1. composed of keratinized stratified squamous epithelium
Sweet glands
Melanocytes
Nota:
1. produce melanin(primarily responsible for skin color)
Round cell + clear cytoplasm
Locate in stratum basale
Sebaceous glands
Hair follicles and hair
Dermis
Nota:
1. composed of a dense connective tissue:
- impact mechanical support
-strength
-thickness(e.g. papillae layer(PL), collagen fibers of the reticular layer(RL)
Hypodermis
Nota:
-contains large amount of adipose tissue
Types of skin
Thick
Nota:
1. epidermis is supported by dermis(a layer of dense fibro-elastic tissue)
2.Merges with the loose supporting tissue of hypodermis
Stratified squamous keratinizing epithilium
Nota:
1.extremely thick
2.keratinized surface layer
Structure
Epidermis(five layers)
Stratum corneum(SC)
Nota:
1. stratified squamous epithelium
2. consist of flattened, closely packed, dead cells and absent nuclei
Stratum granulosum(SG)
Nota:
1. 2-5 layers of nucleated cells
2. basophilic granules(keratohyalin)
Stratum basale(SB)
Nota:
1. single layer of cubondal cells on basement menbrane
Stratum lucidum(SL)
Nota:
- homogenous line of flattened cells
Stratum spinosum(SS)
Nota:
1. 3-4 cells thick
2. polyhydral
3. basophilic
Dermis(three layers)
Subcutaneous layer
Nota:
1. loose connective tissue
2. adipose tissue
Reticular layer
Nota:
1. mainly of bundle of coarse collagenous fibres(in various direction)
Papillary layer
Nota:
Consist of:
1. fine collagenous fibres
2. reticular fibre
3. elastic fibres
-all interweaving with Blood vessels
Hypodermis
Thin
abdominal skin
Nota:
1. thin stratified squamous
2.only stratum corneum and stratum germinativum
Scalp
Papillary layer
Nota:
1. marrow zone of fibred dense irrugular connective tissue
Reticular layer
Nota:
1. Hair follicle associated with sebaceous gland
2.also find cross section of sweet gland
Hair follicle
Nota:
1. features: extended hair bulb and the dermal papilla
2. the main mass of hair bulb= matrix(for hair growth)
Sebaceous gland
Nota:
1. simple branched acinar glands
2. appear encapsulated spherical masses form
3. Vacuolate cytoplasm( for lipid and waxy secretion)
Sweet gland
Nota:
1. simple coil tubular gland
- appear in section as groups of small circular ovoid structure