Comprehensive Skeletal System and Bone Biology Quizlet

what is the purpose of the skeletal system

support, protection and movement

what is the bone made of

dense connective tissue, homopoetive tissue

Epiphysis

2 ends of the bone

Diaphysis

center shaft of bone

what are the 2 kinds of bone marrow

red (hemopoitive) and yellow

what are the two growing layers of cells that help bones grow

periosteum and endosteum

Osteoprogenitor cells

divide mitotically, creates bony tissue

Osteoblasts

bone forming cells

osteocytes

mature cells responsible for maintaining bone

Osteoclasts

bone-dissolving cells

what is the extracellular matrix of the bone made of

fibers, ground substance and hydroxyapatite

ground substance

sugar/protein polymer

hydroxyapatite

hard crystals that are resistant to compressive strength and weak to tensile

what are the 3 classes of bony tissue

compact, spongy and woven

spongy bone

porous lamellar bone (layers)

cortical or compact bone

dense lamellar bone (layered)

central canal

blood vessels in the osteon

lacunae

empty space in the osteon

canaliculi

tiny canals in the osteon

woven bone tissue

breakage or development of bone

what are the two types of developmental bone

intramembranous and endochondral ossification

Intramembranous ossification

produces the flat bones of the skull, most of the clavicle and part of the mandible

- simple OPG-- osteoblasts---osteocytes

Endochondral ossification

produces longs bones

- cartilage precursor

Pharathyroid hormone (PTH)

released when blood calcium is low

- a G coupled receptor

Vitamin D (calcitriol)

produced by liver, skin, kidneys

- lack of vitamin d causes softness of bones

calcitonin

lowers blood calcium when concentration rises to high

- inhibits osteoclast

- promotes osteoblasts

achondroplastic dwarfism

cartilage is not being produced effectively in endochondral ossification which leads to bone growth stunt

osteoporosis

bones breaking down faster due to very low calcium/vitamin D