Biology Muscular and Skeletal Systems

Question 1

The rib cage protects the thoracic organs (heart and lungs), whereas the skull and vertebral column protect the brain and ___ cord

Answer 1

spinal

Question 2

The two major parts of the skeleton are ___ and bone

Answer 2

cartilage

Question 3

___ are cells responsible for synthesizing cartilage

Answer 3

chrondrocytes

Question 4

Bone is a specialized type of mineralized connective ___ that has the ability to withstand physical stress

Answer 4

tissue

Question 5

There are two types of bone: ___ bone and spongy bone

Answer 5

compact

Question 6

Compact bone is ___ bone that does not appear to have any cavities when observed with the naked eye and makes up 80% of the skeleton

Answer 6

dense

Question 7

The bony ___ is deposited in structural units called osteons (Haversian systems)

Answer 7

matrix

Question 8

Each osteon consists of a central microscopic channel called a Haversian canal, surrounded by a number of concentric circles of ___ matrix (calcium phosphate) called lamellae

Answer 8

bony

Question 9

Spongy bone, which can be found at the ends of long bones, in the pelvic bones, skull, and vertebra, is much less dense and consists of an interconnecting ___ of bony spicules (trabeculae); the cavities between the spicules are filled with yellow or red bone marrow

Answer 9

lattice

Question 10

Yellow marrow is ___ and infiltrated by adipose tissue; red marrow is involved in blood cell formation

Answer 10

inactive

Question 11

Osteoblasts synthesize and secrete the organic ___ of the bone matrix; once they have become surrounded by their matrix, they mature into osteocytes

Answer 11

constituents

Question 12

Osteoclasts are large, multinucleated cells involved in bone ___, wherein bone is broken down and minerals (namely Ca2+) are released into the blood

Answer 12

reabsorption

Question 13

Bone formation occurs by either endochondral ossification or by ___ ossification

Answer 13

intramembranous

Question 14

In ___ ossification, existing cartilage is replaced by bone

Answer 14

endochondral

Question 15

Long bones arise primarily through endochondral ___

Answer 15

ossification

Question 16

In intramembranous ossification, ___ (embryonic or undifferentiated) connective tissue is transformed into and replaced by bone

Answer 16

mesenchymal

Question 17

The ___ skeleton is the basic framework of the body, consisting of the skull, vertebral column, and rib cage

Answer 17

axial

Question 18

The axial skeleton is the point of attachment of the appendicular skeleton, which includes the bones of the ___ (limbs) and the pectoral and pelvic girdles

Answer 18

appendages

Question 19

___ serve as bone to bone connectors

Answer 19

ligaments

Question 20

The point of attachment of a muscle to a stationary bone (proximal end in limb muscles) is called the ___

Answer 20

origin

Question 21

The point of attachment of a muscle to the ___ that moves (distal end in limb muscles) is called the insertion

Answer 21

bone

Question 22

___ indicates a straightening of a joint, whereas flexion refers to a bending of a joint

Answer 22

extension

Question 23

Extension and flexion require the contraction of ___ muscles

Answer 23

antagonist

Question 24

Because there are no intervening ___, the pyramidal system is able to provide rapid commands to the skeletal muscles and various other organs

Answer 24

synapses

Question 25

The red nucleus, located in the mesencephalon, is the component of the ___ system primarily in control of skeletal muscle tone

Answer 25

extrapyramidal

Question 26

Skeletal muscle is responsible for voluntary movements and is innervated by the ___ nervous system

Answer 26

somatic

Question 27

Embedded in the fibers of the skeletal muscle system are filaments called ___, which are further divided into contractile units called sarcomeres

Answer 27

myofibrils

Question 28

The myofibrils are enveloped by a modified endoplasmic reticulum that stores calcium ions and is called the ___ reticulum

Answer 28

sarcoplasmic

Question 29

The cytoplasm of a muscle fiber is called ___, and the cell membrane is called the sarcolemma

Answer 29

sarcoplasm

Question 30

The ___ is capable of propagating an action potential and is connected to a system of transverse tubules (T system) oriented perpendicularly to the myofibrils

Answer 30

sarcolemma

Question 31

The T system provides ___ for ion flow throughout the muscle fibers and can also propagate an action potential

Answer 31

channels

Question 32

Because of the high-energy requirements of contraction, ___ are very abundant in muscle cells and are distributed along the myofibrils

Answer 32

mitochondria

Question 33

___ muscle has striations of light and dark bands and is therefore also referred to as striated muscle

Answer 33

skeletal

Question 34

The sarcomere is composed of ___ and thick filaments

Answer 34

thin

Question 35

The thin filaments are chains of ___ molecules

Answer 35

actin

Question 36

The thick filaments are composed of organized bundles of ___ molecules

Answer 36

myosin

Question 37

acthin: actin ___ are thin while myosin filaments are thick

Answer 37

filaments

Question 38

Electron microscopy reveals that the sarcomere is organized as follows: ___ define the boundaries of a single sarcomere and anchor the thin filaments

Answer 38

Z lines

Question 39

In Skeletal muscle, the M line runs down the ___ of the sarcomere

Answer 39

center

Question 40

The ___ is the region containing thin filaments only

Answer 40

I band

Question 41

The ___ is the region containing thick filaments only

Answer 41

H zone

Question 42

The ___ spans the entire length of the thick filaments and any overlapping portions o the thin filaments

