31.2 Immune System

Allergens

are antigens that cause an allergic reaction

Antiseptics

are chemicals, such as soap, vinegar, and rubbing alcohol, to kill pathogens. ex: Rubbing alcohol weakens cell membranes, the microbes nutrients leak out, and the microbe bursts.

Antigens

are protein markers on the surface of cells and viruses that help the immune system identify a foreign cell or virus.

Memory Cells

are specialized T and B cells that provide acquired immunity bc they "remember" an antigen that has previously invaded the body.

Fever

develop when mast cells or macrophages release chemicals that cause the hypothalamus to increase the body's temperature. The infection is controlled when the mast cells chemicals are no longer being made.

Anaphylaxis

is a condition that occurs when the immune system releases a large amount of Histamine, causing airways to tighten and blood vessels to become porous. When blood vessels become porous, blood leaks out of the circulatory system, causing the body to shut down.

Inflammation

is a nonspecific response characterized by swelling, redness, pain, itching, and increased warmth at the infected sight. Inflammation occurs when a pathogen enters the body when tissues are damaged.

Vaccine

is a substance that contains the antigen of a pathogen. the antigen causes your immune system to produce memory cells, but you wont get sick.

Cellular Immunity

is an immune response that depends on T cells. T cells attach to the infected body cells and cause them to burst.

Allergy

is an oversensitivity to a normal harmless antigen.

Passive Immunity

is immunity that occurs w/o the body undergoing an immune response. ~ It is transferred btwn generations through DNA btwn mother and child. ~Genetic immunity is the immunity that a species has bc a pathogen isn't specialized to harming that species ~Inherited immunity occurs when pathogen-fighting antibodies in a mother's immune system are passed to the unborn baby through the umbilical cord & milk

Active Immunity

is immunity your body produces in response to a specific pathogen that has infected or is infecting your body ~Acquired immunity is a type of active immunity occurring after your immune system reacts to a pathogen invasion. It keeps you from getting sick by a particular pathogen more than once.

Antibiotic resistance

occurs when bacteria mutates so that they aren't affected by antibiotics.

Tissue rejection

occurs when the recipient's immune system makes antibodies against the protein markers on the donors tissue.

Low Fevers

stimulate the production of interferons (proteins that prevent viruses from reproducing). They also increase the activity of WBC's by increasing the rate at which they mature (only mature WBC's can destroy pathogens).

Activating T cells

1. A Phagocyte recognizes a foreign invader and engulfs it. Once inside the phagocyte, the invader's antigens are removed, and the phagocyte them on its cell membrane. This is called an Antigen-presenting cell. 2. A T cell encounters the Antigen-presenting cell and binds to it. the A-P cell releases proteins that activate the T cell. 3. When a T cell is activated, it begins to divide and differentiate into two types of T cells: Activated and Memory. The activated T cells fight the current infection, but the Memory T cells act as reserves that will wait for future invasions. 4. The activated T cells bind to and destroy infected body cells. Humoral Immunity: a type of immune response that depends on antibodies. Different types of antibodies fight pathogens by either causing them to burst, inactivate them, or cause them to clump.

Activating B cells

1. A pathogen binds to a B cell. The B cell engulfs the pathogen and puts part of the antigen onto its surface 2. When a T cell encounters an A-P B cell, it binds to the antigens. Then the T cell releases proteins that activate the B cell. 3. Once activated, the B cell divides and differentiates into active B cells and Memory B cells. 4. Activated B cells produce as many as 2000 pathogen-specific antibodies per second. In some cases, antibodies cause pathogens to clump. 5. Phagocytes engulf and destroy the pathogen clumps

How inflammation works

1. Inflammation response begins when mast cells or Basophils release chemicals called Histamines in response to the invasion. 2. Histamine causes the cells in blood vessel walls to spread out. Allowing fluid to move out of the blood vessel and into the surrounding tissues 3. WBC's squeeze out of the capillary and move towards the site of infection. 4. Once outside the circulatory system, the WBC's fight off the infection. When the pathogens are defeated, swelling stops, and tissue repair begins.

