Human Anatomy

The Integument System

Function(s)

1. Physical protection

2. Temperature Regulation

3. Protects against water loss

4. Excretion

5. Synthesis of vitamin D3

Types of Membranes

Serous: line body cavities with no openings (thorax)

Mucous: line cavities that open to outside (anus, nose)

Synovial: line joints (elbow)Cutaneous: SKIN!

Structure of Skin 2 layers – epidermis and dermis

A. Epidermis

Consists only of epithelial cellsNo blood supplyNo nerve supply5 distinct layers of Stratified Squamous

cells

Epidermis

1

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5

Epidermis

Older cells harden in a process called keritinization. (Keratin is waterproof).

Protects the underlying tissues from UV light, chemicals, injury, and microorganisms.

Melanocytes produce melanin. Melanin absorbs UV light.

Skin Color

Is determined by 3 pigments

1. Hemoglobin – red pigment within rbc

2. Melanin – brown pigment in melanocytes

3. Carotene – orange-yellow pigment found in both epidermal cells and dermal fat cells

Dermis contains...

Elastic and fibrous connective tissueBlood vessels integrated within to help

regulate body temperatureNerve tissue carries sensory impuleseHair folliclesSebaceous Glands (oil)Sweat glands

Dermis

Subcutaneous contains...

Adipose tissue (insulation)Larger blood vesselsLarger nerve fibers

Accessory Structuresof the Integument

1. Hair follicles

2. Oil and sweat glands

3. Nails

Hair

Most skin surfacesComposed of

recycled epidermal cells

Arrector pilli muscle controls “goosebumps”

Hair color is genetic

Nails

Keritinization of the epithelial layer

Sebaceous Glands

Attached to hair follicles (usually)

Secrete oil which helps keep hair soft & waterproof

Acne is a bacterial infection of the sebaceous gland

Sweat Glands

Most numerous in palms & solesSweat is mostly water, but also salts and

urea and uric acid.Some are specialized such as the ones

in the ear (ear wax)Response to heat or emotional stress

Regulation of Body Temperature

37°C or 98.6°FHeat Lost = Heat ProducedThermometer is called the hypothalamus

(in the brain)Internal regulation is called homeostasis

(biological balance)Sweating, shivering, flushing, are

examples of temperature regulation

Healing

We will talk more about immune response later on.....

Blood vessels can swell causing fluids to leak into a wound (inflammation)

Scabs are a result of blood clots at the dermal layer

Scars result from larger wounds where new blood vessels had to be formed