Muscle Tissue

Question 1

What is the function of Muscle?

Answer 1

• Movement
• Maintain posture and body position
• Support soft tissues
• sphincters at entrances and exits of certain organ systems
• maintain body temperature

Question 2

What is muscle tissue specialized for?

Answer 2

contraction

Question 3

What usually happens during contraction?

Answer 3

thin actin and thick myofilaments slide pat each other

Question 4

3 different types of muscle

Answer 4

• Skeletal
• Cardiac
• Smooth

Question 5

What are skeletal muscle cells called?

Answer 5

myofibers or other things

-they come together to form fascicles

Question 6

What are myofibers separated by?

Answer 6

endomysium

Question 7

What are fascicles?

Answer 7

bundles of myofibers that are separated by CT called perimysium

Question 8

What is the epimysium?

Answer 8

dense irregular CT that surrounds a collection of fascicles forming an entire muscle

Question 9

What are the CT sheaths continuous with?

Answer 9

Tendons

-these insert onto bones and transmit the force of the entire muscle onto bone

Question 10

What provides the avenue for blood and nerves to myofibers?

Answer 10

CT

Question 11

Are skeletal muscle cells multinucleated?

Answer 11

yes, because they were formed by fusion of several hundred embryonic myoblast precursor cells

Question 12

where are the nuclei in skeletal muscle cells?

Answer 12

in the periphery

-the cytoplasm in occupied by myofibrils

Question 13

What are myofibrils?

Answer 13

actin microfilaments and thick myosin filaments that form repeating functional units called sarcomeres
-make up 80% of volume of cell

Question 14

What is the plasma membrane of a muscle cell referred to as?

Answer 14

the sarcolemma

Question 15

What are the boundaries of a sarcomere?

Answer 15

the Z-lines

Question 16

What is the Z-line?

Answer 16

attachment sight for the thin actin microfilaments

Question 17

What is the I band

Answer 17

Band containing only thin actin filaments

Question 18

What is the M line?

Answer 18

the anchor site for the thick myosin filaments

Question 19

What is the H zone?

Answer 19

band containing only thick myosin filaments

Question 20

What is the A band?

Answer 20

Where thin and thick filaments overlap plus the intervening H zone

Question 21

What bands are the only ones that move during contraction?

Answer 21

H and I bands

• the ones containing just one type of filament
• they bot shorten

Question 22

What is the signal to contract within a sarcomere?

Answer 22

Calcium from the sarcoplasmic reticulum

Question 23

What is Rigor Mortis?

Answer 23

When a loos of ATP source prevents the myosin head from detaching from the actin, thereby locking the muscle in place

Question 24

What are the nerves cells that innervate muscle cells?

Answer 24

Motor neurons

Question 25

Is ever muscle cell in the body innervated?

Answer 25

No, - skeletal muscle are - smooth and cardiac muscles are not all directly innervated

Question 26

What is the place where the muscle and nerve ending meet?

Answer 26

the neuromuscular junction or the motor end plate

Question 27

What is the group of muscle fibers an axon innervates referred to as?

Answer 27

a motor unit

Question 28

What is muscular dystrophy?

Answer 28

an inherited diseases whereby muscle fibers degenerate over time

Question 29

What is Cardiac Muscle?

Answer 29

involuntary striated muscle type found in the wall of the heart -has intercalated discs (combo of desmosomes and gap junctions)

Question 30

Is most cardiac Muscle innervated?

Answer 30

no

Question 31

What controls the rate of contraction is cardiac muscle cells?

Answer 31

hormones or via cardiac conduction system

Question 32

Where is smooth muscle found?

Answer 32

in walls of viscera and blood vessels but also in the integument

Question 33

What does smooth muscle mediate?

Answer 33

visceral organ tone and movement | -in bv walls, it mediates vasodilation and constriction

Question 34

how many nuclei does each muscle cell type have?

Answer 34

Skeletal: lots Cardiac: 1-2 Smooth: 1

Question 35

Where are the nuclei in each type of muscle cell?

Answer 35

Skeletal: in periphery Cardiac: centrally located Smooth also in the center

Question 36

What connects smooth muscle cells?

Answer 36

gap junctions