The Skin you’re in!

Integumentary System

Your skin is fascinating!!

Video: Crash Course – SKIN!

Did you know?

The integumentary system is an organ system consisting of the skin, hair, nails, and exocrine glands. The skin is only a few millimeters thick yet is by far the largest organ in the body.

The average person’s skin weighs 10 pounds and has a surface area of almost 20 square feet.

Skin forms the body’s outer covering and forms a barrier to protect the body from chemicals, disease, UV light, and physical damage.

Function of the Integumentary System

Functions of the Integumentary System

1. Forms a protective covering over the body that prevents infections and water loss.

Functions of the Integumentary System

2. Maintains homeostasis by helping to regulate bodytemperature

Regulation of body temperature

a. Blood vessels in skin help release/hold heat

b. Perspiration (sweating) to keep cool andshivering to keep warm

Functions of the Integumentary System

3. Excretes wastes such as sodium chloride (salt) and, water in your sweat, and urea, which is also in your urine

Functions of the Integumentary System4. Sensory receptors —

Our sense of touch is controlled by a network of nerve endings and touch receptors in the skin known as the somatosensory system.

This system is responsible for all the sensationswe feel - cold, hot, smooth, rough, pressure, tickle, itch, pain, vibrations, and more

Functions of the Integumentary System

5. Produces vitamin D in the epidermis using sunlight

Which is NOT a function of the integumentary system?

1. To prevent substances from entering the body

2. To help keep body temperature stable

3. To remove wastes from the body

4. To absorb oxygen into the body

Layers of Skin

1. Epidermis = surface layer

a) Cells on top part are deadb) New cells are constantly

produced at the bottomc) Melanocytes: cells

produce melanin -pigment that protects your skin and gives it color

Layers of Skin

2. Dermis = layer under epidermis

a) Thicker than epidermis

b) Contains blood vessels, nerves,

oil and sweat glands

3. Hypodermis - Fat cells stored under

the dermis, this insulates the body

Which part of the skin makes new skin cells?

1. Epidermis

2. Dermis

3. Fat cells/Hypodermis

4. Sweat glands

For the next few slides, find the appropriate place on your notes page to label and/or identify the skin and parts of the integumentary system

Label the Skin

Skin Cross-section

1. Epidermis2. Dermis3. Hypodermis4. Hair from hair

follicle5. Sweat Gland6. Oil gland7. Nerve8. Blood Vessels

1

8

7

3

62

4

5

HAIR:- Made of the protein “keratin,” grows from follicle

- Found all over body except lips, palms and solesof feet

- Functions in warmth, protection, and immunedefense

- Characteristic of mammals

Oil Gland

Follicle

MuscleHair Shaft

Epidermis

Dermis

Hair color happens because of a kind of pigment called melanin. Hair has only two types of this pigment - dark (eumelanin) and light (phaeomelanin). They blend together to make up the wide range of hair colors.

If your hair has a lot of eumelanin, it will be black; a little eumelanin and your hair will be blonde.

What determines the amount of eumelanin is your genetic make up (there are a lot of genetic factors that go into hair color – we won’t discuss them)

Hair color

An average scalp has 100,000-150,000 hairs.

Hair is so strong that each hair can withstand the strain of 100 grams (3.5 ounces). An average head of hair could hold 10-15 tons if only the scalp was strong enough!

Human hair grows autonomously, that is each hair is on its own individual cycle. If all our hair were on the same cycle, we would molt!

Hair has the highest rate of mitosis (cell division). An average hair grows 0.3 mm a day and 1 cm per month.

Hair – raising facts:

NAILS:

- Made of the protein “keratin,” grows from root

- Found on fingers and toes (phalanges)

- Functions in protection and as a tool for preciseactivities

Free MarginNail Plate

Nail Bed

Lunula

Matrix

Root

You will go to each station and complete the questions on your page

When done, you will put this page with the notes your have just taken

More on our skin: Walk a bout!