Immune System
Pathogens
Viruses
Types of Barriers
Bacteria
Fungi
Innate Immunity
Adaptive Immunity (Third Line of Defense)
First Line of Defense
Second Line of Defense
Skin & its Secretions (Protects External Boundaries)
Mucous Membranes (Protects Internal Boundaries)
Lymphocytes
Fever
Inflammatory Response
Antimicrobal Proteins
Antibodies
Memory Cells
Phagocytic Leukocytes
Protozoa 
A prokaryote which divides by binary fission
Causes food poisoning, ear & eye infections, and other diseases such as cholera, diarrhea, and etc.
Aceullular, thus needs a host cell to carry out function of life such as reproduction. Can also hold both DNA & RNA. Evolves, mutates, and recombines rapidly.
Cause diseases such as the flu, HIV/AIDS, smallpox, measles common cold, herpes, ebola, and more.
A eukaryote that reproduces with spores
Can cause athlete's foot, mold, ringworms, allergic reactions, respiratory problems, and more.
Simple parasites
Can cause diseases such as Malaria, Leishmaniasis, Toxoplasmosis, and more
Sticky mucus which traps invaders
pH which isn't favorable for pathogens
Lysozymes which are enzymes that break down pathogens
Natural organisms work as completive exclusion by non-harmful microbes
Skin is continuous, thus making it difficult to find an opening. It has several layers and is tough while also being dry. Its pH isn't favorable to pathogens and lysozyme which break down pathogens. Its natural organisms work as competitive exclusion by non-harmful microbes.
Methods of Transmission
Ingested/Swallowed
Animal Vectors
Direct Contact
Bodily Fluids
Blood Contact
Leukocytes (White Blood Cells)
HIV/AIDS
Phagocytes (aids lymphocytes)
Oesinophil (parasites)
Basophil (allergies)
Lymphocytes
B-cells
T-cells
Killer cells
Neutrophil (bacteria/fungi)
Antigen
Antibody
A molecule/substance often upon a virus/cell surface which leads antibodies to form
Produced by mainly by plasma cell, it is a large, globular, y-shaped protein which recognizes specific antigens to bind to them as an immune response. May cause inflammation
Human Immunodeficiency Virus is a retrovirus, which inserts its RNA into host cells, slowly attacks the immune system, making it harder for someone to fight off infections and diseases. At the moment there is no cure but there is treatment
AIDS is the last stage of HIV, where the body can no longer defend itself, possibly developing various diseases and maybe death.
Risk Factors in HIV transmission
Higher Risk: Blood-blood contact, sexual intercourse, oral sex
Lower Risk: Saliva/kissing, ingestion, childbirth, breastfeeding
ABO Blood Groups act to tell if certain antigens on red blood cells are present or not, leading to the four types of A,B, AB, & O.
Acquired Immunity
Active (Antibodies from Self)
Passive (Ready-made Antibodies)
Natural (Maternal Antibodies)
Artificial (Antibodies from other sources)
Natural (Exposure to infectious agent)
Artificial (Immunization)
Move using chemotaxis to respond to invasion with proteins from pathogen or phospholipids from damaged cells. During phagocytosis, they engulf the pathogen using endocytosis, break down the pathogen using lysozymes, and remove anything else.
Neutralization: its attachment halts any effects or entry points for toxins in cells. Also prevents viruses from invading cells and bacteria from functioning, and thus attacking cells
Opsonization: its attachment marks the pathogens so other immune cells can easily identify, find, engulf, and digest them.
Agglutination: antibodies attach to each other, which causes a clumping, enhancing the effects of the previous two functions.
Complement activation: antibodies attach leads to other components to attack the pathogen
Histamine
A small set of organic molecules produced by basophils, which release through circulation, and mast cells, found in connective tissue which release if stimulated by an infection. It heavily affects the body's immune response as it raises the capillaries' permeability to white blood cells and some proteins, permitting early pathogen engagement at the site of infection. They may cause inflammation/hives, itching, sneezing, watery eyes, or more. Categorized as an allergy and antihistamines work to as a drug to oppose the activity of histamine receptors.
Vaccines
Permits someone immunity to a disease without needing to have had it. Vaccines hold antigens as forms of either attenuated/inactivated viruses, weakened toxins, or subparts. Works to create a primary immune response, which creates memory cells that develop immunity, and a secondary immune response which is much faster and stronger in comparison. The vaccine should not typically cause symptoms in a healthy person and can be taken orally or injected
Antibiotics
A treatment drug that aids prokaryotic bacteria prevention which disrupts structure/metabolic pathways. They are ineffective against eukaryotic bacteria and viruses and using them in that context could lead to antibiotic resistance.
Monoclonal Antibodies
When an immune response gets stimulated with an antigen, antibodies are used therapeutically/diagnostically. Specific plasma B-cells are fused with a myeloma cell when the desired antibody are harvested, called hybridioma cells. After screening, selected ones aid in dividing for clones, making large quantities of single, multipurpose antibodies.
Blood Clotting works as a metabolic pathway which prevents blood loss and repairs tissue.