Human Anatomy The Integument System

Function(s) 1. Physical protection 2. Temperature Regulation 3. Protects against water loss 4. Excretion 5. Synthesis of vitamin D 3

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 cells No blood supply No nerve supply 5 distinct layers of Stratified Squamous cells

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 tissue Blood vessels integrated within to help regulate body temperature Nerve tissue carries sensory impulese Hair follicles Sebaceous Glands (oil) Sweat glands

Dermis

Subcutaneous contains... Adipose tissue (insulation) Larger blood vessels Larger nerve fibers

Accessory Structures of the Integument 1. Hair follicles 2. Oil and sweat glands 3. Nails

Hair Most skin surfaces Composed 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 & soles Sweat 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°F Heat Lost = Heat Produced Thermometer 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