the immune system “infection protection” how the body protects itself from disease chapter 10...
TRANSCRIPT
The Immune System
“Infection Protection” How the body protects itself from disease
Chapter 10 (10-2)
Blood
Blood is a liquid tissue with 3 functions:
1. Transportation
2. Regulation
3. Protection
We have between 4-6 L of blood
Purpose of Blood
Transport Regulation Protection
Purpose of Blood
Transport: To carry nutrients to all cells To carry wastes away from cells to
removal organs To carry hormones (chemical
messengers)
Purpose of Blood
Regulation To absorb heat from one part of the
body and release it in a cooler part. To maintain pH and water levels.
Purpose of Blood
Protection To defend the body against disease-
causing agents. To stop the body from bleeding by
clotting.
Components of Blood
Plasma Erythrocytes or Red Blood Cells Leukocytes or White Blood Cells Platelets
Components of Blood
Plasma
Water – 90% Dissolved Material such as: salts, glucose, amino
acids, fatty acids, vitamins, hormones, wastes Proteins
• Albumin – regulates movement of water out of blood• Fibrinogen – involved in clotting• Globulins – many functions such as:
• Transport Proteins – to move substances • Antibodies – to destroy foreign substances and fight
disease.
Red Blood CellsErythrocytes
Carry oxygen and carbon dioxide Made in the bone marrow 30 trillion in the body Does not contain a nucleus Contains hemoglobin – an iron-
containing protein that causes it to be red and to carry oxygen
Red Blood CellsErythrocytes
Fun Facts:• You have 30 trillion RBCs• They live 120 days – then get destroyed.• New cells are formed at the rate of 2 million
per second (same rate they die)• The liver and spleen removed dead cells
and the iron is recycled.
Anemia
When you have too few RBCs or not
enough hemoglobin (low iron in diet).• Symptoms: not enough oxygen in blood,
you get very tired.• Treatment: Eat more iron, get shots of
vitamin B-12 for pernicious anemia.
Sickle Cell Anemia
Genetic Disorder – when RBCs are not formed correctly because hemoglobin is made wrong:• Symptoms: RBCs are sickle
in shape and get stuck in blood vessels causing pain.
• Treatment: Transfusions help.
Sickle Cell Anemia
White Blood Cells Leukocytes
Colorless blood cells Defend the body from bacteria
and viruses Made in the bone marrow Have a nucleus. They can move on their own or
carried by the blood stream. There are five different kinds of
WBCs.
Five types of White Blood Cells
• Neutrophils – phagocytosis of small particles• Monocytes – phagocytosis of large particles• Eosinophils – release clot-digesting agent, combat
allergy-causing substances• Basophils – release heparin – anti-clotting agent,
and histamine – that causes inflammation• Lymphocytes – produce antibodies that are
involved in the immune response
White Blood Cells Leukocytes
Fun Facts:• You have 60 billion white blood cells.• They are made at a rate of 1 million per
second.• When you have an infection they multiply
and congregate in the area of the infection to attack the invader.
• Pus that forms contains WBCs and bacteria.
Leukemia
A type of cancer that produces
white blood cells. Symptoms include very high
WBC count. Treatment: includes bone
marrow transplants and medications.
Platelets
Cell fragments involved in blood clotting.
Form by pinching off bits of cytoplasm from large cells in the bone marrow.
Do not contain a nucleus. Surrounded by a
membrane.
Platelets
Fun Facts• You have 1.5 trillion platelets• They live for 7 days• They are produced at a rate of 200 billion a
day.
Blood Clotting
Good Clotting - helps you to stop bleeding when you have an injury.
Bad Clotting – when you get a clot within a blood vessel that clogs the vessel. You can have a stroke or heart attack from this.
The process is basically the same…
Blood Clotting
Blood Clotting Video
Blood Clotting
1. Platelets stick to the damaged vessel and break.
2. Broken platelets release thromboplastin.3. Thromboplastin converts prothrombin to
thrombin.4. Thrombin converts soluble fibrinogen to
insoluble fibrin.5. Fibrin forms a web to stop the bleeding.
Blood Clotting
To remove clot
The body activates the enzyme plasmin to dissolve the clot after the skin heals.
The body prevents internal clots by:• Having smooth vessels – platelets don’t
get stuck and break.• Anticoagulants (heparin) in blood prevent
clotting.
Clotting Problems
Internal clots form when the vessels are not smooth – caused by build-up of material in veins and arteries.• Symptoms: Can cause death, strokes,
heart attacks if it blocks blood flow.• Treatment: Heparin can be injected to
dissolve the clot if done quickly.
Hemophilia
Genetic disease where a person is
missing one or more clotting factors.• Symptoms – internal or external bleeding
without ability to clot.• Treatment – injections of missing factors,
blood transfusions.
Blood Clotting
http://www.youtube.com/watch?v=HFNWGCx_Eu4&feature=player_embedded
What Causes Disease?
Viruses and bacteria are pathogens. Pathogens are microorganisms that cause disease.Pathogens are everywhere; in food, in air, in water, inside your body.
Our Immune System has three lines of defense.
