Calcium Homeostasis (How bone regulates Ca+2 levels) --- INFLUENCE OF HORMONES--notes

Question 1

What are the two hormones used to regulate calcium levels?

Answer 1

Parathyroid Hormone (PTH)

Calcitonin Hormone

Question 2

What is the job of the Parathyroid Hormone (PTH)

Answer 2

To prevent hypocalcemia (too

LITTLE calcium)

Question 3

Why is the Parathyroid Hormone (PTH) the most important of the two hormones?

Answer 3

Because having too little calcium is deadly. It can cause paralysis of the Respiratory muscles and cause asphyxiation.

Question 4

What will happen if you do not have any Parathyroid Hormone (PTH) in your body?

Answer 4

You will die.

Question 5

PTH raises calcium levels in three ways:

must know the order

Answer 5

1st - Effect on the Intestines

2nd- Effects on the Kidneys

3rd - Effect on Bone

Question 6

How does PTH effect the intestines?

Answer 6

It increases the body’s natural process that you bring calcium into the body. PTH increases the absorption of calcium by the intestines.

eat food = Calcium in intestines = into the blood

Question 7

The action in the intestines is reinforced in what other body organ?

Answer 7

Kidneys

Question 8

How does PTH effect the kidneys? There are two effects. What is the first effect?

Answer 8

1. The first effect is PTH’s way of decreasing any natural process that causes calcium loss: PTH decreases urinary loss of calcium by the kidneys, called calcium excretion.
   (Kidneys will get rid of Calcium unless told not to by PTH)

Question 9

How does PTH effect the kidneys? There are two effects. What is the second effect?

Answer 9

2. The second effect on the kidneys helps the INTESTINES absorb calcium: PTH increases Vitamin D production by the kidneys. Without enough Vitamin D, the intestines can’t bring calcium into the body—it’s an essential part of the process.

MUST HAVE VIT. D for intestines to pull in calcium from food.

Question 10

How does PTH effect the bones?

Answer 10

This effect is PTH’s way of releasing Calcium from storage(bones) in the body that has a surplus of it: PTH causes the bones to release
calcium.

To do this,PTH increases osteoclast activity (bone breakdown)because the only way bones can release their extra store of calcium is to
dissolve them.

Question 11

What percetage of bone can be taken during this process?

Answer 11

1%

Question 12

What is the job of Calcitonin Hormone?

Answer 12

To prevent hypercalcemia (too MUCH

calcium)

Question 13

When are levels of the Calcitonin Hormone high in the body?

Answer 13

When you are a kid and when a women is pregnant.

Question 14

Why is Calcitonin Hormone a strange hormone?

Answer 14

It is not very good at its job of to prevent too much calcium in our body.

Question 15

Calcitonin lowers calcium levels in two ways: A major action and a weak secondary action. What is the major action?

Answer 15

Major action: Decreases osteoclast activity(bone breakdown) to stop the release of calcium from bones. (If calcium levels are high, there doesn’t need to be extra calcium coming out of the bones).

Question 16

Calcitonin lowers calcium levels in two ways: A major action and a weak secondary action. What is the weak secondary action?

Answer 16

Weak secondary action: Increasing the osteoblast activity (bone building). As new bone is made, calcium is pulled into the bones to harden them, which lowers calcium levels in the blood.

Question 17

What is the major action Calcitonin hormone used to treat?

Answer 17

To treat osteoporosis

and in the hospital to lower calcium levels.