Chapter 6

The collagen fibers in adjacent lamellae always run in different directions. Alternating pattern (between direction of collagen fibers in adjacent lamellae) is designed to withstand torsion stresses - the adj lamellae reinforce one another to resist twisting --> you can think of the osteon's design as a "twister resister"

"Twister resister" design

fracture

A break in a bone can also be called....

lamella

A layer, such as of bone matrix in an osteon of compact bone.

lacunae

A small space, cavity, or depression; [....] in bone or cartilage are occupied by cells.

interstitial growth

A type of growth in which the chondrocytes located in lacunae in cartilage divide and secrete new matrix, which expands the cartilage from within

sternum

An example of a flat bone is the....

humerus

An example of a long bone is the....

talus

An example of a short bone is the....

vertebra

An example of an irregular bone is the....

trabeculae

Any of the fibrous bands extending from the capsule into the interior of an organ; strut or thin plate of bone in spongy bone.

osteoblasts

Bone-forming cells are called....

shape

Bones are classified based on....

Volkmann's perforating canals

Canals that run at right angles to the long axis of the bone, connecting the vascular and nerve supplies of the periosteum to those of the central canals and medullary cavity

elastic cartilage

Cartilage with abundant elastic fibers; more flexible than hyaline cartilage.

medullary cavity

Central cavity of a long bone, contains yellow or red marrow

endosteum

Connective tissue membrane covering internal bone surfaces.

compact bone

Dense bone in which the bony matrix is solidly filled with organic ground substance and inorganic salts, leaving only tiny spaces (lacunae) that contain the osteocytes

Endochondral ossification

Embryonic formation of bone by the replacement of calcified cartilage; most skeletal bones are formed by this process.

flat bones consist of a layer of spongy bone sandwiched between two thin layers of compact bone

Gross anatomy of flat bones:

appositional growth

Growth accomplished by the addition of new layers onto those previously formed.

red marrow

Hematopoietic tissue is....

interstitial lamellae

Incomplete lamellae that lie between intact osteons, filling the gaps between forming osteons, or representing the remnants of an osteon that has been cut through by bone remodeling.

spongy bone

Internal layer of skeletal bone. Also called cancellous bone.

osteoclasts

Large cells that resorb or break down bone matrix are called.....

joints, epiphyseal plates of bones, nose, respiratory tract, ear

List (5) common locations of cartilage:

support, protect, movement, mineral homeostatis (storage & release of calcium & phosphorus), blood cell production and triglyceride storage

List (6) functions of the skeletal system:

long bones, flat bones, irregular bones, and short bones

List the (4) different types of bone classifications based on shape:

osteocytes

Mature bone cells are called...

epiphyseal plate

Plate of hyaline cartilage at the junction of the diaphysis and epiphysis that provides for growth in lengeth of a long bone

bone remodeling

Process involving bone formation and destruction in response to hormonal and mechanical factors.

sesamoid bones

Short bones embedded in tendons, variable in size and number, many of which influence the action of muscles; largest is the patella (kneecap).

Central (Haversian) canal

The canal in the center of each osteon that contains minute blood vessels and nerve fibers that serve the needs of the osteocytes.

diaphysis

The elongated shaft of a long bone is called....

epiphysis

The end of a long bone, attached to the shaft is called.....

parathyroid hormone and calcitonin

The endocrine (hormonol) controls of bone remodeling include....

Hyaline cartilage

The most abundant cartilage type in the body; provides firm support with some pliability.

fibrocartilage

The most compressible type of cartilage; resistant to stretch. Forms vertebral discs and knee joint cartilages.

ligaments

This connects bone to bone

tendons

This connects muscle to bone

periosteum

This is a hard protective double-layered connective tissue that covers and nourishes the bone.

osteon

This is a system of interconnecting canals in the microscopic structure of adult compact bone; unit of bone; also called Haversian system.

perichondrium

This is fibrous, connective-tissue membrane covering the external surface of cartilaginous structures.

diploe

This is the internal layer of spongy bone in flat bones

circumferential lamellae

This type of lamellae forms outer surface of compact bone - thin plates that extend around bone.

Sharpey's fibers

Tufts of collagen fibers that extend from its fibrous layer into the bone matrix and secure the periosteum to the underlying bone

yellow marrow

What is found in other parts of the epiphyses and is called "yellow" because the fat cells it contains impart a yellow color?

red marrow

What is found in the proximal epiphyses of adults humerus and femur and is called "red" because of the RBC it is producing gives it a red color?

It resists outward expansion when the cartilage is compressed --> Won't stretch making it a good shock absorber. Contains blood vessels from which nutrients diffuse through the matrix to reach the cartilage cells internally.

What is the function of perichondrium?

It surrounds the cartilage

Where is perichondrium found?

long bones

Which bone shape is longer than it is wide?

short bones

Which bone shape is roughly equal dimensions?

flat bones

Which bone shape is thin and relatively broad?

irregular bones

Which bone type has complex shapes that do not fit easily into any other category?

elastic cartilage

Which cartilage type is found in the ear and epiglottis?

hyaline cartilage

Which cartilage type is found in the following locations? articular cartilage in synovial or diathrosis joint' found in nose, epiphyseal plate, trachea, bronchi, larynx

fibrocartilage

Which cartilage type is found in the pubis symphysis and intervertebral discs?

red marrow

Which marrow type is typically found within the trabecular cavities of spongy bone of long bones and in the diploe of flat bones?

canaliculi

Which microscopic feature of bone connects adjacent lacunae with each other and eventually the Haversian canal?

canaliculi

Which microscopic feature of bone have tiny channels running at the right angles to the long axis of the bone?

canaliculi

Which microscopic feature of bone is formed from cytoplasmic extensions of maturing bone?

point of no stress occurs in the middle of the long bone. At the center of long bones all the forces cancel each other out, which is why internally much less bone material is needed

Why medullary cavity is hollow?

articular cartilage

[....] is hyaline cartilage on the articular surfaces of bones