Bone physiology

Question 1

What is the development of Bone

Answer 1

Mesoderm

Paraxial, intermediate and lateral mesoderm

Skeletal system develops from paraxial and lateral mesoderm

Paraxial mesoderm then separates into blocks called somites

Somites split to form Dermatome, Myoterm and Scleroterm

Question 2

What does dermatome gives rise to ?

Answer 2

Muscles

Question 3

What does Scleroterm gives rise to?

Answer 3

Bones

Question 4

What are the bone cells present in the bone?

Answer 4

Osteogenic cells are stem cells that develop into Osteoblast

Osteoclast causes decalcification of bone

Question 5

What does osteoclast do?

Answer 5

Osteoclast releases enzymes, it breaks down collagen inside the bone

H+ ions combine with chloride to form HCL and this HCL causes demineralization of the bone by breaking down the calcium and phosphate

Question 6

What is meant by Ossification/Osteogenesis?

Answer 6

Process of Bone formation

Question 7

What are Flat bones ?

Answer 7

Ribs
Clavicle
Scapula

Question 8

Intramembraneous ossification

Answer 8

When bone develops directly from mesenchyme

it mostly forms flat bones

Question 9

Endochondral ossification

Answer 9

bone develops from cartilage
Formation of short and long bones

Question 10

Long bones are

Answer 10

Femur
Humerus
Ulnar
Radius
Tibia
Fibula

Question 11

Short Bones are

Answer 11

Carpels
Tarsals
Phalanges

Question 12

What are the functions of Bone

Answer 12

Protects
Movement
Support

Question 13

What are appendicular skeleton ?

Answer 13

Upper limbs
Lower Limbs
Shoulder girdle
Pelvic girdle

Question 14

What does the bone do with calcium

Answer 14

Bone stores the ca and release when the body requires

Question 15

Function of CA

Answer 15

Muscle contraction

Question 16

Do we require ca for blood clotting

Answer 16

yes it is our second messenger

Question 17

Osteoclast ?

Answer 17

Responsible for the resorption of the bone

Question 18

Bone is made up of?

Answer 18

Extracellular Matter (organic and inorganic matrix)
Cellular Matter

Question 19

What does organic matrix and inorganic matrix

Answer 19

organic -Osteoid, collagen, and ground substances

organic matrix gives elasticity

Question 20

What does inorganic matrix

Answer 20

made up of bone minerals , mainly calcium phosphate both get deposited into the bones

Question 21

What does osteoblast do ?

Answer 21

They release alkaline phosphate which breaks down pyrophosphate

Question 22

What happens in the absence of pyrophosphate?

Answer 22

Calcium phosphate gets deposited in the bone in the form of hydroxyapatite

Question 23

Does osteoblasts release anything else?

Answer 23

Yes, it also releases Ankylosis Protein and pyrophosphatase phosphodiesterase 1

Then, it increases pyrophosphates

This inhibits deposition of calcium phosphate in the bone in the form of hydroxyapatite

Question 24

What happens in the deficiency of Ankylosis Protein ?

Answer 24

It decreases pyrophosphate release increases the hydroxyapatite deposition to bone

Question 25

When bone needs to be deposited in the hydroxyapatite crystals, what does it release?

Answer 25

It releases Alkaline Phosphatase

Question 26

When bone does not need to be deposited in the hydroxyapatite crystals, what does it release?

Answer 26

Ankylosis Protein and pyrophosphatase

Question 27

What is the function of pyrophosphate?

Answer 27

Prevents the deposition of hydroxyapatite Both alkaline Phosphatase and Ankylosis Protein work on pyrophosphate but it breaks down on alkaline phosphate and increase on ankylosis protein

Question 28

what are the complications assoc with Alkaline Phosphatase

Answer 28

Bones can become softer and easier to fracture

Question 29

What happens to the deficiency of Ankylosis protein

Answer 29

Extra calcification - ankylosing spondylitis

Question 30

If Ca is too low?

Answer 30

Hypocalcaemia associated with Muscle spasm

Question 31

If Ca is too High ?

Answer 31

Hypercalcemia associated with cardiac arrhythmia

Question 32

Parathyroid hormone works on bone ?

Answer 32

Osteoclasts stimulated to release stored calcium ions from bone

Question 33

Parathyroid Gland Response

Answer 33

Intestinal Response Absorption of calcium increases

Question 34

Parathyroid Gland Response

Answer 34

Kidney absorb calcium ions

Question 35

What is the hormone released by Thyroid hormone/Ce cells ?

Answer 35

Calcitonin

Question 36

What are the other hormones released by thyroid hormone?

Answer 36

T3 and T4

Question 37

What is the function of Calcitonin on bone?

Answer 37

the osteoclast activity decreases and the osteoblast activity unaffected

Question 38

What is the effect of Calcitonin in Intestinal Response?

Answer 38

inhibits the absorption of calcium from the intestine, by this way calcium level slowly decreases

Question 39

What is the effect of calcitonin in the kidney?

Answer 39

It inhibits the reabsorption of calcium from the kidney and promotes the excretion of calcium in the urine

Question 40

What are the 3 ways the calcium would be decreased?

Answer 40

Osteoclast inhibited absorption in the intestine has slowed down Renal reabsorption is inhibited and Renal excretion is promoted

Question 41

What is negative feedback

Answer 41

Release of both hormones (PTH and Calcitonin) is controlled by Negative feedback cycle

Question 42

Factors that affect bone growth

Answer 42

Sex End of puberty Stress - when the body releases cortisol that inhibits growth and increase breakdown

Question 43

Adverse effect of cortisol

Answer 43

inhibits osteoblasts stimulates osteoclasts

Question 44

Hormones that affect bone growth ?

Answer 44

Growth Hormone Hypothyroidism Drug/Steroid use

Question 45

what is the effect of cortisol in bone growth ?

Answer 45

It inhibits the development of Bone growth

Question 46

What is Wolff's Law ?

Answer 46

Long bones are thickest midway along the shaft Curved bones are thickest where they are more likely to buckle