1. INTEGUMENTARY SYSTEM
Chapter 4 Notes

2. I. Classification of Body Membranes
The four major types of membranes are:
A. Synovial Membrane
B. Serous Membrane
C. Mucous Membrane
D. Cutaneous Membrane

3. A. Synovial Membrane
Lines the joint cavities between the ends of bones at freely movable joints.
Secretes a thick, colorless synovial fluid which lubricates and cushions the ends of bones within the joint.

4. B. Serous Membrane
Lines ventral body cavities that lack openings to the outside.
Secrete a watery fluid called serous fluid which helps lubricate the surfaces of the membrane.
Found in the inner lining of the thorax and abdomen. They also cover the organs within these cavities.

5. B. Serous Membrane
Examples: Peritoneum (abdominal cavity), Pleura (lungs), Pericardium (heart)
Serious membrane, shown in red, line ventral body cavities that are closed to the exterior.

6. C. Mucous Membrane
Lines the cavities and tubes that open to the outside of the body.
Usually wet or moist membrane that functions in absorption and secretion
Generally found in the oral and nasal cavities and the tubes of the digestive, respiratory, urinary, and reproductive systems.

7. C. Mucous Membrane
The mucous membrane, shown in blue, lines body cavities that are open to the exterior.

8. D. Cutaneous Membrane
An organ of the integumentary system and is commonly called the skin.
The cutaneous membrane is exposed to the air and is a dry membrane.
Two parts: epidermis and dermis

9. II. Integumentary System
Consists of the cutaneous membrane (skin) and its accessory organs.
“Integument” means covering.
Weighs about six pounds.
As you age your skin loses its elasticity and thins. The thinning process allows the skin to be bruised and damaged easier. The loss of elasticity causes wrinkles and sagging to occur.

10. A. Functions Protection from:
Physical damage - I.S. is a physical barrier that contains keratin, which toughens cells, and pressure receptors, which alerts the nervous system to possible damage.
Bacterial damage - I.S. also has skin secretions that are acidic to inhibit bacterial growth.
Ultraviolet radiation - Melanin provides protection from sun damage.
Thermal damage - Contains heat/cold/pain receptors
Desiccation - Skin contains waterproofing substances including keratin.

11. A. Functions 2. Regulates Body Temperature:
Heat Loss - When the body temperature rises above normal, the dermal blood vessels dilate which allows blood to rush into skin capillary beds. The nervous system then activates sweat glands which acts as a cooling system.
Heat Retention - When the body temperature drops below normal, the dermal blood vessels constrict and sweat glands become inactive.

12. A. Functions 3. Excretion: Sensory Reception:
The integumentary system excretes urea (wastes), salts, and water as sweat.
Sensory Reception:
Along with the nervous system, the skin is embedded with sensory receptors that provide us with information about our external environment.

13. B. Structure of Skin Epidermis
Outer portion of skin and is made up of stratified squamous epithelium.
Avascular - no blood supply of its own.
Capable of keratinization, which means to harden and waterproof the cells in this layer.
It is composed of five layers called strata:

14. 1. Epidermis
Stratum Basale - Cells are constantly undergoing cell division in this layer. Millions are produced daily. Cells in this layer also contain melanin which protects the cells from the sun. This melanin is what causes the tanning effect on our skin. As cells are being produced, the older cells move away and become part of the more superficial layers. FYI - Freckles, Moles, and Skin Cancer

15. 1. Epidermis
Stratum Spinosum and Granulosum - The cells in these layers become flatter, keratinize and die.
Stratum Lucidum - This is the next layer of skin. This layer is the outer layer of skin where there is no hair.
Stratum Coneum - The outermost layer of skin everywhere else on the body. It is about 8 cell layers thick. The cells at the surface continually flake off. We have totally new skin about every days.

16. B. Structure of Skin 2. Dermis
Made up of dense connective tissue that lies underneath and connected to the epidermis.
It is our “hide” (bags, belts).
It is extremely strong and stretchy.
Made up of three layers: Papillary, Reticular, and Subcutaneous tissue.
FYI - Blisters

17. 2. Dermis
Papillary - this layer furnish nutrients and houses pain receptors. It also contains the dermal papillae which forms patterns called finger prints.
Reticular - which is the deepest layer. It contains blood vessels, sweat and oil glands.
Subcutaneous tissue - AKA hypodermis. It is essentially adipose tissue. It is not actually part of the skin, but it does anchor the skin to underlying organs.

18. III. Accessory Organs of the Skin
Hair and hair follicles - each hair develops from epidermal cells at the base of a hair follicle.
Just like skin, hair is dead cells that have gone under keratinization.
The root is the section of the hair hidden in the follicle. The shaft is the part you see.
A bundle of smooth muscles cells called arrector pili is attached to each hair follicle.
Hair color is determined by melanin.

19. III. Accessory Organs of the Skin
Sebaceous Glands - Oil glands are found all over the skin and are considered an exocrine gland.
Their ducts usually empty into a hair follicle, but some open directly onto the skin.
The secretions from these glands are called Sebum. It is a mixture of oily substances and fragmented cells. Sebum is a lubricant to keep skin soft and helps prevent hairs from becoming brittle. Sebum also waterproofs the skin and contains chemicals that help kill bacteria.
FYI - Acne

20. III. Accessory Organs
Sweat Glands - AKA sudoriferous glands; this is a type of exocrine glands. We have about 2.5 million per person. There are two types:
Eccrine glands are far more numerous and produces sweat. Sweat is primarily water and some salt, vitamin C, metabolic wastes, and lactic acid. Eccrine glands function in responding to an elevated body temperature.
Apocrine glands are confined to the axillary and genital areas. Apocrine glands responds to emotional stress. Their secretions contains fatty acids and proteins. Their function is not yet known, but they are activated by nerve fibers during pain, stress and during sexual foreplay.

21. Homeostatic Imbalances of Skin
Infections and Allergies
Athletes Foot
Boils and Carbuncles
Cold Sores
Contact Dermatitis
Impetigo
Psoriasis
Burns
Skin Cancer
Basal Cell Carcinoma
Squamous Cell Carcinoma
Malignant Melanoma