integumentary system & body membranes ch. 4. please turn to page 93 in your book. 2 types of...
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Integumentary System & Body Membranes
Ch. 4
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
• 3) 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.
Ravaged
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
What is skin?
• Its an organ
• Made of cutaneous membrane. Superficial epidermis made of stratified squamous epithelium and dense connective tissue.
• Length of replacement? Youth: 28-30 days, Elderly 45-50 days
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 is 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.
Layers of the Epidermis
Layers of Epidermis
• Stratum Basale – deepest, only epidermal cells
• Stratum Spinosum-make Keratinocytes
• Stratum Granulosum-fuse cells together
• Stratum Lucidum – only on hands/feet• Stratum Corneum – top layer, filled
with keratin
Epidermis Skin Layers
Granulosum
Spinosum
Lucidum
Basale
Corneum
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
2 Regions of Dermis
• Papillary layer – contain capillaries for nutrients for epidermis–pain and touch receptors–Regulates temperature
2 Regions of Dermis
• Reticular Layer – deepest skin layer–Blood vessels, sweat and oil
glands, and deep pressure receptors
–Thick collagen strengthens skin
Papillary and Reticular Layers
Skin Color
• Melanin (yellow, reddish brown, or black)
• Carotene• Oxygen bound to hemoglobin in
dermal blood vessels–Poorly oxygenated blood causes
cyanosis in Caucasians
What do Melanocytes do?
• Produces pigment to protect the cells DNA.
Alterations in Skin Color
• Redness (erythema) – embarrassment, fever, allergy
• Pallor (blanching) – fear, anger• Jaundice (yellow) – liver disorder,
excess bile• Bruises – blood escaped circulated
and clots in tissue spaces
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 hair
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)
Hair Growth
What makes hair look different?
• The amount of melanin secreted
• The shape of the hair is regulated by the shape of the hair follicle which changes the shape of the hair shaft.– Round Hair (straight shaft)= Straight and
Coarse
– Oval Hair= Wavy and Smooth
– Curley Hair (hooked shaft)= Flat
• 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
What are the parts of the nail?
Nail Growth
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.Pheromones And Mates
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
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!!!
Infections and Allergies of Skin
• Athlete’s foot (tinea pedis) – fungus
More Diseases
• Boils and carbuncles – inflammation of hair follicles and sebaceous glands
And another Disease
• Cold sores – herpes simplex virus – activated by emotional upset, fever or UV radiation
Infections and Allergies of Skin
• Contact Dermatitis – itching, redness, and swelling caused by exposure to chemicals (poison ivy)
Still more Disease
• Impetigo – pink, water-filled, raised lesions that develop a yellow crust and rupture – caused by staphylococcus
Infections and Allergies of Skin
• Psoriasis – chronic condition of reddened epidermal lesions covered with dry scales – triggered by trauma, infection, hormones, stress
Vitaligo
• Three possible causes– Autoimmune attack– Malfunctioning nerves– Self destructive cells
• Some treatments such as creams are effective in early stages.
• Can effect anyone.
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
• What are the ABCD’s of Skin Cancer?
• What are the 3deg. Of Burn?
Skin Cancer
LinkBurns
http://www.virtualcancercentre.com/diseases.asp?did=539#What_is
Skin Cancer
• Squamous Cell Basal Cell
Administering Medications
• Transdermal - skin patches for nicotine, motion sickness, birth control – slow absorption
• Subcutaneous – insulin – moderate absorption
• Intramuscular – vaccines – rapid absorption
Developmental Aspects
• 5th month – fetus covered with downy hair (lanugo) that is shed by birth
• Adolescence – skin and hair become more oily as sebaceous glands are activated (acne)
Developmental Aspects
• Aging – hair thinning and baldness – males
• Gray hair – decreasing amount of melanin deposited – caused by anxiety, protein-deficiency, chemotherapy, excessive vitamin A, genetics