A&P Bone lecture

Hematopoiesis

The formation of blood cells (primarily in flat bones and vertebrae)

Osteocalcin

Protein that acts as a hormone to regulate bone formation.

Compact/Cortical Bone

Solid and strong bone found in the cortex, outer area

Spongy (Cancellous) Bone

Internal regions of bone, less dense and made of trabeculae (no osteons)

Trabeculae/Diploe

What forms the branching inner network or cancellous bone

Periosteum

Tough dense covering of entire bone structure except articulations

Epiphysis

Parts of bone that articulate with others, spongy bone w/thin layer of compact bone covered in hyaline cartilage

Diaphysis

Shaft composed of hollow compact bone, strong, bend resistant

Epiphyseal Line

Line between epiphysis and diaphysis, forms epiphyseal plate (hyaline cartilage)

Medullary Cavity

Hollow area in bone lined with endosteum, contains bone marrow

Red Marrow

Hematopoietic tissue, produces BC, mostly in spongy/flat bone, more in children

Yellow Marrow

Composed of adipose (fat) tissue, located in diaphysis, considered fat storage

Endosteum

Inner lining of medullary cavity, mostly osteoblasts

Osteogenic Progenitor Cell (OPC)

Stem cell derived from mesenchymal cell; this is where osteoblasts come from

Mesenchymal Cell

Type of cell that can develop into several type of CT cells

Osteoblast

Cell which produces bone tissue-eventually becomes osteocyte

Osteocyte

Mature bone cell, located in lacunae

Lacunae

Chamber that osteocytes live in

Osteoclast

Breaks down and resorbs bone tissue, multinucleate, rich in phosphatase

Lamellar Bone

Mature bone, compact or spongy

Woven/Embryonic Bone

Immature bone, formed during remodeling and repair

Hydroxyapatite

CA phosphate crystals (brittle) that give bone hardness, how bone stores CA

Collagen

Gives strength and “bendability “-gives bone toughness

Osteon/Haverson Canal

Runs length of bone, contains BV’s, nerves, areolar CT

Canaliculi

Canals linking osteocytes, allow nutrients distribution from BV to cell

Perforating/Volkman’s/Communicating Canals

Roughly perpendicular canals connecting osteons, contain large BV

Intramembranous Ossification

Development of flat bone from mesenchyme, no cartilage

Endochondral Ossification

Long bone development, starts from cartilage

Osteoid

Matrix of collagen fibers secreted by osteoblasts that calcifies

Interstitial Growth

Bone grows in length

Appositional Growth

Bone grows in thickness; osteoblasts add bone to outside/osteoclasts remove bone from inside

Rickets

Bending/weakness of bone in children

Osteomalacia

Similar condition as rickets, but in adults

Hypopituitary dwarfism

Growth hormone deficiency in children, body has normal proportions

Giantism

Growth hormone overproduction

Acromegaly

Growth hormones increase in adult’s hands, feet, and jaw (normal height)

Traumatic Bone Fracture

Due to injury

Spontaneous/Pathologic Bone Fracture

Due to disease

Simple/closed fracture

Protected by uninjured skin

Compound/open fracture

Bone protrudes through broken skin

Fissure fracture

Incomplete longitudinal break

Greenstick fracture

incomplete and on convex side, common in children

Spiral fracture

Due to twisting

Oblique fracture

Complete and at an angle

Comminuted fracture

Bone splinters at impact sight, produces bone fragments

Impacted fracture

Broken fragment is driven into second bone

Compression fracture

Bone is crushed

Depressed fracture

Broken bone is projected inward

Colle’s fracture

Distal radius fracture where distal fragment is placed posteriorly

Pott’s fracture

Fracture of distal fibula with damage to the distal tibial articulation

Stress fracture

Microscopic fractures due to the inability to withstand repeated stress

Shin Splints

Pain in lower tibia due to overuse and improper form/warmup, inflammation of tendons and periosteum, possibility of stress fracture

Bone Grafting

A “paste“of living bone is grafted to injured area to introduce stem cells

Electrical Currents

May stimulate bone growth due to “Wollf’s Law“

Osteoporosis

High loss of mineral content and bone mass that could result in spontaneous fracture, (Hip, spine, wrist)

Osteopenia

Slight drop in bone mineral density “pre-osteoporosis“

Osteogenesis Imperfecta

Genetic disorder of collagen formation in bone

Paget’s Disease

Thick, soft bones due to remodeling caused by osteoblast and osteoclast activity

Osteomyelitis

Microbial infection of bone and marrow

Osteogenic Sarcoma

Originates in osteoblasts, bone forming cancer

Parathyroid Hormone (PTH)

Hormone secreted during hypocalcemia, stimulates osteoclasts to break down bone and add CA to bloodstream

Calcotonin

Hormone secreted by thyroid during hypercalcemia, inhibits clasts, promotes bone formation

Insulin

Hormone that promotes bone growth (type 1 diabetics may have stunted growth)

Sex Hormones (Androgens and Estrogens)

Hormones that promote bone growth and ossification of epiphyseal plate