Muscle Tissue

Question 1

What features distinguish the 3 types of muscular tissue?

Answer 1

controllability, striation, lining/direction of fibers, location of nucleus, # of nuclei

Question 2

general functions of muscular tissue

Answer 2

> produce movement
Stabilize body positions and maintain posture
generates heat through thermogenesis
stores substances using sphincters and moves substances using peristaltic contractions

Question 3

Describe 4 properties of muscular tissue

Answer 3

> excitable = responds to a stimuli
contractible = shorten in length
extensible = extend or stretch
elastic = return to original shape

Question 4

What are 3 connective tissue layers in a skeletal muscle?

Answer 4

epimysium, perimysium, endomysium

Question 5

Describe the microscopic anatomy of a skeletal muscle fiber

Answer 5

individual muscle fibers are bundled into fascicles and are surrounded by 3 C.T. layers that are extensions of the fascia

Question 6

plasma membrane of the muscle fiber

Answer 6

sarcolemma

Question 7

tunnel from surface that directs toward the center of a muscle fiber

Answer 7

Tranverse (T tubule)

Question 8

cytoplasm of a muscle fiber

Answer 8

sarcoplasm

Question 9

sarcoplasm appears stuffed with myofibrils

Answer 9

contractile organelles

Question 10

what surrounds the myofibril

Answer 10

sarcoplasmic reticulum

Question 11

what are inside myofibrils

Answer 11

filaments

Question 12

what are the compartments for filaments called

Answer 12

sarcomeres

Question 13

thin filaments composed of what protein

Answer 13

actin

Question 14

what protein makes up thick filaments

Answer 14

myosin

Question 15

what part of a sarcomere:
separates one sarcomere from another; narrow; plate-shaped

Answer 15

Z-disc

Question 16

what part of a sarcomere:
darker middle part; extends entire length of thick filaments

Answer 16

A-band

Question 17

what part of a sarcomere:
lighter, less dense area; contains rest of thin filaments; Z disc passes through

Answer 17

I-band

Question 18

what part of a sarcomere:
located at the center of A-band; contains thick, but NOT thin filaments

Answer 18

H-zone

Question 19

Outline the steps involved in the sliding filament mechanism of muscle contraction

Answer 19

1. ATP hydrolysis
2. Attachment
3. Power Stroke
4. Detachment
   _________
5. Myosin hydrolyzes ATP
6. myosin enters ready state
7. myosin binds (If Ca2+ releses, binds troponin and tropomysin) actin
8. phosphate release, power stroke
9. ADP release, “rigor”
10. myosin binds ATP, unbinds actin

Question 20

Describe how muscle action potentials are begun at neuromuscular junction.

Answer 20

1. Release of ACh
2. Activation of ACh receptors
3. Production of action potential
4. Termination of ACh activity

Question 21

3 ways to produce ATP

Answer 21

creatinine phosphate, anaerobic glycolysis, aerobic respiration

Question 22

formed from ATP when muscle is relaxed, transfers a high-energy phosphate group to ADP, forming ATP during muscle contraction

Answer 22

creatine phosphate

Question 23

breakdown of muscle glycogen into glucose and production of pyruvic acid from glucose via glycolysis; no oxygen is needed; yields 2 molecules of lactic acid and 2 molecules of ATP

Answer 23

anaerobic glycolysis

Question 24

O2 is required; Inside the mitochondria, pyruvic acid, fatty acids and amino acids are used. When O2 is present, glycolysis, krebs cycles, and the electron transport chain occur

Answer 24

aerobic respiration

Question 25

phases of a twitch contraction

Answer 25

> Latent Period > contraction period > relaxation period > refractory period

Question 26

brief delay between application of the stimulus and beginning of a contraction. The muscle action potential sweeps over the sarcolemma and calcium ions are released from the sarcoplasmic reticulum [twitch]

Answer 26

latent period

Question 27

Ca2+ binds to troponin, myosin-binding sites on actin are exposed, and cross-bridges are formed. Peak tension develops in the muscle fiber. [twitch]

Answer 27

contraction period

Question 28

Ca2+ is actively transported back into the SR, myosin-binding sites are covered by tropomyosin, myosin heads detach from actin, and tension in the muscle fiber decreases [twitch]

Answer 28

relaxation period

Question 29

period of lost excitability [twitch]

Answer 29

refractory period

Question 30

What type of contraction? tension developed in the muscle remains almost constant while the muscle changes its length; used for body movements and for moving objects

Answer 30

isotonic contraction

Question 31

What type of contraction? muscle contraction in which the muscle shortens while generating force; reduces the angle at a joint

Answer 31

concentric isotonic contraction

Question 32

What type of contraction? muscle tension is less than the resistance (muscle lengthens); tension exerted by myosin cross-bridges resists movement of a load and slows the lengthening process

Answer 32

eccentric isotonic contraction

Question 33

What type of contraction? results in NO MOVEMENT; muscle force and resistance are equal; supporting objects in fixed position and posture; no change in length for muscle; important for maintaining posture and for supporting objects in fixed position; stabilize some joints

Answer 33

isometric contraction

Question 34

What type of skeletal muscle fiber? small, appear dark red, least powerful; fatigue resistant; slow-twitch; generates ATP mainly by aerobic respiration

Answer 34

slow oxidative (SO)

Question 35

What type of skeletal muscle fiber? intermediate in size, appear dark red, moderately resistant to fatigue; aerobic respiration and anaerobic glycolysis

Answer 35

fast oxidative-glycolytic fibers (FOG)

Question 36

What type of skeletal muscle fiber? large, white and powerful; generate ATP mainly by glycolysis; fatigue quickly

Answer 36

fast glycolytic (FG) fibers

Question 37

muscle-muscle connection

Answer 37

fascia

Question 38

sheet or band of fibrous connective tissue

Answer 38

fascia

Question 39

skeletal muscle-bone connection

Answer 39

tendon

Question 40

connects 2 muscle bellies

Answer 40

aponeurosis