skeletal system

What are the five functions of the skeletal system?

1) Form and size provide body shape 2) Protect internal organs 3) Provide muscle attachment 4) Produce red blood cells in bone marrow 5) Store materials (calcium, magnesium, phosphorus, fat)

What are the two types of bone tissue?

Compact (cortical) and Spongy (cancellous)

What is compact (cortical) bone?

Hard and rigid bone tissue found in the shaft of long bones

What is spongy (cancellous) bone?

Lightweight bone with air spaces; found in joints and ends of bones

What is the main difference between compact and spongy bone?

The distance between the growth of the osteon rings

What is a Haversian canal?

A center opening in bone tissue that contains blood vessels and nerves

What is an osteocyte?

A mature bone cell that maintains bone tissue

What are canaliculi?

Tiny channels that connect osteocytes and allow nutrient exchange

What are lamellae?

Concentric rings of bone matrix surrounding the Haversian canal

What is a lacuna?

A small space that contains an osteocyte

What is ossification?

The process of bone formation from cells and cartilage

What are osteoblasts?

Bone-building cells that produce bone matrix around osteocytes

What are osteoclasts?

Bone-destroying cells that release acid to break down bone

What maintains balance between osteoblasts and osteoclasts?

Homeostasis

What are the steps of ossification?

Step 1: Cells + calcium + vitamin D
Step 2: Cartilage and osteoblast cells form
Step 3: Ossification process → bone

What are the five steps of bone formation (ossification)?

Cartilage forms; periosteum produces osteoblasts
Primary ossification center forms in diaphysis
Osteoclasts create space for blood vessel maturity
Osteoblasts travel to epiphysis for secondary ossification center
Increased cell division in epiphyseal disk allows growth before total ossification

What are the steps of bone repair?

Blood escapes from broken vessels to form a hematoma
Hematoma and granulation tissue form
Cartilaginous callus develops
Bony callus and cartilaginous remnants form spongy bone
Remodeling occurs — spongy bone turns to compact bone; osteoclasts remove fragments

What are the types of bone fractures?

Greenstick: Stress fracture; bone bends and cracks but not all the way through
Transverse: Simple, clean break across the bone
Comminuted: Bone is smashed into pieces
Spiral: Bone fracture caused by twisting
Compound: Bone breaks through the skin

What is the epiphyseal disk?

Area of dividing cells that allows for bone growth

What is articular cartilage?

Layer of hyaline cartilage cushioning the epiphysis (joint area)

What is red marrow?

Found in spongy bone; produces red blood cells and stores iron in hemoglobin

What is spongy bone?

Porous bone that produces red marrow and reduces bone weight

What is compact bone?

Dense bone that provides strength and structure

What is the medullary cavity?

Hollow area in the diaphysis that stores yellow marrow

What is the endosteum?

Thin layer of cells lining the medullary cavity; produces marrow cells

What is yellow marrow?

Found in the diaphysis; stores fat and is made of adipose tissue

What is the periosteum?

Thick vascular covering of the diaphysis; produces osteoblasts

What is the proximal epiphysis?

The end of the bone closest to the body; location of red marrow

What is the diaphysis?

The shaft of the bone; location of yellow marrow

What is the distal epiphysis?

The end of the bone farthest from the body