Chapter 5: Lesson 4

Question 1

Skeletal muscle

Answer 1

The type of muscle tissue that connects to bones and generates the forces that create movement.

Question 2

Fascia

Answer 2

Connective tissue that surrounds muscles and bones.

Question 3

Epimysium

Answer 3

Inner layer of fascia that directly surrounds an entire muscle, commonly referred to as the “deep fascia.”

Question 4

Fascicles

Answer 4

Largest bundles of fibers within a muscle. Fascicles are surrounded by perimysium.

Question 5

Perimysium

Answer 5

Connective tissue surrounding a muscle fascicle.

Question 6

Endomysium

Answer 6

Connective tissue that wraps around individual muscle fibers within a fascicle.

Question 7

Glycogen

Answer 7

Glucose that is deposited and stored in bodily tissues, such as the liver and muscle cells; the storage form of carbohydrate.

Question 8

Myoglobin

Answer 8

Protein-based molecule that carries oxygen molecules into the muscles.

Question 9

Myofibrils

Answer 9

The contractile components of a muscle cell; the myofilaments (actin and myosin) are contained within a myofibril.

Question 10

Myofilaments

Answer 10

The filaments of a myofibril; include actin and myosin.

Question 11

Actin

Answer 11

The thin, stringlike, myofilament that acts along with myosin to produce muscular contraction.

Question 12

Myosin

Answer 12

The thick myofilament that acts along with actin to produce muscular contraction.

Question 13

Sarcomere

Answer 13

The structural unit of a myofibril composed of actin and myosin filaments between two Z-lines.

Question 14

Z-line

Answer 14

The meeting point of each sarcomere.

Question 15

Neural activation

Answer 15

The nervous system’s signal that tells a muscle to contract.

Question 16

Neuromuscular junction

Answer 16

The specialized site where the nervous system communicates directly with muscle fibers.

Question 17

Synapse

Answer 17

A junction or small gap between the motor neuron and muscle cells.

Question 18

Motor unit

Answer 18

A motor neuron and all of the muscle fibers that it innervates.

Question 19

Action potential

Answer 19

Nerve impulse that is relayed from the central nervous system, through the peripheral nervous system, and into the muscle across the neuromuscular junction.

Question 20

Neurotransmitters

Answer 20

Chemical messengers that cross the synapse between neuron and muscle and assist with nerve transmission.

Question 21

Acetylcholine (ACh)

Answer 21

A neurotransmitter that helps the action potential cross the synapse into the muscle, which initiates the steps in a muscle contraction.

Question 22

Sliding filament theory

Answer 22

The series of steps in muscle contraction involving how myosin (thick) and actin (thin) filaments slide past one another to produce a muscle contraction, shortening the entire length of the sarcomere

Question 23

Excitation-contraction coupling

Answer 23

The physiological process of converting an electrical stimulus to a muscle contraction.

Question 24

Power stroke

Answer 24

The myosin heads bind to actin and pull them toward the sarcomere center, which slides the filaments past each other, shortening the muscle.

Question 25

Adenosine triphosphate (ATP)

Answer 25

A high-energy molecule that serves as the main form of energy in the human body; known as the energy currency of the body.

Question 26

Resting length

Answer 26

The length of a muscle when it is not actively contracting or being stretched.

Question 27

Type I muscle fibers

Answer 27

Muscle fibers that are small in size, generate lower amounts of force, and are more resistant to fatigue.

Question 28

Type II muscle fibers

Answer 28

Muscle fibers that are larger in size, generate higher amounts of force, and are faster to fatigue.

Question 29

All-or-nothing principle

Answer 29

Motor units cannot vary the amount of force they generate; they either contract maximally or not at all.

Question 30

Capillaries

Answer 30

The smallest blood vessels and the site of exchange of elements between the blood and the tissues.