Endocrinology 15 Flashcards
How many parathyroid glands are there?
4
What kind of cells do the parathyroid glands contain?
Chief cells
What cells are the source of PTH?`
Chief cells
What are the overall actions of PTH?
It increases calcium in the plasma and decreases phosphate in the plasma
What is Osteocytic Osteolysis?
The breakdown of bone by osteoclasts or osteocytes?
What cells are on the surface of bones?
Osteoblasts and osteoclasts
What cells are inside the bones?
Osteocytes
Where are osteocytes derived from?
Osteoblasts
What can the osteocytes make contact with?
Cells on the surface of the bone with their projections
How does Osteocytic Osteolysis work?
Osteocytes under the influence of parathyroid hormone move calcium from the readily exchangeable pool of calcium and is pumped to the blood
What do Osteoclasts do?
They increase the reabsorption or the eating away of bone
How do osteoclast cause reabsorption/eating away of bone
They have long processes that attach to the surface of the bone and create a closed-off space between the osteoclast and the solid portion of the bone. It then secrets acids and hydrogen ions into the space and causes them to lower the pH and become more acidic. It also secretes enzymes that eat away the bone.
What do Osteoblasts secrete and what do they do?
They secrete osteoid material and fill up the hole created by osteoclasts which attract osteocytes and deposit calcium and phosphate
How is the blood plasma affected by PTH?
It has increased levels of calcium due to bone breakdown and increased absorption from GI tract. And decreases Phosphate levels due to excretion in the kidney
How does PTH affect the kidney?
It increases the excretion of phosphate ions and increases the reabsorption of calcium so it can go back into the blood
