Skin Color and Vitamin D

what pigments in the epidermis influence skin color?

melanin and carotene

what is melanin?

red-yellow or brown-black pigment

what is the function of melanin?

protects skin from UV radiation by absorbing UV from reaching cell’s nucleus

what happens if UV radiation reaches cells?

if UV gets inside nucleus, it damages DNA and causes cancer

what is melonama?

cancer from melanocytes; melanocytes become cancerous and constantly divide

why do dark-skinned individuals have a less chance of getting melonama?

their skin is good at protecting its cells because a lot of melanin is produced, so more UV radiation gets more absorbed

what is carotene?

orange-yellow pigment found in orange vegetables

which pigment can only be found in diet? (not produced by body)

carotene

what is the function of carotene?

can be converted to vitamin A, which is essential for skin health and eye retina

how does blood flow influence skin color?

sends blood flow and makes skin red because of the hemoglobin in red blood cells

what is cyanosis?

bluish tint from skin not receiving oxygen-rich blood

what causes cyanosis?

extreme cold, heart failure, or asthma

how does the amount of oxygenated skin make skin look red or blue?

more oxygen in skin → more red

less oxygen in skin → more blue

how does extreme cold cause cyanosis?

body keeps blood close to core to keep body warm (away from skin)

how does heart failure cause cyanosis?

heart cannot send oxygen-rich blood to skin

how does asthma cause cyanosis?

body cant take in enough oxygen and cant send oxygen-rich blood to skin

what are the health conditions that affect skin color?

jaundice

pituitary tumor

vitiligo

what is jaundice?

buildup of bilirubin in blood from liver failure or too many red blood cells dying at once

what is bilirubin?

yellow-pigment produced when red blood cells die

how does liver failure cause jaundice?

if it fails, then it cant clean bilirubin out of blood and makes skin and whites of eyes yellow

how do a lot of red blood cells dying cause bilirubin?

release too much bilirubin

what is pituitary tumor?

spits out too much melanocyte stimulating hormones (MSH) and increases production of melanin (changes skin color)

what is vitiligo?

autoimmune system attacks melanocytes, causing a loss of melanocytes and loss of color

how is vitamin D produced?

from epidermal cells from UV radiation

sun stimulates body to make vitamin D

what hormone is produced when liver and kidneys convert vitamin D?

calcitriol

what is calcitriol?

hormone essential for body to absorb calcium and phosphate ions

what are rickets?

Vitamin D deficiency in children cause loss of bone integrity because low calcium absorption occurs from no vitamin D to make calcitriol body needs to absorb calcium

why do rickets only happen in children?

bones are still growing