Unit 3 Day 2 Anatomy Before everything else, getting ready is the secret to success. Henry Ford

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