Chapter 9: The Muscular System

Question 0

Contractility

Answer 0

the ability of muscle to shorten forcefully

Question 1

What are the functions of the Muscular System? (7)

Answer 1

• movement of the body
• maintenance of posture
• respiration
• production of body heat
• communication
• constriction of organs and vessels
• contraction of the heart

Question 2

Excitability

Answer 2

the capacity of muscle to respond to a stimulus

Question 3

Extensibility

Answer 3

muscle can be stretched beyond its normal resting length and still be able to contract

Question 4

Elasticity

Answer 4

is the ability of muscle to recoil to its original resting length after being stretched

Question 5

Fasciculi

Answer 5

numerous visible bundles that a muscle is composed of

Question 6

perimyseum

Answer 6

heavy connective tissue surrounding the fasciculi of muscle

Question 7

epimysium

Answer 7

connective tissue that surround the entire muscle composed of dense collagenous connective tissue

Question 8

Muscular Fascia

Answer 8

connective tissue sheets within the body located superficial to the epimysium, separates and compartmentalizes individual muscles of group of muscles

Question 9

Motor neurons

Answer 9

specialized nerve cells that stimulate muscles to contract

Question 10

myoblasts

Answer 10

less mature, multi-nucleated cells that develop muscle fibers

Question 11

hypertrophy

Answer 11

enlargement of muscles after body grows, number of muscle fibers stays relatively the same

Question 12

Sarcolemma

Answer 12

the plasma membrane of a muscle fiber

Question 13

endomysium

Answer 13

loose connective tissue with reticular fibers that surrounds muscle fibers

Question 14

T tubules

Answer 14

along the surface of the sarcolemma, extending to the extracellular environment with the interior of the muscle fiber

Question 15

myofibril

Answer 15

consists of actin and myosin, extend to the end of the muscle fiber

Question 16

Sarcomeres

Answer 16

basic ordered units of skeletal muscle that contain myofibrils

Question 17

neuromuscular junction

Answer 17

point where neurons are sent in the muscle

Question 18

titin

Answer 18

coil spring on end of myosin allows sarcomere to stretch

Question 19

What is globular actin?

Answer 19

one actin molecle

Question 19

What is F actin?

Answer 19

twisted pair of globular actin

Question 20

What is the job of tropomyoisin

Answer 20

to reveal or conceal the active binding sites

Question 21

what does myosin do?

Answer 21

binds to active sites

Question 22

what does troponin do?

Answer 22

binds to calcium, tropomyosin, and G actin in order to expose actin

Question 23

What is a cross-bridge?

Answer 23

when myosin head binds to active site

Question 24

I bands

Answer 24

light bands

Question 25

A bands

Answer 25

Dark bands

Question 26

H zone

Answer 26

region inside A band that appears to be lighter because actin and myosin do not overlap

Question 27

M line

Answer 27

middle of H zone holding myosin in place

Question 28

What does the sarcoplasmic reticulum do?

Answer 28

supplies calcium

Question 29

how does the sarcoplasmic reticulum supply calcium

Answer 29

through ion channels and voltage-gated channels

Question 30

antiport, synport

Answer 30

sends two things in two different direction, sends two things in the same direction

Question 31

charges of cell at resting potential

Answer 31

- inside (K+ and proteins-), + outside (Na+)

Question 32

How does the sodium/potassium pump work?

Answer 32

pumps 3 Na+ out and 2 K+ in

Question 33

Ligand-gated ion channel

Answer 33

molecules bind to receptor

Question 34

Voltage gated ion channel

Answer 34

open and close in response to short voltage changes across plasma membrane

Question 35

Bi-gated channel

Answer 35

lids on both ends

Question 36

visceral or unitary smooth muscle

Answer 36

occurs in sheets, has numerous gap junctions found in digestive, reproductive, and urinary tracts

Question 37

multiunit smooth muscle

Answer 37

occurs as sheets, walls of blood vessels, fewer gap junctions, cells or groups of cells act as independent units, only contracts when stimulated by nerves of hormones. ex: arrector pili, iris of the eye

Question 38

origin

Answer 38

fixed end of muscle attached to bones

Question 39

insertion

Answer 39

muscle end attached to bone with greatest movement

Question 40

belly

Answer 40

largest portion of the muscle between origin and insertion

Question 41

aponeuroisis

Answer 41

a very large tendon

Question 42

agnonist

Answer 42

muscle that when it contracts causes an action

Question 43

antagonist

Answer 43

a muscle working in opposition to agonist (when you move a bowling ball back to prepare to bowl, biceps)

Question 44

synergists

Answer 44

muscles that work together to cause movement

Question 45

prime mover

Answer 45

plays the major role in synergistics

Question 46

fixator

Answer 46

stabilizing joints in synergistics

Question 47

Neuromuscular junction

Answer 47

specialized synapse between motor neuron and muscle fiber

Question 48

neurotransmitter

Answer 48

substance released by presynaptic membrane that stimulates or inhibits the production of action potential in the postsynaptic membrane