1. The Integumentary and Immune Systems

2. 36–3 The Integumentary System The Skin 1. Epidermis 2. Dermis
Section Outline
Section 36-3
36–3 The Integumentary System
The Skin
1. Epidermis
2. Dermis
3. Skin Cancer

3. Roles of the Skin The skin or integumentary system has four roles
It acts as a barrier against infection and injury
It helps to regulate body temperature
It removes waste products from the body
Provides protection against UV radiation from the sun
It also serves as a way through which sensations are transmitted to the nervous system

4. Layers of the Skin Made of two main layers Epidermis – outer layer
The outer layer consists of dead skin cells
The inner layer is made of living cells
These undergo rapid cell division, constantly making new cells and pushing older cells to the surface
Also contains melanin (pigment)
Dermis – contains collagen fibers, blood vessels, nerve endings, glands, smooth muscle and hair follicles

5. Figure 36-13 The Structure of Skin
Section 36-3

6. Disorder of the Integumentary System
Skin cancer
Excessive exposure to UV radiation can lead to an abnormal growth of cells in the skin

7. A. Nonspecific Defenses 1. First Line of Defense
Section Outline
Section 40-2
40–2 The Immune System
A. Nonspecific Defenses
1. First Line of Defense
2. Second Line of Defense
B. Specific Defenses
1. Humoral Immunity
2. Cell-Mediated Immunity
C. Acquired Immunity
1. Active Immunity
Passive Immunity
D Diseases of the Immune System

8. The body’s primary defense mechanism
The Immune System
The body’s primary defense mechanism
May destroy invaders by engulfing them by special cells or by chemically marking them for destruction and elimination
Functions by being able to recognize proteins on the surface of cells
It can distinguish between self and non-self
The non-self, or invading foreign proteins are referred to as antigens

9. Nonspecific vs. Specific
Two types of defense mechanisms
Non-specific – physical and chemical barriers
1st line of defense - Keep pathogens out of your body
Done by skin, mucous, sweat and tears
The secretions contain lysozyme, and enzyme which breaks down the cell walls of bacteria
2nd line of defense – inflammatory response
If pathogens do enter your body, phagocytic white blood cells move into the area to destroy the bacteria
The immune system also releases a chemical that increases your body temperature
The fever kills the bacteria because they can only exist in a narrow temperature range.
The fever also increases heart rate so wbc can get to the infection site faster.

10. Figure 40–7 The Inflammatory Response
Section 40-2
Wound
Skin
Phagocytes move into the area and engulf the bacteria and cell debris
Bacteria enter the wound
Capillary

11. Specific Defense
A specific defense against a pathogen is called an immune response
Pathogens that trigger this response are called antigens
These may be viruses, bacteria or other pathogens such as fungi, parasites, etc.
The immune response attacks the particular disease-causing agent with a response especially for that pathogen
There are two types of wbc’s that recognize specific antigens
B cells – humoral immunity – pathogens and antigens in body fluids
T cells – cell-mediated immunity – pathogens and antigens inside living cells

12. Primary and Secondary Immune Responses
Section 40-2
Interval between exposures
Antibody Concentration
First exposure
Second exposure
Time

13. Acquired Immunity
Two types of acquired immunity
Active – appears after exposure to an antigen
May be natural (the body fights an infection)
May be artificial (through vaccination)
Vaccine – injection of a weakened form of an antigen to produce an immune response
Passive – receiving antibodies to fight off an infection – only lasts a short time because the body will eventually destroy the foreign antibodies
May be natural – antibodies are passed to a baby through the placenta and through breast milk
May be artificial – vaccines may contain antibodies to protect and prevent disease

14. 40–3 Immune System Disorders A. Allergies Autoimmune Diseases
Section Outline
Section 40-3
40–3 Immune System Disorders
A. Allergies
Autoimmune Diseases
HIV and AIDS

15. Allergies
An overreaction of the immune system
Allergy causing antigens enter the body and attach themselves to certain white blood cells
These white blood cells initiate the inflammatory response
Produce chemicals called histamines
Asthma – a chronic respiratory disease where the air passages become narrower than normal, causing wheezing, coughing and difficulty breathing
May be treated with medications that relieve the symptoms of asthma

16. Autoimmune Disorders
The immune system has the ability to recognize self and non-self
When the immune system makes a mistake and attacks its own cells, it produces and autoimmune disease
Examples
Type I diabetes – insulin-producing cells of the pancreas are destroyed
Multiple sclerosis – antibodies destroy the functions of the neurons in the brain and spinal cord
Lupus – attacks normal connective tissue, leading to inflammation and pain in the joints
some of the autoimmune diseases may be treated with immune suppressing drugs
However, this therapy is not used often or must be monitored carefully

17. AIDS is an autoimmune disease that results from infection with HIV
HIV and AIDS
AIDS is an autoimmune disease that results from infection with HIV
Normally healthy patients die from microorganisms that don’t normally cause disease, from extremely rare forms of cancers and pneumonia and from pathogens that healthy people can normally fight off
HIV –is a virus that can evade the defenses of the immune system and attacks key cells in the immune system

18. Transmission and Prevention of HIV
Transmitted through bodily fluids such as blood, semen, vaginal secretions and breast milk
Through any form of sexual intercourse
Through shared needles that are contaminated with infected blood
Through contact with blood or blood products
From infected mother to child, through pregnancy, birth and/or breast feeding