The Four main types of vaccines

1. Some vaccines contain whole dead bacteria or viruses 2. Live attenuated vaccines contain weak living vaccines 3. Component vaccines use only the parts of pathogens that contain the antigen, such as the protein coat of a virus that has had its genetic material removed. 4. Toxoid vaccines are made from inactivated bacterial toxins, which are chemicals a bacterium produces that causes a person to become ill

How WBC's attack pathogens

1. When a pathogen enters the body, BASOPHILS in the bloodstream or MAST CELLS found in other tissues release CHEMICAL SIGNALS. 2. These signals attract other WBCs to the site of the infection. 3. If the pathogen is a PARASITE, EOSINOPHILS come and spray it with poison. 4. If the pathogen is a VIRUS, BACTERIUM, or FUNGUS, NEUTROPHILS and MACROPHAGES go to work.

AIDS

Acquired immune deficiency syndrome is the final stage of the immune systems decline due to HIV. AIDS is the condition of having a worn-out immune system. A person with AIDS can have several opportunistic infections (fungal infections, TB, pneumonia, cancers) and very few T cells.

Types of White Blood Cells

Basophil: makes chemicals that cause inflammation in the BLOODSTREAM. Mast cell: makes chemicals that cause inflammation in other BODY TISSUES. Neutrophil: engulfs pathogens and foreign invaders; phagocyte Macrophage: engulfs DEAD or DAMAGED body cells and some bacteria; phagocyte Lymphocyte: DESTROYS infected body cells or produces proteins that inactivate pathogens Eosinophil: injects POISONOUS packets into parasites, such as Protozoa

How Leukemia weakens the immune system

Bone marrow produces WBC's that don't mature. In effort to replace the defective WBC's, the bone marrow produces more WBC's. Non of these new cells mature into effective WBC's Eventually, the bone marrow spends all of its time making fewer RBC's and platelets than are needed to replace those that die or become damaged.

Types of Proteins that fight off pathogens:

Complement Proteins: made by WBC's and certain organs. ~Some complement proteins weaken a pathogen's membrane ~others attracts phagocytes to the infected area. ~ another kind causes microbes to stick to the walls of blood vessels, where they can more easily be found and destroyed by circulating phagocytes Antibodies:proteins made by B cells. Antibodies destroy pathogens in one of three ways: ~They might make the pathogen ineffective by binding to the pathogens membrane proteins ~Might cause pathogens to clump, making it easier for phagocytes to engulf and destroy Interferons: Proteins produced by body cells infected by a virus. ~They stimulate uninfected body cells to produce enzymes that prevent viruses from entering & infecting them. ~ If a virus cant enter a healthy cell, it cant reproduce ~ Other interferons stimulate an inflammation response

HIV reproduction

HIV infects T cells (WBC's that trigger immune responses). When HIV enters a T cell, it become ineffective and can no longer stimulate an immune response. Although it can't function in the immune system, it remains alive as a host to produce new HIV.

HIV

Human immunodeficiency virus is a retrovirus that contains RNA instead of DNA. It contains 9 genes that weaken the immune system. HIV can't live long outside of the body.

GVHD

In Graft-versus-host disease, the donor marrow makes antibodies against the hosts healthy cells. Chemotherapy and radiation treatments kill both cancerous and healthy cells leaving the immune system open to opportunistic infections.

Phagocyte

Is a cell that destroys pathogens by surrounding and engulfing them.

Opportunistic Infection

Is an infection caused by a pathogen that a healthy immune system would normally be able to fight off.

Leukemia

Is cancer in the bone marrow. It prevents the bone marrow from functioning properly. In one type of leukemia, bone marrow produces defected WBC's. To cure Leukemia, cancerous bone marrow must be replaced with healthy marrow from a donor.

Immune System

Is the body system that fights off infection and pathogens. It relies on the physical barriers of the body to keep pathogens out.

HIV treatment

Is very expensive, complicated, and only slows- but doesn't cure- the disease. Because HIV constantly mutates, many different drugs may have to be taken.

Body's Defence System

Skin: is the first line of defence protecting our insides. It secretes oil and sweat making skin hypertonic and acidic. Many pathogens are unable to survive this kind of environment. Eyes, Nose, Ears, Mouth: have extra protection. mucous membranes in these organs use hairlike cilia covered in sticky liquid to trap pathogens before they can get into the body

Types of lymphocytes:

T cells: destroy body cells that are infected with pathogens B cells: produce proteins that inactivate pathogens that havent infected a body cell yet

High fevers

The Hypothalamus can no longer regulate body temperature. Enzymes that control chemical reactions in the body stop functioning . This can lead to seizure, brain damage, and death.