Tissues 8- Skin

Question 1

Describe the structure of the skin

Answer 1

3 layers
Epidermis:
Mainly formed by keratinacytes arranged in 4 layers
Move up on the skin and differentiates to make kertain in different layers
Also contains langerhan cells, merkel cells and melanocytes

Dermis

subcutaneous tissue

Question 2

explain the function of the skin,

What is a cause of eczema

Answer 2

Barrier function:
stops irratins and alergins getting in
waterproofing
Protection against injury and radiation

Barrier made of Corneocytes and lipids
defect in filagrin gene causes eczema (sign of gene defect is palmar hyperlinearity)

Question 3

recall the development, function and control of melanocytes

Answer 3

Produces melanin- packaged in melanosomes.
Interacts with keratinocytes
When keratinocytes exposed to UV rays they produce a hormone called melanocyte stimulating hormone.
Darker skin people have a high base level of melanin
Derived embrology from neural crest

Question 4

What happens in rickets

Answer 4

Caused by vit-d deficiency

soft bones

Question 5

Describe the basement membrane zone of the skin

Answer 5

Complex set of proteins that hold together epidermis and dermis.

If proteins are damaged they can get blistering disorders
genetic fault in protein or auto immune disease

Question 6

What is the dermis made up of (5)

Answer 6

Made up of:
Collagen 70%
Elastin
gylcoaminoglycans 
Fibroblasts
Immune cells

Question 7

What are the two types of sweat glands

Answer 7

Eccrine
all over the body
salty sweat

apocrine
open on hair follicles
armpits and groins
viscous sweat subject to bacterial metabolism -smells

Question 8

How do melanocytes protect keratinocyte nuclei

Answer 8

They produce melanin in the form of melanosomes,

These act as a protective cap over the nuclei to stop UV rays damaging the DNA