Physiology Exam 2 Chapter 20

Front 1

What are the muscle types

Back 1

Striated and smooth muscle

Front 2

What are the two types of striated muscle

Back 2

skeletal and cardiac

Front 3

Why is smooth muscle called that?

Back 3

There are no striations.

Front 4

Skeletal muscle makes up what percentage of body mass?

Back 4

40-45%

Front 5

What does skeletal muscle affect?

Back 5

Metabolism, mobility, and strength

Front 6

What is loss of muscle mass associated with?

Back 6

Disease, injury, and aging

Front 7

What is sarcopenia?

Back 7

Loss of muscle mass due to aging.

Front 8

What attaches bone to muscle?

Back 8

Tendons

Front 9

How far along the muscle does a muscle fiber run?

Back 9

The entire length

Front 10

Describe the structure of a muscle fiber

Back 10

The myofiber is covered by the basal lamina. Filled with many “myonuclei” which regulate its own domain. Satellite cells surround orbit the myofiber under the basal lamina

Front 11

Satellite cells

Back 11

stem cells that assist with muscle regeneration

Front 12

What is a sarcomere?

Back 12

A muscle unit. It gives the muscle striations. Made of actin and myosin

Front 13

A band

Back 13

overlap of actin and myosin

Front 14

I band

Back 14

Part of the muscle that contains actin only

Front 15

M line

Back 15

mid line of the sarcomere. Exactly at the center of the two Z discs Contains only actin.

Front 16

H Zone

Back 16

where the sarcomere contracts/expands. This can chance size and can disappear depending on the contraction. Contains only myosin.

Front 17

Thick filament

Back 17

myosin

Front 18

Thin filament

Back 18

Actin

Front 19

G actin

Back 19

a two stranded helix of F actin. Where myosin binds.

Front 20

Tropomyosin

Back 20

binds the troponin to actin. BLOCKS myosin binding site

Front 21

Troponin

Back 21

long filament wrapping around the G actin double helix.

Front 22

Light chain

Back 22

the part of the chain that connects the tail to the head of the myosin

Front 23

Heavy chain

Back 23

the tail of myosin

Front 24

How does Myosin crawl on actin?

Back 24

The myosin is bound to the actin on the myosin binding site. ATP binds to myosin and myosin drops the actin. Myosin hydrolyses ATP into ADP-Pi (which has a weaker bond to the myosin head, so the myosin will attach to the actin). Pi drops off POWERSTROKE! ADP releases, rigor mortis again.

Front 25

Rigor mortis

Back 25

you ran out of ATP and are stuck to the actin wherever you are

Front 26

Slow sliding filament theory

Back 26

each myosin head provides one crossbridge to actin, but because there are freaking thousands of them it gives the muscle the ability to have some/a lot of contraction.

Front 27

Each myosin head provides ___ which interacts with an actin filament

Back 27

cross bridge

Front 28

What moves during contraction?

Back 28

Z bands move together. H band shrinks. I band shrinks.

Front 29

Maximum contraction means?

Back 29

Actin is totally covered.

Front 30

What happens if you go past maximum contraction?

Back 30

Actin will overlap

Front 31

Tropomyosin movement

Back 31

Ca will bind to troponin, and will force a conformational change. Troponin and tropomyosin will move. Myosin binding site is exposed. Actomyosin and powerstroke occurs. Movement of the thin filament (actin) back

Front 32

What happens if Ca ions are not present

Back 32

the tropomyosin will block the binding site on G-Actin

Front 33

Where is Ca sequestered?

Back 33

Sarcoplasmic reticulum

Front 34

Explain the cross bridge cycle

Back 34

Add ATP in the presence of calcium, and you get tension. Remove ATP and the tension will remain there due to rigor mortis. Remove ATP in the absence of Ca2+ and tension releases. When Calcium is added again, tension will resume.

Front 35

The triad

Back 35

T tubule plus 2 sarcoplasmic reticulums

Front 36

What are the receptor molecules in the triads?

Back 36

DHPR and RyR

Front 37

DHPR

Back 37

senses a voltage change due to an action potential. Located in the T tubule

Front 38

RyR

Back 38

Calcium channel which is opened by the DHPR. Located in the SR

Front 39

Excitation contraction coupling

Back 39

action potential causes a release in Ach. Ligand gated Ach channels open. AP in muscle. The T tubules will depolarize. DHPR senses the depolarization and changes confirmation. RyR opens and calcium is released. Troponin binds calcium and tropomyosin moves. Cross bridge/POWERSTROKE. Muscle contraction.

Front 40

ACh antagonist

Back 40

inhibits ACh

Front 41

What are the ACh antagonists?

Back 41

Curare and atropine

Front 42

ACh agonist

Back 42

blocks the inhibitors

Front 43

What are the ACh agonists

Back 43

Nicotine

Front 44

What is the blocking vesicle toxin?

Back 44

Botulinium

Front 45

What is the release vesicle toxin

Back 45

black widow venom

Front 46

What is the blocking inhibitory neuron toxin and what does it do?

Back 46

Tetanus. It stops other muscles from relaxing.

Front 47

Isometric contraction

Back 47

the bones do not move and the whole muscle stays the same length

Front 48

Isotonic contraction

Back 48

The muscle shortens or lengthens and the bones move

Front 49

If you are holding a book stationary in the air, what muscle contraction are you using?

Back 49

Isometric

Front 50

If you are lifting a book what muscle contraction are you using?

Back 50

Isotonic

Front 51

Elastic components

Back 51

components at the end of muscle to keep the muscle from tearing itself apart

Front 52

How much stretching does isometric twitching cause?

Back 52

Slight

Front 53

How much stretching does isotonic twitching cause?

Back 53

More than isometric.

Front 54

Isotonic eccentric contracton

Back 54

stretch muscle outward so another part can contract

Front 55

What is the length-tension relation?

Back 55

There is a perfect length of contraction which the muscle has. Between 2 and 2.25 um.