Chapter 6 Bones & Skeletal Tissues

What is cartilage composed of primarily?

Water

How well is the recovery of cartilage?

Very resilient - has the ability to spring back after being compressed

Does the cartilage contain blood vessels and/or nerves?

No blood vessels or nerves

What is the perichondrium? peri=outer chondro=cartilage

connective tissue surrounding cartilage

Appositional growth

increase in bone thickness

interstitial growth

growth from within

When does cartilage growth typically stop?

Adolescence

Hyaline Cartilage

Most abundant cartilage - provides support with flexibility and resilience (articular, costal, respiratory, and nasal)

Elastic Cartilage

Contains more stretchy elastic fibers, are better for repeated bending (external ear & epiglottis)

Fibrocartilage

Contains fibrous bundles of collagen, such as that of the intervertebral disks in the spinal cord and menisci

Bone Functions

"Some Men Prefer Big Apples For Himself"
Support
Mineral Storage
Protection
Blood Cell formation
Anchorage
Fat Storage
Hormone Production

Axial Skeleton

Portion of the skeletal system that consists of the skull, rib cage, and vertebral column

Appendicular Skeleton

Bones of the limbs and limb girdles that are attached to the axial skeleton

Bone Shapes

Long, short, flat, irregular

Compact Bone

Dense outer layer of bone

Spongey Bone

Filled with red or yellow bone marrow

Locations of bone marrow

Children: red bone marrow is located in spongy and the medullary cavity of most bones in the body,
As they grow red bone marrow degenerates and turns into fatty tissue yellow bone marrow

Adults: red bone marrow located axial skeleton flat bones, skull, and vertebrae.

Periosteum

A dense outside layer that covers the entire bone except for the joint surfaces
(supplied with nerve fibers + blood vessels... broken bones are painful)

Endosteum (endo=in)

Lines the medullary cavity

Bone Markings

Provides information about how a bone and its attached muscles & ligaments work together

Diaphysis

Shaft of a long bone (growth)

Ephysis

End of a long bone

Ephyseal line

Finished growing

Articular Cartilage

hyaline cartilage that covers ends of bones at moveable joints

Nutrient artery and vein

supply the diaphysis of a long bone; usually just one nutrient artery and vein per bone

Osteon

structural unit of compact bone

Central Canal

Contains blood vessels and nerves that serve the Osteon's cell

Concentric Lamellae

layers of bony matrix around a central canal

Lacunae (lake)

Small spaces between the lamellae which contain osteocytes

Canaliculi

Hairlike canals that connect lacunae to each other and the central canal

Organic portion of bone

Includes bone cells and osteoid which allows it to resist tension, "soft"

Inorganic portion of bone

Mineral salts (hyrdoxapatite) that allow it to resist compression, "hard"

Ossification

Formation of bone tissue

Embryonic Skeleton

Composed of fibrous connective tissue membranes and hyaline cartilage

What are the two types of Ossification?

Endochondral & Intramembranous

Endochondral Ossification

Bone forms by replacing hyaline cartilage

Intramembranous ossification

Bone develops from a fibrous membrane

Osteoblasts

Bone building cells
(bob the "builder")

Osteoclasts

Break down bone

Steps of Endrochondral Ossification

"Boys Can Spot Dirty Elbows"
Bone Collar forms
Cartilage calcifies
Spongy Bone
Diaphysis grows
Epiphysis ossify

Steps of Intramembranous Ossification

"Only Pretty Boys Care"
Ossification center
Periosteum forms
Bone Matrix
Compact Bone

Epiphyseal plate thickness

Maintains a constant thickness

Epiphyseal plate closure

Long bones stop growing when the Epiphysis + Diaphysis fuse together (Females - 18 yrs of age
Males - 21 yrs of age)

Bone remodeling is the result of ...

Bone resorption and deposit

What happens to the osteoclasts when resorption is complete?

Osteoclasts undergo apoptosis (cell death)

Hydroxyapatite

mineral salts made mostly of calcium phosphate, are found in inorganic composition of bones

Which type of ossification forms skull bones?

intramembranous (bone replaces fibrous CT - mostly flat bones) examples: bones of skull

Which type of ossification is more complex?

endochondral

Which ossification center is in the epiphysis of long bones?

secondary ossification center

periosteal bud

A vascular connective tissue bud from the perichondrium that enters the cartilage of a developing long bone and contributes to the formation of a center for ossification

where can you find periosteum?

on the outermost layer of your bones (peri=outside or on top of)

Lamalle

layers of bone matrix

Lacunae

rings of bone matrix

In a flat bone the bone marrow is likely to be which color?

Red (short, flat, and irregular bones have red marrow)

What is the epiphyseal line made out of?

hyaline cartilage

What process does longitudinal bone growth mimic?

endochondral ossification (because it has hyaline cartilage)

What happens if osteoclasts are more active than osteoblasts?

loss of bone density

Which is more abundant is the body? inorganic or organic portion?

inorganic portion (ratio between the two provides strength)

For bone remodeling which enzymes break down organic and inorganic portions?

Osteoclasts - inorganic portion
Lysosmal - organic portion

If you break a bone, which form of ossification does it resemble more?

Endochondral Ossification (only bones of skull and clavicles do not have endochondral ossification)