How Can We Protect Ourselves From
Pathogens?
First Line of Defense
Physical Barriersprevent entrance of pathogens or trap them and washes them away.
• Skin• membranes• mucus• sweat• urine
Chemical Barriers
kill or inhibit pathogen activity.
•Stomach acid•tears•saliva
Second Line of Defense
If a pathogen gets past first line of defense, it starts an infection.
This activates the second line of defense to have an inflammatory response.
Inflammatory Response
Symptoms:
Swelling, pain, warmth, redness
Cause of Symptoms: Cells that got damaged by infection release
chemicals. These chemicals cause more blood to flow to
area ,which causes symptoms. Macrophages (large white blood cells) come to the
area to ingest bacteria.
As Inflammatory response continues...
Pus forms from mixture of dead cells, white blood cells, bacteria and body fluid.
If pathogen is a virus, damaged cells produce interferon that protects other cells from damage.
Third Line of Defense
If inflammatory response is insufficient, the immune system takes over.
The immune system creates antibodies and other specialized cells to stop pathogens.
Each antibody or specialized cell is made for a specific pathogen.
The Immune Response(The Immune System)
Provides immunity to pathogens
Requires that the body can distinguish between
“self” and foreign material.
Involves production of antibodies and
specialized cells.
Is triggered by an antigen.
Lymphocytes
Cells that recognize antigens and either
a) produce antibodies
b) kill foreign cells
Types of lymphocytesa) B cells
b) T cells
Type of Immune Responses
Primary Immune
Response The first time you are
exposed to antigen. No antibodies for first
five days. Over the next 10-15
days rise in antibodies.
Secondary Immune
Response Second exposure to same antigen. Within 1-2 days
high levels of antibodies are in blood.
Type of Immune Responses
B Cells and Antibodies
B cells are stimulated by helper T cells when they see a bacterial antigen.
Helper T cells only recognize antigen after it is ingested by a phagocyte and has been displayed on phagocyte’s membrane.
B cells then produce plasma cells and memory B cells.
Plasma cells make antibodies. Memory B cells divide to make more plasma
cells without needing helper T cells – secondary response.
T Cells and Antibodies
T cells are stimulated by helper T cells when they see a virus-infected cell (antigen).
Helper T cells only recognize antigen after it is ingested by a phagocyte and has been displayed on phagocyte’s membrane.
T cells then produce killer T cells and memory T cells.
Killer T cells seek and destroy antigen. Memory T cells produce killer T cells without
needing helper T cells – secondary response.
Suppressor T Cells
Shut down the killer T cells when the infection is stopped.
Types of Immunity
Active Immunity Body produces its own
antibodies or killer T cells
Results from having the disease.
Results from use of vaccines containing dead or weakened virus.
Passive Immunity Body receives
antibodies from a source Results from receiving
antibodies from mother’s milk.
Results from vaccine containing only antibodies
Blood Types
Antibodies play a part in blood types, transfusions, and transplants.
There are four different blood types: A,
B, AB, and O. You are a certain blood type if your
blood contains certain antigens.
ABO Blood Types
There are two antigens: A and B If you have blood type A, you have A antigens and
B antibodies. If you have blood type B, you have B antigens, and
A antibodies. If you have blood type AB, you have both A and B
antigens and no antibodies. If you have blood type O, you have neither antigen
and both A and B antibodies.
Transfusions
A blood recipient cannot have antibodies to the antigens he is receiving.
Example:
If you have A blood, you cannot safely receive B or AB blood because you have B antibodies.
Challenge
Which blood type can give blood to anyone?
Which blood type can receive blood from anyone?
Universal Blood Donor
A person with blood type O is called the universal donor. Why?
Answer: His blood contains no antigens so no one will react to it.
Transplants
Transplanted organs trigger the recipient’s immune system to fight these foreign cells - called rejection
To control this effect, the immune system is often suppressed prior to transplant through medications.
Universal Blood Recipient
A person with blood type AB is the universal recipient.
Why?
Answer: His blood contains both antigens and no antibodies, so his blood will not react to any blood type.
AIDS
Acquired Immune Deficiency Syndrome - affects the immune system.
Caused by HIV (human immunodeficiency virus).
Acquired by body fluid transfer. The virus attacks helper T cells. Why is this
bad?
Answer:
Body can’t produce antibodies or killer T cells and can’t fight diseases.
Symptoms: swollen glands, fever, weakness, weight loss, inability to fight common illnesses, fungi, cancers (Kaposi’s sarcoma).
No cure.
Immune Disorders
Allergies – overreaction to an antigen that is not normally harmful. It triggers the inflammatory response – when the body makes histamines. To reduce symptoms – take antihistamines.
Immune Disorders
Autoimmune Diseases – when the body fails to recognize its own cells as self and produces antibodies against its own cells.• Lupus (various organs, kidneys), Multiple
sclerosis (nerves), rheumatic fever (heart and joint tissue)
Immune Disorders
Cancer – body doesn’t recognize foreign cells as foreign and lets them multiply uncontrollably. Suppression of immune system often results in cancer.