Lecture 6 Skeletal And Muscle Physio

Question 0

Bone ossification begins @ 8th week of development and terminates at age ________

Answer 0

20

Question 1

Functions of the skeletal system are

Answer 1

Support 
Protection of organs 
Attaches muscles allows mvmt
Marrow produces RBCs and WBCs
Calcium storage

Question 2

Bone ossifies in 2 ways what are they

Answer 2

Intramembranous ossification

Endochondral ossification

Question 3

Describe intramebranous ossification From what does bone develop from
Osteoblasts role along fibers
And under periosteum

Answer 3

Flat bones ( skull, clavicle, mandible)
Develop from fibrous CT membrane
Osteoblasts produce spongy bone along fibers
Osteoblasts create compact bone under periosteum

Question 4

What are fontanels

Answer 4

Unossified membranes in skull that remain at birth

Before subject to intramebranous ossification

Question 5

What does endochondral ossification entail

From what does it develop

Answer 5

Most bones develop this way
From hyaline cartilage
First cartilage is laid down in rough shape of a bone to be
The cartilage becomes spongy bone
Periosteum forms and osteoblasts beneath lay down compact bone

Question 6

Articular cartilage and epiphysial plate are

Answer 6

Unossified cartilage

Question 7

How does bone grow in length post natal

Answer 7

Endochondral growth taking place at epiphysial plates

Cartilage grows and matrix near diaphysis becomes bone

Question 8

When does growth in length stop

Answer 8

When epiphyseal plate ossifies into epiphyseal line

Question 9

Growth in diameter is also known as

Answer 9

Appositional growth

Question 10

How does growth in diameter occur

Answer 10

Due to activity of osteoblasts beneath periosteum of long bones and
Osteoclast beneath medullary endosteum resorb bone
Allows the size of the cavity to keep pace with the growing bone

Question 11

Bone growth and remodelling is effected by 3 factors which Are

Answer 11

Mechanical stress
Nutrition
Hormones

Question 12

Explain how mechanical stress promotes bone growth

Answer 12

Moderate exercise increases osteoblast activity in areas of stress
More building than breaking

Question 13

When an. Injury happens to a bone that restricts movement we see an instance of ________ osteoblast activity without change in _____ activity.

Answer 13

Deceased osteoblast

No change in osteoclast

Question 14

Injury that restricts movement in bone leads to decrease in

Answer 14

Bone mass
Bone formation decreases
Breakdown continues
Weights or electric currents may help

Question 15

How does nutrition effect bone

Ie; what vitamins and minerals important

Answer 15

Calcium and PO4 ( phosphate ) required for production of bone matrix
Vitamin c for collagen
Vit d for increased Ca2+ absorption from small intestine

Question 16

What results from inadequate vitamin d

Answer 16

Rickets

Soft bones / vitamin d needed to help absorb calcium

Question 17

What hormones are important for bone growth ?

Answer 17

GH
Thyroid
Estrogen
Testosterone

Question 18

Estrogen and testosterone increase _____ activity and can cause ossification of epiphyseal plate creating _________

Answer 18

Osteoblast

Epiphyseal line

Question 19

Which hormone inhibits osteoclast activity

And what does that do?

Answer 19

Calcitonin

And increases calcium from blood to bone

Question 20

Parathyroid hormone increases bone reabsorption ( destruction of matrix ) by

Answer 20

Increasing osteoclast activity and
Decreasing osteoblast activity
This increases blood calcium

Question 21

Which hormone increases blood Calcium and which decreases

Answer 21

Increases blood Ca2+ parathyroid

Decreases : calcitonin

Question 22

Osteoporosis risks

Answer 22

Age/  decrease in sex hormones 
Inadequate diet / vit d and ca2+
Illness - excess parathyroid hormone 
Lack of exercise or low body weight 
Stress - cortisol 
Menopause - drop in estrogen 
Smoking - drop in estrogen

Question 23

How is bone repaired ?

Answer 23

Fracture - blood clot
Clot replaced with callus
Callus ossifies via endochondral and intramebranous ossification.
Takes 4-6 weeks or longer depending on bone length

Question 24

What is a callus in bone

Answer 24

Fibrous network + fibrous cartilage islets