Chapter 8- Skeletal Muscle Mechanism

Question 1

How do filaments on smooth muscle differ from filaments on skeletal?

a. They contain 2 M-lines
b. they cannot bind to actin sites
c. they do not have troponin
d. all the above

Answer 1

c.

Question 2

Trypomyosin does not block actin from binding
True/False

Answer 2

true

Question 3

The thick filaments of smooth muscle contain…
a. calmodulin
b. light chain kinase
c. PTSD
d. all above

Answer 3

b

Question 4

**

Describe how contraction is regulated in smooth muscle

Answer 4

Ca+ activates calmoduin changing it to a bent conformation. This allows the bent calmoduin to bind and activate myosin light chain kinase. The kinase phosphoralates the light chain on myosin which activates myosin to bind to actin. If there is no Ca+ then no phosphorilation and therefore no myosin binding.

Question 5

Smooth muscles don’t have T-tubules.
True/False

Answer 5

True

Question 6

Where do V-gated Ca++ channels reside in smooth muscle?
a. T-tubules
b. Sacromeres
c. Plasma membrane
d. Sarcoplasmic reticulum

Answer 6

c.

Question 7

When Ca++ binds to and opens Ca++ gated ryandine receptors
a. SERCA
b. CICR
c. Tonic SM
d. MLCK

Answer 7

b

Question 8

Lable the steps of Ca++ regulation in order
Calcium enters the cell
Ca++ binds to ryandine receptors
Depolarization
Ca++ released from S.R.
V-gated Ca++ channels open
G-protien coupled receptors activate
IP3-gated channels on S.R. open
GPCR’s release IP3 messagers

Answer 8

3
5
1
4
2
6
8
7

Question 9

What pumps Ca++ back into the S.R. in smooth and skeletal muscle?

Answer 9

SERCA Pump

Question 10

What are the 2 types of smooth muscle?

Answer 10

multi-unit and single-unit

Question 11

List the characteristics of single unit smooth muscle

Answer 11

1. Contain gap junctions
2. only some of the cells recieve direct neural signals
3. found in the intestines

Question 12

List the characteristics of multi-unit smooth muscle.

Answer 12

1. found in the eye
2. individual cells recieve drect neural signals
3. contracts independantly

Question 13

Which of the following means a cell is capable of initiating it’s own contration?
a. Myogenic
b. CIRC
c. Ryanocidic
d. Miogenic

Answer 13

a.

Question 14

What are the 2 types of myogenic excitation potentials?

Answer 14

pacemaker and slow-wave

Question 15

Slow wave potential is only seen in ….
a. Skeletal muscle
b. The digestive tract
c. Smooth muscle
d. A and B

Answer 15

b.

Question 16

Draw slow-wave potential triggering an action potential

Answer 16

Week 6 slide 2
The smooth muscle alternates between depolarization and repolarizations

Question 17

____ can nudge the starting Vm so that slow-wave may reach threshold

a. peptides
b. hormones
c. nucleotides
d. Ca++

Answer 17

b.

Question 18

How is smooth muscle well suited for long-term contraction?

a. it consumes less ATP
b. it has slow removal of Ca++
c. troponin doesn’t cross bridge
d. A and B

Answer 18

d.

Question 19

How is smooth musc. suited for moving contents through hollow organs

a. consumes less ATP
b. exerts tesion even when stretched
c. it’s striated with gap junctions
d. it contains a sliding filament system

Answer 19

b.

Question 20

List the 5 features of Cardiac Muscle

Answer 20

1. excitable cells
2. striated with gap junctions
3. sliding filament system
4. involantary movement
5. Ca++ release via CICR

Question 21

The gap junctions found in skeletal and cardiac musc. are the same

true/false

Answer 21

False

Question 22

cardiac muscles have T-tubules

true/false

Answer 22

true

Question 23

Describe Cardiac Ca++ release

Answer 23

week 6 slide 5
T-tubules contain many voltage gated Ca++ channels which open when the AP is triggered. This is however, not enough to cause contraction so the Ca++ binds to a Ryandine receptor inside the muscle cell. This triggers a Ca++ release from the SR which is enough to trigger AP

Question 24

Cardiac musc. fibers do not extend the length of the entire muscle

true/false

Answer 24

true

Question 25

**Describe the structure of cardiac muscle**

Answer 25

They are branched and cnnected by intercalated disks. The boundy of the cell is at the disks.

Question 26

(------) attach muscle to bones a. ligaments. b. Tendons. c. Muscle fiber. d. all above.

Answer 26

b

Question 27

series elastic component involves... a. tension generated by sacromeres and transmitted to bone by tendon. b. contraction is generated by muscle fibers after signaling to the motor end plate. c. an external load is pulled by tendons and stretched across a joint. d. a and c

Answer 27

a

Question 28

muscles push never pull true/false

Answer 28

false

Question 29

what are the 3 types of contraction?

Answer 29

1. isotonic 2. isokinetic 3. isometric

Question 30

Match the definations to thier type of contraction Load is constant, muscle length changes velocity is constant, muscle length changes length is constant, tesion increase

Answer 30

1. isotonic 2. isokinetic 3. isometric

Question 31

varying amount of force generated in a whole muscle a. tension b. tetanus c. graded contration d. fatigue

Answer 31

c

Question 32

what are the two primary factors that influence force generation?

Answer 32

1. # of muscle fibers 2. Tension developed by each fiber

Question 33

List the factors that influence muscle tension

Answer 33

1. frequency of stimulation 2. Resistance to fatigue. 3. Length of fiber at onset of contraction 4. Thickness of the fiber.

