9-1. Muscle Tissue

Question 1

What are the functions of muscle?

Answer 1

1. producing movement (all body mvts are caused by muscles contracting)
2. maintaining posture (must contract skeletal muscles to hold body in standing or sitting position)
3. generating heat (contract produces heat that helps maintain constant body temp)

Question 2

What is a characteristic that is unique to muscle?

Answer 2

contractility

Question 3

What are the characteristics of muscle?

Answer 3

1. excitability (receive and respond to stimuli)
2. contractility (shorten forcibly when stimulated)
3. extensibility (ability to be stretched)
4. elasticity (return to original length)

Question 4

What are the types of muscle?

Answer 4

skeletal, cardiac, smooth

Question 5

Which muscle types are striated?

Answer 5

skeletal and cardiac

Question 6

Which muscle types are voluntary?

Answer 6

skeletal

Question 7

Which muscle types are involuntary?

Answer 7

cardiac and smooth

Question 8

What do you call a muscle cell?

Answer 8

muscle fiber

Question 9

What are the differences in muscle fibers in the types of muscle tissues?

Answer 9

skeletal - elongated, cylindrical and multinucleate, running parallel to each other in bundles

cardiac - branched, interconnecting to each other at intercalated discs

smooth - spindle shaped cells with one centrally located nuclus

Question 10

Skeletal muscle can contract ___, but ____ than other types.

Answer 10

powerfully and quickly; fatigues faster

Question 11

Which muscle type is striated and involuntary?

Answer 11

cardiac

Question 12

Which muscle type is striated and voluntary?

Answer 12

skeletal

Question 13

Which muscle type is not striated?

Answer 13

smooth

Question 14

endomysium

Answer 14

covering of connective tissue around each muscle fiber

Question 15

fascicle

Answer 15

bundles of skeletal muscle fibers

Question 16

perimysium

Answer 16

connective tissue covering around a fascicle

Question 17

epimysium

Answer 17

thick layer of connective tissue wrapped around entire muscle

Question 18

deep fascia

Answer 18

sheet of fibrous connective tissue that binds muscles together into functional groups, allowing free movement

Question 19

blood supply

Answer 19

muscles are highly vascular because contraction requires lots of energy, nutrients and oxygen. Capillaries are within the endomysium, so each muscle fiber is in close contact with blood

Question 20

nerve supply

Answer 20

to contract, skeletal muscle must be stimulated by a nerve impulse. Each fiber makes contact with part of a motor neuron

Question 21

tendon

Answer 21

thick sheet of connective tissue that attaches muscle to bone

Question 22

What are the connective tissue layers, from fiber level up?

Answer 22

endomysium (around each fiber) >

perimysium (around each fascile) >

epimysium (around entire muscle) >

deep fascia (binds together into functional groups) >

tendon (connects to bone)

Question 23

sarcolemma

Answer 23

plasma membrane surrounding each muscle fiber

Question 24

sarcoplasm

Answer 24

fluid filling each fiber

Question 25

multinucleate

Answer 25

many nuclei, lying near the edge of the sarcolemma

Question 26

In addition to the usual organelles, muscles have many ___.

Answer 26

mitochondria

Question 27

sarcoplasmic reticulum

Answer 27

network of fluid filled channels running lengthwise thorugh the cell

Question 28

Transverse tubules

Answer 28

running from surface of sarcolemma to interior of fiber, perpendicular to the sarcoplasmic reticulum

Question 29

myofibril

Answer 29

rodlike, running lengthwise through entire cell; contractile elements of muscle

Question 30

What filaments make up myofibril?

Answer 30

thick filaments - myosin thin filament - double stranded helix of actin, with trotomyosin lying in the groove between the strands and troponin covering myosin attachment sites

Question 31

What structures are unique to muscle fibers?

Answer 31

T-tubules and myofibril

Question 32

What causes striation?

Answer 32

thin and thick filaments partially overlap (light shines through the areas where there are only thin filaments)

Question 33

I bands

Answer 33

light bands containing only thin filaments

Question 34

A bands

Answer 34

dark bands where thin and thick filaments overlap

Question 35

Z lines

Answer 35

dense protein that serves as an attachment line for the thin filaments

Question 36

sarcomere

Answer 36

part of myofibril between two Z lines

Question 37

What is the fundamental contractile unit of muscle?

Answer 37

sarcomere