EXAM 2 REVIEW

what does the bifid spinous process look like?

what does the bifid spinous process look like?

bony landmark that makes two centers for ossification

what is hydroxyapatite and what is it made up of?

crystalized mineral salts made up of calcium and phosphate

what makes up of 50% of the bone?

hydroxyapatite

what makes up the hardness of the bone?

hydroxyapatite

what makes up 25% of the bone?

collagen

what makes the bone strong

collagen (strong)

what percentage of water makes up of the bone

25%

what is the end part of the bone called?

epiphysis and the articular cartilage (hyaline type)

what is a metaphysis?

a growth plate that becomes a epiphyseal line

what is the epiphyseal growth plate from the metaphysis closed by?

estrogen

1

epiphysis

2

diaphysis

3

epiphysis

4

articular cartilage

5

epiphyseal line

6

spongy bone

7

medullary cavity

8

nutrient foramen (tube of the side)

9

endosteum

10

periosteum

11

articular cartilage

what is the nutrient artery?

two veins that sends branches upward and downward to the bone marrow

what is the function of a nutrient artery?

ramifies in the medullary membrane and give twigs to the adjoining canals

where does the nutrient arteries passes through within the compact bone?

the nutrient foramen

what are osteocytes?

mature bone cells and are the main cells in bone tissue

what is the function of osteocytes

maintains the bone’s bone tissue and daily metabolism such as the exchange of nutrients and waste in the blood

osteocytes do not undergo

cell division

before turning into an osteocytes, osteocytes start outs as

osteoblasts

what are osteoblasts

bone building cells

what is the function of osteoblasts

synthesize and secrete collagen and other organic components needed to build the bone matrix and also initiated calcification

what are osteoblasts responsible for?

bone deposition, or forming new bones, and forms the bone matrix

regarding calcium, what happens during bone deposition?

calcium is deposited into the bones. Ca+2 from blood to bone (osteoclasts)

what are osteoclasts?

big cells from monocytes (white blood cells)

where are the osteoclasts located in

THE endosteum

what are the functions of the osteoclasts

bone resorption or breaking down of bones

regarding calcium, what happens during bone resorption?

osteoclasts breaks down bone minerals releasing calcium into the blood. Ca+2 bone to blood

what are bone scans?

diagnostic procedures from a radioactive tracer

how are bone scans performed?

a radioactive tracer is absorbed by the bone from an injection though the veins

bone scans are used to measure

bone density

what is intramembranous ossification

where the bone forms from mesenchyme

how does intramembranous ossification produce bones?

mesenchymal tissue is converted into bone which creates flat bones

what is the first step of intramembranous ossification (O)

development of ossification center

what is the second step of intramembranous ossification (C)

Calcification

what is calcification?

where mineral salts makes the bone hard while collagen fibers making the bone strong

what is the third step of intramembranous ossification (T)

formation of the trabeculae

what is the fourth step of intramembranous ossification (P)

development of the periosteum

what is ossification?

process of bone formation

what is endochondral ossification

the development of long bones

what happens during endochondral ossification?

cartilage is replaced with bone making the bone stretch out like a bread stick which is why the bone is long

what is the first step of endochondral ossification? (D)

development of cartilage

what is the second step of endochondral ossification? (G)

growth of cartilage

what is the third step of endochondral ossification? (P)

development of the primary ossification center

what is the fourth step of endochondral ossification? (S)

development of the secondary ossification

what is the fifth step of endochondral ossification? (A)

formation of articular cartilage and the epiphyseal plate

what is appositional growth?

where the bone grows wider or thicker in diameter

what is the first step in appositional growth

differentiate periosteal cells into osteoblast

what is the second step in appositional growth

periosteal ridges fuse forming an endosteum or lined tunnel

what is the third step in appositional growth

osteoblasts in the endosteum build new concentric lamellae inward toward the center of the tunnel forming a osteon

what is the fourth step in appositional growth

bone grows outwards as osteoblasts build new lamellae then more osteons forms as new periosteal ridges fold over blood vessels

what is interstitial growth?

the bone growing longer

first major event in interstitial growth

cartilage grows on the epiphyseal side of the epiphyseal plate

second major event in the interstitial growth

bone replaces cartilage on the diaphyseal side of the epiphyseal plate by endochondral ossification

what is the epiphyseal plate?

located in the metaphysis and a layer of hyaline cartilage of a growing bone by endochondral ossification

how many zones does the epiphyseal plate have?

