Integumentary System & Body Membranes

Ch. 4 and 5

Please Turn to Page 93 in Your Book.

• 2 types of body membranes: Epithelial and Connective

• A membrane= a very thin strong pliable tissue which covers, lines or connects parts of an organism

Epithelial Membranes• Simple organs which contain epithelial and

connective tissue there are 4 types:– Cutaneous Membrane: Skin– Mucous Membranes: (Mucosa) Epithelium

on loose connective tissue. Lines body cavaties that open to the outside. Ex.Most form Secretions

– Serous Membrane (Serosa): Simple Squamous epithelium on areolar connective tissue. Line closed body cavities

– Synovial Membranes: Only connective tissue, They line joints and tendons.

What do all membranes have in common?

• 1) They all have layers

• 2) Serous and Mucous Membranes have parietal layers forming the outside wall and visceral layers that cover the organs

• The Serous Membrane secretes a fluid like the mucosal membranes which decrease friction.

Serous Membranes To Know:

• Serous – Peritoneum- Lining of the abdominal cavity

and its organs– Pleura- Lining of the lungs and thoracic cavity– Pericardium- Membrane around the heart

• All have visceral and parietal layers.

But Repairable!

How did this pimple happen to YOU?

• .

Questions?• What is acne?-Acne is a disorder resulting from the action of hormones and other

substances on the skin's oil glands (sebaceous glands) and hair follicles

• What causes it? The hair, sebum, and keratinocytes that fill the narrow follicle may produce a plug, which is an early sign of acne. The plug prevents sebum from reaching the surface of the skin through a pore. The mixture of oil and cells allows bacteria Propionibacterium acnes (P. acnes) that normally live on the skin to grow in the plugged follicles. These bacteria produce attract white blood cells that cause inflammation. When the wall of the plugged follicle breaks down, it spills everything into the nearby skin – sebum, shed skin cells, and bacteria – leading to lesions or pimples. Hormonal changes , heredity, and some medications.

• How is it treated? Benzoyl peroxide – destroys P. acnes, and may also reduce oil productionResorcinol – can help break down blackheads and whiteheadsSalicylic acid – helps break down blackheads and whiteheads. Also helps cut down the shedding of cells lining the hair folliclesSulfur – helps break down blackheads and whiteheads

• What doesn’t cause it? Chocolate, caffeine, greasy foods, dirt, stress- no effect

• Who gets it? (Hint its not nobody) yup, anybody, slows down after 40 or 50.

In order to find out how we all get pimples, we need to know the parts of

the skin.

Review parts of the skin

So here is how it happens…

• .

or

What is skin?

• Its an organ

• Made of cutaneous membrane. Superficial epidermis made of stratified squamous epithelium and dense connective tissue.

Is skin the same thing as the integumentary system?

• No.

• Skin is a cutaneous membrane

• Integumentary system includes sweat and oil glands, hair, and nails.

• Integument= covering

What are the jobs of the skin?Pg. 95

• Regulates heat loss.• Excretory functions for urea, salts, and

water. • Water Retention• Manufactures proteins• Synthesizes vitamin D• Integrate with the nervous system for touch

sensation

What are the three layers of the skin?

*

What is the job of the epidermis?• Keratinizes: becomes hard for protection

• Avascular: only the lowest level of the epidermis is close enough to capillaries to gain nutrients. That means: the skin you see is all dead! Shedding skin doesn’t hurt!!!

• Contains Melanin: pigment produced by melanocytes.

Factoid:Your epidermis

is completely new every 30 days!

What is an appendage of the skin?

• Append= to hang on

• These are things that “hang on” or are attached to the skin.

• Appendages include: Glands, Hair, and Nails

• All appendages are part of the epidermis

What is the job of hair and hair follicles?

• Guards the head and eyes as well as respiratory tract from particles & impact.

• Head Hair retains body heat. All other body hair is a vestigial feature.

• Hair Follicles grow hairFactoid:

Hair grows for three of four years, than rests for a few weeks. Each hair is on its own cycle.

90%grow/10% rest. Loose: 100/day

What are the parts of the hair follicle?Pg. 96• Root of hair is enclosed in the hair follicle

(The hair bulb matrix= zone of growth which contains melanin).

• Hair grows up the shaft to the surface of the skin.

• The bulk of hair is dead. There are 3 layers to hair: 1) Medulla, 2) Cortex, 3) Cuticle (Protection against abrasion, Damage=Split Ends)

What makes hair look different?

• The amount of melanin secreted

• The shape of the hair– Round Hair= Straight and Coarse

– Oval Hair= Wavy and Smooth

– Curley Hair= Flat

What are the parts of the nail?

