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• The immune systems help to protect against pathogens.

• If the immune system recognizes an antigen, it will launch an attack.

• The white blood cell with the matching antibody to fit the antigen must be found.

• The white blood cell will multiply and release many antibodies to flag the antigens.

• Memory cells and antibodies will stay in the body forever

Jobs of white blood cells

1. To release antiBodies to mark pathogens2. To engulf flagged pathogens

Vaccine• Weakened or dead version of the pathogen• Immune system sees the antigen• Prepares by making antibodies and memory cells

HIV• A virus that causes AIDS• AIDS is a disease that damages/weakens the

immune system.• AIDS victims are helpless to attacks by other

infections.

Allergy• Sometimes the immune system

recognizes antigens on usually harmless environmental substances.

• When the immune system attacks a usually harmless environmental substance, such as pollen, peanuts, dust, shellfish etc., it is called an allergic reaction.

Organ Transplants• Can be dangerous because the immune system

does not accept foreign cells. • The immune system can reject a transplanted

organ and attack it. • Sometimes the immune system “forgets” it’s own

cells, and launches an attack.

Endocrine System• Made of organs called glands that secrete

hormones• Hormones are chemical messages that travel

through the blood.• Nerve cells in the nervous system also release

chemical messages

• Hormones have specific shapes that are received by specific receptor molecules.

• Hormones deliver messages to target cells with the matching receptor molecules.

• If a cell does not have the matching receptor molecule, it will not receive the message.

• Hormones deliver messages that tell cells to make changes.

• Cells with receptor molecules will respond to the message from the hormone and make a change.

• The hormone adrenaline is released by the brain.

• The hormone adrenaline is released by the brain.

• Adrenaline matches the receptor molecules on the pacemaker cells.

• Adrenaline hormone tells the pacemaker cells to increase heart rate.

The Pancreas

• The pancreas is a gland that secretes the hormone insulin.

• Insulin is a hormone that regulates blood sugar levels.

• If blood sugar gets high, the pancreas releases insulin to tell target cells to remove glucose from the blood.

• Blood sugar high- pancreas releases insulin• Blood sugar back to normal- pancreas stops

secretion• Blood sugar high- pancreas secretes insulin• Blood sugar normal- pancreas stop secreting

insulin

The regulation of blood sugar levels by the hormone insulin in a feedback mechanism!!• Blood sugar increases• Insulin increases• Blood sugar decreases• Insulin decreases

The “specific shapes” of biology

• Enzymes + Substrate (reactant)• Antibodies + Antigens (on pathogens)• Hormones + Receptor molecules (on target cells)

The “Feedback Mechanism” Responses

• Heart Rate responds to Exercise• Guard cell responds to Water loss• Insulin responds to Blood sugar