muscle fibers white coloured fibers ?
it rich in glycogen and glycolytic enymes, low myoglobin and has poor blood supply,fatigue easily cause low ATPase activity
aerobic type 1 muscle fibers gives red colour, why ?
abundant myoglobin and oxyge , rich blood supply,
v resistant to fatigue cause hv high ATPase activity
describe alpha motor neurons and gamma motor neurons
a-motor neurons : innervate EXTRAfusal muscle fibers located throughout the muscle, contraction of these muscle provide movement
y-motor neurons : innervate INTRAfusal muscle fibers found within the muscle spindle, modify sensitivity of fiber’s afferent axon to force
summation is ___________
the adding together of individual muscle twitches to make a whole muscle contraction
