Ch. 11: The Musculoskeletal System

Question 1

3 main types of muscle

Answer 1

Skeletal, smooth, cardiac

Question 2

Skeletal muscle

Answer 2

Involved in support and movement, propulsion of blood in the venous sys, and thermoregulation. Appears striated, is under voluntary (somatic) control, is polynucleated, and can be divided into red (slow-twitch) fibers that carry out oxidative phosphorylation and white (fast-twitch) fibers that rely on anaerobic metabolism

Question 3

Smooth Muscle

Answer 3

In the respiratory, reproductive, cardiovascular and digestive systems. It appears nonstriated, is under involuntary (autonomic) control, and is uninucleated. It can display myogenic activity or contraction without neural input

Question 4

Cardiac muscle

Answer 4

Comprises the contractile tissue of the heart. It appears striated, is under involuntary (autonomic) control, and is uninucleated (sometimes binucleated). It can also display myogenic activity. Cells are connected w intercalated discs that contain gap junctions

Question 5

Sarcomere

Answer 5

Basic contractile unit of striated muscle. Made of thick myosin and thin actin filaments

Question 6

Troponin and Tropomyosin

Answer 6

Found on the thin filament and regulate actin-myosin interactions

Question 7

Sarcomere can be divided into

Answer 7

Different lines, zones, and bands

Question 8

Z-lines

Answer 8

Boundaries of each sarcomere are defined by Z-lines

Question 9

M-line

Answer 9

Located in the middle of the sarcomere

Question 10

I-band

Answer 10

Contains only thin filaments

Question 11

H-zone

Answer 11

Consists of only thick filaments

Question 12

A-band

Answer 12

Contains the thick filaments in their entirety. It is the only part of the sarcomere that maintains a constant size during contraction

Question 13

Myofibrils

Answer 13

Sarcomeres attached end-to-end

Question 14

Myocyte

Answer 14

Muscle cell or muscle fiber, contains many myofibrils

Question 15

Sarcoplasmic Reticulum

Answer 15

Surrounds myofibrils, calcium containing modified endoplasmic reticulum

Question 16

Sarcolemma

Answer 16

Surrounds myofibrils the cell membrane of a myocyte

Question 17

T-tubules

Answer 17

A system of T-tubules is connected to the sarcolemma and oriented perpendicularly to the myofibrils, allowing the incoming signal to reach all parts of the muscle

Question 18

Neuromuscular Junction:

Answer 18

Muscle contraction begins at the neuromuscular junction, where the motor neuron releases acetylcholine that binds to receptors on the sarcolemma, causing depolarization

Question 19

Depolarization

Answer 19

Spreads down the sarcolemma to the T-tubules, triggering the release of calcium ions

Question 20

Calcium

Answer 20

Binds to troponin, causing a shit in tropomyosin and exposure of the myosin binding sites on the actin thin filament

Question 21

Sliding filament model

Answer 21

Shortening of the sarcomere occurs as myosin heads bind to the exposed sites on actin, forming cross bridges and pulling the actin filament along the the thick filament, resulting in contraction

Question 22

Muscle Relaxation

Answer 22

Acetylcholine is degraded by acetylcholinesterase, terminating the signal and allowing calcium to be brought back into the SR. ATP binds to the myosin head, allowing it to release from actin

Question 23

Simple twitch

Answer 23

An all or nothing response exhibited by muscle cells

Question 24

Frequency Summation

Answer 24

Addition of multiple simple twitches before the muscle has an opportunity to fully relax

Question 25

Tetanus

Answer 25

Simple twitches that occur so frequently as to not let the muscle relax at all can lead to tetanus, a more prolonged and stronger contraction

Question 26

Oxygen Debt:

Answer 26

Muscle cells have additional energy reserves to reduce oxygen debt (the diff between the amt of oxygen needed and the amt present) and forestall fatigue

Question 27

Creatine Phosphate

Answer 27

Can transfer a phosphate group to ADP forming ATP

Question 28

Myoglobin

Answer 28

Heme containing protein that is a muscular oxygen reserve

Question 29

Endoskeleton

Answer 29

Internal skeletons (like those in humans)

Question 30

Exoskeletons

Answer 30

External skeletons (like those in arthropods)

Question 31

human skeletal system divisions

Answer 31

Axial and appendicular skeletons

Question 32

Axial skeleton

Answer 32

Consists of structures in the midline such as the skull, vertebral column, ribcage, and hyoid bone

Question 33

Appendicular skeleton

Answer 33

Consists of the bones of the limbs, the pectoral girdle and the pelvis

Question 34

Bone is derived from

Answer 34

Embryonic mesoderm and includes both compact and spongy (cancellous) types

Question 35

Compact Bone

Answer 35

Provides strength and is dense

Question 36

Spongy or cancellous bone

Answer 36

Has a lattice-like structure consisting of bony spicules known as trabeculae. The cavities are filled w bone marrow

Question 37

Long bones contain

Answer 37

Shafts called diaphyses that flare to form metaphyses and that terminated in epiphyses

Question 38

Epiphysis

Answer 38

Contain an epiphyseal (growth) plate that causes linear growth of the bone

Question 39

Periosteum

Answer 39

Bone is surrounded by a layer of connective tissue called periosteum

Question 40

Tendons

Answer 40

Bones to muscle

Question 41

Ligaments

Answer 41

Bones to bones

Question 42

Bone matrix

Answer 42

Has both organic components, like collagen, glycoproteins, and other peptides, and inorganic components, like hydroxyapatite

Question 43

Lamellae

Answer 43

Concentric rings that bone is organized into

Question 44

Haversian or Volkmann’s canal

Answer 44

Center of the concentric rings

Question 45

Osteon or Haversian system

Answer 45

Structural unit of lamellae and Volkmann’s canal

Question 46

Lacunae

Answer 46

Between lamellar rings, where osteocyte reside, which are connected with canaliculi to allow for nutrient and waste transfer

Question 47

Bone remodeling

Answer 47

Carried out by osteoblasts (build bone) and osteoclasts (resorb bone)

Question 48

Parathyroid Hormone

Answer 48

Increases resorption of bone, increasing calcium and phosphate concentrations in the blood

Question 49

Vitamin D

Answer 49

Also increases resorption of bone, leading to increased turnover and, subsequently, the production of stronger bone

Question 50

Calcitonin

Answer 50

Increases bone formation, decreasing calcium concentrations in the blood

Question 51

Cartilage

Answer 51

Firm, elastic material secreted by chondrocytes. Its matrix is called chondrin. Usually found in areas that require more flexibility or cushioning. Avascular and not innervated

Question 52

Endochondral ossification

Answer 52

In fetal life, bone forms from cartilage through endochondral ossification.

Question 53

Intramembranous ossification

Answer 53

Some bones, esp those of the skill, form directly from undifferentiated tissue (mesenchyme)

Question 54

Classification of joints

Answer 54

Immovable or movable

Question 55

Immovable joints

Answer 55

Fused together to form sutures or similar fibrous joints

Question 56

Movable joints

Answer 56

Usually strengthened by ligaments and contain a synovial capsule

Question 57

Synovial fluid

Answer 57

Secreted by the synovium, aids in motion by lubricating the joint

Question 58

Articular Cartilage

Answer 58

Each bone in the joint is coated with articular cartilage to aid in movement and provide cushioning

Question 59

Antagonistic Pairs

Answer 59

Muscles that serve opposite functions come in antagonistic pairs; when one muscle contracts the other lengthens