Unit 4: Skeletal System Part 2

Line is formed after plate has stopped producing bone

Difference between epiphyseal plate and line

2

How many kinds of mature bone cells are there?

Osteocyte

Bone cells

Osteoblasts

Bone-forming cells

Osteoblasts

Cell that makes and release lamellae/matrix

Osteoblasts

Cell active during growth and repair

Osteoclasts

Bone-destroying cells

Osteoclasts

Cells that break down bone matrix for remodeling and release of calcium

Osteoblasts and Osteoclasts

What bone cells go through remodeling

Hyaline Cartilage

What are embryonic bones made of?

Osteoblasts secrete bone matrix and cover the cartilage, cartilage is digested away leaving the medullary cavity

Bone formation

Articular cartilage of joints, epiphyseal plate, nose, ears, and ribs

Parts not ossified at birth

Stay cartilage for life

How long are articular cartilage of joints not ossified?

Stays cartilage until done growing at end of adolescence; new cartilage grows and eventually is replaced by bone

How long are epiphyseal plate not ossified?

Stay cartilage for life

Nose and ears = elastic

Ribs = hyaline

How long are nose, ears, and ribs not ossified?

Epiphyseal plates

Longitudinal growth of long bones

Epiphyseal plates

Cartilage in plate and on heads of bones grows and then is ossified to make new bone

Epiphyseal plates

To widen the bone osteoblasts add bone tissue to the outside of the diaphysis

It widens; bone gets eaten away so the bone stays light

What happens to the medullary cavity as bone tissue is added to the outside of the disphysis?

Epiphyseal plates

bone growth is controlled by growth and sex hormones here

They ossify

What happens to your epiphyseal plate after puberty?

At specific spots/sites

Where is bone remodeling done?

Bone remodeling

Localized changes at bone markings or repair sites

No

Are bones static?

the needs and availability of calcium in the bloodstream, hormone control, and stress from exercise and gravity

Why are bones modified/remodeled

Neurotransmitter release, muscle contraction, and blood clotting

Why is calcium needed?

Activates osteoclasts to break down bone and release calcium

What does Parathyroid Hormone activate?

Activates osteoblasts to deposit calcium

What does Calcitonin activate?

Bone fracture

A break in a bone

Closed (simple) fracture

Break that does not penetrate the skin

Open (compound) fracture

Break that penetrates the skin

Reduction and Immobilization

How are bone fractures treated?

Realignment of the bone

What is reduction?

Closed reduction

Manual manipulation

Open reduction

Surgery using rods and pins

Allows for bone repair; cast or traction for bad breaks on weight bearing long bones

What is immobilization?

6-8 weeks

How long is normal repair of fractures

Incomplete

At birth, the skull bones are?

Fontanelles (soft spot)

Bones are joined by fibrous membranes

Sutures

Fontanelles are completely replaced with bone within 2 years after birth called?

10 years old

At birth skull is much larger proportionally to lower body and by what age are appropriate proportions reached?

6-11 years old

Face matures and grows outwards during what ages so the jaw matures and cheek and chin bones start to adjust in puberty

Posteriorally; c-curve

At birth primary curvature in thoracic region of spine curves which way?

Intervertebral disc reshaping

During first year of life secondary curvature develops due to what?

Cervical region

As infant learns to control its head where does the curvature develop?

Lumbar region

As infant learns to walk where does the curvature develop?

Osteoporosis

Bone thinning

Over 65 years

Osteoporosis is most common in women over what age?

Because of loss of estrogen during menopause

Why does osteoporosis happen in women?

70 years

Osteoporosis occurs in men over what age?

Spine - can lead to vertebral collapse and hump like appearance

Femur - hip breaks are common

What bones are most affected by osteoporosis?

Calcium poor diet, not enough protein or vitamin D, not enough exercise, and smoking

How can osteoporosis be exacerbated (made worse)?