Chapter 6: The Skeletal System

What is bone made up of?

Bone, cartilage, dense connective tissue, adipose & nervous tissue.

What are the functions of the skeletal system?

Support, protection, movement, blood cell formation, hormone production, fat storage.

What cartilage covers the epiphysis of the long bone?

Articular cartilage

Where is the endosteum found?

Medullary cavity.

What is the connective tissue that surrounds the diaphysis?

Periosteum.

Define hydroxyapatite.

Mineral salts (calcium phosphate & calcium hydroxide) combined to form crystals.

What is extracellular matrix made up of?

15% water, 30% collagen, & 55% crystallized mineral salts

What are the 4 types of bone cells?

Osteoprogenitor, osteoblasts, osteocytes, osteoclasts

Which of the following bone cells remodel bones and cause them to release calcium?

Osteoclasts.

Which of the following bone cells matures bone cells?

Osteocytes

Which of the following bone cells is a bone builder and secretes matrix? This type of bone cell initiates calcification

Osteoblasts

What are the two parts of the bone?

Compact & spongy bone.

What are the two types of bone ossification?

Endochondral & intramembranous.

What are the zones of the epiphyseal plate

Resting zone, proliferation zone, hypertrophic zone, calcification zone, ossification zone.

Define fracture.

It is a break in the bone.

What is an Open Fracture?

A fracture in which the bone breaks through the skin, increasing the risk of infection.

What is a Comminuted Fracture?

A fracture where the bone is shattered into multiple fragments, making it more difficult to heal.

What is a Vertebral Compression Fracture?

A fracture that occurs in the vertebrae, often due to osteoporosis or trauma, leading to the collapse of the bone.

What are the 3 phases of the healing process of the bone?

Reactive phase, reparative phase, bone remodeling phase.

Reactive Phase?

- The first phase of healing, also known as the early inflammatory phase.

- A blood clot (hematoma) forms at the fracture site.

- Inflammation occurs as the body begins clearing out dead bone cells.

Reparative Phase?

Divided into two steps:

a) Fibrocartilaginous callus formation - Soft callus made of collagen and cartilage forms around the fracture to stabilize the bone.

b) Bony callus formation - The soft callus is gradually replaced by a hard (bony) callus made of spongy bone.

Bone Remodeling Phase?

The last phase, where the bony callus is remodeled into strong, compact bone.

Osteoclasts resorb any excess bone, and the bone structure returns to its original shape.

What organ produces calcitriol?

Kidneys

Which mineral helps form bone extracellular matrix?

Magnesium

Which vitamin is needed for collagen synthesis and is the main bone protein? List one deficiency of this vitamin.

- Vitamin C

- Deficiency leads to decreased collagen production.

Which vitamin is needed for synthesis of bone proteins? List one deficiency of this vitamin.

- Vitamins K and B12

- Deficiency leads to abnormal protein production in bone extracellular matrix & decreased bone density.

Which vitamin forms active calcitriol and helps build bone by increasing absorption of calcium from the digestive canal into the blood?

Vitamin D

Which hormone is secreted from the anterior lobe of the pituitary gland?

Growth Hormone (GH)

Define osteopenia.

Reduced bone mass below normal.

Define osteosarcoma.

Bone cancer that primarily affects osteoblasts.