OTD 339: Skeletal System

What are the 6 functions of bone?

1. support structure, framework, provide for muscle attachment
2. Lever System ( function as levers to allow for movement)
3. protection of vital organs
4. storage of minerals (calcium, phosphate)
5. storage of fat (yellow bone marrow)
6. produces blood c

What is the shaft or the long middle portion of a long bone called?

Diaphysis

An end of a long bone is called a

Epiphysis

There are two epiphyses, a __________ and ___________ end.

proximal, distal

What is the flared portion of the shaft that connects to the ends called?

Metaphysis

The boundary of Metaphysis and Epiphysis

epiphyseal line

Where is articular cartilage located?

located on ends of bones, smooth

What is the purpose of articular cartilage?

to reduce friction

What does periosteum surround?

surrounds bone

How many layers of periosteum are there? What are they?

1. Collagen
2. Mesenchyme

Collagen surrounding bone is made of what type of CT?

made of fibrous CT

Which layer of periosteum is the outer layer?

collagen is the outer layer

Which layer of periosteum is the inner layer?

mesenchyme is the inner layer

Collagen surrounding bone allows for what?

Allows for vessels and nerves to pass into bone

The mesenchyme layer of periosteum contains what type of cells?

contains osteoprogenitor cells

osteoprogenitor cells are bone specific _______________ cells.

mesenchymal cells

osteoprogenitor cells support what kind of growth?

support appositional growth

What is the medullary cavity?

inner hollow space in the shaft of the diaphysis filled with yellow marrow

What is endosteum?

the layer of CT that lines medullary cavity
- contain osteoprogenitor cells as well
- "inner" layer

The periosteum surrounds the outside of the bone, whereas the endosteum surrounds the ___________ of the bone.

inside

What type of tissue is bone?

connective tissue

If bone is CT, then what does that mean it is made out of?

made of cells and IC substance

What is the IC substance of bone made of?

made of collagen, elastin & calcium salts

the collagen in the IC substance of bone is strong against...

strong against tension

the calcium salts (tricalcium phosphate & calcium carbonate) in the IC substance of bone are strong against...

strong against compression

What is the exterior bone made of?

Made up on compact, hard bone

Where is the exterior bone thicker at on the bone?

thicker in diaphysis

Why is the exterior bone thicker in the diaphysis?

it is thicker to provide extra support and decrease risk of injury in our long bones

Interior bone looks _________ in appearance

spongey

Spongey bone (interior bone) is usually found in what places?

found in epiphyses and flat bones, such as skull and ilium

spongy bone is also called...

also called cancellous bone

What are the 4 bone cells?

1. Osteoprogenitor
2. Osteoblasts
3. Osteocytes
4. Osteoclasts

Osteoprogenitor cells

bone specific stem cells derived from mesenchyme, can divide to form other bone cells (specifically blasts/clasts)

Osteoblasts

form/build bone, secrete IC substance/matrix (once they become surrounded by matrix, they become an osteocyte)

Osteocyte

maintain structure & function of bone (no IC substance produced)

Osteoclasts

break down/destroy bone (also called resorption
- bone eaters

bones are constantly "remodeling"... what does this mean?

bones are constantly being broken down and new bone being rebuilt as we grow

Osteon/Haverian System

functional unit of compact bone
- work togethers to maintain structure of bone

There are 4 major structures of an Osteon (Haverian System)... what are they?

1. Haverian Canal
2. Lamellae
3. Lacunae
4. Canaliculi

Haverian Canal

extends length wise through the center of the osteon
- contains blood vessels, lymph vessels & nerves

Lamellae

surround canal, several layers of calcified matrix

Lacunae

sack like space filled with fluid (lake like) between Lamellae that house the osteocytes

Canaliculi

crack like, radiate out from Lacunae to connect osteocyte with other Lacunae & the Haverian canal

Look at powerpoint and drawing to understand the structure of the what?

to understand the structure of the osteon

Volkmann's canals penetrate the compact bone in what way?

penetrate the compact bone transversely or perpendicularly

Volkmann's canals provide a route for what?

provide a route for blood vessels

The Volkmann's canals meet up with Haversian canals to make a way for the...

blood vessels

What do the Volkmann's canals also meet up with?

meet up with the medullary cavity

Spongy bone is also called what?

cancellous bone, trabecular bone

spongy bone is _______ to compact bone

deep

T/F Spongy bone contains osteons

False: spongy bone contains no true osteons

What does spongy bone contain instead of osteons?

needle-like bony spikes called trabeculae

red bone marrow fills the "sponge", nourishes the cells and surrounds the bone cells in ___________ bone

spongy

T/F spongy bone contains lucunae & canaliculi

True

Where can you find spongy bone?

- flat, short & irregular bone
- epiphyses of long bones

What are the 6 different types of bones in the human body?

1. Long bones
2. Short bones
3. Flat bones
4. Irregular bones
5. Sesmoid
6. Wormian bones

Long bones

levers (ex: phalanges, femur, tibia, humerus, metacarpals)

Short bones

cube shaped bones (bones in wrist & ankle --> tarsals, carpals)

Flat bones

look like a sandwich, parallel layers of compact bones separated by spongy bone (ex: ilium, scapula, ribs, sternum, clavicle)

Irregular bones

peculiar/irregular shaped (ex: vertebrae, ischium, ethmoid)

Sesmoid bone

floats within a fascia or tendon (ex: patella)

Wormian bones

specific to skull, sutural, little tiny bones formed by extra sutures, not present in everyone, extra, small sutures