Muscle physiology

Question 1

Muscle is a group of what

Answer 1

Fascicles

Question 2

What is the plasma membrane of muscle called?

Answer 2

Sarcolemma

Question 3

What is the cytoplasm of the muscle

Answer 3

Sarcoplasm

Question 4

myofibrils contain what?

Answer 4

Contractile machinery

Question 5

Smooth ER in muscle is what

Answer 5

Sarcoplasmic reticulum, contains many mitochondira- high energy

Question 6

what gives muscle striated appearance

Answer 6

myofibrils

Question 7

What is myofibrils made of

Answer 7

It is bundle of overlapping thick and thin filaments made up from proteins actin and myosin

Question 8

what is a sarcomere

Answer 8

Z line to Z line

Question 9

What are the three proteins in thin filaments

Answer 9

Actin, Tropomyosin, and Troponin

Question 10

What does actin have

Answer 10

Binding sites for myosin

Question 11

What type of protein is Actin

Answer 11

Contractile

Question 12

What does each g Actin have

Answer 12

Binding site for myosin

Question 13

What is tropomyosin

Answer 13

Regulatory protein, overlaps binding sites on actin for myosin

Question 14

What is Troponin

Answer 14

Regulatory protein

Question 15

Troponins three proteins do what?

Answer 15

Attach to actin, attach to tropomysoin and binds calcium reversibly

Question 16

What does calcium binding to troponin regulate?

Answer 16

Skeletal muscle contraction

Question 17

The tails of thick filaments face what?

Answer 17

M-lines

Question 18

Myosin head has how many binding sites

Answer 18

2, one for actin, one for ATP

Question 19

What is TItin

Answer 19

Support protein, achors thick filaments between M-line and Z-line, provides structural support and elacticity

Question 20

What happens within a sarcomere to ( A band , I band, H zone and sarcomere) during contraction

Answer 20

A band stays same length
I band shortens
H zone shortens
Sarcomere shortens

Question 21

What is the crossbridge cycle

Answer 21

Cyclical formation of links between actin and myosin resulting in the sliding of thin filaments toward the M line of a sarcomere

Question 22

During high energy form during cross cycle, what is bound to myosin and what is affinity for action

Answer 22

ADP and Pi bound to myosin, high affinity for actin

Question 23

What does Crossbridge cycle rely on

Answer 23

ATP hydrolysis

Question 24

Analogous to what

Answer 24

Rowing boat through water, our paddle is crossbridge

Question 25

Link of thick filament to thin

Answer 25

Oar contact with water

Question 26

Power stoke

Answer 26

Myosin head moves propelling thin filament toward center of muscle ( oar propelling boat)

Question 27

Thick and thin filaments

Answer 27

Oar breaks contact with water

Question 28

What is excitation contraction coupling. What does it depend on?

Answer 28

Sequence of events whereby an action potential in the sarcolemma causes contraction Depends on neural input from motor neuron

Question 29

What does excitation contraction coupling require

Answer 29

Calcium release from the sarcoplasmic reticulum

Question 30

What occurs if no calcium in contraction?

Answer 30

Troponin holds tropomysoin over myosin binding sites on actin. No crossbrdiges form, muscle is relaxed

Question 31

When calcium is present what is role in excitation contraction coupling

Answer 31

Calcium Present - binds to troponin, causing movement of troponin, causing movement of tropomyosin, exposing binding sites for myosin on actin Crossbridges form, cycle occurs

Question 32

List the steps of excitation contraction coupling

Answer 32

1. Action potential in sarcolemma. 2. Action potential down T tubles. 3. DHP receptors of T tubules open Ca2+ channels . 4. Calcium increases in cytosol 5. Calcium binds to troponin shifting tropomyosin 6. Cross bidge cycling occurs

Question 33

What must occur to terminate the contraction?

Answer 33

Calcium must leave troponin, allowing tropomyosin to cover myosin binding sites on actin

Question 34

ATP is used by muscle how?

Answer 34

Crossbridge cycle, splitting of ATP by myosin ATPase(power stroke) Binding of fresh ATP to myosin to cause dissociation

Question 35

Sources of ATP in muscle

Answer 35

Phosphorylation of ADP by creatine phosphate Oxidative phosphorylation of ADP in mitochondria Anaerobic Glycolysis

Question 36

How to maintain adequate oxygen to muscle

Answer 36

Increase ventilation Increase heart rate and contraction Dilate vessels to muscle

Question 37

Glucose is substrate for oxidative phosphorylatio for how long then what is after rthat

Answer 37

30 min, then fatty acids dominant