anatomy and physiology chapter 6

What are the functions of the skeletal system?

• Body support

• organ protection

• body movement

• mineral storage

• blood cell production

ligament

strong bands of connective tissue, holds bones to bones; allows some but not extensive movement

Joints

two or bone bones together, allows movement between bones

chondroblast

cartilage-producing cells

chondrocyte

mature cartilage cell; matrix surrounded chondroblast

lacuna

small space or cavity; potential space within the matrix of bone or cartilage normally occupied by a cell

perichondrium

double-layered protective connective tissue surrounding cartilage, containing fibroblasts

articular cartilage

hyaline cartilage covering the ends of bones within a synovial joint; has no perichondrium, blood vessels or nerves

appositional growth

to place one layer of bone, cartilage, or other connective tissue against and an existing layer; chondroblasts in perichodrium add new cartilage, grows in width

interstitial growth

chrondrocytes in the center of the tissue divide and add more matrix or space in between the existing cells

what are the 3 types of bone cells?

• osteoblasts

• osteoclasts

• osteocytes

osteoblast

bone building cells, have extensive endoplasmic reticulum and numerous ribosomes

what do osteoblasts produce?

collagen and proteoglycans

osteocytes

mature bone cell surrounded by bone matrix

where are osteocyte cells housed

by bone matrix spaces, lacuna

where are osteocyte cells extensions housed?

in long narrow spaces called canalievil

osteoclasts

large, multinucleated cell that absorbs bone

what differences are there between spongey bone and compact

• amount of bone matrix

• formation

• how porous each is

spongy bone

porous, less bone matrix, formed with trabeculae

compact bone

contains matrix, dense, few pores and formed with osteons

gross anatomy of long bones

1. diaphysis

2. epiphysis

3. periosteum

4. endosteum

5. articular cartilage

6. epiphyscal plate

7. spongey bone

8. compact bone

9. medullary cavity

10. red marrow

11. yellow marrow

cleft lip

results of the maxillae do not form normally

cleft palate

occurs when the palatine processes of the maxilla do not fuse with one another

what does a cleft palate produce

openings between nasal and oral cavities, making it difficult to drink, eat or speak

what are the steps of endochonral ossification

1. cartilage model formation

2. bone collar formation

3. primary ossification center formation

4. secondary ossification center formation

5. adult bone

what occurs during cartilage formation

cells aggregate in future bone formation regions

what occurs during bone collar formation

blood vessels surround the cartilage model, osteochondral cells become osteoblasts to form bone

what occurs during primary ossification center formation

forms as osteoblasts, produce bone on the surface of calcified cartilage

what occurs during secondary ossification center formation

replacement of cartilage by bone continues till it is all bone, except epiphyseal plate and articular surfaces

what occurs during adult bone formation

spongy, compact bone fully develops and the epiphyseal plate becomes a line

what factors affect the bone growth

• nutrition

• hormones

what are the bone repair steps?

1. hematoma formation

2. callus formation

3. callus ossification

4. bone remodeling

external callus

connects broken ends of bone to bone

internal callus

forms between ends of the broken bone

what regulates blood Ca 2+ levels

• PTH

• calcitonin

• calcitriol

where does PTH act

in kidney tubules and bone cells

where does calcitriol act

in kidney tubules, small intestine and bone cells

where does calcitonin act

in bone cells

how does PTH effect Ca2+ levels

increases

how does calcitriol affect Ca2+ levels

increases

how does calcitonin affect Ca2+ levels

decreases

how does aging effect the skeletal system

• bone matrix becomes more brittle

• loss of bone, increases likelihood of fractures

• ligaments and tendons become less flexible causing a decrease in range of motion