Post on 01-Jan-2016
transcript
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!
A. Epidermis
Consists only of epithelial cellsNo blood supplyNo nerve supply5 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 tissueBlood vessels integrated within to help
regulate body temperatureNerve tissue carries sensory impuleseHair folliclesSebaceous Glands (oil)Sweat glands
Hair
Most skin surfacesComposed of
recycled epidermal cells
Arrector pilli muscle controls “goosebumps”
Hair color is genetic
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