Chapter 9 Review

Question 1

fascia

Answer 1

-Sheet of dense connective tissue that encloses a muscle

Question 2

myosin

Answer 2

• Protein that, with actin, forms the filaments that interact to contract muscle fibers

Question 3

actin

Answer 3

-Protein in a muscle fiber that forms the thin filaments that slide between filaments of the protein myosin, shortening the muscle fibers

Question 4

tendon

Answer 4

-Muscle to Bone

Question 5

ligament

Answer 5

-Bone to Bone

Question 6

aponeuroses

Answer 6

-Muscle to Muscle

Question 7

myofibrils

Answer 7

-Overlapping parallel groups of thick and thin filaments in a repeating pattern; the underlying basis for the striation pattern

Question 8

sarcomeres

Answer 8

-A repeating patter of units formed from striations

Question 9

I bands

Answer 9

• light bands

- composed of thin actin filaments held by direct attachments to Z lines, which are in the middle of the I bands

Question 10

Z lines

Answer 10

-Found in the middle of I bands

Question 11

H zones

Answer 11

• part of the A bands

- consists only of thick filaments

Question 12

A bands

Answer 12

• dark bands
• thick myosin filaments overlapping thin actin filaments
• includes: H zones and M lines

Question 13

M lines

Answer 13

• part of the A bands

- consists of proteins that help hold the thick filaments in place

Question 14

troponin

Answer 14

-three protein subunits and are attached to actin

Question 15

tropomyosin

Answer 15

-rod-shaped and occupy the longitudinal grooves of the actin helix

Question 16

sarcoplasmic reticulum

Answer 16

• corresponds to the endoplasmic reticulum. Membranous channels in the sarcoplasm of a muscle fiber that surrounds each myofibril and runs parallel to it.

Question 17

transverse tubules

Answer 17

• A set of membranous channels that extends into the sarcoplasm as invaginations continuous with the sarcolemma and contains extracellular fluid

Question 18

triads

Answer 18

-Region where the actin and myosin filaments overlap

Question 19

neurotransmitters

Answer 19

• Biological messenger molecules that convey neural information

Question 20

lower motor neurons

Answer 20

• Neurons that control effectors, including skeletal muscle fibers.
• Normally a skeletal muscle fiber contracts only upon stimulation by its motor neuron

Question 21

neuromuscular junctions

Answer 21

• The synapse where a motor neuron axon and a skeletal muscle fibers.
• Here the muscle fiber membrane is specialized to form a motor end plate, where nuclei and mitochondria are abundant and the sarcolemma is extensively folded.

Question 22

motor end plate

Answer 22

• Where nuclei and mitochondria are abundant and the sarcolemma is extensively folded.

Question 23

synaptic cleft

Answer 23

• A small gap that separates the membrane of the neuron and the membrane of the muscle fiber

Question 24

Acetylcholine(ACh)

Answer 24

• The neurotransmitter that motor neurons use to control skeletal muscle contraction.

Question 25

myosin crossbridges

Answer 25

-A myosin head can attach to an actin binding site forming a cross-bridge, and bend slightly, pulling on the actin filament

Question 26

sliding filament theory

Answer 26

• When sarcomeres shorten, the thick and thin filaments do not change length

Question 27

ATPases

Answer 27

• An enzyme found in myosin heads

- it catalyzes the breakdown of ATP to ADP and a phosphate

Question 28

lactic acid threshold

Answer 28

• anaerobic threshold

- glycosis breaks down glucose molecules to yield pyruvic acid, which would normally enter the citric acid cycle.

Question 29

lactic acid

Answer 29

• dissociates rapidly to form lactate ion and hydrogen ion, both of which leave muscle cells by facilitated diffusion
• created from pyruvic acid when the oxygen supply is low

Question 30

threshold stimulus

Answer 30

-the fiber remains unresponsive until it reaches a certain strength of stimulation

Question 31

skeletal muscle

Answer 31

• multiple nuclei
• transverse tubules
• triads
• voluntary

Question 32

cardiac muscle

Answer 32

• single nucleus
• transverse tubules
• intercalated disks
• diads
• involuntary

Question 33

smooth muscle

Answer 33

• single nucleus
• lacks transverse tubules
• involuntary

Question 34

intercalated disks

Answer 34

-Complex intercellular junctions that include components of desmosomes and gap junctions

Question 35

peristalsis

Answer 35

• Alternare contractions and relaxations of the longitudinal and circular muscles.
• In the intestines it pushes food down the digestive tract

Question 36

motor unit

Answer 36

• Together a motor neuron and a muscle fiber control it

Question 37

synaptic vesicles

Answer 37

-tiny vesicles that stores neurotransmitters