• Used for protection

• The root of the nail is embedded in the skin. Grows from the nail matrix. The cells, heavily Keratinized die.

• Extends along the nail bed.

• Lunula – moon shaped beginning of nail Fig4.7 pg. 102 Lun= moon

                                                     

Factoid: Nails grow faster

in the summer than the winter. Fingernails

grow 3-4X faster than toe nails.

What do Melanocytes do?

• Produces pigment to protect the cells DNA.

What are the three layers of the skin?

What is the job of the dermis?

• Its leather. Protective, strong, living, and houses many other tissues.

• Sweat Glands: maintain body temp. Excrete waste.

• Hair follicles/bulbs: for warmth

• Nerves: pain, pressure, temperature

• Blood vessels: maintain body temp

What do the cutaneous glands do?

• Exocrine glands that secrete onto the surface of the skin. Sebaceous & Sweat

• Sebaceous Glands- Produce oil all over the body. Sebum used for softening, water retention, killing bacteria. Increases when testosterone is produced= Oily skin.

• Sweat Glands- helps maintain homeostasis

What are the two types of sweat glands?

• Eccrine Glands: Cover Body, Contain H2O, Salt, Vit. C, Wastes, Lactic Acid

• pH 4-6: antibacterial

• Sweat pores are not easily visible, Contain nerve endings for regulation

• Develop 4th month gestation

And the Other One? .

• Apocrine glands- auxiliary and genital areas. Ducts empty into hair follicles.

• Milky-yellowish in color, odorless. Body odor occurs when bacteria eat it. *Thought to be used in excreting pheromones*

• Develop 6th month gestation.

Why do you not have wrinkles when your young?• Collagen fibers: Strong and keep the skin

hydrated (attract H2O).• Elastic fibers: Keep skin elastic. Like all

elastic its less so after time. • Loose fat in the hypodermis. = sagging• Decrease in subcutaneous tissue, causes

dryness, cold sensitivity, and bruising in the elderly

What happens when the epidermis and dermis separate?

• A blister

• Caused by friction or burns.

What causes goose bumps?

• Smooth muscles called Arrector pili that attach to hair follicles contract. Figure 4.5 pg. 100

What is the job of the hypodermis?

• Anchors the skin

• Shock absorber

• Insulates from temperature change

• Gives shape to fatty areas of the body

Fat Lab Time

Diseases of the Skin and Aging

Brace Yourself

Problems of the skin

• Bedsores or Decubitus Ulcers- Caused by pinching off of the blood supply to the skin. Occurs over bony areas of the body. See figure 4.4 on Pg. 98

Cyanosis or Turning Blue

• Not a problem with the skin, but a problem that can be seen in the skin.

• Mostly visible in Causasions

• In people of color cyanosis can be seen in the mucous membrane and the nail bed

• Typical of a heart attack

Other Problems

• Jaundice-Yellow cast to the skin caused by bile from the liver being absorbed by the blood. Indicative of liver disease

• Hematoma and Bruises- caused by blood, escaping from damaged blood vessels, clotting under the skin.

Alopecia

• Fancy word for balding

• By age 50, 1/3 of your hair follicles may be lost

• Severe alopecia can happen to anyone at any age and is not thought to be genetic. ALL BODY HAIR is lost!!! Factoid:

Testosterone overload causes hair growth

to go into hyper speed. Instead of years

of growth, they have weeks. hair barely immerges

went the old is pushed out.

What are the problems with smoking and sun on the

epidermis?• Leathery skin

• Cold sore (herpes outbreak)

• Depressed immune system

• All from DNA damage.

Review Burns and Skin Cancer

• .

Skin Cancer

       

• A: Asymmetry, spots will not look the same on both sides

• B: Border irregularity, blurry and/or jagged edges • C: Color, more than one hue • D: Diameter, larger than a pencil eraser • E: Elevation, raised above the surface and has an

uneven surface & Evolving, changing

Skin CancerImages

Developmental Aspects

• Most cells undergo mitosis until end of puberty; after that only skin and intestinal cells keep dividing

• Aging: epithelial membranes thin, skin loses elasticity/sags, glands become less active

Cosmetic Collagen - Botox

Cosmetic Collagen

• What is collagen? A protein that makes tendons, ligaments, and other connective tissues strong.

• In 1981, FDA approved the use of cattle collagen by injection to minimize wrinkles and scars

• Drawbacks – lasts only a few months, expense, allergic reactions to cattle collagen (now use person’s own collagen from thighs and hips).