Anatomy and Physiology Chapter 5 The Integumentary System

Functions of skin

Protection, Thermoregulation, Cutaneous Sensation, Vitamin D synthesis, Blood Reservoir, Excretion and Absorption.

Protective elements of skin

Keratin, Lipids, Glandular Secretions, Melanin

Thermoregulation

Controls internal temp

Vitamin D synthesis

You need Vitamin D to absorb calcium

Epidermis

Superficial layer of skin. Avascular. 4 different cell types (Keratinocytes, Melanocytes, Langerhans cells, merkel cells)

Keratinocytes

90% of cells. Keratin

Melanocytes

8% of cells. Melanin (Pigments and absorb uv radiation.

Langerhans Cells

Immune function

Merkel cells

Touch

Layers of skin (Superficial to deep)

Epidermis, Dermis

Epidermal Layers (deep to superficial)

Stratum Basale, Stratum spinosum, Stratum granulosum, Stratum lucidum, Stratum corneum.

Stratum Basale

Keratinocytes, Melanocytes, Langerhans cells and Merkel cells are here. Deepest layer, and mitosis occurs.

Stratum Spinosum

Keratinocytes and Langerhans cells are here. Production of melanocytes here.

Stratum granulosum

Lamellar granules, apoptosis occurs here.

Stratum lucidum

Present only in thick skin

Stratum corneum

Keratin, and continuously shed (Outermost layer)

Dermis

Deep layer, Beneath epidermis, Vascular, LAyers: Papillary and reticular

Papillary Layer

Areolar connective tissue, Dermal papillae (finger like projections)

Reticular layer

Thickest layer, dense and irregular connective tissue

Hypodermis

Not apart of skin

Skin color

Hemoglobin, Cerotene, Melanin

Hemoglobin

Pigment in Red blood cells that carry oxygen. Oxygen in blood positively correlates with blood in area.

Carotene

Ingested- accumulates in stratum corneum. Color: Orangish yellow.

Melanin

Only pigment synthesized in skin. Freckles are bunches of melanocytes.

Albinism

Not capable of producing melanin

Vitiligo

Loss of melanocytes in patches of skin

Function of Hair

Protection, light touches

Anatomy of Hair

Shaft, root, hair bulb, hair papilla, matrix, arrector pilli muscle.

Shaft of hair

(Inside skin layer) Medulla, Cortex, Cuticle

Root of hair

Medulla, cortex, cuticle, (Outer hair part) Internal root sheath, external root sheath, dermal root sheath(Dermis)

Hair Follicle

Surrounds root

Alopecia

Condition characterized by the rapid onset of hair loss in a sharply defined area. Cause by genetics, endocrine disorder, chemo, or stress.

Skin exocrine glands

Sebaceous Glands, Sudoriferous gland, Apocrine gland, ceruminous gland

Seabaceous gland

Simple acinar, holocrine, duct opens into hair follicle. Secrete sebum.

Sebum

Prevents hair from drying out, keeps skin soft and pliable, prevents excessive evaporation of water.

Sudoriferous(Sweat) glands

Merocrine and ceruminous and apocrine glands

Merocrine (Eccrine) Gland

Simple tubular, found in palms, soles, and forehead, duct terminates on epidermis. Watery secretion, that regulates boy temp and does waste removal.

Apocrine(sweat) gland

Simple tubular, found in armpit and genital regions. Secretions are viscous (functions at puberty and stimulated during stress or sexual arousal).

Ceruminous (Wax) Gland

Simple tubular, merocrine, found in external auditory meatus (Ear). Excretes cerumen

Cerumen

Sticky barrier that stop the entrance of foreign bodies into ear.

Nails

Tightly packer keratinized cells

Nail body

Visible portion of nail. (from distal to proximal) Free Edge, Nail body, Luluna, Eponychium, Nail root (None visible).

Lunula

is white (Thickened stratum basale)

Nail root

Under skin

Eponychium

Cuticle

Burns

1st, 2nd and 3rd degree burns. Tissue damage cause by extreme heat.

First degree burn

Hurts epidermis. Sunburn

Second Degree Burn

Damage dermis and hurt epidermis. blistering.

Third degree burn

Damage everything- need a skin graf. Charing

Rule of nines

ID the depth and severity of a burn