lecture 1: outline 9

With calcium you want to stay at what level

10 milligrams

What hormone regulates calcium

Parathyroid hormone (most crucial), vitamin d, and calcitonin.

What happens if you have low levels of calcium

low levels hyper-excite the neuromuscular system causing full body convulsions and you die or respiratory arrest.

What happens if you can’t make the three factors that help calcium production

Calcintonia-no effect physiologically. Has good medicinal effects

Vitamin d-you’ll get sick in the long run run

PT-you’ll die

How many parathyroid glands do you have

4 next to the thyroid gland. Very small, size of uncooked lentil

Calcium levels also refer to

Blood levels

If calcium in not binding to a receptor or sensor

It will be picked by the controller, when signal is low enough (below 10) the controller will secrete parathyroid form PTH, PTA. PARATHYROID CELLS will sense low blood calcium and secrete PTH

How does the parathyroid cell operate in terms of negative feedback (what’s true for the cell is true for the gland)

Has a transmembrane protein that’s a calcium receptor-which is important for any negative feedback system. The receptor and controller regulate parathyroid hormone (PTH) secretion based on calcium levels in the blood, ensuring homeostasis.

What does the parathyroid cell do if calcium is low

receptor will alert the biochemical pathway that not enough calcium is biding to the receptor or sensor. The controller will know this when the signal is great (below 10 mmg) and it will initiate synthesis/secretion of PTH

UV is necessary to

stimulate epithelial cells and convert a molecule of 70 hydrocholesterol (steroid hormone) to a hydroxylate. It will wait to activate an enzyme until UV comes; the enzyme will cause hydroxylation. That will go into the bloodstream as cold calciferol

Is cold calciferol a hormone

No, it’s a pro-hormone or pre-hormone. It’s on its way. It becomes a hormone by going to the liver. Liver will use an enzyme to hydroxylate it by attaching an alcohol or (hydroxyl group) which will convert it into its active form calcidiol. It will go to the kidney; kidney cells will secrete an enzyme that will add a third hydroxyl group and from there you get calcitriol.

When does cold calciferol become a hormone

when it becomes calcitriol, a mature vitamin D. It can now bind to receptors on target cells and cause a physiological change.

3 hypercalcemic mechanisms

1. 1. PTA and calcitriol will stimulate formation of osteoclast in the bone, you are removing calcium from bone into the bloodstream, driving calcium higher

2. 2. PTH stimulates calcium reabsorption in the kidney tubules. ions go into the kidney, and the kidney will take control signals from other systems and put more/less of an ion in urine. SO, it’ll put calcium into the blood instead.

3. 3.Calcitriol binds receptors lining the intestine cells. It promotes intestinal absorption (on the lumen) of calcium. It increases the efficiency of calcium uptake from the diet, leading to higher serum calcium levels.

The last step of the formation of calcitriol can’t be activated until

PTH stimulates the kidney cells to release the enzyme that will put that third hydroxyl there.

PTH is what type of hormone

protein hormone. Single polypeptide

Calcitriol (active vitamin D) is what type of hormone

Modified steroid hormone derived from cholesterol.

What type of protein is the calcitonin

A protein hormone

Made by the thyroid gland c cells, activated when calcium gets a little too high. Does the opposite of PTH: inhibits osteoclasts, boosting osteoblasts. It will encourage calcium to leave the blood and go to the bone

What effect does calcitonin effect the kidneys?

It has a hypocalcemic effect. Kidney cells will bind to calcitonin and take up calcium, promoting its excretion.

Calcitonin is the opposite of

PTH. A weak counterweight.

Makes and females both produce

estrogen and testosterone

Estrogen in females is produces in a

Cyclical cycle. Reaches a peak on a monthly basis

After menopause levels of estrogen will

Decrease

Testosterone in males will go

Up at 18 and will and drop drop over decades. This allows them to produce kids at 80.

Estrogen and testosterone are boosters in

Osteoblasts activity

Problem: when one goes away you lose osteoblast lose that stimulation. This is why women are more vulnerable to osteoporosis ( menopause lowers estrogen dramatically)

Osteopenia

Bone weakness, tied to age, everyone will have some degree of this. It can become a problem

Makes skeletons are

Denser, thicker than female skeletons. Causing women to be more effected by even small amounts of bone erosion

Osteoporosis can cause

Broken bones easier.

Osteoporosis targets what part of bone

It will target spongy bone since it’s weaker than compact bone so it will be especially weak in WEIGHT BEARING BONES (femur)

When old people break their hip they actually break their

It’s actually the proximal end of the femur.

Why is easier to break your back when your older

Vertebral bodies has a lot too spongy bone, therefore when your older you can easily break your back.

What do kidney cells do when they see calcitonin

What can treat osteoporosis

Hormone replacement therapy. Pills of estrogen

What’s the risk of giving women over 50 estrogen

Increased risk of heart attacks, strokes, urinary cancer, mammary cancer, and breast cancer

The solution over giving women estrogen

Two classes of drugs:

Selective estrogen: modulate estrogen receptors . They have good effects on osteoblasts, but don’t activate tissues to become cancerous

Pysphospody: osteoclasts will undergo apoptosis earlier when interacting with this. This allows it to match up with the formation of osteoblasts.

Another way to help with osteoporosis

Working out (utilizes Wolfe law), salmon calcitonin ( same amount a human makes but it’s more powerful. Can be ingested or snorted. Will stimulate osteoblasts to reach osteoclasts), and parathyroid hormone (physiologically weird because it stimulates osteoclasts activity but if it s pharmaceuticals given in doses it will do the opposite- help osteoporosis)

Protein hormones produce different effects in

Different animal. A fish hormone can affect a human more powerfully than when the hormone comes from the Hume. Ex: salmon calcitonin is better/more powerful for humans

There is two similar molecules that are not the same, what are the differences.

Calcidol and Calcitrol