4. Skeletal Muscle and Nerve Tissue

Question 1

Where is calcium stored within a muscle?

Answer 1

In the Sarcoplasmic Reticulum

Question 2

How many dendrites and axons for a bipolar neuron?

Answer 2

Single dendrite (with multiple extensions) and one axon

Question 3

What is the function of gamma motor nerve fibers?

Answer 3

Contraction of the intrafusal muscle fibers in response to the Neuromuscular Spindle Apparatus detecting an excessive stretch

Question 4

What two chains does Myosin have?

Answer 4

Heavy chain with a globular head

Light chain

Question 5

From smallest unit to largest, what are the divisions of a muscle?

Answer 5

Sarcomere -> Myofibrils -> Myocyte (Myofiber) -> Fascicle -> Muscle

Question 6

What does Tropomyosin do?

Answer 6

Wraps between actin strands and holds troponin

Question 7

What is this type of neuron?

Answer 7

Multipolar

Question 8

What is marked here as 2?

Answer 8

A Band

Question 9

What connects the Transverse Tubule to the Terminal Cisternae?

What do they do?

Answer 9

“End Feet”

Allow for calcium release

Question 10

What is actin made of?

Answer 10

G-Actin Monomers

(globular protiens)

Question 11

What features can be used to identify Skeletal Muscle?

Answer 11

Peripheral nucleii

Striations

Multiple nucleii

Question 12

What is this type of neuron?

Answer 12

Pseudounipolar

Question 13

What is this type of neuron?

Answer 13

Bipolar

Question 14

What two regions of a Myofibril shorten during muscle contraction?

Answer 14

The H Zone and the I Band

Question 15

Where do Oligodendrocytes operate?

Answer 15

CNS

Question 16

What makes up the “thick filament” of a muscle fiber?

Answer 16

Myosin

Question 17

What is Sarcoplasmic Reticulum?

Answer 17

Tubular system which acts like smooth ER.

Question 18

Do Schwann cells wrap around parts of single axons or many axons together?

Answer 18

Parts of a single axon

Question 19

What keeps the muscles from contracting all the time?

Answer 19

Tropomyosin blocks the myosin binding sites

Question 20

Where are myosin going one direction attached to the myosin going the other direction?

Answer 20

M line / M disc

Question 21

What is the function of the Axon Hillock?

Answer 21

Sums up all of the action potentials from the dendrites, and sends a signal down the axon if it is sufficient.

Question 22

What is an intrafusal muscle fiber?

Answer 22

Muscle fiber that senses length and rate of change of a muscle

Question 23

Do Oligodendrocytes wrap around parts of single axons or many axons together?

Answer 23

Many axons together

Question 24

What is the connective tissue layer surrounding the outside of the entire spinal nerve?

Answer 24

Epineurium

Question 25

What makes up the "thin filament" of a muscle fiber?

Answer 25

Actin

Question 26

How many dendrites and axons for a multipolar neuron?

Answer 26

Multiple dendrites, one axon

Question 27

What is a Type 1A sensory nerve fiber?

Answer 27

Afferent innervation to an intrafusal muscle fiber (sends strech sensory information to the spine)

Question 28

What are the basic characteristics of type 2 muscle fibers?

Answer 28

Less mitochondria than type 1 More explosive contractions Fatigues quickly Less myoglobin

Question 29

What determines the length of an Actin filament?

Answer 29

Nebulin

Question 30

What is an extrafusal muscle fiber?

Answer 30

Muscle fiber under voluntary control, in charge of contracting the muscle fibers.

Question 31

What is marked here as 4?

Answer 31

M Line

Question 32

What are the basic characteristics of Type 1 muscle fibers?

Answer 32

Low fatigability Slow Contraction Abundant Myoglobin for O2 Very Aerobic Many Mitochondria

Question 33

What fascial covering covers the fascicles?

Answer 33

Perimysium

Question 34

What are Transverse (T) Tubules?

Answer 34

Bits of Sarcolemma (membrane) that penetrate the cell.

Question 35

What are the characteristics of a pseudounipolar neuron?

Answer 35

A cell body connected to a cell process with a dendrite branch and an axon branch.

Question 36

What serves as the defined border of a sarcomere?

Answer 36

Z disks

Question 37

What is the Sarcoplasm?

Answer 37

Cytoplasm of a muscle cell

Question 38

Does the A Band shorten during contraction?

Answer 38

No. Only the H Zone and the I band shorten

Question 39

What does Calcium do to incite muscle contraction?

Answer 39

It binds to Troponin, which then causes Tropomyosin to change conformation, and no longer block the Myosin binding sites on the Actin Filament

Question 40

What connective tissue layer wraps a single myelinated or unmyelinated axon?

Answer 40

Endoneurium

Question 41

What is marked here as 1?

Answer 41

I Band

Question 42

What is the Sarcolemma?

Answer 42

The membrane around myocytes that penetrates the muscle cell as T tubules

Question 43

What all is contained within the H Zone?

Answer 43

Myosin fibers and the M line

Question 44

Why is it important to have electrical impulses shuttled into the cell?

Answer 44

So that the myocyte can contract all at once, instead of from the outside in.

Question 45

What is the function of Alpha-Motor nerve fibers?

Answer 45

Sends the signal to contract to a muscle

Question 46

What attaches to the Z disk?

Answer 46

Actin and Titin (which in turn holds myosin)

Question 47

What is marked here as 5?

Answer 47

Z Disk

Question 48

What is contained within the I band?

Answer 48

Actin The Z Disk (straddles sarcomeres)

Question 49

What is defined as the A band?

Answer 49

Distance from end to end of myosin within one sarcomere.

Question 50

What fascial covering covers the myofibers?

Answer 50

Endomysium

Question 51

What fascial covering surrounds the muscle itself?

Answer 51

The epimysium

Question 52

What is marked here as 3?

Answer 52

H Zone

Question 53

What holds the Myosin to the Z disk, thus holding Myosin in place?

Answer 53

Titin protiens

Question 54

What connective tissue layer wraps a fascicle of nerve fibers together?

Answer 54

Perineurium

Question 55

What are Terminal Cisternae?

Answer 55

Flattened sacs of sarcoplasmic reticulum laying alongside the T tubules.

Question 56

Where do Schwann cells operate?

Answer 56

Peripheral Nervous System

Question 57

How many nerves innervate one myofiber? How many fibers might one nerve innervate?

Answer 57

1 More than one