Chapter 11- The Musculoskeletal System

Question 1

3 types of muscle

Answer 1

1. skeletal (supporting body/ voluntary movement)
2. smooth (involuntary movement/ peristalsis)
3. cardiac (maintain rhythmic contraction of heart w/o NS input)

Question 2

sarcomeres

Answer 2

basic contractile unit of skeletal muscle. made of thick and thin filaments. thick are bundles of myosin. thin are made of actin (troponin and tropomyosin help regulate interaction b/w thin and thick)

Question 3

different fibers in skeletal muscle

Answer 3

red fibers (aka. slow-twitch fibers)- high myoglobin content
white fibers (aka. fast-twitch fibers)- contain less myoglobin

Question 4

smooth vs skeletal muscle nuclei

Answer 4

skeletal- multinucleated

smooth- single nucleus

Question 5

tonus

Answer 5

constant state of low-level contraction by smooth muscle

Question 6

myogenic activity

Answer 6

smooth muscle can contract without NS input. muscle cells contract directly in response to stretch or other stimuli. both smooth and cardiac exhibit myogenic activity.

Question 7

cardiac muscle characteristics

Answer 7

autonomic NS. appears striated. may contain two nuclei, usually only one. each cell is connected by intercalated discs which contain gap junctions (cytoplasm is shared b/w those cells)

Question 8

what is required for muscle contraction?

Answer 8

Ca2+ and ATP

Question 9

I-band

Answer 9

only thin filaments

Question 10

H-zone

Answer 10

only thick filaments

Question 11

which band always remains constant with respect to size

Answer 11

A-band

Question 12

which structure separates each sarcomere

Answer 12

Z-line

Question 13

sarcoplasmic reticulum (SR)

Answer 13

cover myofibrils. modified endoplasmic reticulum with high Ca2+ concentration.

Question 14

sarcolemma

Answer 14

cell membrane of myocyte. capable of propagating and distributing action potential.

Question 15

myocyte

Answer 15

muscle cell

Question 16

where does Acetylcholine bind during an action potential

Answer 16

receptors on the sarcolemma, causing depolarization

Question 17

what is responsible for the powerstroke in muscle movement

Answer 17

the dissociation of ADP and P from myosin. the binding of ATP is required for releasing the myosin head from the actin filament.

Question 18

without Ca2+…

Answer 18

myosin-binding sites will be covered by tropomyosin and contraction will be prevented

Question 19

tetanus

Answer 19

very frequent contractions so that the muscle is unable to relax. this can cause muscle fatigue

Question 20

creatine phosphate

Answer 20

created by transferring phosphate from ATP to creatine during times of rest (1 way to reserve energy b/c it can be reversed quickly to generate ATP quickly)

Question 21

axial skeleton

Answer 21

skull, vertebral column, ribcage, hyoid bone (small bone in anterior of neck used for swallowing.

Question 22

appendicular skeleton

Answer 22

bones of limbs, pectoral girdle, and pelvis

Question 23

skeleton is created from 2 major components

Answer 23

bone and cartilage

Question 24

3 major segments of bone

Answer 24

1. epiphysis (ends)
2. metaphysis(near the end)
3. diaphysis (middle long part)

Question 25

epiphysis

Answer 25

epiphyseal plate (growth plate, site of longitudinal growth), spongy bone, periosteum (muscle attachment here/ fibrous sheet that surrounds long bones)

Question 26

diaphysis

Answer 26

periosteum, compact bone, marrow cavity

Question 27

compact bone vs. spongy/cancellous bone

Answer 27

compact- strong and dense, outermost bone | s/c- lattice structure with trabeculae filled with bone marrow, internal core of bone

Question 28

bone marrow

Answer 28

red marrow- hematopoietic stem cells (generate all cells in blood) yellow marrow- made of fat and is relatively inactive

Question 29

tendons

Answer 29

attach muscle to bone

Question 30

ligaments

Answer 30

pieces of fibrous tissue that connect bones together at joints. strengthen movable joints.

Question 31

bone matrix

Answer 31

organic (collagen, glycoproteins, peptides) and inorganic (Ca, phosphate, hydroxide ions all together form hydroxyapatite crystals) components

Question 32

osteons/ Haversian systems

Answer 32

structural units of bony matrix.

Question 33

lamellae

Answer 33

each osteon contains concentric circles of bony matrix.

Question 34

Haversian canals

Answer 34

longitudinal channels (those with axis parallel to the bone)

Question 35

Volkmann's canals

Answer 35

transverse channels (those with an axis perpendicular to the bone)

Question 36

lacunae

Answer 36

between lamellar rings are these small spaces. these house mature bone cells known as osteocytes.

Question 37

canaliculi

Answer 37

lacunae are interconnected by tiny channels which allow for the exchange of nutrients and wastes between osteocytes and the Haversian and Volkmann's canals

Question 38

osteoblast vs. osteoclast

Answer 38

blast- builds bone (uses Ca and phosphate from bone) | clast- chew bone, macrophages of bone and resorb it.

Question 39

parathyroid hormone

Answer 39

peptide hormone released by the parathyroid glands in response to low blood Ca, promotes resorption of bone, increasing the concentration of Ca and phosphate in the blood

Question 40

Vitamin D

Answer 40

activated by parathyroid hormone also promotes the resorption of bone.

Question 41

calcitonin

Answer 41

a peptide hormone released by the parafollicular cells of the thyroid in response to high blood calcium, promotes bone formation, lowering blood calcium levels

Question 42

cartilage

Answer 42

chondrin (secreted by cells called chondrocytes)- softer and more flexible than bone

Question 43

endochondral ossification

Answer 43

hardening of cartilage into bone. responsible for formation of most long bones in body.

Question 44

intramembranous ossification

Answer 44

undifferentiated embryonic connective tissue (mesenchymal tissue) is transformed into and replaced by bone--- this occurs in the skull

Question 45

immovable joints

Answer 45

bones fused together to form sutures or similar fibrous joints (found in head, anchor bones of skull together)

Question 46

movable joints

Answer 46

joints (elbow/ knee), ball-and-socket joints (shoulder/ hip)

Question 47

what do ligaments consist of

Answer 47

synovial capsule (encloses actual joint cavity-articular cavity)

Question 48

synovium

Answer 48

layer of soft tissue that secretes synovial fluid (lubricates movement of structures in the joint space)

Question 49

articular cartilage

Answer 49

contributes to the joint by coating the articular surfaces of the bones so that impact is restricted to the lubricated joint cartilage

Question 50

synergistic

Answer 50

working together to accomplish the same function

Question 51

flexor and extensor

Answer 51

antagonistic pairs. flexor- decreases angle across joint. extensor- increases this angle.

Question 52

abductor

Answer 52

moves part of body away from midline

Question 53

adductor

Answer 53

moves part of body toward the midline

Question 54

medial vs. lateral rotation

Answer 54

m- rotating axis toward midline | l- rotating axis away from midline

Question 55

what causes Ca2+ release from bones

Answer 55

parathyroid