Chp. 6: Bones + Skeletal Systeem

The internal framework of the human body is?

Skeletal System

The internal framework consist of:

-Bones

-Cartilage

-Ligament

-Tendons

Major functions of Skeletal System:

1. Support

2. Mineral Storage

3. Lipid Storage

4. Blood Cell Production

5. Movement

6. Protection

What skeletal component is responsible for the storage of lipids?

Yellow Marrow (fat)

Which part of the bone does blood cell production occur?

Red Marrow

What mineral is stored within skeletal system?

Calcium

What are the three classifications in bones?

1. Shape

2. Internal Tissue

3. Bone Marking

How many bones are in the body total?

206

The bones are split into how many distant categories?

6

What are the bone categories?

Long Bone, Flat Bone, Sesamoid Bone, Short Bone, Irregular Bone and Sutural Bone

What is a Long Bone?

Cylinder shaped, longer than they are wide

Example of Long Bone:

Femur & Humerus

What is a Short Bone?

Cube-like, equal in length, width and thickness. Offer support & stability

Example of a Short Bone:

Carpals in the wrist

What is a Flat Bone?

Thin and often curved. They protect vital organs & offer wide areas of muscle attachments.

Examples of Flat Bones:

Sternum, Ribs & Skill Root

What is a Sesamoid Bone?

Tiny, round bones (look like seeds). Inside tendons to shield joint pressure & friction.

What is a Irregular Bone?

Unique shape, fit in NO other category. Highly specialized protection.

Examples of Irregular Bones:

Vertebrae & Tarsal Bones

What is s Sutural Bone?

Small, Flat and jigsaw like. Found between/within the joint.

Example of Sutural Bone:

Skull

Internal Tissues is split into how many types of osseous tissue?

2

What are the two bones produced by osseous tissue?

1. Compact Bone

2. Spongy Bone

Explain Compact Bones:

Packed tightly together, dense & have osten. Also mainly in the outer portion of the bones.

What is osten?

Structure of the compact bone, contains lamella & circum. lamella that wraps around the bone. (Thick & Strong)

Explain Spongy Bone:

Open, lightweight, yellow and has trabeculae.

Mainly inside the ends of long bones.

(yellow= bc of yellow marrow=store fat/good source of energy)

What is trabeculae?

Tiny beams like rods, contains NO blood vessels and spaces filled with red bone marrow.

Bone Markings are split into how many functional groups?

3

What are the 3 functional groups of bone marking?

1.Depression/Grooves

2. Projection

3.Opening/Tunnels

What are depression/grooves?

Features along the bone surface (indentations)

What are Projections?

Where tendons and bones attach, cause bumps that STICK OUT!

What is Openings/Tunnels?

Pathways that allow nerves and blood vessels to go through.

What are the structures of long bones?

-Diaphysis

-Epiphysis

-Metaphysis

What is the Diaphysis?

Middle/Shaft portion= Thick wall of compact bone (crazy strength)=Dense

What is inside the Diaphysis/Middle portion of the bone?

Medullary/Marrow Cavity

What is the Epiphysis?

Wide part @ the end of bone→ Mostly spongy BUT covered in compact.

What is the Metaphysis?

Between the Diaphysis & Epiphysis

The parietal bone of skull is called…

Flat bone

The flat bone resembles…

Sandwich

What is Diploe

Layer of spongy bone between compact bone.

What is Bone Osseous Tissue?

Dense, connective tissue that makes up bones.

Contains 2 bones= Spongy & Compact

What is inside the bone osseous tissue?

4 cells & Matrix

What are the 4 type of cells in bone osseous tissue?

1. Osteoprogenitor

2. Osteoblast

3. Osteoclast

4. Osteocytes

What is the Osteoprogenitor?

Mesenchymal stem cell that divides to produce osteoblast

What is the Osteoblast?

Build bones (matrix)

What is the osteoclast?

Breakdown matrix & release osteolysis

What is the Osteocytes?

Maintains bone

Where does osteocytes live?

The lacune & communicate through the canaliculi.

Which of the cells mange bone density?

Osteoblast & Osteoclast

What is Matrix?

Materials surrounding bone cells

What are the 2 types of Matrix?

1.Inorganic

2.Organic

Inorganic Matrix

2/3 of matrix=calcium phosphate (hard part of the bone)

Organic Matrix

1/3 of matrix=protein fibers (collagen)

Do bones adapt to pressure?

Yes because they are living tissue

What is the primary way bones adapt to pressure?

Through the process called Homeostasis, which is a cycle of remodeling.

• Balancing bone building and breaking done (must balance)

Less stress on bones=

WEAK

(dont use it, you lose it)

Why is weight bearing exercises good?

Applies stress and tension, which stimulates osteoblast

What keeps everything moving inside?

FUEL

What kind of fuel do we need for bone growth?

Raw Nutrients:

• Vitamin C= for collagen

• Vitamin A= Osteoblast activity

• Vitamin K & B12- bone protection

What other fuel do we need for bone growth?

• Growth Hormones, Thyroxine, Estrogen, Androgen, Calcitonin and Parathyroid

What are the 2 ways bones form?

Endochadral Ossification and Intramembranous Ossification

What is Endochandral Ossification?

Change from tissue into hyaline cartilage then replaced by bones

*MOST bones develop this way, growth occurs @ epiphyseal plate until close to puberty

What is Epiphyseal Cartilage

(Epiphyseal Plate=growth plate)

• Tiny opening, pre-puberty and start to grow

What is Epiphyseal Lines

Left over scars/lines where growth plates were.

• Post-Puberty/Adults

• Bone has replaced cartilage and NO longer grow

What is Intramembranous Ossification?

Develop straight from connective tissue into bones (NO cartilage)

-Produce mainly flat bones

(also known as: Dermis Ossification)- occurs in dermis

What are the steps of production in Intramembranous Ossification?

1. Mesenchymal become osteoblast

2. Blast produces bone matrix & harden with minerals

3. New bone grows & forms spongy inside & compact outside

(Cells Gather→ Build→ Bones Grow)

How does inactivity cause bone loss?

The less stress on bones, means less bone building. Osteoclast removes bone faster then osteoblast can build.

How much bone mass can be lost in just a few weeks of inactivity?

1/3

What is a fracture?

Break/Crack of the bone

To repair fractures, it must go through how many stages?

4

What are the 4 stages of repair for a fracture?

1. Hematoma→ Blood Clot= Vessels break causing blood to collect around the fracture

2. Callus→ Temporary “Bridge”= New tissue forms around broken ends

3. Bone Replacement→ New Bone= Temp cartilage is replaced w spongy bone

4. Remodel→ Clast removes extra/old bone & Blast build new bone

(Think: Blood, Bridge, Bone, Strength)

What is osteopenia?

Bones become thin/weak with age

What age does osteopenia begin?

Between 30-40

What percentage of bone mass do women lose with osteopenia?

8% per decade

What percentage of bone mass do men lose with osteopenia?

3% per decade

What is Osteoporosis?

SEVERE bone loss

• Affects normal functions

• Makes bones fragile and easier to break

What age does osteoporosis start to occur?

Over 45

What percentage do women lose with osteoporosis?

29%

What percentage do men lose with osteoporosis?

18%