CH 6) BONE TISSUE

-supports body

-facilitates movement

-protects organs

-rbc production

-stores and releases minerals and fat

function of the skeletal system (5)

hematopoiesis

-formation of blood cells

-carried out by red bone marrow

-active in childhood

-converts to yellow during adulthood

long bone

bones that are longer than they are wide

-humerus, femur, metacarpals, metatarsals

examples of long bone

flat bone

thin and curved bone; serves as a point of attachment for muscles and protects internal organs

-cranial, sternum, scapula, ribs

examples of flat bone

short bone

cube-shaped bone that is approximately equal in length, width, and thickness; provides limited motion

-carpals and tarsals

examples of short bones

irregular bone

bone of complex shape; protects internal organs from compressive forces

-vertebra, pelvis

examples of irregular bones

sesamoid bone

small, round bone embedded in a tendon; protects the tendon from compressive forces

-patella

example of a sesamoid bone

sutural bones (wormian bones)

irregular bones formed between cranial bones as sutures fuse; unique to every person

articular cartilage

hyaline cartilage covering the joint surface at the epiphyses

compact bone

bone tissue forming the walls of the diaphysis and the bony coverings of spongy bone

diaphysis

shaft of the long bone

endosteum

a connective tissue membrane lining the medullary cavity

epiphysis

enlarged proximal and distal ends of a long bone

epiphyseal line

part of the bone that replaces the epiphyseal growth plate

head

rounded epiphysis

medullary cavity

space within the diaphysis

neck

bony connection between the head and diaphysis of the long bone. The anatomical neck occurs with the epiphyseal line, where the surgical neck occurs at the junction of the epiphysis to the diaphysis where a joint replacement would be made.

periosteum

a dense connective tissue membrane covering the external bone surface

red marrow

red blood cell forming tissue that fills the spaces of spongy bone tissue

spongy bone

bone tissue filling the epiphyses and lining the medullary cavity

yellow marrow

a fatty material occupying the medullary cavity

sandwhich of compact, spongy, and compact bone

anatomy of a flat bone

proximal epiphyses, flat bones, irregular bones

where is red marrow found in an adult? (3)

osteoblasts

bone-forming cells, builds bone by secreting collagen and calcium salts

osetocytes

mature bone cells, maintains bone;

live in lacuna

osteoclasts

bone cells that break down bone matrix

osteogenic cell

bone stem cell (oligopotent)

osteoid

organic bone matrix secreted by osteoblasts;

rich in collagen

osteons

structural unit of compact bone;

cylindrical structure

concentric lamellae

circular layers of bony matrix around a central canal

central canal of osteon

contains blood vessels and nerves of the osteon

perforating canals

run horizontal, supplies central canal with outside vessels and nerves

interstitial lamellae

lay between osteons

circumferential lamellae

beneath periosteum,

covers entire circumference

lacuna

small cavities in bone that contain osteocytes

-no osteons

-arranged in lattice-like spicules, light weight

-houses bone marrow

-contains lacuna and osteocytes

characteristics of spongy bone

osteogenesis

process of bone formation

ossification

process of adding hard calcium salts to harden bone

intramembranous ossification

ossification in the membrane

develops from mesenchymal cells

-FLAT BONES develop this way

1. mesenchymal cells differentiate into capillaries and osteogenic cells

2. osteoblasts begin building bone at ossification centers, secretes osteoid

3. osteoid calcifies and bone hardens

4. osteoblasts become osteocytes

5. crowded blood vessels condense into red marrow

process of intramembranous ossification

endochondral ossification

ossification of hyaline cartilage

LONG BONES develop this way

1. mesenchymal cells differentiate into chondroblasts

2. hyaline calcifies at ossification centers

-chondrocytes stop cartilage production

-chondrocytes produce ALKALINE PHOSPHATES

-alk phos brings calcium to area

3. area calcifies and chondrocytes die

4. blood vessels infiltrate and enlarge cavity

-brings osteoblasts

-dead cartilage is remodeled into bone

5. perichondrium becomes periosteum

-bone collar forms under periosteum

-primary ossification center develops in diaphysis

6. chondrocytes and cartilage grow at ends of bone

AFTER BIRTH

7. secondary ossification center develops in epiphysis

8. cartilage remains at epiphyseal plate and joint

process of endochondral ossification

(good luck lol)

reserve zone of epiphyseal plate

anchors plate to epiphysis (cartilage)

proliferative zone of epiphyseal plate

chondrocytes replicate, growth plate cartilage grows

maturation/hypertrophy zone

chondrocytes grow and age, secretes cartilage that will soon be replaced with bone

calcification zone of epiphyseal plate

matrix becomes calcified, chondrocytes die

capillaries and osteoblasts invade and lay down osteoid

zone of ossification

(last region) consists of calcified chondrocytes and osteoblasts,

anchors plate to diaphysis

hi! study this diagram or else

wolff's law

bone responds and adapts to forces by reinforcing areas of demand (creates projections and markings)

"use it or lose it"

osteophytes

aka bone spurs

degenerative bone growths due to improper body mechanics

osteogenesis imperfecta

"brittle bone disease"

mutation that causes lack of collagen

fracture

broken bone

transverse fracture

fracture straight across long axis

oblique fracture

fracture at an angle to the bone

spiral fracture

a fracture in which the bone has been twisted apart

comminuted fracture

bone breaks into many fragments

impacted fracture

ends drive into one another, result of compression

greenstick fracture

bending and incomplete break of a bone; most often seen in children

open (compound) fracture

broken bone penetrates through the skin

closed (simple) fracture

break that does not penetrate the skin

bone bruise

inner trabecular is fractured,

requires long healing process

osteoporosis

condition that causes loss of bone density

1. fracture hematoma (bone bleeds and clots)

2. callus formation

3. osteoclasts reabsorb dead bones, osteoblasts ossifies callus

4. cartilage of calli is replaced by trabecular

process of bone repair

calcium

essential for

-bone/tooth development

-heart rate and contractions

-nerve impulse

-blood clotting

-hardening bone

vitamin k

needed for calcium absorption