Pathology Unit MYP Year 3 Summative Practice

This set covers essential pathology terminology, the three lines of defense, differences between bacteria and viruses, vaccine types, and the key historical figures in immunology as presented in the lecture notes.

Vector

An agent that carries and transmits an infectious pathogen into another living organism.

Antigen

A substance that induces an immune response from the body via the production of antibodies.

Antibody

A blood protein produced by the body when it detects antigens; antibodies work to fight the antigen.

Antibiotic

A medicine used to combat bacterial infections (from "anti bio" meaning "anti life").

Bacteria

Unicellular microscopic organisms that are considered alive and do not need a host cell to reproduce.

Epidemic

A widespread outbreak of a disease.

Histamine

A substance released by the body in response to allergies or injuries; it is a main cause of allergies.

Immunity

Resistance to a certain disease.

Herd Immunity

Communal immunity of a population to a certain disease.

Infectious/Contagious

Able to be transmitted to people, such as through airborne means.

Disease

An illness inflicted by pathogens.

Pandemic

A severe outbreak that is more contagious than an epidemic and spreads rapidly around the world, such as COVID-$19$.

Pathogen

Microorganisms that can cause ailments upon and/or subsequently after the entry of the body.

Sterilize

To sanitize or rid certain objects and matter of bacteria.

Vaccine

A substance that induces the production of antibodies against certain diseases; it contains small amounts or pieces of live or killed pathogens.

Virus

An infectious agent that is not alive, is much smaller than bacteria, and must use a host cell to reproduce.

White Blood Cells

Part of the immune system that prevents infection and fights diseases in the body; they are generated in the bone marrow and trained in the thymus.

Inflammation

The second layer of defense involving swelling and redness due to the concentration of blood to generate heat to kill pathogens and/or bacteria.

Killer T-Cells

Immune cells that kill infected host cells after being activated by helper T-Cells.

Helper T-Cells

Cells that coordinate action by sending chemical signals to other cells and signaling B-Cells to help fight infection and make antibodies.

B-Cells

Cells produced in the bone marrow that produce antibodies and tag infected cells so T cells can kill them.

Phagocyte

A cell with the ability to digest foreign materials such as viruses, bacteria, and dust.

Macrophage

A type of White Blood Cell that kills infectious substances by engulfing them through phagocytosis and inducing an immune response.

$1^{\text{st}}$ Line of Defense

Physical and chemical barriers including the skin (waterproof barrier), cilia (nose/throat hairs), stomach acids, and mucus.

$2^{\text{nd}}$ Line of Defense

The defense layer where White Blood Cells like neutrophils and macrophages surround and kill pathogens, often involving inflammation.

$3^{\text{rd}}$ Line of Defense

The layer of defensive immune system cells including B cells, Helper T cells, and Killer T cells.

RNA Viruses

Also known as retroviruses, these use RNA as genetic material and perform reverse transcription; they are unstable and can mutate, examples include Hepatitis and HIV.

DNA Viruses

Stable viruses like polio and herpes that use DNA as genetic material and travel to the nucleus to take over replication.

Capsid

Coatings of viral DNA that accumulate inside a host cell until it reaches capacity and bursts open.

Live, Attenuated Vaccines

Vaccines containing weakened living microbes; very effective for diseases like measles, mumps, and chickenpox.

Inactivated Vaccines

Vaccines containing dead microbes killed by heat, chemicals, or radiation, such as those for rabies and whooping cough.

Subunit Vaccines

Vaccines containing only a specific piece of the pathogen; several doses are required for full effectiveness.

Toxoid Vaccines

Vaccines containing inactivated toxins from bacteria, requiring booster shots for a stronger response, such as for tetanus.

Plasma Cells

A factory unit formed from B cells that produces an excessive amount of antibodies.

Memory B and T cells

Cells that retain information about pathogens to allows the body to easily churn out antibodies and defensive measures in the future.

Penicillin

The world's first broadly effective antibiotic substance, discovered by A. Fleming in $1928$ from mold in a petri dish.

M. Montagu

A contributor who introduced smallpox inoculation to Britain in $1717$ after learning the practice (called variolation) in Turkey.

E. Jenner

Scientist who in $1796$ used cowpox inoculation to provide immunity against smallpox, marking the beginning of vaccination.

L. Pasteur

The progenitor of modern immunology who proved 'germ theory' and suggested methods of pasteurization: filtration, heat, and chemical solutions.

J. Lister

The "Father of Modern Surgery" who pioneered antiseptic surgery by using phenol (carbolic acid) to sterilize instruments and wounds.

J. Salk

Creator of the Polio vaccine in $1955$ who used a inactivated virus to provide immunity without making the person sick.