Skin Flashcards
1
Q
What is the skin?
A
Combination of tissues with its own blood supply, accounts for 16% total body weight
- largest organ in the body
- acts as major compartment separator
- helps with homeostasis, sensory reception and protection from external environment
2
Q
What are the three layers of the skin?
A
- epidermis
- dermis
- hypodermis
3
Q
Describe the epidermis
A
- epithelium
- forms boundary between internal and external compartments
4
Q
Describe the dermis
A
- connective tissue
- gives structural strength
5
Q
Describe the hypodermis
A
- fat
6
Q
What are the five layers of the epidermis?
A
- stratum germinativum
- stratum spinosum
- stratum granulosum
- stratum lucidum
- stratum corneum
7
Q
Describe the stratum germinativum
A
- bound to basement membrane by hemidesmosomes
- bound to other cells by desmosomes
- regular assortment of organelles
- stem cells
8
Q
Describe the stratum spinosum
A
- spinous layer
- created after cell death
- cells shrink bu desmosome junctions create spines
9
Q
Describe the stratum granulosum
A
- defined by presence of keratohyalin granules
- accumulations of protein around keratin intermediate filaments
10
Q
Describe the stratum corneum
A
- keratohyalin converted to keratin
- disulphide linkages give strength
- no organelles
- desmosomes bind cells
- 30 day turnover
11
Q
What two layers compose the dermis?
A
- papillary layer
- reticular layer
12
Q
Describe the papillary layer
A
- loose connective tissue
- irregular interface with epidermis
- cellular e.g. macrophages
- blood vessels
- nerve endings
13
Q
Describe the reticular layer
A
- dense irregular connective tissue
- collagen bundles in 3 planes
- elastic fibres
