The Integumentary

System

Skin, Hair and Nails

Now using the microscopes. Examine your skin, hair and nails.

In your spiral, diagram what you see.

Organs of the integumentary system

skinhairnails

The name is derived from the Latin integumentum, which means “a covering.”

Label and color the parts of the integumentary system

finger nail

SkinThe largest organ in your bodyFunctions

Covers the body and prevents water lossProtects the body from injury and infectionRegulates body temperatureEliminates wastes (sweat)Produces vitamin DGathers information about the environmentStores fat for fuel and insulation

Prevents Water Loss

Skin prevents water from leaking out of your body

Prevents Infection

Skins acts as a barrier to bacteria and viruses

Maintains Homeostasis

Helps to keep the body temperature normal

Has blood vessels that tell the body when it is hot or coldHot – blood vessels get larger and sweating

occursCold – blood vessels constrict to keep blood

in the body’s core

Eliminates Waste

Sweating eliminates dissolved waste from your body

Gathers Information

Skin contains nerves that can feel pain or pressure

Provide Vitamin D

With the help of sunlight, your skin produces vitamin D

Vitamin D is essential in calcium absorption from food

Layers of Skin

Skin consists of three main layersepidermisdermissubcutaneous

layer

subcutaneous layer

Epidermis

Outermost layer30-60 cells thickNo nerves or blood vesselsTop layer is deadNew cells formed at the bottom of this layerSkin cells shed every 2 weeksWhere nails growContains melanin

EpidermisWhere nails growContains melaninEvery minute, 30,000 - 40,000 skin cells fall off95% of your skin cells make new cells5% make melaninMore sun exposure

= more melanin (tan)

Dermis

Middle layerContains nerves and

blood vesselsContains sweat

glands, oil glands and hair follicles

Contains collagen and elastin that allows skin to stretch

subcutaneous layer

Made mostly of fatKeeps you warmAbsorbs shockAttaches your skin

to the underlying tissue

hair

Made of a strong, dead protein, called keratin

Grows out of a tiny tube called a follicle

Hair growth is caused by rapid mitosis in the follicle

Hair follicles are everywhere exceptlipspalmssoles

hair

Over 100,000 follicles on the scalpEach follicle is attached to a gland that

secretes sebum (oil)Color is partially determined by

melanin

nails

Modified hair that grows from your cuticle

Made of keratinNo nerve endingsProtects the end of fingers and toesTakes 6 months to grow from cuticle to

tip

nails

Fingernails grow faster than toenailsNails grow faster on your dominant

handNails DO NOT grow after death

Body systems that work with the integumentary system;respiratory system to get oxygen

and remove carbon dioxidecirculatory system to deliver

oxygenexcretory system to eliminate

waste