Muscle, Bone, and Skin

Question 1

Osteoblasts

Answer 1

Secrete collagen and organic compounds upon which bone is formed. They are incapable of mitosis. As osteoblasts release matrix materials around themselves, they become enveloped by the matrix and differentiate into osteocytes

Question 2

Osteocytes

Answer 2

Incapable of mitosis. They exchange nutrients and waste materials within the blood.

Question 3

Osteoclasts

Answer 3

Resorb bone matrix, releasing minerals back into the blood. They are though to develop from the white blood cells called monocytes

Question 4

Role of vitamin D

Answer 4

Help restore calcium stores in the bone by promoting calcium absorption through the digestive system

Question 5

Physiological importance of calcium

Answer 5

Too much calcium causes membranes to become hypo-excitable, leading to fatigue and memory loss. Too little results in cramps and convulsions

Question 6

Vitamin D synthesis

Answer 6

Ultraviolet radiation activates a molecule in the skin that is a precursor to vitamin D. The activated molecule is modified by enzymes in the liver and kidneys to produce vitamin D.

Question 7

Keratinocytes

Answer 7

Cells that produce the protein keratin, which helps waterproof the skin

Question 8

Melanocytes

Answer 8

Transfer melanin (skin pigment) to keratinocytes