BLOOD and IMMUNITY Chapter 10

Itty Bitty Life Forms

Blood and The Body's Defense Against Disease Videos

Is the blood in your veins blue? (answer is at the bottom of the page)

I. Blood-

A.(is a fluid tissue that has 3 functions) Transport, Regulation, and Protection

-the average adult contains approximately 6 liters of blood, if a liter is lost it considered to be life threatening

B. COMPOSITION of BLOOD

55% plasma
45% red blood cells, white blood cells & platelets

1. Plasma- is clear, straw colored liquid

a. plasma composition: 90% water, 7% proteins (albumins, fibrinogen, globulins), & 3% other (glucose, amino acids, fatty acids, vitamins, wastes)

2. Red Blood Cells (RBC's)- also called Erythrocytes

a. disked shaped
b. contain iron filled pigments called hemoglobin which transports oxygen
c. these cells do NOT have a nucleus (this characteristic enables blood to be transfused to other people)
d. made in bone marrow of ribs, sternum, skull, pelvic bone, vertebrae & long bones of limbs
e. RBC's are stored in the spleen which aids the liver in destroying old RBC's

f. Anemia is a condition when a person has too few RBC's or insufficient amount of hemoglobin

3. White Blood Cells (WBC's)- also called Leukocytes

a. larger than RBC's and protect the body from disease causing organisms such as bacteria & viruses
b. contain one or more nuclei
c. made in the same places as the RBC's and also in the lymph nodes

d. Leukemia is a blood cancer which involves the over production of WBC's 2 basic typesWBC's:

1. Phagocytic WBC's	= engulf antigens with pseudopods
2. Lymphocytes	= make antibodies to destroy antigens

antigens- foreign bodies that cause an immune response; mostly made of proteins such as bacteria or viruses

4. Platelets- initiate blood clotting

a. small, clear, disk-shaped cell ( smaller than RBC's)
b. also formed in the bone marrow

C. BLOOD CLOTTING: STEPS of CLOT FORMATION

1. The ruptured platelet & site of injury both release enzyme called thromboplastin.
2. Thromboplastin changes to prothrombin, a plasma protein, into thrombin
3. Thrombin, an enzyme, converts fibrogen into strands of fibrin
4. Fibrin forms a network of strands that traps RBC's & platelets to form clot

D. CLOTTING PROBLEMS

1. Platelet and vitamin K deficiency both reduce the body's ability to clot.
2. Hemophilia is a hereditary disease that lacks one of the steps of clotting. (see steps above)
3. Thrombus is a clot that is attached to a vessel wall.
4. Embolus is a traveling clot (traveling thrombus)

5. Blockage of the coronary artery will lead to a myocardial infarction.
6. Blockage of the artery that leads to the brain will lead to a stroke.

BLOOD TYPING There are 4 main blood types. Each blood type is determined by a particular antigen (that is not the same disease causing antigen) called agglutinogens of the surface of red blood cells. The plasma of human blood contains antibodies called agglutinins. Knowing your blood type is very important when it comes to blood transfusions. For example, a person who is Blood Type A, can not receive blood from someone who is Blood Type B, because the B blood contains antibodies that attack A antigens which are found in the person containing Blood Type A. If this were to happen, the blood would begin to clump together which is called agglutination and the end result would be death.

Blood Type	Antigens	Antibodies	Can receive from	Can be given to
A	A	anti B	A, O	A, AB
B	B	anti A	B, O	B, AB
AB	A and B	none	A,B, AB, O	AB
O	none	anit A & antiB	O	A, B, AB, O

Immunity- DEFENSE AGAINST DISEASE

1. Skin

2. Acidic Stomach

3. Immunity = the ability of body to resist a particular disease

In 1796, Edward Jenner developed a vaccine for smallpox. He used a vaccine which consisted of a weakened or dead bacteria or virus. In each case, the organism or poison can still act as an antigen, but because it is weakened or modified, it can no longer cause disease.

Bodies of Immunity, lie in the body's ability to distinguish between itself & nonself

Pathogens- bacteria, viruses & other microorganisms that cause disease

Lymphocytes- (a type of white blood cell) are the cells of the immune system that recognize specific antigens & either produce antibodies or kill foreign cells directly. There are 2 types of lymphocytes; B lymphocytes, or B cells, and T lymphocytes, or T cells. T cells dervie their name from the site at which they are made, the thymus gland. B cells derive their name from the site at which they are made, the marrow of bones.

Immune Response- the reaction of the immune system to the presence of foreign cells

TYPES of IMMUNITY

1. Inborn immunities- are present at birth, some pathogens humans are naturally immune to

2. Aquired immunity- immunity develops over a person's lifetime

a. Active immunity- body produces antibodies either as result of or exposure to a disease [ex. measles or vaccination]

b. Passive immunity- "borrowed immunity" a person is given antibodies from another person or animal (temporary)

Immune System Disorders

AIDS- Acquired Immune Deficiency Syndrome

Acquired means people pick up the desease from other people. Immune deficiency means a breakdown of the body's immune system. Syndrome means a group of symptoms that indicate disease.

HIV- Human immunodeficiency virus attacks the helper T cells in the immune system. This is the virus that leads to AIDS

Allergies are an overreaction to an antigen that is NOT harmful to our bodies, but our immune system doesn't see it that way. Pollen is a typical example which causes symptoms of runny nose, swollen eyes, sneezing, coughing or a rash. These symptoms are caused by the body's release of histamine. Histamine induces an inflammatory response, and to defend this overreaction of the body a person will take antihistamines to stop the release of histamines.

Biology Trivia

1. Is the blood in your veins blue? answer

2.Why doesn't blood usually clot in your blood vessels? answer

3. What was the name of the bacteria that was responsible for the death of approximately 25 million people in late 1320's? answer

4. How did the bubonic plague get its name & why was it nicknamed black death. answer

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