Lecture 10

Question 1

3 cells that are responsible for the formation and maintenance of bone

Answer 1

1. Osteoblasts
2. Osteoclasts
3. Osteocytes

Question 2

Osteoblasts

Answer 2

Bone forming cells

Question 3

Osteoclasts

Answer 3

Bone degradation

Question 4

Osteocytes

Answer 4

Maintaining bone
(These are previously osteoblasts that are completely surrounded by bone matrix) Therefore just maintain bone in its immediate vicinity

Question 5

Making bone

Answer 5

creating calcium phosphate complexes (calcium crystallization)

Question 6

6 Reasons Why is Calcium is critical for physiology

Answer 6

• Intracellular signaling
  
  • Hormone secretion
  • Blood clotting
  • Neural excitability
  • Muscle contraction
    
    • Building and maintaining bone

Question 7

Locations of Calcium

Answer 7

1. Extracellular matrix
2. Extracellular fluid
3. Intracellular Ca2+

Question 8

RANK

Answer 8

receptor activator of nuclear factor kappa B

Question 9

RANKL

Answer 9

RANK ligand

Question 10

Osteoprotegerin (OPG)

Answer 10

secreted by osteoblasts (bone forming) to block RANKL/RANK interaction

Question 11

Denosumab

Answer 11

bone anti-resorptive drug (prevents bone loss)

Question 12

Antiresorptive drugs

Answer 12

slow down the resorption (absorption) or breakdown part of the remodeling cycle

Question 13

Parathyroid Hormone (PTH)

Answer 13

a hormone released from the 4 parathyroid glands (chief cells)
Function: increases plasma calcium concentration
Stimulus: very sensitive to low plasma calcium

Question 14

PTH increases plasma calcium concentration by …

Answer 14

acting directly on bone and kidney

Question 15

3 Hormones that control plasma Ca 2+ levels

Answer 15

1. PTH (parathyroid hormone)
   
   2. Calcitriol (aka 1,25-dihydroxycholecalciferol)
   3. Calcitonin

Question 16

3 Target sites of hormones that control plasma calcium levels

Answer 16

1. Bones
2. Kidneys
3. Digestive tract

Question 17

3 organs are crucial in the development of calcitriol

Answer 17

1. Skin
2. Liver
3. Kidney

Question 18

Calcitonin

Answer 18

• Secreted from the C cells of the thyroid gland
• Calcitonin is a peptide hormone
• Release triggered by high plasma calcium concentrations
  -tones down calcium levels

Question 19

How does PTH control blood phosphate?

Answer 19

• increases phosphate release from bone
• decreases phosphate reabsorption in the kidney

Question 20

How does PTH effect the bones and kidney?

Answer 20

• increases bone reabsorption through increasing RANKL and decreasing OPG expression

Question 21

How does Calcitrol control blood phosphate?

Answer 21

increases phosphate absorption by intestine and reabsorption by kidney

Question 22

Hypercalcemia

Answer 22

too much calcium homeostasis

Question 23

Symptoms of Hypercalcemia

Answer 23

• Groans (constipation)
• Moans (fatigue, depression)
• Bones (bone pain)
• Stones (kidney stones)
• Psychiatric overtones (depression, weakness and confusion)

Question 24

Symptoms of Hypocalcaemia

Answer 24

• C (convulsions)
• A (Arrhythmias)
• S (spasms, seizures and stridor)
• T (Tetany)
  People can die from this

Question 25

Hypocalcaemia

Answer 25

too little calcium homeostasis

Question 26

Arrhythmias

Answer 26

a condition in which the heart beats with an irregular or abnormal rhythm.

Question 27

Tetany

Answer 27

a condition marked by intermittent muscular spasms, caused by malfunction of the parathyroid glands and a consequent deficiency of calcium