Chapter 8 Reagan Winter

Question 1

fascia

Answer 1

Layers of fibrous connective tissue.

Question 2

aponeuroses

Answer 2

Broad fibrous sheets.

Question 3

myofibrils

Answer 3

Contractile fibers in muscle cells.

Question 4

myosin

Answer 4

A protein that, with actin, contracts muscle fibers.

Question 5

actin

Answer 5

A protein that forms filaments that slide between filaments of the protein myosin, contracting muscle fibers.

Question 6

striations

Answer 6

Bands of a skeletal muscle fiber.

Question 7

I bands

Answer 7

The light bands, composed of thin actin filaments directly attached to structures called Z lines.

Question 8

A bands

Answer 8

The dark bands, composed of thick myosin filaments overlapping thin actin filaments.

Question 9

M line

Answer 9

A thickening, Consists of proteins that help hold the thick filaments in place.

Question 10

sarcomere

Answer 10

The structural and functional unit of a myofibril.

Question 11

sacroplasmic reticulum

Answer 11

Membranous network of channels and tubules of a muscle fiber, corresponding to the endoplasmic reticulum of other cells.

Question 12

transverse tubules

Answer 12

Membranous channel that extends inward form a muscle fiber membrane.

Question 13

cisternae

Answer 13

Enlarged portions of sarcoplasmic reticulum near the actin and myosin filaments of a muscle fiber.

Question 14

motor neuron

Answer 14

A neuron that transmits impulses from the central nervous system to an effector.

Question 15

neuromuscular junction

Answer 15

Synapse between a motor neuron and a skeletal muscle fiber.

Question 16

motor end plate

Answer 16

Specialized portion of muscle fiber membrane at a neuromuscular junction.

Question 17

neurotransmitters

Answer 17

Chemical that an axon end secretes on an effector (muscle or gland) or another neuron.

Question 18

motor unit

Answer 18

A motor neuron and its associated muscle fibers.

Question 19

troponin

Answer 19

Proteins apart of the actin filament.

Question 20

tropomyosin

Answer 20

Protein apart of the actin filament.

Question 21

sliding filament model

Answer 21

Sarcomeres shorten because cross bridges pull on thin filaments. A myosin cross bridge can attach to an actin binding site and bend slightly, pulling on the actin filament. Then the head can release, straighten, combine with another binding site further down the actin filament, and pull again.

Question 22

ATPase

Answer 22

Enzyme, which catalyzes the breakdown of ATP and ADP and phosphate, releasing energy that puts myosin cross bridge in a cocked position.

Question 23

actetylcholine

Answer 23

A type of neurotransmitter, which is biochemical secreted at axon ends of many neurons; transmits nerve messages across synapses.

Question 24

musclue impulse

Answer 24

Impulse that travels along the war ole man to the transverse tubules.

Question 25

acetylcholinesterase

Answer 25

An enzyme that catalyzes breakdown of acetylcholine.

Question 26

creatine phosphate

Answer 26

A muscle biochemical that stores energy.

Question 27

hemoglobin

Answer 27

Oxygen carrying pigment in red blood cells.

Question 28

myoglobin

Answer 28

A pigmented protein in muscle that carries oxygen.

Question 29

pyruvic acid

Answer 29

An intermediate product of carbohydrate oxidation.

Question 30

lactic acid

Answer 30

An organic compound formed from pyruvic acid during anaerobic respiration.

Question 31

oxygen debt

Answer 31

The amount of oxygen required after physical exercise to convert accumulated lactic acid to glucose.

Question 32

fatigue

Answer 32

A muscle exercised strenuously for a prolonged period may lose its ability to contract.

Question 33

threshold stimulus

Answer 33

Stimulation level that must be exceeded to elicit a nerve impulse or a muscle contraction.

Question 34

all-or-none response

Answer 34

Phenomenon in which a muscle fiber completely contracts when it is exposed to a stimulus of threshold strength.

Question 35

myogram

Answer 35

A recording of muscular contraction.

Question 36

twitch

Answer 36

A brief contraction of a muscle fiber followed by relaxation.

Question 37

latent period

Answer 37

Time between application of stimulus and the beginning of a response in a muscle fiber.

Question 38

period of contraction

Answer 38

When the muscle pulls at its attachments.

Question 39

peroid of relaxtion

Answer 39

When the muscle returns to its former length.

Question 40

summation

Answer 40

Increased force of contraction by a skeletal muscle fiber when a twitch occurs before the previous twitched relaxes.

Question 41

tetanic contraction

Answer 41

Continuous, forceful muscular contraction without relaxation.

Question 42

recruitment

Answer 42

Increase in number of motor units activated as stimulation intensity increases.

Question 43

sustained contraction

Answer 43

Summation and recruitment together can produce a sustained contraction of increasing strength.

Question 44

muscle tone

Answer 44

A response to nerve impulses that originate repeatedly from the spinal cord and stimulate a few muscle fibers.