Muscle Physiology 1

Question 1

what are the 5 main functions of skeletal muscle

Answer 1

maintain posture 
purposeful movement 
respiratory movements 
heat production 
contribution to whole body metabolism

Question 2

what are the two types of striated muscle

Answer 2

Cardiac

Skeletal

Question 3

How is skeletal muscle stimulated

Answer 3

Neurogenic stimulation

Question 4

Where does the calcium that stimulated skeletal muscle contraction come from

Answer 4

the lateral sacs of the sarcoplasmic reticulum

Question 5

what neurotransmitter is at the neuromuscular junction of skeletal muscle

Answer 5

acetyl choline

Question 6

what is a skeletal muscle motor unit

Answer 6

a single alpha motor neurone and all the muscle fibres it supplies

Question 7

muscles that give fine movements (eg. eye movements, intrinsic hand muscles) have more muscle fibres to one alpha motor neurone true/false

Answer 7

false

have less muscle fibres per alpha motor neurone

Question 8

muscles that give powerful movements have more muscle fibres per alpha neuron true/false

Answer 8

true

Question 9

what makes up a muscle

Answer 9

muscle fibres arranged in motor units

Question 10

what are muscle fibres made out of

Answer 10

Myofibrils

-specialised intracellular structures

Question 11

what are myofibrils made up of

Answer 11

Actin and myosin arranged in sarcomeres

Question 12

Actin is a thin, light coloured protein true/false

Answer 12

true

Question 13

Myosin is a thin, dark coloured protein true/false

Answer 13

false

fat, dark coloured protein

Question 14

what is the definition of a functional unit

Answer 14

the smallest component capable of performing all of the functions

Question 15

what lines are sarcomeres found between

Answer 15

Z lines

Question 16

What are the 4 zones of a sarcomere

Answer 16

A band
H-zone
M-line
I band

Question 17

what is the A band

Answer 17

thick filaments (myosin) with thin filaments overlapping at both ends (actin)

Question 18

what is the H zone

Answer 18

In the middle of the A band

A lighter area where the thin filaments dont overlap the thick

Question 19

what is the M line

Answer 19

Extends vertically down the middle of the A band through the H zone

Question 20

what is the I band

Answer 20

remaining proportions of thin filaments that don’t project into the A band

Question 21

How is muscle tension produces

Answer 21

the sliding of actin and myosin over each other to shorten the muscle

Question 22

what are the stages of muscle contraction

Answer 22

1. nerve produces an action potential on the surface of the muscle
2. action potential spreads down the T tubules triggering release of calcium from the sarcoplasmic reticulum
3. calcium binds to troponin which moves troponin out the way exposing the actin binding site
4. with the binding of ATP, the myosin cross bridge binds to the binding site on actin triggering the power stroke

Question 23

what are the stages of muscle relaxation

Answer 23

ATP allows the calcium to be taken up by the sarcoplasmic reticulum and for the cross bridge to be released.

troponin covers up the binding site again.