Musculo syst

Question 1

What are the three types of muscles?

Answer 1

Skeletal muscle, Smooth muscle, Cardiac muscle

Question 2

What nervous system innervates skeletal muscle?

Answer 2

Somatic nervous system

Question 3

What gives skeletal muscle its striated appearance?

Answer 3

Sacromeres (arrangement of actin and myosin into repeating units)

Question 4

Why is skeletal muscle multinucleated?

Answer 4

It is formed as individual muscles fuse into long rods during development

Question 5

What characterizes red-fibers/slow-twitch fibers?

Answer 5

High myoglobin content, derive energy aerobically, contain many mitochondria, carry out oxidative phosphorylation

Question 6

What characterizes white fibers/fast-twitch fibers?

Answer 6

Less myoglobin, less iron, lighter color, can contract rapidly but fatigue quickly

Question 7

What is the function of tendons?

Answer 7

Anchor muscle to bones

Question 8

What is a sacromere?

Answer 8

Basic contractile unit of skeletal muscle

Question 9

What are the thick filaments in a sacromere made of?

Answer 9

Bundles of myosin

Question 10

What are the thin filaments in a sacromere made of?

Answer 10

Actin, troponin, tropomyosin

Question 11

What role does titin play in muscle structure?

Answer 11

Acts as a spring, anchors actin & myosin filaments together

Question 12

What is the Z-line in a sacromere?

Answer 12

Boundary of each sacromere

Question 13

What is the A-band in a sacromere?

Answer 13

Full thick filaments with any overlap with thin filaments

Question 14

What happens to the A-band during muscle contraction?

Answer 14

It remains constant in size

Question 15

What is myogenic activity?

Answer 15

Contracting of smooth muscles without nervous system input

Question 16

Where is smooth muscle found?

Answer 16

Respiratory tree, Digestive tract, Bladder, Uterus, Blood vessel walls

Question 17

What is the role of intercalated discs in cardiac muscle?

Answer 17

Contain gap junctions allowing rapid & coordinated depolarization

Question 18

What is the primary function of cardiac muscle?

Answer 18

Involuntary contraction

Question 19

What initiates the depolarization in cardiac muscle?

Answer 19

SA node

Question 20

What neurotransmitter slows the heart rate?

Answer 20

Acetylcholine from the vagus nerve

Question 21

What effect does norepinephrine have on the heart?

Answer 21

Increases heart rate and greater contractility

Question 22

Fill in the blank: Calcium release from the _______ triggers muscle contraction.

Answer 22

Sarcoplasmic reticulum

Question 23

What happens when acetylcholine binds to the sarcolemma?

Answer 23

Opens Na channels, starting an action potential

Question 24

What is the sarcoplasmic reticulum?

Answer 24

Modified ER covering that surrounds the myofibrils

Question 25

What is the role of T-tubules?

Answer 25

Propagate action potentials and distribute them to all sacromeres

Question 26

What occurs after calcium ions bind to troponin?

Answer 26

Tropomyosin is moved out of the way, allowing myosin to bind to actin

Question 27

What is tonus in smooth muscle?

Answer 27

A constant state of low level contractions

Question 28

tetanus

Answer 28

muscle is unable to relax due to too frequent contractions

Question 29

Latent period

Answer 29

The time between reaching the threshold and the onset of contraction

Question 30

Simple twitch

Answer 30

Response of single muscule fiber to abbreviate stimulus at the threshold or above it

Question 31

Frequency summation

Answer 31

Frequent and prolonged contractions combined and become stronger and more prolonged

Question 32

What happens to the sarcolemma during relaxation?

Answer 32

It repolarizes

Question 33

What happens to the acetylcholine during relaxation?

Answer 33

It gets degraded by acetylcholinestrase

Question 34

what happens on the sarcolemma when acetylcholine is released?

Answer 34

Na channels open and Na enters the muscle cell

Question 35

Till where do these Na channels open?

Answer 35

till the T-tubule

Question 36

what happens when calcium is released from these sarcoplasmic reticulum?

Answer 36

It attaches to the troponin, which loses the tropomyosin & opens the actin for myosin to bind

Question 37

What happens when ATP attaches to myosin?

Answer 37

Myosin of detaches from the actin

Question 38

What happens to myosin when it hydrolyzes ATP?

Answer 38

It enters high energy state

Question 39

How does myosin bring back and pushes on actin?

Answer 39

it does this when P group is released

Question 40

What happens to the actin when calcium is there?

Answer 40

Calcium binds to troponin which loosens tropomyosin and opens actin for myosin to bind

Question 41

Oxygen debt

Answer 41

the difference between the amount of oxygen needed by the muscles - the actual amount present

Question 42

What are the two reserves muscles have for energy?

Answer 42

creatine phosphate and myoglobin

Question 43

When does muscle become fatigue?

Answer 43

When it starts to produce lactic acid

Question 44

what are the reserves of slow Twitch red muscles?

Answer 44

They use oxidative phosphorylation to make ATP because they have high levels of mitochondria

Question 45

what are the reserves of fast twitch red muscles?

Answer 45

they rely on glycolysis and fermentation to make ATP because they have less mitochondria

Question 46

What happens to oxyhemoglobin curve during exercise?

Answer 46

It shifts to the right Increase concentration of carbon dioxide, hydrogen ions, body temperature

Question 47

How is lactic acid metabolized?

Answer 47

It is converted to pyruvate It needs more oxygen for this

Question 48

muscle spasticity

Answer 48

a condition where muscles become stiff, tight, and resistant to movement

Question 49

Influx

Answer 49

entry of large number of molecules

Question 50

invasive

Answer 50

tending to spread in a quick and aggressive manner