Transcript skin and immune system

The Skin and Immune System
Go to
Section:
Section Outline
Section 36-3
36–3 The Integumentary
System
The Skin
1.Epidermis
2.Dermis
3.Skin Cancer
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 36-13 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
Section 40-2
40–2
Go to
Section:
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
2. Passive Immunity
D.
Diseases of the Immune System
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
• 1st 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:
Figure 40–7 The Inflammatory Response
Section 40-2
Skin
Wound
Phagocytes move into the
area and engulf the bacteria
and cell debris
Bacteria enter
the wound
Capillary
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:
Primary and Secondary Immune Responses
Antibody Concentration
Section 40-2
Interval
between
exposures
First
exposure
Second
exposure
Time
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
Section 40-3
40–3 Immune System Disorders
A. Allergies
B. Autoimmune Diseases
C. HIV and AIDS
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
Go to
Section: