Download Chapter 35- Infectious Diseases

CHAPTER 35INFECTIOUS DISEASES
PATHOGENS
• What is an infectious disease?
• When a microorganism harms the body.
• Five types:
• Bacteria
• Fungi
• Parasitic Worms
• Viruses
• Protists
GERM THEORY OF DISEASE
• Scientists- Pasteur and Koch
• Symbionts vs pathogens
• Symbionts- microorganisms that cause no harm, live in symbiosis
with host
• Pathogen- microorganisms that harm the host
DISEASE AND HOW THEY SPREAD
• Coughing
• Sneezing
• Physical contact
• Body fluids
• Contaminated water/food
ANIMAL CONNECTION
• Vectors• Carry pathogens but it does not harm the actual carrier.
( Ex. Mosquitos carry Zika)
• Zoonosis- diseases that can be transmitted from animal to
human
DEFENSES AGAINST INFECTIONS
• Your body’s first line of defense!
• Non-specific Defense
• Skin, tears, secretions like phlegm, boogers, inflammatory
response, interferons, fever.
NON-SPECIFIC DEFENSE
• Inflammatory response
• Causes infected areas to become red and swollen.
• Pathogen stimulates mast cells to produced HISTAMINES.
• Histamines are chemicals that cause increase blood flow and fluids to
affected area.
• Blood vessels swell and release liquid, causes swelling
• White blood cells called phagocytes engulf pathogen and destroy it.
• The area increases in temperature, infected area may feel warm.
INTERFERONS
• Interferons- when viruses infect organism, certain cells produce
protein that interferes with the viruses production of protein
for reproduction.
• This slows down how quickly viruses can reproduce and allows
the body to start SPECIFIC DEFENSES.
FEVER
• Immune system releases chemical that increase body
temperature.
• Pathogens don’t like heat or extreme cold. It slows
their reproduction and also speeds up the immune
system responses.
CRASH COURSE- NON-SPECIFIC DEFENSE
Crash Course Non specific Defenses
SPECIFIC DEFENSES
• Specific response identifies the “self” to and “other” (pathogen), it
reacts to destroy any foreign substance.
• It responds to SPECIFIC pathogens.
• Immune system recognizes self and other by chemical markers, like a
password.
• Once it identifies an intruder; it uses chemical weapons to destroy it
and it also stores chemical make up of pathogen into its memory.
IMMUNE RESPONSE
• The specific recognition, response, and memory.
Antigens- specific immune molecules, a foreign substance that can stimulate an immune
response
Antigens are located on outer surfaces of pathogens
HOW DOES THE BODY RESPOND TO ANTIGENS?
• It increases the number of cells that attack the invaders or
produce proteins called antibodies.
• Antibodies- role is to tag antigens for destruction by immune
cells.
• Where do you find antibodies?
• May be attached to immune cells or free floating in
plasma(blood).
ANTIBODIES
• Immune system makes up to 10 billion antibodies.
• Each bind to a specific antigen.
LYMPHOCYTES
• B cells and T cells are the main type of cells that sustain the immune system.
• They are both types of lymphocytes;
• Both are made in bone marrow although T cells mature in the THYMUS while
B cells mature in bone marrow.
• Each B and T cell can recognize any particular antigen. (passed down by genes)
• B cells- have embedded antibodies discover antigens in body fluids.
• T cells – must presented with the antigen by infected body cells or immune
cells that have encountered the antigen.
HUMORAL IMMUNITY
• Depends on actions of antibodies that circulate in the blood and
lymph.
• Antibodies on B cells bind to antigens on the surface of antigens.
• Pg. 1017
• This causes growth and division of many B cells (PLASMA and
MEMORY)
PLASMA AND MEMORY B CELLS
• Plasma cells produces and releases antibodies that are carried
in blood. Flags the antigen when it binds to it, makes other
parts of the immune system to attack and destroy it.
• Plasma cells die after infection is gone but some B cells that
recognize the antigen remain. These become B Memory cells,
they react quickly when same pathogen enters the body again.
CELL MEDIATED IMMUNITY
• Depends on macrophages and several types of T cells.
• Defends against Viruses, fungi.
• T cells also protect from our own cancerous cells
• Pg. 1019
• When a cell is infected by a pathogen or macrophage, the cell displays the antigen and
then calls on CYTOTOXIC cells- kills the cells by puncturing their membranes with
APOPTOSIS- programmed cell death