A&p I Exam 2 Review

Front 1

In Skeletal muscle Ca⁺⁺ is released and then binds to troponin. What does Ca bind to in smooth muscle?

Back 1

Calmodulin

Front 2

Skeletal muscle makes up what % of total body weight?

Back 2

40%

Front 3

Smooth muscle makes up what % of total body weight?

Back 3

10%

Front 4

T or F. The skeletal muscle fiber is spherical in shape?

Back 4

False.
It is cylindrical in shape.

Front 5

The muscle cell membrane and the outer collagen layer are what make up the:

Back 5

Sarcolema

Front 6

This outer layer of the muscle fiber fuses the muscle fibers with the the tendons.

Back 6

Collagen layer

Front 7

What electrically insulates each individual muscle fiber from each other?

Back 7

The Sarcolema

Front 8

There are hundreds to many thousands of these in each muscle fiber.

Back 8

Myofibrils

Front 9

Myofibrils are organelles specialized to do what?

Back 9

They are specialized for contraction or shortening of the muscle cell.

Front 10

Myofibrils are made up of 2 different interdigitating filaments named.

Back 10

Actin and Myosin

Front 11

Which myofibril is your favorite myofibril?

Back 11

Mine too.

Front 12

What part of the myosin filament interacts with the active sites of the actin filament.

Back 12

The cross-bridges

Front 13

The I band has which myofilament only.

Back 13

Actin

Front 14

T or F. The A band has overlapping myosin and actin filaments

Back 14

True

Front 15

Which myofilament, actin or myosin, attaches to the Z disk?

Back 15

Actin

Front 16

The Sarcomere is defined as

Back 16

the fundamental contractile subunit of the myofibrils, and is the region between the Z disks.

Front 17

In skeletal muscle, the resting length is approximately 2.0 microns. Why do we care?

Back 17

Because at the length of 2 microns, it is at the length that allows for the greatest number of interactions between actin and myosin to occur during muscle contraction.

Front 18

Skeletal muscle is what size range in diameter?

Back 18

10-80 microns

Front 19

Smooth muscle is what size range in diameter?

Back 19

1-5 microns

Front 20

Skeletal muscle fibers are electrically insulated from each other. Which type of smooth muscle is as well?

Back 20

Multiunit smooth muscle.

Front 21

Can each multiunit smooth muscle fiber contract independently from each other?

Back 21

Yes because like skeletal muscle, they too are electrically isolated from each other.

Front 22

What are the two types of principal smooth muscles

Back 22

1. Multiunit
2. Visceral (unitary)

Front 23

Dense bodies are analogous to what in skeletal muscle?

Back 23

Z disks

Front 24

A skeletal muscle fiber is innervated by how many motor neurons?

Back 24

One

Front 25

Smooth muscles do not have a striated appearance because they do not have what?

Back 25

Sarcomeres

Front 26

Cytoplasm is what in muscle cells?

Back 26

Sarcoplasm

Front 27

Endoplasmic reticulum is called what in the muscle cell?

Back 27

Sarcoplasmic reticulum

Front 28

The sarcoplasmic reticulum is very extensive in slow contracting or rapid contracting muscle cells?

Back 28

Rapidly contracting

Front 29

The Sliding filament model of actin myofilaments depicts the contraction as a passive process, but is it?

Back 29

No. The actin are pulled inward, they don't just slide inward.

Front 30

The actin myofilament is made up of 2 primary protein components that wrap around each other and contain active sites. What are the components?

Back 30

F-actin

Front 31

Tropomyosin covers the active sites while the muscle is in what state?

Back 31

Relaxation

Front 32

The myosin head groups have what kind of activity?

Back 32

ATPase activity

Front 33

Is the ATP needed to make the myosin head group interact with the actin active sites, or to pull the head into the ready position?

Back 33

For pulling the head group into the ready position.

Front 34

ATPase enzymes need what intracellular cation to be active?

Back 34

Magnesium

Front 35

Blah Blah Blah. Ba Blah Blah Blah.

Back 35

6 Blahs and a Ba.

Front 36

Contracting against a load that is too great, maximum tension is generated, but the the muscle as a whole does not shorten, is what type of contraction?

Back 36

Isometric

Front 37

What type of contraction happens when muscle shortens and moves a load while maintaining a constant tension.

Back 37

Isotonic

Front 38

T or F. Inertia is involved in an isotonic contraction

Back 38

True

Front 39

About how many secretory vesicles are there in the terminal axon?

Back 39

300,000

Front 40

In each secretory vesicle, there are about how many molecules of acetylcholine?

Back 40

10,000

Front 41

Describe the whole process of the release of acetylcholine starting with an action potential arriving and ending with acetylcholine being hydrolyzed.

Back 41

1. An action potential travels down the axon.
2. Voltage gated Ca⁺⁺ channels are stimulated to open allowing it into the cell (terminal axon).
3. Ca⁺⁺ stimulates a certain number of the secretory vesicles to release (exocytocytosis) acetylcholine.
4. Acetylcholine diffuses across the synaptic cleft (20-30microns away), and binds to the acetylcholine receptors (dual function protein = ligand gated non-selective ion channel)in the motor end plate.
5.Na⁺ moves into the cell and causes the muscle it to depolarize = an end plate potential.

Front 42

On skeletal muscle, acetylcholine receptors are what kind of receptor (just the name)?

Back 42

Nicotinic

Front 43

How wide is the synaptic cleft?

Back 43

20-30 microns

Front 44

What happens to acetylcholine after it is used?

Back 44

Acetylcholinesterase floating in the synaptic cleft hydrolyze it.

Front 45

The physical length of smooth muscle is short at about what length?

Back 45

20 to 500 microns = .5mm

Front 46

Skeletal muscle is a lot longer the skeletal muscle cell can run the length of

Back 46

the muscle.

Front 47

Give examples of where multiunit smooth muscles are found in the body.

Back 47

In the pupil (ciliary muscle), or piloerector muscles

Front 48

Multiunit muscles are controlled by the ________ nervous system.

Back 48

autonomic

Front 49

Gap Junctions are found in which type of smooth muscle?

Back 49

Visceral

Front 50

A collection of visceral smooth cells can depolarize and contract as a unit because a wave of depolarization can pass from one cell to the next due to Gap Junctions. This collection is called a..

Back 50

..functional syncytium

Front 51

How much time is the onset of smooth contraction? (Spike Potential duration)

Back 51

50-100 miliseconds

Front 52

How long is the duration of a smooth muscle contraction?

Back 52

1-3 seconds

Front 53

Resting membrane potential of smooth muscle is..

Back 53

-50mV to -60mV

Front 54

The resting membrane potential is less negative because these cells are more...

Back 54

permeable to Na⁺

Front 55

Skeletal action potentials last .5-1 milisecond. About how long is a smooth muscle spike action potential?

Back 55

50 miliseconds

Front 56

In smooth muscle, what kind of action potential would provide for a prolonged muscle contraction?

Back 56

Plateau

Front 57

The autonomic nerve endings in smooth muscle are called..

Back 57

axon varicosities VS. motor end plates in skeletal muscle.

Front 58

Neurotransmitter binding to the smooth visceral muscle cell causes a ___________ potential.

Back 58

junctional
VS end plate potentials like in skeletal muscle.

Front 59

Threshold of smooth visceral muscle is

Back 59

-70mV