Download
1 / 16
180 likes | 292 Views
Integumentary System. Unit 3: Integumentary System A&P Chapter 5. Learning Goals. Copy at TOP of page 43 1) Describe the 3 layers of the skin including the location and what structures are found in each. 2) Explain the 5 functions of the skin including how each relates to homeostasis.
E N D
Integumentary System Unit 3: Integumentary System A&P Chapter 5
Learning Goals • Copy at TOP of page 43 • 1) Describe the 3 layers of the skin including the location and what structures are found in each. • 2) Explain the 5 functions of the skin including how each relates to homeostasis.
1. Integumentary System • The Integumentary system includes: • Skin – largest organ of the body • Accessory Organs: • Hair • Nails • Serves to protect the viscera (internal organs)and regulate temperature
11. Structure of the Skin • The skin is composed of 3 layers from superficial to deep:
1. Epidermis • Outermost layer of skin • Stratum Corneum – hard outermost layer of epidermis • Produces a protein called keratin • Keratinization causes hardening of dead skin cells, making skin waterproof. • Stratum Basale – produces new cells of epidermis • Contains Langerhans cells (for immunity) and melanocytes (make pigment to give skin color)
2. Dermis • Thick layer of connective tissue containing: • Dermal papillae – ridges that cause fingerprints and provide gripping surface • Collagen & elastic fibers – stretching & movement • Blood vessels • Sensory Nerves • Sebaceous Glands • Hair Follicles
3. Hypodermis (Subcutaneous Layer) • Deepest layer of skin • Composed of loose connective tissue and adipose tissue (fat) • Helps to store energy, insulate body, and provides protective padding
IV. Five Functions of the Skin • 1. Protection • Physical barrier to disease, dirt, and UV radiation • Bacteria and other invaders are prevented entry by the top dead layer of skin and the acidic, oily secretion from sebaceous glands (sebum).
2. Regulates Water Loss • Keratinization of the dead skin outer layer also prevents water from entering or leaving the skin, even when immersed in water. • Skin works with the urinary system to sweat off some excess water.
3. Produces Vitamin D • Melanocytes produce melanin to protect against harmful UV radiation from the sun and also to produce Vitamin D • Vitamin D helps regulate the uptake of calcium by the digestive system. • Calcium is needed for strong bones.
4. Gathers Sensory Information • Sensory receptors are linked to the nervous system • Receptors specialize in sensing • Touch • Pressure • Pain • Temperature (hot & cold) • Many receptors in hands
5. Regulates Body Temperature • When the body is too hot, the skin will help to release heat to cool the body temperature back to 98.6°: • Sweat • Dilation of dermal blood vessels
When the body is too cold, the skin will help to raise body temperature back to 98.6° by generating heat: • Shivering (muscle contraction) • Goosebumps (contraction of arector pili muscles attached to hair follicles) cause hair to trap heat • Constriction of dermal blood vessels
Bad things happen when body temp. is not constant: • 1. Hypothermia -Lower body temp. than normal interferes with the body’s normal functions and eventually ends in death
` • 2. Hyperthermia—Higher body temp. than normal results in dehydration (from excess sweating) andheat stroke.
