Module11 Skeletal Muscle

Question 1

List 3types of muscles

Answer 1

cardiac, skeletal, smooth muscle

Question 2

basic characteristics of muscles

Answer 2

excitability -produce electrical impulses
contractility- able to shorten in length,
extensibility and elasticity

Question 3

state the mechanism of skeletal muscle excitation and how it terminated

Answer 3

neuromuscular transmission and terminated by breakdown of Ach by acetycholinesterase

Question 4

can skeletal muscle contract without nervous stimulation ?

Answer 4

nope, UNLESS it is stimulated by neurons then only it contracts (voluntary)

Question 5

why we feel ‘hot’ after having heavy meal ?

Answer 5

muscles start working and need more effort to digest food it is called exothermic reaction

Question 6

connective tissue that covered whole muscle is known as ?

Answer 6

epimysium
perimysium -surrond muscle fibers
endomysium - surround myofibrils

Question 7

thin myofilaments made up of ?

Answer 7

actin, troponin, tropomyosin

Question 8

explain the mechanism of muscle contraction

Answer 8

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

Question 9

muscle needs ATP in order to contract, how can ATP regenerate ?

Answer 9

1) interaction of ADP with creatine phosphate
2) anerobic glycolysis (2ATP)
3) aerobic respiration (36 ATP)

Question 10

where creatine phosphate comes from and how it generate ATP for skeletal muscle contraction?

Answer 10

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.

Question 11

reduce affinity of myosin for actin causes the myosin to unbind from the actin filament and muscle relaxation
the statement is true or false ?

Answer 11

true!when ATP bind to myosin it reduces it affinity and muscle relax

Question 12

list types of muscle fibers

Answer 12

aerobic (type 1) (s) -high endurance
intermediate (type 2A) (FR)-high oxidative fast twitch
anaerobic (type 2b) (FF) - little endurance easily fatigue

Question 13

3types of muscles unit ?

Answer 13

1) slow (s)motor unit -maintain upright posture
2) fast fatigable (FF) motor unit - sprinting, jumping
3) fast fatigue resistance(FR) motor unit - marathon

Question 14

describe :

1) spatial summation -
2) temporal summation -

Answer 14

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)

Question 15

torn of ligament is called sPrain

torn/stretch of muscle or Tendon is sTrain

Answer 15

yas its a true statement

Question 16

Differentiate hypertrophy and atrophy.

Answer 16

hyperthropy - increase power&muscle mass

atrophy - muscle is not used in long time/only used in weak contraction.

Question 17

what gives anaerobic type 2b muscle fibers white coloured fibers ?

Answer 17

it rich in glycogen and glycolytic enymes, low myoglobin and has poor blood supply,fatigue easily cause low ATPase activity

Question 18

aerobic type 1 muscle fibers gives red colour, why ?

Answer 18

abundant myoglobin and oxyge , rich blood supply,

v resistant to fatigue cause hv high ATPase activity

Question 19

describe alpha motor neurons and gamma motor neurons

Answer 19

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

Question 20

summation is ___________

Answer 20

the adding together of individual muscle twitches to make a whole muscle contraction