ch7

Question 1

bone tissue

Answer 1

osseous tissue = calcified connective tissue

Question 2

4 types of bones

Answer 2

long, short, irregular, flat

Question 3

examples of these bones

Answer 3

long: ulna, femur
short: talus, carpal
irregular: sphenoid bone, vertebra
flat: scapula, sternum

Question 4

compact bone

Answer 4

outer layer of all bones, diaphysis of long bones

Question 5

spongy bone

Answer 5

heads of long bones, middle of others

Question 6

epiphysis

Answer 6

head of long bones

Question 7

diaphysis

Answer 7

shaft of long bone

Question 8

periosteum

Answer 8

sheath covering bone

Question 9

endosteum

Answer 9

lines internal surface

Question 10

epiphyseal plate

Answer 10

EP in children, EL in adults

Question 11

oreo analogy of flat bone

Answer 11

layer of compact bone, layer of spongy bone, layer of compact bone

Question 12

4 types of bone cells

Answer 12

osteogenic, osteocyte, osteoclast, osteoblast

Question 13

osteoblast

Answer 13

bone building, in endosteum and periosteum

Question 14

osteogenic

Answer 14

uses mitosis to form osteoblasts, in endosteum and periosteum

Question 15

osteoclasts

Answer 15

uses HCl to dissolve bone, in endosteum and periosteum

Question 16

osteocytes

Answer 16

stress sensors, regulates bone remodelling, resorb/deposit bone, maintain blood [] of Ca and PO. in lacuna surrounded by bone matrix

Question 17

bone matrix

Answer 17

1/3 organic component provides flexibility
2/3 inorganic component provides strength

Question 18

osteons

Answer 18

cylinders stacked on top of each other, lamellae wrapped around a central canal

Question 19

how do blood vessels and nerves enter?

Answer 19

via nutrient foramina - central canal - perforating canals - osteocyte to osteocyte via gap junctions

Question 20

spicules and trabeculae

Answer 20

rods, trabeculae (arranged around stress lines)

Question 21

bone marrow location

Answer 21

long bone = medullary (marrow) cavity
spongy bone = spaces
compact bone = larger central canals

Question 22

red marrow

Answer 22

makes blood cells, in kids in all bones, in adults in axial skeleton

Question 23

yellow marrow

Answer 23

in adults fatty yellow bone marrow in long bones of limbs. makes blood cells when red marrow is unavailable

Question 24

3 types of bone development

Answer 24

intramembranous ossification, endochondral ossification, bone growth/remodelling

Question 25

intramembranous ossification

Answer 25

this produces flat bones of skull, clavicle, mandible. transitions from embryonic CT (mesenchyme) to bone. it develops between blood vessels.4 stages

Question 26

stages of intramembranous o

Answer 26

deposition of osteoid tissue into embryonic mesenchyme - calcification of osteoid tissue and entrapment of osteocytes - honeycomb of spongy bone with developing periosteum - filling of space to form compact bone at surfaces, leaving spongy bone in middle

Question 27

endochondral o

Answer 27

bone develops from pre existing model of hyaline cartilage. produces all the other bones. transitions from embryonic CT to hyaline cartilage to bone. 6 stages

Question 28

skeletal dysplasia

Answer 28

achondroplasia - common pituitary dwarfism - lack of growth hormone

Question 29

where does the transition between cartilage and bone happen in the bone?

Answer 29

at the primary and secondary ossification center and at the metaphysis of one epiphyseal plate

Question 30

appositional growth

Answer 30

widening and thickening

Question 31

bone remodelling

Answer 31

absorption of old bone and deposition of new bone - at all stages of life osteoclasts/blasts maintain, grow or dissolve bone

Question 32

wolff's law of bone

Answer 32

bone adapts to the stress thats put on it - use it or lose it

Question 33

physiology of osseous tissue - mineral deposition

Answer 33

crystallization process - Ca and Po removed from blood and deposited along collagen fibres

Question 34

ectopic ossification

Answer 34

when bone is deposited in the wrong place

Question 35

mineral resorption

Answer 35

dissolving bone, releases minerals into blood. cell responsible for this is osteoclast

Question 36

functions of calcium in bone 99%

Answer 36

neuron communication, muscle contraction, blood clotting, enzyme cofactor

Question 37

hypocalcemia

Answer 37

Ca deficiency of calcium in the blood. excessive stimulation of nervous system - muscle spasms.

Question 38

hypercalcemia

Answer 38

excess of calcium in blood (rare)

Question 39

calcium homeostasis regulated by three hormones

Answer 39

calcitriol, parathyroid, calcitonin

Question 40

what do the calcium hormones target?

Answer 40

osteoclasts (releases Ca) osteoblasts (deposit Ca) kidneys (changes rate of reabsorption from urine/blood) intestine (changes rate of reabsorption)

Question 41

osteoporosis

Answer 41

loss of bone density - estrogen maintains bone density, so after menopause no estrogen, which means more dissolving of bone

Question 42

how to prevent osteoporosis

Answer 42

adequate calcium (1000mg), weight bearing exercises, increase bone mass before age 40