Chapter 12 - Muscular System

Question 1

A muscle is surrounded by _____.

Answer 1

fascia

Question 2

Beneath the fascia, the fibrous covering of a muscle is called the _____.

Answer 2

epimysium

Question 3

A muscle is a bundle of _____, which are separated by the _____.

Answer 3

fascicles, perimysium

Question 4

Fascicles are made up of individual _____, which are separated by the _____.

Answer 4

muscle fibers, endomysium

Question 5

Muscle fibers contain many _____, which consist of repeating _____.

Answer 5

myofibrils, sarcomeres

Question 6

The functional unit of a muscle is the _____.

Answer 6

sarcomere

Question 7

The thick filament in a sarcomere is _____, while the thin filament is _____.

Answer 7

myosin, actin

Question 8

The _____ is associated with the M line and contains cross bridges.

Answer 8

myosin

Question 9

The _____ is attached to Z lines and contains binding sites for myosin.

Answer 9

actin

Question 10

_____ is a fibrous protein that covers actin’s binding sites.

Answer 10

Tropomyosin

Question 11

_____ binds to tropomyosin and has a binding site for _____.

Answer 11

Troponin, Ca²⁺

Question 12

A motor unit consists of a ___ ___ and all of the ___ ___ it innervates.

Answer 12

motor neuron, muscle fibers

Question 13

The functional junction between a motor neuron and a muscle cell is called the _____ junction.

Answer 13

neuromuscular

Question 14

The neurotransmitter released at the neuromuscular junction is _____.

Answer 14

acetylcholine (ACh)

Question 15

ACh binds to receptors on the ___
___ ___, triggering an action potential.

Answer 15

motor end plate

Question 16

The impulse travels across the muscle fiber membrane to the _____.

Answer 16

T-tubule

Question 17

The impulse causes the _____ to release _____ into the sarcoplasm.

Answer 17

sarcoplasmic reticulum, Ca²⁺

Question 18

Ca²⁺ binds to _____, causing _____ to expose the myosin-binding site.

Answer 18

troponin, tropomyosin

Question 19

Myosin binds to actin and performs the ____ ____, leading to muscle contraction.

Answer 19

power stroke

Question 20

Contraction continues as long as ____ and ____ are present.

Answer 20

Ca²⁺, ATP

Question 21

A single muscle contraction is called a _____.

Answer 21

twitch

Question 22

_____ is when multiple twitches build to increase tension.

Answer 22

Summation

Question 23

_____ is a gradual increase in contraction strength with repeated stimulation.

Answer 23

Treppe

Question 24

When muscle contractions become continuous due to frequent stimuli, it is called a _____.

Answer 24

tetanus

Question 25

The _____ principle states that muscle fibers either contract fully or not at all.

Answer 25

all-or-none response

Question 26

_____ refers to increasing the number of motor units recruited for a stronger contraction.

Answer 26

Recruitment

Question 27

_____ is the maintenance of a partially contracted state.

Answer 27

Tonus

Question 28

_____ contractions generate force with movement.

Answer 28

Isotonic

Question 29

_____ contractions generate force without movement.

Answer 29

Isometric

Question 30

_____ contractions shorten the muscle, while _____ contractions lengthen it.

Answer 30

Concentric, eccentric

Question 31

The ____ ____ ____ explains how sarcomeres shorten to contract a muscle.

Answer 31

Sliding Filament Theory

Question 32

The ____ and ____ of the sarcomere decrease in length during contraction.

Answer 32

H zone, I band

Question 33

The more cross bridges that form, the greater the _____ a muscle can produce.

Answer 33

force

Question 34

The ideal sarcomere length for maximal force production is ____ μm.

Answer 34

2 - 2.25

Question 35

_____ metabolism provides short-term energy using ATP, creatine phosphate, and glycolysis,

Answer 35

Anaerobic

Question 36

_____ metabolism provides long-term energy through the _____ and _____.

Answer 36

Aerobic, Krebs cycle, oxidative phosphorylation

Question 37

___ ___ occurs when the body must restore energy after exercise.

Answer 37

Oxygen debt

Question 38

_____ fibers (Type I) are slow-twitch, highly aerobic, and red in color.

Answer 38

Slow oxidative

Question 39

_____ fibers (Type IIa) have both aerobic and anaerobic capabilities.

Answer 39

Fast oxidative-glycolytic

Question 40

_____ fibers (Type IIx) are fast- twitch, highly anaerobic, and white in color.

Answer 40

Fast glycolytic

Question 41

___ ___ is a reversible, exercise-induced reduction in a muscle's ability to generate force.

Answer 41

Muscle fatigue

Question 42

_____ fatigue occurs in the muscle itself, while _____ fatigue involves the CNS.

Answer 42

Peripheral, central

Question 43

Possible causes of muscle fatigue include increased ____ ____, decreased ____, and depletion of ____ ____.

Answer 43

phosphate concentration, ATP, muscle glycogen

Question 44

Aerobic training leads to ____ muscle mass, while anaerobic training leads to ____ muscle mass.

Answer 44

less, more

Question 45

Muscle growth can occur through ____ (increase in cell number) or ____ (increase in cell size).

Answer 45

hyperplasia, hypertrophy

Question 46

_____ motor neurons have cell bodies in the spinal cord and innervate skeletal muscles.

Answer 46

Lower

Question 47

_____ motor neurons originate in the brain and control lower motor neurons.

Answer 47

Upper

Question 48

The ___ ___ ___ provides information about muscle length and triggers contraction in response to stretching.

Answer 48

muscle spindle apparatus

Question 49

The ___ ___ ___ monitors tendon tension and triggers relaxation to prevent injury.

Answer 49

Golgi tendon organ

Question 50

_____ muscle cells are striated, branched, and connected by gap junctions.

Answer 50

Cardiac

Question 51

Cardiac muscle behaves as a _____ unit and generates its own ____ ____.

Answer 51

single, action potentials

Question 52

_____ muscle lacks sarcomeres and uses _____ instead.

Answer 52

Smooth, dense bodies

Question 53

Smooth muscle is controlled by the _____ nervous system.

Answer 53

autonomic

Question 54

Single-unit smooth muscle cells are connected by ___ ___, allowing coordinated contractions.

Answer 54

gap junctions

Question 55

Multiunit smooth muscle cells are controlled by ___ ___ ___ for more precise control.

Answer 55

individual nerve fibers

Question 56

The ____ ____ is a specialized smooth ER thats stores Ca²⁺ in the muscle cell.

Answer 56

sarcoplasmic reticulum

Question 57

The _____ system delivers electrical impulses deep into muscle fibers.

Answer 57

T-tubule

Question 58

_____ synapses in smooth muscle allow neurotransmitter release along an axon.

Answer 58

Varicosities