Lecture 5

Question 1

Short term importance of calcium?

Answer 1

Neuromuscular excitability

Vessicle Exocytosis

Blood clotting cascade

2nd messenger cascades

Enzyme co-factor

Question 2

Long term importance of Calcium

Answer 2

Structural support in bones and teeth

Milk production

Egg laying

Question 3

How does body regulate short term calcium metabolism?

Answer 3

The body maintains blood calcium concentrations by regulating Ca reabsorption from bone and renal tubes

Question 4

Long term regulation of calcium metabolism

Answer 4

Maintains total amount of Ca in body by

Regulating dietary Ca absorption from intestine

Question 5

Where are the parathyroid glands located?

Answer 5

4 small glands on the corners of the thyroid gland

Question 6

How is PTH involved in immediate calcium homeostasis?

Answer 6

Increase Ca resorption from bone “fluid” into plasma by activating Ca pumps

Question 7

How is PTH involved in long-term Ca balance

Answer 7

Increase Ca resorption from mineralized bone into the bone fluid

• indirectly activates osteoclasts

Question 8

What does osteoblast and osteoclast balance depend upon?

Answer 8

Mechanical stress (exercise)

Plasma Calcium concentrations

Hormonal changes (ie estrogen)

Question 9

What is PTH?

Answer 9

Parathyroid Hormone

Question 10

3 Effects PTH has on kidneys

Answer 10

Increase reabsorption of Ca from renal tubules

Decrease reabsorption of phosphorus

Helps activate Vitamin D

Question 11

Relationship between Phosphorus and Ca?

Answer 11

Form Crystals

If phosphate goes up Ca goes down

Question 12

What secretes Calcitonin (CT)

Answer 12

C cells that are found in thyroid gland

Question 13

Overall function of Calcitonin

Answer 13

Opposite of PTH

Question 14

SHort term Long Term effects of Calcitonin

Answer 14

Short Term

• decrease Ca movement from bone fluid to plasma

Long term

• Decrease bone resorption by inhibiting osteoclasts

Question 15

Regulation of Calcitonin

Answer 15

CT release stimulated by high plasma Ca

CT inhibited by low plasmas Ca

Question 16

How is Vitamin D both a nutrient and a hormone?

Answer 16

Hormone

• Produced by the skin, activated by UV radiation, released into blood and acts on intesting

Nutrient

Produced in insufficient quantities so considered a nutrient

Question 17

3 Functions of Vitamin D

Answer 17

Increase calcium absorption from the intestine

Increase phosphate absorption from intesting

Increase bone responsiveness to PTH

Question 18

Overall function of Vitamin D

Answer 18

For long term Ca balance (not short term regulation)

Question 19

3 Disorders of calcium metabolism

Answer 19

1. Hyperparathyroidism
2. Vitamin D Deficiency
3. Milk Fever

Question 20

3 things that might cause an increase of PTH secretion

Answer 20

Diet: Low Ca or Vit D, high phosphorus

Chronic renal disease

Primary hyperparathyroidism : Tumor

Question 21

2 Symptoms of Hyperparathyroidism

Answer 21

Weakend bones or fractures

Increase kidney stones

Question 22

3 reasons why kidney disease causes increase of PTH release

Answer 22

Kidneys cannot excrete phosphorus effectively

Less kidney activation of Vit D, so less absorption of Ca from gut

Less reabsorption of Ca from renal tubules

Question 23

What is Rickets?

Answer 23

Vit D deficiency in younger animals

Question 24

What is osteomalacia?

Answer 24

Vit D deficiency in older animals

Question 25

How would Vit D deficiency effect PTH levels

Answer 25

Decreased intestinal absorption of Ca, thereore increase PTH to compensate