Skeletal System

Question 1

function of the skeletal system

Answer 1

storage of calcium, lever system, protection for vital organs

Question 2

red marrow

Answer 2

hematopoietic stem cells (immature cells) that make RBCs, WBCs, and osteoclasts

Question 3

yellow marrow

Answer 3

mesenchymal stem cells that make osteoblasts, osteocytes and adipocytes

Question 4

osteoclasts

Answer 4

cells that can help degrade bone and release calcium from bones, multinucleated

Question 5

osteoblast

Answer 5

help build bone, deposit calcium in bone to make it stronger, single nucleated

Question 6

osteocytes

Answer 6

bone cells

Question 7

adipocytes

Answer 7

fat cells (yellow and in yellow marrow)

Question 8

modeling

Answer 8

chondrocytes –> cartilage –> osteoblasts –> osteoid + hydroxyapatite

Question 9

chondrocytes

Answer 9

lay down more cartilage
die and leave cartilage

Question 10

osteoblasts

Answer 10

form the osteoid that binds to cartilage

Question 11

growth hormone

Answer 11

stimulates chondrocytes to produce cartilage and osteoblasts
occurs until epiphysial closure occurs –> influenced by genetics
hypothalamus –> pituitary gland –> GHRH

Question 12

lacunae

Answer 12

areas in canaliculi where osteocytes are housed

Question 13

canaliculi

Answer 13

canal, allows cells to have access to blood, connect the central canal to cells, connection between cells

Question 14

lamellae

Answer 14

spaces where cells will reside, concentric layers

Question 15

haversian canal (central canal)

Answer 15

where there is blood supply and helps keep the osteocyte cells alive

Question 16

remodeling

Answer 16

osteoblasts and osteoclasts always working

Question 17

degrade bone

Answer 17

osteoclast activity > osteoblast activity

Question 18

build bone

Answer 18

osteocalst activity < osteoblast activity

Question 19

sclerostin (anti-anabolic effect)

Answer 19

secreted by osteocytes
inhibit osteoblast activity
breakdown bone

Question 20

osteoporosis characteristics

Answer 20

bone shatters when osteoporosis bone is broken and need to replace bone
factors: pickup plate, step of a curb, get out of the shower
1:4 men to women

Question 21

osteoporosis risk factors

Answer 21

genetics, race (asians more likely), smoking (can limit hunger)

Question 22

osteoporosis in women vs men

Answer 22

women
- bone loss at age 45
- 3% decline/decade
- menopause at 55-60 years old that causes a 9% decline, osteoblast activity < osteoclast, decrease in estrogen levels

men
- bone loss at age 55
- 3% decline/decade

Question 23

estrogen

Answer 23

can help lower secretion of sclerostin so no estrogen means secretion of sclerostin and osteoblast activity inhibited, increasing rate of bone loss

Question 24

mechanosensors

Answer 24

Stimulate osteoblast activity
depositing in more bone to prevent hepisopetate
d = m/v and increase in exercise and decrease in density
deoxygenation

Question 25

osteoporosis affect of diet

Answer 25

not enough calcium centers, body takes it from the bone drink milk

Question 26

osteoporosis preventions

Answer 26

resistance training increase skeletal muscle tension, increase bone strength 40-60% strength before one breaks

Question 27

calcium homeostasis (too high)

Answer 27

calcitonin decreases vitamin D levels, thyroid increases kidneys decrease calcium reabsorption bones increase osteoblast activity small intestine decreases calcium absorption

Question 28

calcium homeostasis (too low)

Answer 28

parathyroid hormone, low calcium levels, increased vitamin D kidneys increase calcium reabsorption in proximal tubules bones increase osteoclast activity small intestine increases calcium absorption

Question 29

RBC formation (erythropoiesis)

Answer 29

RBCs shelf life is 120 days and can't replicated because no nucleus hematopoetic stem cells --> erythroblasts (lose nucleus) --> reticulates --> erythocytes

Question 30

epo (erythropoietin)

Answer 30

released by kidneys stimulates erythropoiesis formation

Question 31

hematopoietic

Answer 31

stem cells in the bone that make RBCs stem cells

Question 32

RBC death (eryptosis)

Answer 32

changes conformation of cell membrane

Question 33

apoptosis

Answer 33

a form of programmed cell death usually occurs in the nucleus

Question 34

macrophage

Answer 34

degrade RBCs and located in the spleen and liver

Question 35

heme

Answer 35

bilirubin converted in bile urobilin --> yellow color filters by urination

Question 36

globin

Answer 36

alpha and beta chains broken down and sent back to bone to reform hb in eryptosis

Question 37

iron (Fe+)

Answer 37

converted into transferrin --> to transport iron iron goes to bone to reform hb liver can store iron as feritin