Body Plan 08: Muscle

Question 1

What are the four major properties of muscle?

Answer 1

1) Excitable
2) Contractible
3) Extensible
4) Elastic

Question 2

What are the three major functions of muscle?

Answer 2

1) Motion
2) Posture
3) Heat

Question 3

Myoblasts

Answer 3

Differentiate from mesenchymal cells; proliferate through mitosis

Question 4

What are the three types of muscles?

Answer 4

Skeletal, cardiac, smooth

Question 5

What are the characteristics of skeletal muscle?

Answer 5

Develop from somites, varied in length, syncytium, peripheral nuclei, striated, long and cylindrical fibers

Question 6

What is the hierarchical structure of skeletal muscles?

Answer 6

Muscle tissue contains muscle fibers which contain myofibril

Question 7

Sarcolemma

Answer 7

The cell membrane of a muscle fiber

Question 8

Sarcomere

Answer 8

The contractice unit of muscle, runs z-line to z-line

Question 9

Myofilaments

Answer 9

The two filaments of muscle: actin and tropomyosin

Question 10

I-band

Answer 10

The section of the sarcomere that only contains thin filaments; shrinks during contraction

Question 11

Z-disc/Z-line

Answer 11

Located in the I-band, it is the border between two sarcomeres

Question 12

A-band

Answer 12

The section of sarcomere that is not the I-band. The outer edges contain thin and thick filaments

Question 13

H-zone

Answer 13

The section of the sarcomere in the middle of the A-band, where only thick filaments reside; shrunk during contraction

Question 14

M-line

Answer 14

Running directly in the middle of the sarcomere, this section has thick filaments

Question 15

Sarcoplasmic reticulum

Answer 15

Modified endoplasmic reticulum that stores calcium in muscles

Question 16

Epimysium

Answer 16

The connective tissue that surrounds the muscle

Question 17

Perimysium

Answer 17

The connective tissue that surrounds the fasciculi

Question 18

Endomysium

Answer 18

The connective tissue that surrounds individual muscle fibers. It is the basal lamina of the cell

Question 19

Dystrophin

Answer 19

A protein expressed in sarcolemma that complexes with glycoproteins to connect contractile machinery to the endomysium

Question 20

Duchenne muscular dystrophy

Answer 20

Absence of dystrophin; results in irregularity of muscle fiber sizes and internalized nuclei

Question 21

Motor unit

Answer 21

A motor neuron and all of the muscle fibers that it innervates

Question 22

What are the three skeletal muscle types?

Answer 22

Type 1, Type 2A, Type 2X

Question 23

What are some characteristics of cardiac muscles?

Answer 23

Branching and striated; 1-2 centrally located nuclei; can be irregular

Question 24

Where do cardiac muscles derive from?

Answer 24

Splanchnic mesoderm

Question 25

Intercalated disks

Answer 25

Unique to cardiac muscles, these disks connect different cardiac muscles together to contract as one unit

Question 26

Fasciae adherentes

Answer 26

Anchor actin filaments in cardian intercalated disks

Question 27

Maculae adherentes

Answer 27

Desmosomes of the cardiac muscle

Question 28

Where do smooth muscles derive from?

Answer 28

Splanchnic mesoderm

Question 29

What are some characteristis of smooth muscles?

Answer 29

One central nucleus, not striated, fusiform, involuntary contraction