Answer 42

A band

Question 43

When the muscles contract, the ___ move toward each other

Answer 43

Z lines

Question 44

During contraction, the A band is not reduced in size, whereas the H zone and ___ are

Answer 44

I band

Question 45

Z is the end of the alphabet and therefore the end of your ___

Answer 45

sarcomeres

Question 46

M is the middle and is attached to the mighty myosin ___

Answer 46

filaments

Question 47

I is the thinnest letter so the ___ has only thin filaments

Answer 47

I band

Question 48

___ is a thick letter and has only thick filaments

Answer 48

H (zone)

Question 49

The ___ is an in between sized letter and the A band includes the overlap of thick and thin

Answer 49

A band

Question 50

Muscle ___ is stimulated by a message from the somatic nervous system sent via a motor neuron

Answer 50

contraction

Question 51

The link between the nerve terminal (synaptic bouton) and the sarcolemma of the muscle fiber is called the ___ junction

Answer 51

neuromuscular

Question 52

The space between the nerve terminal and the neuromuscular junction is known as the synapse, or ___ cleft

Answer 52

synaptic

Question 53

In skeletal muscle, the ___ diffuses across the synaptic cleft and binds to special receptor sites on the sarcolemma

Answer 53

neurotransmitter

Question 54

In skeletal muscle, if enough receptors are stimulated, the permeability of the ___ is altered and an action potential is generated

Answer 54

sarcolemma

Question 55

In skeletal muscle, once an action potential is generated, it is conducted along the sarcolemma and the ___ and into the interior of the muscle fiber

Answer 55

T system

Question 56

In ___ muscle, once an action potential is generated, the sarcoplasmic reticulum releases calcium ions into the sarcoplasm

Answer 56

skeletal

Question 57

In skeletal muscle, once the sarcoplasmic ___ releases calcium ions, calcium ions initiate the contraction of the sarcomere by binding to troponin C on the actin filaments

Answer 57

reticulum

Question 58

In skeletal muscle, once calcium ions initiate the contraction of the sarcomere, allosteric changes occur in the proteins that allow ___ heads to bind to these sites on the actin

Answer 58

myosin

Question 59

In skeletal muscle, after allosteric changes, use of energy allows a power stroke to occur, pulling the ___ closer together

Answer 59

Z bands

Question 60

In skeletal muscle, once a power stroke occurs, actin and ___ slide past each other, and the sarcomere contracts

Answer 60

myosin

Question 61

A simple ___ is the response of a single muscle fiber to a brief stimulus at or above the threshold stimulus and consists of a latent period, a contraction period, and a relaxation period

Answer 61

twitch

Question 62

The ___ period is the time between stimulation and the onset of contraction

Answer 62

latent

Question 63

During the latent period, the action potential spreads along the ___, and Ca2+ ions are released

Answer 63

sarcolemma

Question 64

After the ___ period, there is a brief relaxation period during which the muscle is unresponsive to stimulus; this period is known as the absolute refractory period

Answer 64

contraction

Question 65

When the contractions begin to combine, becoming stronger and more prolonged, this is known as ___ summation

Answer 65

temporal

Question 66

When the ___ become continuous when the stimuli are so frequent that the muscle cannot relax this type of contraction is known as tetanus and is stronger than a simple twitch of a single fiber

Answer 66

contractions

Question 67

If ___ is maintained, the muscle will fatigue, and the contraction will weaken

Answer 67

tetanus

Question 68

___ is a state of partial contraction

Answer 68

tonus

Question 69

___ are never completely relaxed and maintain a partially contracted state at all times

Answer 69

muscles

Question 70

During periods of strenuous activity, skeletal muscles convert glucose to pyruvic acid through the process of ___

Answer 70

glycolysis

Question 71

Glycolysis enables ___ muscles to continue contracting even in the absence of oxygen

Answer 71

skeletal

Question 72

Lactic acid is generated in the absence of ___ in muscle contraction when pyruvic acid reacts with the enzyme lactate dehydrogenase

Answer 72

oxygen

Question 73

when ___ acid is generated, this process allows the pyruvate to enter the citric acid (or Krebs) cycle

Answer 73

lactic

Question 74

Smooth muscle is responsible for involuntary actions and is innervated by the ___ nervous system

Answer 74

autonomic

Question 75

___ muscle is found in the digestive tract, bladder, uterus, and blood vessel walls, among other places

Answer 75

smooth

Question 76

Smooth muscle cells possess one centrally located nucleus and lack the ___ of skeletal muscle

Answer 76

striations

Question 77

Smooth muscle
nonstriated, one nucleus per cell, involuntary/autonomic nervous system, smooth, continuous contractions
Cardiac Muscle
striated, one to two nuclei per cell, involuntary/autonomic nervous system, strong, forceful contractions
Skeletal Muscle
___, multinucleated cells, voluntary/somatic nervous system, strong, forceful contractions

Answer 77

striated

Question 78

In vertebrates, energy can be temporarily stored in a high-energy compound called ___ phosphate

Answer 78

creatine

Question 79

___ has a high oxygen affinity (found in muscle tissue) and maintains the oxygen supply in muscles by tightly binding to oxygen

Answer 79

myoglobin