Question 34

Draw a single twitch

Answer 34

question 9 notebook

Question 35

Draw what twitch summation looks like on a graph

Answer 35

week 5 slide 27

Question 36

all fibers associated with a single motor neuron a. Muscle unit. b. Motor unit. c. Neural unit. d. None of the above.

Answer 36

b

Question 37

which of the following best describes the relationship between muscle fibers and motor neurons a. Each motor neuron only innervates one muscle fiber. b. Each motor neuron branches to one motor neuron. c. Each motor neuron innervates many muscle fibers, but can choose to contract a certain number. d. Each motor neuron contracts, all associated fibers.

Answer 37

d

Question 38

strength of contraction is determined by (--------) a. Size of load. b. Number of motor units recruited c. Size of the muscle fiber. d. Number of motor neurons.

Answer 38

b

Question 39

which of the following vary from contraction to contraction? a. frequency of stimulation. b. Resistance to fatigue. c. Thickness of fiber. d. Size of load. e. a and d

Answer 39

a

Question 40

smooth sustained contraction at maximal strength due to rapid stimulation a. tetanus b. Twitch summation. c. Tension. d. Fatigue

Answer 40

a

Question 41

Draw Tetanus

Answer 41

question 16 in notebook

Question 42

why is it not ideal for muscle fibers to be longer? a. Thin filaments, overlap, interfering with cross bridge. b. Actin sites are pulled away from myosin. c. Maximum Crossbridge generates maximum tension. d. b and c

Answer 42

b

Question 43

what two factors that influence muscle tension are constant?

Answer 43

resistance to fatigue and fiber thickness

Question 44

which four steps in contraction use ATP?

Answer 44

1. Power stroke. 2. Cross bridge. 3. SERCA 4. Na/K pump

Question 45

The ATP supply comes from a. Hydrolysis. b. Glycolysis. c. My light chain. d. All of the above.

Answer 45

b

Question 46

which is not a pathway that supplies ATP to muscle muscles a. Creatine phosphorylation. b. Glycolysis. c. Oxidative phosphorylation. d. Oxygen hydrolysis.

Answer 46

d

Question 47

you are a sprinter about to run a race. Once you start, where does your energy mostly come from? a. Glycolysis. b. Oxidative phosphorylation. c. Creatine phosphorylation. d. all of the above

Answer 47

c

Question 48

Creatine acts as a (-------)?

Answer 48

storage molecules

Question 49

In an aerobic enviorment which of the following occur? a. glycolysis b. ox-phos c. creatine phos d. all of the above

Answer 49

b

Question 50

Which ATP source wold be utilized most on a long walk?

Answer 50

oxidative phosphorylation

Question 51

Lable each characteristic as Glycolysis (G), Ox-phos (O), or Creatine phos (CP) 1. 1st source of ATP 2. anaerobic 3. aerobic 4. susbstitutes ox-phos 5. used in long term exercise 6. only works in presence of glucose 7. used in short, high intensive activity 8. fueled by glucose/fatty acids 9. slowest 10. storage for O2 11. shortest duration

Answer 51

1. CP 2. G 3. O 4. G 5. O 6. G 7. CP 8. O 9. O 10. CP 11. G

Question 52

occurs when the muscle can no longer respond to stimuli with the same amount of contration a. tetanus b. fatigue c. frequency d. graded contraction

Answer 52

b

Question 53

list the 3 main factors that contribute to muscle fatigue

Answer 53

1. local increase in inorganic phosphate 2. leakage of Ca+ out of the cell 3. depletion of glycogen stores

Question 54

a motor unit can be composed of 2 or more types of fibers true/false

Answer 54

false

Question 55

motor units have the ability to interconvert between fiber types true/false

Answer 55

true

Question 56

list the 3 major types of muscle fibers

Answer 56

1. slow-oxidative 2. fast oxidative 3. fast glycolytic

Question 57

which of the following use oxidation as it's ATP source? a. type I fibers b. type IIa fibers c. type IIx fibers d. a and c

Answer 57

b

Question 58

which of the skeletal muscle fiber types use glycolysis as their ATP source?

Answer 58

type IIx fibers

Question 59

fast fibers have lower myosin ATPase activity than slow true/false

Answer 59

false

Question 60

which is not a factor that influences the speed of contraction? a. size of load b. atp source utilized c. type of fiber d. none of the above

Answer 60

d

Question 61

how does myosin ATPase influence the speed of contraction?

Answer 61

the faster is can reset the faster cross bridging can re-trigger

Question 62

label whether each characteristic belongs to oxidative fibers or glycolitic fibers? 1. few mitochondria 2. glycogen stores 3. lots of myoglobulin 4. lots of glycolytic enzymes 5. lots of mitochondria 6. lots of capillaries

Answer 62

1. GF 2. GF 3. OF 4. GF 5. OF 6. OF

Question 63

Which types of muscles are involuntary?

Answer 63

unstriated and cardiac

Question 64

smooth muscle is regulated by the sympathetic nervous system true/fasle

Answer 64

f

Question 65

smooth muscle is striated true/false

Answer 65

f

Question 66

smooth muscle uses myosin, actin, trypomyosin, and troponin true/false

Answer 66

f

Question 67

smooth muscle releases Ca+ using multiple mechanisms true/false

Answer 67

t

Question 68

list some places where smooth muscle is found

Answer 68

blood vessels, airways, eyes, uterus, stomach

Question 69

why doesnt smooth cells appear striated?

Answer 69

they have no sacromeres

Question 70

describe the structure of smooth muscle cells

Answer 70

question 45