MID - chapter 4.1 muscular tissue

Question 1

results from alternating contraction and relaxation of muscles

Answer 1

motion

Question 2

prime function of muscle

Answer 2

changing chemical energy into mechanical energy to perform work

Question 3

properties of muscular tissue

Answer 3

1. electrical excitability
2. contractility
3. extensibility
4. elasticity

Question 4

property of responding to stimuli by producing action potentials

Answer 4

electrical excitability

Question 5

ability to generate tension to do work

Answer 5

contractility

Question 6

ability to be extended or stretched

Answer 6

extensibility

Question 7

ability to return to original shape after contraction or extension

Answer 7

elasticity

Question 8

skeletal muscle tissue composition

Answer 8

fascia
tendons
aponeurosis
somatic motor neurons
satellite cell
sarcolemma
myofibrils

Question 9

• primarily attached to the bones, striated, and voluntary
• well supplied with nerves and blood vessels.

Answer 9

skeletal muscle tissue

Question 10

lines the body wall and limbs that surround and support muscles, allows free movement of muscles, carries nerves and blood vessels, and fills space between muscles

Answer 10

fascia

Question 11

rope-like extensions of connective tissue beyond muscle fibers that attach the muscle to bone or other muscle

Answer 11

tendons

Question 12

wide and flat extensions of connective tissue beyond muscle fibers that attach the muscle to bone or to other muscles

Answer 12

aponeurosis

Question 13

provide the nerve impulses that stimulate skeletal muscle to contract

Answer 13

somatic motor neurons

Question 14

myoblasts that persist after birth

Answer 14

satellite cells

Question 15

muscle fiber’s plasma membrane surrounding the sarcoplasm

Answer 15

sarcolemma

Question 16

contractile elements of skeletal muscle

Answer 16

myofibrils

Question 17

Skeletal Muscle Fiber Proteins

Answer 17

1. CONTRACTILE PROTEINS
   - myosin
   - actin
2. REGULATORY PROTEINS
   - tropomysin
   - troponin
3. STRUCTURAL PROTEINS
   - titin
   - alpha-actinin
   - myomesin
   - nebulin
   - dystrophin

Question 18

Proteins that generate force during muscle contractions

Answer 18

contractile proteins

Question 19

• makes up thick filament
• binds to myosin binding sites on actin molecules of thin filament during muscle contraction

Answer 19

myosin

Question 20

• main component of thin filament
• each actin molecule has a myosin-binding site where myosin head of thick filament binds contraction.

Answer 20

actin

Question 21

Proteins that help switch the muscle contraction process on and off

Answer 21

regulatory proteins

Question 22

• Regulatory protein that is a component of thin filament
• when a skeletal muscle fiber is relaxed, this covers myosin binding sites on actin molecules.

Answer 22

tropomysin

Question 23

when calcium ions (Ca2) bind to troponin, it changes shape.

Answer 23

troponin

Question 24

Proteins that keep thick and thin filaments of myofibrils in proper alignment, give myofibrils elasticity and extensibility, and link myofibrils to the sarcolemma and extracellular matrix.

Answer 24

structural proteins

Question 25

connects Z disc to M line of sarcomere

Answer 25

titin

Question 26

proteins of Z discs that attaches to actin molecules of thin filaments and to titin molecules

Answer 26

alpha-actinin

Question 27

wraps around entire length of each thin filament

Answer 27

nebulin

Question 28

links thin filaments of sarcomere to integral membrane proteins in sarcolemma

Answer 28

dystrophin

Question 29

surrounds each myofibril

Answer 29

sarcoplasmic reticulum

Question 30

- thick and thin filaments within the myofibril arranged in compartments - the thick and thin filaments produce striations

Answer 30

sarcomere

Question 31

COMPONENTS OF SARCOMERE

Answer 31

1. Z discs 2. A band 3. I band 4. H zone 5. M line

Question 32

Narrow, plate-shaped regions of dense material separate one sarcomere from the next

Answer 32

Z discs

Question 33

Dark, middle part of the sarcomere extends the entire length of thick filaments and includes those parts of thin filaments that overlap thick filaments

Answer 33

A band

Question 34

Lighter, less dense area of sarcomere that contains the remainder of thin filaments but no thick filaments. A Z disc passes through the center of each I band.

