Unit 2 Anatomy/Physiology Written

Functions of Bone and Skeletal System:

Provide structural framework

• Support soft tissue

• Points of attachment for skeletal muscles

Protect internal organs

Assist in movement (with muscles)

Mineral storage of calcium and phosphorous

Production of blood cells in red bone marrow

Triglyceride storage in yellow bone marrow

Diaphysis

• Bone shaft (portion between the epiphysis)

Articular cartilage

• Located where bones come together to form a joint

• Reduces shock and friction

Medullary cavity

• Located within the shaft (diaphysis) of the long bone, inter most part of the bone

• Hollow cavity filled with yellow bone marrow in adults

Osteons

• Circular shaped units that make up compact bone

• Formed by concentric layers of matrix called lamellae and has a central canal with a nervous and blood supply.

• Also known as the Haversian system

Trabeculae

• Latticework

• cancellous bones containing numerous bars or plates that forms partitions in organs

• support/strengthens: follow the lines of stress in spongy bone

Epiphysis

• Ends of long bones

Periosteum

• dense connective tissue that forms the outer covering of a bone

Compact bone

• Solid dense bone tissue, no air spaces

• Strong support 

• In diaphysis of long bones

  • Central haversian canal: blood vessels and nerves

  • Concentric lamellae: rings of hard, calcified extracellular matrix

  • Osteocytes: bone cells built by osteoblasts

Spongy bone

• Lightweight

• Covered by a protective layer of compact bone (inside the layer)

• Contains latticework called trabeculae

• Supports red bone marrow

• Does not contain osteons

• Makes up epiphysis of long bone and other types of bone (short, flat and irregular shaped bones)

Red bone marrow

• Specialized tissue that produces blood cells, found in medullary cavity in most long bones (in infants)

Development of cartilaginous model

• Structure is covered by perichondrium, cells gather in the site where the bone will form and become chondroblasts

Growth of cartilage model

• Chondroblasts are now called chondrocytes. Chrondocytes increase in size. Cartilage begins to clacify and die.

Formation of primary ossification center

• Perichondrium is now called the periosteum because the bone is present. Small cavities become the primary ossification center. A nurient artery appears in the center.

Development of medullary cavity

• Osteoclasts break down spongy bone and begin to form the medullary cavity. Spongy bone remains present in the epiphysis and is not replaced with a medullary cavity or compact bone. Wall of diaphysis is replaced with compact bone. Primary ossification center expands to ends of bone.

Formation of primary ossification center

• Secondary ossification center forms in the epiphysis. Medullary cavity fills with red bone marrow.

Formation of articular cartilage and epiphyseal plate

• Line of cartilage remains between the epiphysis and diaphysis until adulthood

Stress Fracture

• Tiny cracks in the bone by repetitive overuse (smallest type)

Comminuted Fracture

• Bone breaks into more than two pieces

Greenstick fracture

• Incomplete break where a bone bends and cracks on one side instead of snapping completely into separate pieces

Buckle or Torus Fracture

• Incomplete fracture in which the break doesn’t go all the way through the bone

• They are compression fractures which means the break is caused by sudden pressure on the bone

Avulsion Fracture

• It’s where a small piece of bone attached to the tendon or ligament gets pulled away form the main part of the bone

Growth Plate Fracture

• Break in the developing layer of soft cartilage near the ends of a child/teenager’s long bones

Compression Fracture

• Partial collapse/break in the spinal bone (vertebrae)

How many regions does the vertebrae have and how many are there within each region?

5 regions

• Cervical vertebrae: 7 bones, neck

• Thoracic vert: 12 bones, chest/ribs

• Lumbar vert: 5 bones, lower back

• Sacrum: made of fused vert

• Coccyx: made of fused vert

Normal curves of vertebral column

• Infant has 1 concave curve

• Adult has 4 curves

• Purpose

  • Increase strength

  • Help maintain balance

  • Absorb shock

  • Protects vertebrae from breaks

Ribs

12 pairs

• In back connects to:  Corresponding thoracic vertebrae

• In front connect to: 

  • Pairs #1-7 Sternum by costal cartilage = true ribs

  • Pairs #8-10 Indirectly to rib #7= false ribs

  • Pairs #11-12 Do not connect = floating ribs

Ear

Hemostasis

• It constricts blood vessels and forms blood clot to stabilize the broken ends of the bone

Inflammatory phase

• Immune system sends white blood cells, macrophages to fracture site in which its purpose is to clear the germs around the break to reduce infection

Reparative phase

• Chondroblasts are dispersed, which are responsible for forming cartilage, and they form a soft callus made of fibrous tissue which acts as a temporary bridge between the broken ends

Development of Hard Callus

• Soft callus gets replaced by hard callus made of bone tissue, specialized cells called osteoblasts which deposit minerals like calcium and phosphorus making the callus more rigid

Remodeling phase

• The body enters this phase by sending osteoclasts to breakdown and absorb the extra tissues formed earlier

Steps of Fracture Repair

• Hemostasis

• Inflammatory Phase

• Reparative Phase

• Development of hard callus

• Remodeling Phase

Vertebrae

1. Protects spinal cord, supports head

2. Attaches ribs, pelvic girdle, muscles of back

3. Intervertebral disc: cartilage between

How many regions does vertebrae have and how many are there?

5 regions
Cervical vertebrae: 7 bones, neck
Thoracic vert: 12 bones, chest/ribs
Lumbar vert: 5 bones, lower back
Sacrum: made of fused vert
Coccyx: made of fused vert

Normal curves of vertebral column:

• Infant has 1 concave curve

• Adult has 4 curves

• Purpose

  • Increase strength

  • Help maintain balance

  • Absorb shock

  • Protects vertebrae from breaks