Integumentary System

The Skin

3 Main Layers of Tissue

1. Epidermis – outermost layer of the skin• Made up of 5 smaller layers• No blood vessels or nerve cells• Stratum corneum (outermost part)

constantly shed and replace cells

2. Dermis – the “true skin”• Contains blood vessels, nerves, sweat and

oil glands, and hair follicles• Fingerprints

3. Hypodermis (subcutaneous fascia)• Innermost layer• Made of elastic and fibrous connective

tissue and adipose tissue (fatty)• Connects the skin to underlying muscles

2 Main Types of Glands

1. Sudoriferous Glands• Sweat glands – extend through the dermis and

open at the surface of the skin at pores• When sweat interacts with bacteria on the

skin, odor occurs• Removes excess water and cools the body

2. Sebaceous Glands• Oil glands – open onto hair follicles• Produces sebum which keeps the skin from

becoming dry and brittle• Helps to prevent infections b/c it is slightly acidic• When the oil gland becomes plugged, a pimple

or blackhead forms

Hair and Nails

• Hair• Each hair contains a root• Helps to protect the body• Covers all body surfaces except the

palms of the hands and the soles of the feet

• Alopecia – baldness• Nails

• Protect the fingers and toes from injury

• Made of dead, packed skin cells• If lost, nails will regrow if the nail bed

is not damaged

Functions of the Integumentary System

1. Protection – barrier to the sun and pathogens or germs, hold moisture in, prevents deeper tissues from drying out

2. Sensory Perception – nerves in the skin help the body to respond to pain, pressure, temperature, and touch

3. Body Temperature Regulation – helps the body retain or lose heat• Blood vessels dilate (get bigger) - excess heat

can escape through the skin…this is why your cheeks get red when working out!

• Blood vessels constrict (get smaller) – the heat is retained in the body…why your fingers get “skinnier” and your rings are loose when your hands are cold!

Functions of the Integumentary System (cont.)

4. Storage – temporary storage for fat, glucose, water, vitamins, and salts

5. Absorption – certain substances can be absorbed through the skin (transdermal)

WHAT MEDICATIONS CAN YOU THINK OF THAT ARE ABSORBED

THROUGH THE SKIN??

Functions of the Integumentary System (cont.)

6. Excretion – eliminates excess salt, water, and heat through perspiration

7. Production – helps in the production of vitamin D

Pigmentation

• Melanin (a brownish black pigment) is produced by specialized cells called melanocytes

• UV light (sun rays) activate melanin• Carotene also helps to determine skin color• Albino – absence of color pigments• Erythema – reddish color of the skin (burns)• Jaundice – yellow discoloration of the skin• Cyanosis – bluish discoloration of the skin

caused by insufficient oxygen

WHY MIGHT A PERSON HAVE JAUNDICE??

What are these different conditions?