Go to Section: The Skin and Immune System

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

Go to Section: Roles of the Skin The skin 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

Go to Section: 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

Go to Section: Figure The Structure of Skin Section 36-3

Go to Section: Disorder of the Skin Skin cancer –Excessive exposure to UV radiation can lead to an abnormal growth of cells in the skin

Go to Section: Section Outline 40–2The 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 2.Passive Immunity D. Diseases of the Immune System Section 40-2

Go to Section: The Immune System The body’s primary defense mechanism May destroy invaders by engulfing them by special cells or by 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

Go to Section: Nonspecific vs. Specific Two types of defense mechanisms –Non-specific – physical and chemical barriers 1 st line of defense - Keep pathogens out of your body –Done by skin, mucous, sweat and tears 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

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

Go to Section: 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, fungi, parasites The immune response attacks the particular pathogen with a response designed especially for it Two types of wbc’s that recognize specific antigens –B cells – pathogens and antigens in body fluids –T cells – pathogens and antigens inside living cells

Go to Section: Interval between exposures First exposure Second exposure Time Antibody Concentration Section 40-2 Primary and Secondary Immune Responses

Go to Section: Acquired Immunity Two types of acquired immunity –Active – appears after exposure to an antigen May be natural (you get sick) 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 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

Go to Section: Section Outline 40–3Immune System Disorders A.Allergies B.Autoimmune Diseases C.HIV and AIDS Section 40-3

Go to Section: Allergies An overreaction of the immune system –Allergy causing antigens enter the body and attach themselves to certain white blood cells –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

Go to Section: 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 an 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

Go to Section: 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 – a virus that can evade the defenses of the immune system and attacks key cells in the immune system

Go to Section: Transmission and Prevention of HIV Transmitted through bodily fluids –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