A&P 1 Bone

Osteo

Bone

Long bones

diaphysis & epiphysis

Short bones

block ish in shape no epiphysis or diaphysis

Flat bones

Flat and can be curved

Sesamoid bones

Sesame seed shape (patella)

Irregular bones

Variety of shapes and sizes (vertebrae)

Sutural bones

Only found in the skull “extra bone”

What are the topographical features on bones called?

Bone markings

What do bone markings indicate?

Where muscle attaches and nerve/blood vessel passings

What are the two types of bone markings?

Projections & Depressions

What are projections?

Part of articulating surfaces or serves as attachment sites for muscles/ligaments

What are depressions?

Part of a joint or where a curvature is required

What type of tissue is bone?

supporting connective tissue

The extracellular matrix in bone is..

a solid matrix of hydroxyapatite

What is hydroxyapatite?

Calcium phosphate and calcium hydroxide

What fraction of the matrix is inorganic hydroxyapatite and organic collagen protein?

2/3 hydroxyapatite - 1/3 collagen

What do collagen fibers do?

Support the framework for mineral deposits

Bone cells

Osteocytes

Bone cells live within the..

Lacunae

The outer surface of the bone is covered by..

A membrane called- periosteum

Periosteum

Composed of outer fibrous layers and an inner cellular layer

Inside the bone is lined with..

Endosteum

Osteoblast

synthesize new bone matrix (bone growth) obtain calcium ions from blood, maintains proper calcium levels

Osteoclast

Dissolve bone matrix, release calcium into the bloodstream, maintains proper calcium levels

What percentage can blood calcium NOT fall below? What can happen?

30% DEATH

Osteoprogenitor cells

Bone stem calls that give rise to osteoblast and osteoclast

What are the two types of bone?

Compact & Spongy

Compact bone is made of? Why?

Densely packed hydroxyapatite, can within high compression forces

Osteons

A bundle of microscopic tubular structures

Basic structural unit of compact bone?

Osteons

What is the central canal?

A passageway for nerves & blood vessels

What are the “onion layers” seen in bone?

Concentric lamellae

What are the dark spots in bone called?

Osteocytes

What is embedded within small pockets?

Lacunae

Lacunae is connected together and to the central canal via..

The canaliculi

Hard lamellar material between the tubular osteons is called the..

Interstitial lamellae

What does the interstitial lamellae do?

Helps secure the osteons together

The entire diaphysis is surrounded by..

Circumferential lamellae

Spongy bone is..

Porous, consist of cuss crossing struts and plates called trabeculae which makes it looks like a sea sponge

All bones contain both

Compact and spongy regions

Spongy is the primary site of..

Osteogenesis and osteolysis (calcium is put into and out of bone)

Spongy bone is good at..

Taking compression forces and pulling forces from many different directions

Compact bones is good at

Taking compression forces from one direction

Long bones often have

Chambers called bone cavities

Bone cavities are filled with

Bone marrow- red marrow (blood) yellow marrow (adipose)

What are skull bone cavities called?

Sinuses

Bones are wrapped in superficial connective tissue called?

The periosteum

The periosteum does what?

Defines the bones boundary and provides a route for nerves and blood vessels

The internal cavities and trabeculae are covered by a thin layer of connective tissue called

Endosteum

Ossification

The formation of new bone by the conversion of other tissue into bone tissue

Different ways of ossification

Intramembranous ossification (fetal development) endochondral ossification

What is intramembranous ossification?

Responsible for producing the flat bones of the skull, facial bones, and clavicles begins when osteoblast develop from fibrous connective tissue aka dermal bones)

What is endochondral ossification?

All other bones develop through endochondral ossification!

Why are they called dermal bones?

The osteoblast develop from the deep layer of the dermis

When is ossification complete?

Mainly teen years but for the xiphoid process it’s early 40s

In children long bones grow between?

The diaphysis and epiphysis in a narrow zone called the epiphyseal plate

Epiphyseal plate

Composed of cartilage until bone growth is complete

The remnant of the plate is called

Epiphyseal line

T/F Bones are highly vascular

True

T/F bones are highly innervated

True especially the periosteum

T/F an external callus of cartilage and bone fragments form around AND inside a broken bone

True

How long do most broken bones take to heal?

Weeks-months

3 types of cartilage found in the adults human skeleton

Hyaline cartilage, fibrocartilage, elastic cartilage

Most abundant cartilage

Hyaline

Where do hyaline cartilage cover?

Articulating surfaces of bone within synovial joints

Tough and stiff cartilage

Fibrocartilage

Fibrocartilage

Absorbs compression forces very well, shock absorbers, allows a slight twisting motion

Elastic tissue

Most flexible, least abundant, ears and epiglottis

All cartilage is composed of

Extracellular matrix and has very few cells

Cartilage tissue is covered by a dense connective tissue called

perichondrium

Damage to the cartilage takes a long or short time to heal?

LONG

The remodeling of bones is called

Bone flux

most common complications foot problems

Bunions, hallux valgus, and hammertoes

Main ingredient in bone

Calcium 99% of the body’s calcium is in the skeleton

Calcium in the body

Blood calcium concentration is regulated by the endocrine system, hormones PTH and calcitonin, when too high it is released into the thyroid gland and stimulates osteoblast to remove Ca++ from blood and put it into bone, when Ca++ is low PTH is released from the parathyroid gland and stimulates osteoclast to dissolve bone calcium

Other minerals in bone

Potassium, sodium, phosphate, carbonate, and magnesium these make up 2/3 of the bone the other 1/3 is collagen

with age..

Bones gets thinner and weaker, osteopenia is inadequate ossification of the bone resulting in loss of bone mass