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Unit 3 Day 2 Anatomy
Before everything else, getting ready is the secret to success.
Henry Ford
Today’s Agenda
Notes on Objective 1 Epidermis
Practice labeling skinNotes on objective 2
Epidermis is
KeratinizedStratified Of 4 cell types
Epidermis continued Keratinocytes- make keratin protein
Melanocytes—make melanin Merkel’s cells – touch reception
Langerhan’s cell – macrophage-like
Layers of Epidermis Totally new epidermis every 35-45 days due to
layering
Stratum Basal—basal layer Deepest layer Single row of keratinocytes Some Merkel cells 25% melanocytes Much mitosis
Stratum Spinosum (spiny layer)
Several cell layers thick Little mitosis Keratinocytes with spine-like projections
Langerhan’s cells present
Stratum Granulosum (granular layer)
Very thin, 2-3 layers of flattened cells
Granules of keratohyalin give its name
Keratinization begins here, as lower cells rise to this layer, die and leave keratin later to be abraded away.
Stratum lucidium (clear layer) found only in really thick skin
Thin layer with keratohyalin and tonofilaments.
Stratum Corneum (horny layer)
Broad layer, 20-30 cell layers thick
All dead, keratinized cells.
1
2
3
4
5
6
7
89
10 11
1. Sebaceous gland
2. Root of the hair
3. Epidermis
4. Dermal Papilla
5. Arrector pilli
6. Dermis
7. Bulb of the hair
8. Hair follicle
1. Covering of follicle
2. External root sheath
3. Internal root sheath
4. Cortex
5. Bulb of the follicle
6. Adipose tissue
Spider bite
Ringworm fungus
Acne
Fig. 38.3, p. 646
hair
EPIDERMIS
DERMIS
hypodermis(subcutaneouslayer)
oil glandhair follicle
blood vessels
sensoryneuron
sweat gland
smooth muscle
Slide 3
Fig. 38.3, p. 646
hair
EPIDERMIS
DERMIS
hypodermis(subcutaneouslayer)
oil glandhair follicle
blood vessels
sensoryneuron
sweat gland
smooth muscle
Slide 6
Fig. 38.5, p. 648
stratum corneumthe outermost layer ofepidermis; composedof dead, flattened,keratinized cells
deeper skin layers;composed of living,rapidly dividingepidermal cells
dermis
Slide 7
Fig. 38.6, p. 649
