the body’s defenses california standards 10.a., b. & c
Post on 31-Mar-2015
218 Views
Preview:
TRANSCRIPT
The Body’s Defenses
California Standards 10.a., b. & c.
Pathogens• Pathogens are disease causing agents
such as:1. bacteria2. viruses3. prions and4. single cell organisms
First Line of Defense
1. Skin: prevents pathogens from entering the body
Skin = the first line of defense
The skin is the organ which defends the body
from infection by blocking the entry of pathogens.
2. Mucous Membranes: found in your nose and throat and stop the entry of pathogens into your body.
Second Line of Defense
1. Inflammatory Response
2. Temperature Response
3. Proteins
4. White Blood Cells
1.Inflammatory Response
• A series of events that suppress infection and speed recovery
• Histamine: increase blood flow by dilating blood vessels.
• White blood cells invade infected area
• Swelling and redness occurs
When the skin is punctured pathogens are allowed to enter the body.Pathogens
capillary
Injured or damaged cells release the
chemical histamine which causes the blood vessels to dilate increasing blood flow to the
area. This blood flow causes swelling and redness to the area.
Increased blood flow bring white blood cells that attack and destroy pathogens. The presence of ‘puss’ at a wound is the presence of white blood cells.
2. Temperature Response
• 1. Higher temperature called a fever
• 2. Bacteria do not grow well at high temperatures
• 3. Enzymes are destroyed or denatured
Temperature Response
Basically, the temperature is a response that is helpful in
fighting pathogens because bacteria do not grow well at
high temperatures.
Bacteria and Antibiotics
Antibiotics are specifically used to kill bacterial infections. They do nothing for viral, or virus caused, infections.
3. Proteins• 1. Complementary System made
up of 20 different proteins.
• 2. Punctures cell membrane of bacteria
• 3. Interferon released to fight viruses
4. White Blood Cells
• Neutrophils
• Macrophages
• Natural Killer Cells
Neutrophils
• Engulf and destroy pathogens
• Release chemicals that kill bacteria and themselves
Macrophages
• Kill and ingest pathogens
• Clear dead cells and other debris
• Found in spleen and lungs
Natural Killer Cells
• Attacks cells infected with pathogens
• Puncture cell membrane
• Detect and kill cancer cells
• Skin• Mucous membranes• Inflammatory response• Temperature• Protein• White blood cells
Nonspecific Defense:
Third Line of Defense
Specific Defense Against Disease
The last type of defense against invading
organisms is the specific line of defense. This defense by your body attacks specific
pathogens and in the process produces antibodies that in the future can attack that
specific pathogen if it occurs again.
Third Line of Defense• Immune Response: consists of an army
of cells that combat specific pathogens
• Antigen: a substance that triggers an immune response
• Antibody: a ‘Y-shaped molecule that is produced by plasma cells when exposed to an antigen.
Non-functioning immune response
A person’s immune response is not functioning well if it is unable to fight pathogens. This is because their body cannot produce the specific antibody for that pathogen. AIDS is just such a disease because a patient’s body inability to defend itself against invading organisms.
Antibodies and Antigens• An antibody is produced by your
body in response to a specific antigen.
• An antigen is a foreign substance which causes the body to produce a specific antibody.
Antibodies attacking an antigen
‘Y’ shaped antibody
Antibodies
Antibodies are substances formed by the human body in response to
foreign proteins entering the body.
Resistance to Disease
• Immunity – resistance to a particular disease.
• Vaccination – a medical procedure used to produce immunity.
• Vaccine – a solution of dead or modified pathogens that can no longer cause disease.
Vaccines and Infection
Vaccines are effective in preventing disease because they are dead or modified pathogens
with antibodies directed against a specific pathogen.
The End
top related