Ch.9 Muscles and Muscle Tissue

Question 1

Three types of muscle tissue are

Answer 1

Skeletal, cardiac, and smooth

Question 2

Characteristic of Skeletal muscle

Answer 2

striated,voluntary, responsible for overall body mobility

Question 3

Characteristic of Cardiac muscle

Answer 3

only in the heart, Striated, intercalated disc, branching

Question 4

Characteristic of Smooth muscle

Answer 4

visceral, nonstriated, spindle-shaped, involuntary

Question 5

4 Special characteristics of Muscle Tissue

Answer 5

• excitability/ responsiveness (receive and respond to stimulus)
• Contractility (shorten)
• extensibility (extend or stretch)
• elasticity (recoil and resume)

Question 6

4 Muscle functions

Answer 6

Producing movement
maintaining posture and body position
stabilizing joints
generating heat
protection

Question 7

List the three connective tissue sheaths from external to internal

Answer 7

Epimysium “overcoat” surrounds the whole muscle
Perimysium surround each fascicle
Endomysium surround each individual muscle fiber

Question 8

Plasma membrane

Answer 8

Sarcolemma

Question 9

a red pigment that stores oxygen

Answer 9

myoglobin

Question 10

A single fiber contains hundreds to thousands of rod-like ______ that run parallel to its length

Answer 10

Myofibrils

Question 11

______ the smallest contractile unit of a muscle fiber, the functional unit of skeletal muscle

Answer 11

Sarcomere

Question 12

The order of muscle structure

Answer 12

myofibrils> muscle fiber > fascicles > Muscles

Question 13

Thick filaments consist of

Answer 13

protein myosin, two heads and two tails

Question 14

Thin Filaments consist of

Answer 14

protein actin, tropomysosin (mom strand) , and troponin (dad gun)

Question 15

During contraction, they link the thick and thin filaments together forming

Answer 15

cross bridges

Question 16

The Sarcoplasmic reticulum regulates intracelllar level of ionic _____ , also final trigger for contraction

Answer 16

calcium

Question 17

What are the changes when contraction occurs

Answer 17

the I bands shorten, the distance between successive Z discs shortens, the H zone disappear, and the contagious A bands move closer together but their length does not change

Question 18

Each axon ending gives off several short, curling branches that collectively form an elliptical _________ with a single muscle fiber

Answer 18

Neuromuscular junction/ end plate

Question 19

The axon terminal and the muscle fiber are exceedingly close but they remain separated by

Answer 19

synaptic cleft

Question 20

Small membranous sacs containing the neurotransmitter ACh

Answer 20

synaptic vesicles

Question 21

________ triggers electrical events that ultimately generate an action potentioal

Answer 21

Acetycholine

Question 22

After ACh binds to the ACh receptors its effects are quickly terminated by ________

Answer 22

Acetylcholinesterase

Question 23

A disease characterized by drooping eyelids, difficulty swallowing and talking and generalized muscle weakness, involves a shortage of ACh receptors

Answer 23

Myasthenia gravis

Question 24

How does a motor neuron stimulate a skeletal muscle fiber

Answer 24

nerve impulse reaches end of axon, release of ACh into the synaptic cleft
ACh diffuses across the cleft and attaches to ACh receptors on the sarcolemma
ACh binding triggersa electrical events, action potential

Question 25

Steps in Excitation-Contraction Coupling

Answer 25

1. Action potential propagates along the sarcolemma and down the T tubules
2. Calcium ions are released
3. Calcium binds to troponin and removes the blocking action of tropomyosin
4. Contraction begins, myosin binding to actin forms cross bridges