Chapter 7 - Bones

Question 1

cartilage

Answer 1

covers many joint surfaces of mature bone

Question 2

ligaments

Answer 2

hold bones togetther at joints

Question 3

tendons

Answer 3

attach muscle to bone

Question 4

functions of skeleton

Answer 4

• support
• protection
• movement
• electrolyte balance: phosphate/calcium levels
• acid-base balance: buffers blood against large pH changes by altering phosphate and carbonate salt levels
• blood formation: red bone marrow is producer of blood cells

Question 5

flat bones

Answer 5

• thin, curved plates
• protect soft orgrans
• ex. skull bones

Question 6

long bones

Answer 6

• longer than wide
• rigid levers acted upon muscles; crucial for movement

Question 7

short bones

Answer 7

• approximately equal in length and width
• glide across one another in multiple directions

Question 8

irregular bones

Answer 8

• elaborate shapes that do not fit into other categories

Question 9

compact bone

Answer 9

dense outer shell of bone

Question 10

spongy bone

Answer 10

• loosely organized bone tissue
• found in the center of ends and shafts of long bones and in the middle of nearly all others
• covered by compact bone

Question 11

anatomy of a long bone

diaphysis

Answer 11

elongated, cylindrical shaft

Question 12

anatomy of a long bone

epiphysis

Answer 12

knobby region, joint, surface for bone to bone articulation, tendon and ligament attachment

Question 13

anatomy of a long bone

metaphysis

Answer 13

region found between the diaphysis and epiphysis, contains the epiphyseal growth plate

Question 14

anatomy of a long bone

epiphyseal line

Answer 14

remnant of the growth plate, made of a thin layer of compact bone

Question 15

general features of bones

articular cartilage

Answer 15

layer of cartilage that covers joint surface; allows joint to move more freely

Question 16

general features of bones

nutrient foramina

Answer 16

minute holes in the bone surface that allows blood vessels to penetrate
(little holes)

Question 17

general features of bones

periosteum

Answer 17

external sheath covering most of bone
* outer fibrous layer of collagen
- some fibers continuous with tendons
- perforating fibers: penetrate into bone matrix
* inner osteogenic layer of bone-forming cells
- important to bone growth and healing of fractures

Question 18

osteogenic cells

Answer 18

stem cells found in endosteum and inner layer of periosteum
* arise from embryonic mesenchyme
* multiply continuously and give rise to most other bone cell types

Question 19

osteoblasts

Answer 19

bone forming cells
* hardens when minerals are deposited
* stress stimulates osteogenic cells to multiply repidly and increase the number of osteoblasts which reinforce bone
** osteocalcin:** hormone stimulates insulin secretion of pancreas

Question 20

osteocytes

Answer 20

osteoblasts that have become trapped in the matrix
* act as strain sensors: when stressed, produce biochemical signals that regulate bone remodeling

Question 21

osteoclasts

Answer 21

blone-dissolving cells found on bone surface
* cells often reside in resorption bays
* dissolving bone is part of bone remodeling
* repairs microfractures, releases minerals into blood, reshapes bones in response to use/disuse

Question 22

bone marrow

Answer 22

soft tissue occupying marow cavities of long bones and small spaces of spongy bone

Question 23

red marrow (myeloid tissue)

Answer 23

• contains hemopoietic tissue (which produces blood cells)
• in children: found in every bone
• adults: found in skull, vertebrae, ribs, sternum, pelvic gridle

Question 24

calcium homeostasis

Answer 24

• phosphate is a component of DNA, RNA, ATP, phospholipids, and pH buffers
• calcium needed in neuron communication, muscle contraction, blood clotting, and exocytosis
  minerals deposited into skeleton, withdrawn when needed for above purposes ^

Question 25

calcitriol

Answer 25

* most active form of vitamin D * produced by actions of skin, liver, and kidneys * hormone that raises blood calcium level

Question 26

rickets/osteomalacia

Answer 26

inadequate calcitriol results in abnormal softness of bones in children and adults

Question 27

calcitonin

Answer 27

secreted by the thyroid gland when blood calcium levels rise too high * lowers blood calcium concentration * may inhibit bone loss in pregnant and lactating women

Question 28

parathyroid hormone

Answer 28

PTH: secreted by parathyroid glands * released when calcium levels low in blood

Question 29

orthopedics

Answer 29

branch of medicine dealing with prevention and correction of injuries and disorders of bones, joints, and muscles

Question 30

achondroplastic dwarfism

Answer 30

* long bones stop growing in childhood * normal torso, short limbs * failure of cartilage growth in metaphysis * spontaneous mutation produces mutant dominant allele (doesn't have to have a genetic componet)

Question 31

pituitary dwarfism

Answer 31

* lack of growth hormone * normal proportions with short stature

Question 32

anabolic steroid affect on bone

Answer 32

* cause growth to stop * epiphyseal plate "closes" prematurely * results in short adult stature

Question 33

stress fracture

Answer 33

break caused by abnormal trauma to a bone (ex. in a fall)

Question 34

pathological fracture

Answer 34

* break in bone weakened by disease (such as bone cancer or osteoporosis) * usually caused by a stress that would not break a healthy bone

Question 35

4 types of bone fractures

Answer 35

1. nondisplaced 2. displaced 3. comminuted: shatter plates 4. greenstick: bends then splinters

Question 36

# fractures 4 steps of the healing process

Answer 36

1. hematoma formation 2. soft callus formation 3. hard callus formation 4. bone remodeling

Question 37

closed reduction

Answer 37

procedure in which bone fragments are manipulated into their normal positions without surgery

Question 38

open reduction

Answer 38

involves surgical exposure of the bone and the use of plates, screws, or pins to realign the fragments

Question 39

cast

Answer 39

normally used to stabilize and immobilize healing bone

Question 40

osteoporosis

Answer 40

the most common bone disease * severe loss of bone density * estrogen: maintains bone density in both sexes; inhibits resorption by osteoclasts * postmenopausal white womens at greatest risk * young female athletes with low body fat, stop ovulating

Question 41

treatments of osteoporosis

Answer 41

ERT: estrogen replacement therapy slows bone resorption, but increases risk of breast cancer, stroke, heart disease Drugs: fosamax, actonel: destroy osteoclasts PTH: slows bone loss if given as daily injection (2 year max = leads to bone cancer Prevention = best treatment = exercise