Muscular and Skeletal Systems

Question 1

Skeletal System

Answer 1

• an endoskeleton serves as the framework within all vertebral organisms
• muscles are attached to the bones permitting movement
• provides protection by surrounding delicate internal organs w/ bone

Question 2

Cartilage

Answer 2

• a type of connective tissue that is softer and more flexible than bone
• chrondocytes are cells responsible for synthesizing cartilage

Question 3

Bone

Answer 3

a specialized type of mineralized connective tissue that has the ability to withstand physical stress

Question 4

Compact Bone

Answer 4

dense bone that does not appear to have any cavities when observed with the naked eye

Question 5

Osteons

Answer 5

this is where the bony matrix is deposited

Question 6

Spongy Bone

Answer 6

much less dense and consists of an interconnecting lattice of bony spicules

Question 7

Yellow Marrow

Answer 7

inactive and infiltrated by adipose tissue

Question 8

Red Marrow

Answer 8

involved in blood cell formation

Question 9

Osteocytes

Answer 9

cells found in bone tissue

Question 10

Osteoblasts

Answer 10

synthesize and secrete the organic constituents of the bone matrix

Question 11

Osteoclasts

Answer 11

large, multinucleated cells involved in bone reabsorption, wherein bone is broken down and materials are released into the blood

Question 12

Bone Formation

Answer 12

occurs either by endochondrial ossification or by intramembranous ossification

Question 13

Endochrondial Ossification

Answer 13

existing cartilage is replaced by bone - long bones arise from this process

Question 14

Intramembranous Ossification

Answer 14

mesencymal connective tissue is transformed into and replaced by bone

Question 15

Organization of the Skeleton

Answer 15

-the axial skeleton is the basic framework of the body, consisting of the skull, vertebral column, and rib cage

Question 16

Origin

Answer 16

the point of attachment of a muscle to a stationary bone

Question 17

Insertion

Answer 17

the point of attachment of muscle to the bone that moves

Question 18

Extension

Answer 18

indicates a straightening of a joint

Question 19

Flexion

Answer 19

refers to a bending of a joint

Question 20

Muscular System

Answer 20

nervous control of the muscular system involves the axons of the pyramidal cells of the motor cortex

Question 21

Pyramidal System

Answer 21

able to provide rapid commands to the skeletal muscles and various other organs

Question 22

Skeletal Muscle

Answer 22

responsible for voluntary movements and is innervated by the somatic nervous system

Question 23

Myofibrils

Answer 23

filaments embedded in fibers

Question 24

Sarcomeres

Answer 24

• further divided myofibrils
• composed of thin and thick filaments
• thin filaments are chains of actin molecules
• thick filaments are composed of organized bundles of myosin molecules

Question 25

Sarcoplasmic Reticulum

Answer 25

enveloped myofribrils by a modified endoplasmic reticulum

Question 26

Sarcolemma

Answer 26

the cell membrane muscle fiber, capable of propagarting an action potential and perpendicular to the myofibrils

Question 27

T system

Answer 27

provides channels for ion flow throughout the muscle fibers and can also propogate an action potential

Question 28

Striated Muscle

Answer 28

skeletal muscle that has striations of light and dark bands

Question 29

Z-lines

Answer 29

- define the boundaries of a single sarcomere and anchor the thin filaments - when the muscles contract, z lines move toward each other

Question 30

M-lines

Answer 30

runs down the center of the sarcomere

Question 31

I-band

Answer 31

the region containing thin filaments

Question 32

A-band

Answer 32

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

Question 33

Contraction

Answer 33

- stimulated by a message from the somatic nervous system sent via motor neuron - depolarization of the motor neuron results in the release of neurotransmittors from the nerve terminal - once an action potential is generated, it is conducted along the sarcolemma and the T system and into the interior of the muscle fiber, which causes the sarcoplasmic reticulum to release calcium ions into the sarcoplasm

Question 34

Neuromuscular Junction

Answer 34

the link between the nerve terminal and the sarcolemma of the muscle fiber

Question 35

Rigor Mortis

Answer 35

all of the muscles in the body go into this state several hours after death. Muscles contract and go rigid because of the absence of ATP

Question 36

Isotonic

Answer 36

occurs when a muscle shortens against a fixed load while tension on the muscle remains constant

Question 37

Dynamic

Answer 37

includes both concentric and ecentric types of contractions. Results in a change in length of the muscle with corresponding change in tension on that muscle

Question 38

Concentric

Answer 38

a type of dynamic contraction where muscle fibers shorten and the tension on the muscle increases

Question 39

Eccentric

Answer 39

a type of dynamic contraction where the muscle fiber lengthens and the tension on the muscle increases

Question 40

Isometric

Answer 40

occurs when both ends of the muscle are fixed and no change in length occurs during the contraction, but the tension increases

Question 41

Stimulus and Muscle Reponse

Answer 41

- only a stimulus above a minimal value, called the threshold value, can elicit a contraction - strength of contraction cannot be increased by recruiting more muscle fibers

Question 42

Simple Tuition

Answer 42

the response of a single muscle fiber to a brief stimulus at or above the threshold stimulus and consists of a latent period, contraction period, and a relax action period

Question 43

Absolute Refractory Period

Answer 43

occurs after contraction and is a brief period during which the muscle is unresponsive to the stimulus

Question 44

Temporal Stimulation

Answer 44

when contractions combine becoming stronger and more prolonged

Question 45

Tetanus

Answer 45

contractions become continuous when the stimuli are so frequent that the muscle cannot relax