4 zones

what is zone one of the epiphyseal plate

zone of resting cartilage

what is zone two of the epiphyseal plate

zone of proliferation (GROWTH) cartilage

what is zone three of the epiphyseal plate

zone of hypertrophic cartilage (accumulates glycogen)

what is zone four of the epiphyseal plate

zone of calcified cartilage

what minerals are needed for bone growth

calcium, phosphorus, magnesium, fluoride, and manganese

what vitamins are needed for bone growth

A,B,D,K, and B12

what hormones are needed for bone growth

IGF (insulin for growth), hGH (human growth hormone), thyroid hormones (T3 and T4), estrogen and testosterone

what proteins are needed for bone growth

intrinsic factor (IF) where vitamin B12 is absorbed in the bones or RBC (red blood cells)

what kind of bone is the intrinsic factor?

a glycoprotein

how are intrinsic factors produced?

the parietal cells of the gastric mucosa synthesizes and secretes glycoproteins

what happens in the intrinsic factor?

vitamin b12 is absorbed in the small intestines

what happens if we don’t have the intrinsic factor?

vitamin b12 cannot be aborded in which bone growth or RBC (red blood cell) production cannot occur

how many steps are there in fracture repair?

4

what is the first step in fracture repair

the formation of fracture hematoma (bruising)

what is the second step of fracture repair?

fibrocartilaginous callus formation (soft bone))

what is the third step in fracture repair

boney callus formation (hard bone)

what is the fourth step in fracture repair?

bone remodeling

what is bone remodeling?

the final phase of a fracture repair

what happens during bone remodeling?

dead parts of the broken bone are reabsorbed by osteoclasts and then the compact bone replaces the spongy bone around the periphery of the fracture

what is bone resorption (osteo)?

breakdown of the bone matrix by the osteoClasts

in detail how the osteoclasts break down the matrix?

it removes bone tissue by removing the matrix and breaking up the organic bone

what does the parathyroid hormone (PTH) do?

regulated the Ca2+ in our blood usually when the calcium level is low

the regulation of calcium in the blood should be

9-11 mg

what happens when there is extra calcium in the blood?

it is deposited into the bones like a safe

regarding osteoclasts, what happens when the body needs calcium?

the calcium stored in the bones is removed by the osteoclasts

when the blood has a calcium level of 9-11 mg where does the excess calcium go?

the bones. it is stored in the bones like a safe (911)

what is calcium needed for in the body (homeostasis)?

muscle contraction, nerve impulses, and causes blood clotting (DOES NOT PREVENT IT)

how is homeostasis maintain when the calcium level is not between 9-11 mg?

the calcium stored in the bones is removed and placed into the blood to raise the calcium level in the blood.

what regulated the calcium levels in the blood and make sure it reaches the right levels?

the parathyroid hormone which increases calcium level in the blood

the parathyroids stops releasing calcium when

the negative feedback loops signals from the increased calcium levels

what is the parathyroid hormone?

a hormone secreted by the parathyroid gland and allows calcium to leave the blood in and out through the blood IF the calcium in the blood is not at the right level.

what is bone density

the amount of matter per cubic centimeter of bones

what is calcitonin?

inhibits activity of osteoclasts and secreted by the thyroid gland (because its a hormone)

what happens during calcitonin?

it speed blood Ca+ uptake by the bone and accelerates Ca+ deposition in the bone, decreases blood levels of calcium by putting calcium into bone or removes calcium from the blood and put it into bone

what happens when bone deposition exceeds bone resorption

the bone increases in mass and density

what is osteoporosis?

decrease in bone mass and makes the bones porous