Muscle Physiology

Question 1

3 types of muscles

Answer 1

Skeletal=single/bi nucleated
Cardiac =multi nucleated
Smooth =single nucleated

Question 2

Cardiac muscle

Answer 2

Relatively short
30-200 um
Diameter:5-10um
No striations

Question 3

Functions of skeletal muscle

Answer 3

• Movement of the skeleton
• Posture
• Support of visceral organs
• Body temperature
• Energy storage

Question 4

Smallest anatomical structure in a skeletal muscle

Question 5

(Smallest)functioal structure of the skeletal muscle

Answer 5

Sarcomere

Question 6

The borders of the sarcomere and move closer together during contraction are

Answer 6

Z lines

Question 7

Sarcomere

Answer 7

The main contractile,functional unit of the skeletal muscle fibres

Question 8

The neuromuscular junction

Answer 8

-acetylcholine is released onto the neuromuscular junction
-it binds to acetyl choline receptor
-when acetyl choline receives an action potential(acetyl choline receptors are stimulated)sodium gated Channels open
-signal is carried along the nerve

Question 9

Where are calcium ions stored

Answer 9

Stored in the sarcoplasmic reticulum

Question 10

Where are ion channels located in

Answer 10

In the t-tubules

Question 11

Actin

Answer 11

Muscle thin filament

Question 12

Tropomyosin

Answer 12

Stiffens and stabilises actin,preventing actin binding at rest

Question 13

Troponin

Answer 13

-where calcium binds
-has 3 subunits,each with a specific role

Question 14

skeletal muscle contraction requires what form of sracoplamic reticulum

Answer 14

Calcium

Question 15

Thin filament

Answer 15

Actin

Question 16

Cross bridge model

Answer 16

-myosin head joins atp
-bound atp is hydrolysed= phosphate is released(still attached to myosin head)
-myosin head moves and grabs actin=phosphate is released
-power stroke
-atp is released(another myosin head binds to atp)

Watch lecture

Question 17

What happens to atp in order for powerstroke to occur

Answer 17

Hydrolyse to form atp and inorganic phosphate

Question 18

What affects the force of muscle

Answer 18

Developed due to the action of the cross bridges

Question 19

What are isotonic contractions

Answer 19

-muscle contracts,shortening in length
-eg lifting an object which is easy to move

Question 20

List types of muscle fibre types

Answer 20

-slow-twitch oxidative fibres(type 1)
-fast twitc oxidative glycolytic fatigue resistant muscles(type 2a)
-fast twitch glycolytic fatiguable fibres (type 2b)

Question 21

Fastest contracting muscles in skeletal muscles are:

Answer 21

Type 2b