Exercise 12 Skeletal Muscle Structure

Question 1

What is the structure that is surrounds individual skeletal muscle by a layer of areolar connective tissue?

Answer 1

Endomysium

Question 2

What is the structure called in which skeletal muscle fibers are grouped into bundles?

Answer 2

Fascicles

Question 3

What surrounds the fascicles by a layer of dense irregular connective tissue?

Answer 3

Perimysium

Question 4

A muscle is formed from a number of fascicles that are surrounded by a dense regular connective tissue layer called..

Answer 4

Epimysium

Question 5

_______ are connective tissues that attach the muscle to bone.

Answer 5

Tendons

Question 6

Skeletal muscle tissue contains elongated cells called..

Answer 6

Muscle fibers or cells

Question 7

The plasma membrane in muscle fibers can conduct an electrical signal called an action potential is called…

Answer 7

Sarcolemma

Question 8

The __________ ___________ is endoplasmic reticulum that is specialized to store Ca ions.

Answer 8

Sarcoplasmic reticulum

Question 9

Tube-like invaginations that transmit the action potential deep inside the fiber to widened areas of the sarcoplasmic reticulum called terminal cisternae.

Answer 9

T-tubules

Question 10

__________ is the smallest structural and contractile unit of a muscle myofibril composed of thick and thin filaments. Shortens when muscles fiber is stimulated to contract.

Answer 10

Sarcomere

Question 11

________ molecules make up the majority of the thin filament and contain a binding site for the myosin molecules of thick filament.

Answer 11

Actin

Question 12

A strand of ________ molecules is nestled between the actin molecules.

Answer 12

Tropomyosin

Question 13

Several _______ molecules bind at precise intervals along the tropomyosin strand.

Answer 13

Troponin

Question 14

Thick filaments are composed of ________ molecules that appear golf club-like

Answer 14

Myosin

Question 15

When myosin heads attach to actin, they are called..

Answer 15

Crossbridges

Question 16

While looking at a model of contractile proteins, which is the actin?

Answer 16

The helix formation of rounded proteins covered by tropomyosin. These are uncovered when troponin moves the tropomyosin out of the way.

Question 17

While looking at a model of contractile proteins, which is the tropomyosin?

Answer 17

The long strands that surround actin and covers actin. This is moved by troponin so the myosin heads can bond to actin during the power stroke.

Question 18

While looking at a model of contractile proteins, which is the troponin?

Answer 18

The protein that moves the tropomyosin away from the actin. Oval-like balls occurring every now and then on the helix actin.

Question 19

The lighter colored bands with a dark stripe down the middle are the __________.

Answer 19

I bands

Question 20

The stripes that secure the thin filaments are __________

Answer 20

Z discs

Question 21

__________ are dark-colored bands that extend the length of the thick filaments.

Answer 21

A band

Question 22

In the A band of a relaxed muscle, thin filaments overlap the thick filaments except in the middle of the A band, the _________, which appears lighter.

Answer 22

H zone

Question 23

The ___________ is found in the middle of the H zone and secures the thick filaments.

Answer 23

M line

Question 24

Each skeletal muscle fiber is stimulated to contract by a ________ ________

Answer 24

Motor neuron

Question 25

Within the muscle, the axon of a motor neuron divides into many branches or _________ __________.

Answer 25

Axon Terminals

Question 26

At the neuromuscular junction, each axon terminal divides into ___________ ______ _________.

Answer 26

Synaptic end bulbs

Question 27

Within the synaptic end bulbs are ________ __________ filled with acetylcholine (neurotransmitter molecules)

Answer 27

Synaptic vesicles

Question 28

What is the synaptic cleft?

Answer 28

The space between the synaptic end bulb and the sarcolemma.

Question 29

What is the motor end plate?

Answer 29

The region of the sarcolemma directly across from the synaptic end bulb.