Integumentary System

Integumentary System

• The skin covers the entire surface of the human body.

• An adult’s skin covers about ___ square meters of surface area.

• The skin has several _____ organs, which is why it is referred to as the integumentary system.

Integumentary System

The Skin has Three regions: the epidermis and the ______. The ______________ lies below the skin.

Structure of the Skin--Epidermis

• The epidermis, the outer region of the skin, is made up of ________ squamous epithelium.

• New cells continually produced in the stratum ________ of the epidermis are pushed outward and become the keratinized cells of the stratum ________.

Structure of the Skin--Epidermis

Stratum Basale• Basal cells, which lie _______ to the dermis, are

constantly dividing and producing new cells.• As they move farther from the dermis, they

receive less and less _______ and nutrients and eventually die and sloughed off.

• Langerhan cells are _________ found deep in the epidermis. They feed on microbes and then travel to lymphatic organs, where they stimulate the immune system to react.

• __________ are found deeper in the epidermis. They produce melanin, the pigment responsible for skin color.

Structure of the Skin--Epidermis

• When skin is exposed to sun, melanocytes produce more _____ to protect the skin from damaging UV radiation.

• A pigment called carotene is present in epidermal cells and gives the skin of Asians a yellowish hue.

• The pinkish color of fair-skinned people is due to the pigment ________ in the red blood cells in the capillaries of the dermis.

Why do some people freckle when exposed

to the sun?

What is the name of the hereditary disease where an individual lacks

the ability to produce melanin?

Structure of the Skin--EpidermisStratum Corneum

• As cells are pushed toward the surface of the skin, they become flat, forming the tough, uppermost layer of eh epidermis, the stratum corneum.

• Cells are hardened by a process called ___________, which waterproofs the cells with a protein called keratin.

• Keratinization protects the body from water ____ and water ____, allowing individuals to live in the desert or a tropical rain forest without damaging our inner cells.

Over much of the body, keratinization

is minimal, but a couple of parts in

particular are extremely

waterproofed. What are they?

Structure of the Skin--Dermis

• The dermis, which is composed of dense _________ connective tissue, lies beneath the epidermis.

• It contains collagenous and elastic ______, blood vessels, and nerve fibers.

Why does a person blush?

Structure of the Skin—HypodermisSubcutaneous Layer

• The hypodermis is made up of loose connective tissue and ________ tissue, which insulates the body from heat and cold.

• Excessive adipose tissue results in obesity.

At what stage in life would you have the most adipose

tissue?

Accessory Structures of the SkinHair, Nails, and Glands

• Both hair and nails are produced by the division of epidermal cells and consist of keratinized cells. Hair color is a result of ______.

• Sweat glands are numerous and present in all regions of the skin. Sweating helps ______ body temperature.

• __________ glands are associated with a hair follicle and secrete sebum, which lubricates the hair and skin

• Mammary glands located in the breasts produce milk after childbirth.

Marie Antoinette’s hair supposedly turned

white overnight after she heard she would

be sent to the guillotine. Explain why

you believe or disbelieve this story.

Hair• Hair is found on all

parts of the body ______ the palms, soles, lips, nipples, and portions of the external reproductive organs.

• The portion of a hair that within the follicle is called the ___. The portion that extends beyond the skin is called the shaft.

Hair

• When women produce more male sex hormone than usual, they can develop hirsutism, a condition characterized by excessive body and facial hair.

• In males, baldness (Alopecia) occurs when the hair on the head fails to regrow.

• The lifespan of a head hair is approximately three to _____ years.

A poor diet, or excessive dieting,

can cause a persons hair to fall

out. How long could it take to

regain a beautiful head of hair?

Nails• Nails grow from

special epithelial cells at the base of the nail region called the nail _____.

• The visible portion of the nail is called the nail body or ______.

• The cuticle is a fold of skin that hides the nail root.

• Nails grow about 1mm per week.

Glands• There is normally

between 90 (leg) and 400 (palm/soles) sweat glands per square cm.

• Every hair is attached to at least ____ sebaceous gland.

• Acne vulgaris is the result of _________ of the sebaceous gland.

Disorders of the Skin:Skin Cancer

• Skin cancer, which is associated with ultraviolet radiation occurs in three forms. Basal cell carcinoma and squamous cells carcinoma can usually be removed surgically. _______ is the most dangerous form of skin cancer.

UV rays are associated with

cancer of the skin. Should a person prevent all exposure to

UV light?

Danger Signals for Cancer

C hange in bowel or bladder habits

A sore that does not heal

U nusual bleeding or discharge.

T hickening or lump in breast or elsewhere

I ndigestion or difficulty in swallowing

O bvious change in wart or mole

N agging cough or hoarseness

Disorders of the Skin:Staphylococcal Infections

Disorders of the Skin

• Athlete’s Foot: caused by a ______ infection that usually involves the skin of the toes and soles.

• ________: a highly contagious disease occurring most often in young children. Bacterial

• Psoriasis: a chronic condition in which the skin develops pink or reddish patches covered by silvery scales due to overactive cell division.

• __________: a skin disorder not caused by a dry scalp, but by an accelerated rate of keratinization in certain areas of the scalp.

Functions of the IntegumentarySystem

1. _______. The skin provides protection against abrasion and UV light. It also prevents the entry of microorganisms and dehydration by reducing water loss from the body.

2. ________. The integumentary system has sensory receptors that can detect heat, cold, touch, pressure, and pain.

3. ________ _ production. When exposed to UV light, the skin produces a molecule that can be transformed into vitamin D.

Functions of the IntegumentarySystem

4. ________ regulation. Body temperature is regulated by controlling blood flow through the skin and the activity of sweat glands.

5. _________. Small amounts of waste products are lost through the skin and in gland secretions.

Touch

• Different receptors– ______, pressure,

hot, ____…

• # of sensors vary– 3 heat/1cold

• More touch in fingers toes & lips

Why do people’s nose and ears turn red on cold winter

days?

When melanin is evenly distributed, _____ occurs. When

melanin collects in specific areas, then ________ occur.

_______

______________________

A blush is a result of a rush of _______ to

vessels in the ______ layer.

______(baby fat)

The story is impossible. Hair color results form melanin that is added to the hair in the hair bulb as the hair

grows. The hair itself is dead. To turn white, the hair must

grow out without the addition of melanin. This, of course,

takes considerably more time than one night.

_______

No. UV light stimulates the production of a

precursor molecule in the skin that is modified by the liver and kidneys into vitamin D. Without

enough vit. D, one would suffer from _______

On cold days, skin blood vessels of he ears and nose can ______,

bringing warm blood to the ears and nose, thus preventing tissue _____ from the cold. The increased blood

flow makes the ears and nose appear _____.