Answer 34

I band

Question 35

Narrow region in the center of each A band contains thick filaments but no thin filaments

Answer 35

H zone

Question 36

Region in the center of H zone that contains proteins that hold thick filaments together at the center of the sarcomere

Answer 36

M line

Question 37

- forms the wall of the heart, striated, and involuntary - have the same arrangement of actin and myosin and the same bands, zones, and Z discs as skeletal muscle fibers

Answer 37

cardiac muscle tissue

Question 38

- fibers connect to one another through intercalated discs, which contain both desmosomes and gap junctions. - remains contracted 10 to 15 times longer than skeletal muscle tissue due to prolonged delivery of Ca into the sarcoplasm.

Answer 38

cardiac muscle tissue

Question 39

- contracts when stimulated by its own auto rhythmic fibers - Due to its continuous, rhythmic activity, cardiac muscle depends greatly on aerobic respiration to generate ATP

Answer 39

cardiac muscle tissue

Question 40

- located primarily in internal organs - non-striated - involuntary - contain intermediate filaments and dense bodies - the function of dense bodies is similar to that of the Z discs in striated muscle

Answer 40

smooth muscle tissue

Question 41

- the duration of contraction and relaxation of smooth muscle is longer than in skeletal muscle since it takes longer for Ca to reach the filaments. - muscle fibers contract in response to nerve impulses, hormones, and local factors - muscle fibers can stretch considerably and still maintain their contractile function.

Answer 41

smooth muscle tissues - visceral smooth muscle - multiunit smooth muscle

Question 42

- found in the walls of hollow viscera and of small blood vessels - many fibers form a network that contracts in unison

Answer 42

visceral smooth muscle

Question 43

- found in large blood vessels, large airways to the lungs, arrector pili muscles, and the eye, where it adjusts pupil diameter and lens focus. - The fibers operate independently rather than in unison

Answer 43

multiunit smooth muscle

Question 44

- occurs because cross-bridges attach to and "walk" along the thin filaments towards the center of the sarcomere - as the thin filaments slide inward, the Z discs come closer together and the sarcomere shortens

Answer 44

muscle contraction

Question 45

- repeating sequence of events that causes sliding of the filaments - an increase in Ca2 concentration in the cytosol starts filament sliding; a decrease turns off the sliding process

Answer 45

contraction cycle

Question 46

____________: released at the neuromuscular junction triggers a muscle action potential, which leads to muscle contraction.

Answer 46

Acetylcholine

Question 47

1. Nerve impulse arrives at axon terminal of motor neuron and triggers release of acetylcholine (ACh). 2. ACh diffuses across synaptic cleft, binds to its receptors in the motor end plate, and triggers a muscle action potential (AP). 3. Acetylcholinesterase in synaptic cleft destroys ACh so another muscle action potential does not arise unless more ACh is released from motor neuron.

Answer 47

skeletal muscle contraction

Question 48

4. Muscle AP traveling along transverse tubule opens Ca2+ release channels in the sarcoplasmic reticulum (SR) membrane, which allows calcium ions to flood into the sarcoplasm. 5. Ca binds to troponin on the thin filament, exposing the binding sites for myosin. 6. Contraction: power strokes use ATP; myosin heads bind to actin, swivel, and release; thin filaments are pulled toward center of sarcomere.

Answer 48

skeletal muscle contraction

Question 49

7. Ca release channels in SR close and active transport pumps use ATP to restore low level of Ca2+ in sarcoplasm. 8. Troponin–tropomyosin complex slides back into position where it blocks the myosin binding sites on actin. 9. Muscle relaxation.

Answer 49

skeletal muscle contraction

Question 50

Muscle fibers have three sources for ATP production:

Answer 50

1. creatine 2. anaerobic glycolysis 3. aerobic respiration - muscular fatigue - recovery oxygen uptake

Question 51

- _______ kinase catalyzes the transfer of a high-energy phosphate group from creatine phosphate to ADP to form new ATP molecules. - _______ phosphate and ATP provide enough energy for muscles to contract maximally for about 15 seconds.

Answer 51

- Creatine

Question 52

- can provide enough energy for 2 minutes of maximal muscle activity. - Glucose is converted to pyruvic acid in the reactions of glycolysis, which yield two ATPs without using oxygen.

Answer 52

anaerobic glycolysis

Question 53

- muscular activity that occurs over a prolonged time depends on mitochondrial reactions that require oxygen to produce ATP.

Answer 53

aerobic respiration

Question 54

________: inability of a muscle to contract forcefully after prolonged activity ________2. Elevated oxygen use after exercise

Answer 54

muscular training