BIOM PART TWO - Lecture 3

Question 1

Where is 99% of calcium found?

Answer 1

In the bones

Question 2

What is calcium stably stored as?

Answer 2

Hydrooxyapatite

Question 3

What is the hydroxyapatite made out of?

Answer 3

Calcium salts and phosphate which provide structural integrity

Question 4

What is 1% of calcium found in?

Answer 4

Soft Tissues

Question 5

How much is intracellular?

Answer 5

0.9%

Question 6

How much is extracellular?

Answer 6

0.1%

Question 7

What are intracellular and extraceullar calcium ions in the soft tissue essential for?

Answer 7

Neuromuscular excitation, blood coagulation, hormone secretion, enzyme activity, fertilization

Question 8

What are characteristics of extraceullar calcium?

Answer 8

Very tightly regulated

50% ionized

40% Protein-Bound

10% complexed with phosphate and citrate

Extraceullar fluid/plasma

Bone

Question 9

What are characteristics of Intracellular Calcium?

Answer 9

Highly regulated

More abundant than extraceullar

Largely associated with membranes in mitochondria, ER, plasma membrane

Question 10

How is the total body Ca2+ calculated?

Answer 10

Intake - Output

Question 11

What is the intake of Ca2+?

Answer 11

Diet
1/3 absorbed in small intestine

Absorption is hormone regulation

Recommended = 1000mg/day

Question 12

What is the output of Ca2+?

Answer 12

Kidney’s

Body can’t make it so it has to be replaced

Question 13

What are three hormones that regulate movement of calcium between bone, kidney’s and intestine

Answer 13

Parathyroid Hormone (PTH)

Calcitriol (Vitamine D3)

Calcitonin

Question 14

What is PTH?

Answer 14

A peptide made by parathyroid hormone

Question 15

How is PTH secrete?

Answer 15

Secretly continuously (not stored)

Question 16

What does PTH help with?

Answer 16

Regulating calcium

Question 17

Can Parathyroid gland be surgically removed?

Answer 17

No - thyroid gland can however.

Question 18

What are the Two types of cells in the Parathyroid Gland?

Answer 18

Chief Cells

Oxyphils

Question 19

What do Chief Cells do?

Answer 19

Secrete PTH

Question 20

What happens when plasma Ca2+ falls?

Answer 20

PTH acts to raise the CA2+ levels back to normal via 3 mechanisms

Question 21

What is the first mechanism?

Answer 21

Stimulate Osteoblasts to reabsorb bone

Question 22

What is the Second Mechanism?

Answer 22

Stimulate kidneys to reabsorb Ca2+

Question 23

What is the Third Mechanism?

Answer 23

Stimulate the kidneys to produce an enzyme that will activate Vitamin D to better absorb Ca in the intestinal epithelium

Question 24

What is Hypocalcaemia?

Answer 24

Too low of Ca2+ in the blood

Question 25

What does Hypocalcaemia do?

Answer 25

Increase PTH secretion, stimulates the reabsoprtion of Ca2+ back into the blood

Question 26

What is Hypercalcameia?

Answer 26

Too much Calcium

Question 27

What happens with Hypercalcemia?

Answer 27

Decrease in PTH

Question 28

What is your bone constantly doing?

Answer 28

Constantly being formed and reabsorbed

Question 29

What does your bone contain?

Answer 29

Calcified ECM

Question 30

How does the calcified ECM form?

Answer 30

When the calcium phosphate crystals (hydroxyapatite) precipitate and attach to lattice for structural support

Question 31

What is the most common form of calcium phosphate?

Answer 31

Hydooxyapatate

Question 32

What happens in Bone Deposition?

Answer 32

Osteoblasts are going to secrete a matrix of collagen proteins which become hardened by deposits of hydroxyapatite

Question 33

What happens in Bone reabsorption?

Answer 33

Osteoclasts dissolve hydroxyapatite and return the bone Ca2+ into the blood