MUSCULAR SYSTEM

Question 1

Two main aspects to muscle contraction:

Answer 1

electrical component
mechanical component

Question 2

Electrical Component Structures

Answer 2

Sarcolemma

Transverse tubules

Sarcoplasmic reticulum

Question 3

Mechanical Component Structures

Answer 3

Myofibrils
Myofilaments

Question 4

3 Proteins of Actin Myofilament

Answer 4

Actin

Tropomyosin

Troponin

Question 5

The primary function of skeletal muscle cells is to

Answer 5

generate force by contracting, or shortening.

Question 6

The parallel arrangement of myofilaments in a sarcomere allows them to

Answer 6

interact, which causes muscle contraction

Question 7

When sarcomeres shorten, ____, ____, _____, and ____ all shorten to produce muscle contraction

Answer 7

myofibrils
muscle fibers
muscle fascicles
muscles

Question 8

During muscle relaxation, sarcomeres ____

Answer 8

lengthen

Question 9

The basis of the electrical properties of skeletal muscle cells is the

Answer 9

movement of ions across the cell membrane

Question 10

Ions can move across the cell membrane through ion channels. State the two different channels

Answer 10

Leak ion channels

Gated ion channels

Question 11

the charge difference in unstimulated cell, results of three factors. state them.

Answer 11

 Concentration of K+ inside the cell membrane is higher than that outside the cell membrane
 Concentration of Na+ outside the cell membrane is higher than that inside the cell membrane
 Cell membrane is more permeable to K+ than to Na+

Question 11

The phospholipid bilayer interior is a _________ environment, which inhibits the movement of charged particles

Answer 11

hydrophobic

Question 12

Occurs when the excitable cell is stimulated

Answer 12

action potential

Question 13

When K+ moves out of the cell, the inside of the cell membrane becomes more ______ and the outside becomes more ______.

Answer 13

negative; positive.

Question 14

Release of ______ at the neuromuscular junction will produce an action potential in the sarcolemma

Answer 14

acetylcholine

Question 15

Occurs when acetylcholine is no longer released at the neuromuscular junction

Answer 15

muscle relaxation

Question 16

keeps acetylcholine from accumulating within the synaptic cleft where it would act as a constant stimulus at the motor end-plate, producing continuous contraction in the muscle fiber.

Answer 16

Acetylcholinesterase

Question 17

the mechanical component of muscle contraction

cause the sarcomeres to shorten and the muscle will contract

Answer 17

Cross-Bridge Movement

Question 18

Response of a muscle fiber to a single action potential along its motor neuron

Answer 18

Muscle Twitch

Question 19

the gap between the time of stimulus application to the motor neuron and the beginning of contraction

Answer 19

Lag phase/latent phase

Question 20

commences once the Ca2+ released from the sarcoplasmic reticulum initiates cross-bridge formation and cross-bridge cycling.

Answer 20

Contraction phase

Question 21

much longer than the contraction phase, because the concentration of Ca2+ in the sarcoplasm decreases slowly due to active transport into the sarcoplasmic reticulum

Answer 21

Relaxation phase

Question 22

state the two major types of skeletal muscle fibers

Answer 22

Slow-Twitch Muscle Fibers (Type I)

Fast-Twitch Muscle Fibers (Type II)

Question 23

contract more slowly, have a better-developed blood supply, have more mitochondria, and are more fatigue-resistant than fast- twitch muscle fibers

Answer 23

Slow-Twitch Muscle Fibers (Type I)

Question 24

have a less-well-developed blood supply

have very little myoglobin, fewer and smaller mitochondria

contract rapidly for a shorter time and fatigue relatively quickly

Answer 24

Fast-Twitch Muscle Fibers (Type II)

Question 25

Temporary state of reduced work capacity

Answer 25

Muscle Fatigue

Question 26

contain less actin and myosin than do skeletal muscle cells

Answer 26

SMOOTH MUSCLE

Question 27

the most stationary, or fixed, end of the muscle

Answer 27

origin

Question 28

Muscle is connected to the bone by a ____

Answer 28

tendon

Question 29

the end of the muscle attached to the bone undergoing the greatest movement

Answer 29

insertion

Question 30

Members of a group of muscles working together to produce a movement

Answer 30

synergists

Question 31

plays the major role in accomplishing the desired movement

Answer 31

Prime mover

Question 32

are muscles that hold one bone in place relative to the body while a usually more distal bone is moved

Answer 32

fixators

Question 33

effects of aging

Answer 33

 Reduction in muscle mass
 lower response time for muscle contraction
 Reduction in stamina
 Increased recovery time
 Loss of muscle fibers begins as early as 25 years of age, and by age 80 the muscle mass has been reduced by approximately 50%