Immune System Lecture Notes Flashcards

Flashcards covering the divisions of the immune system, types of pathogens, physical and mechanical barriers, and the mechanisms of adaptive immunity including B and T cell functions.

Immune system

Functional system of the body, used as body’s defense system against pathogens.

What is a phagocyte cell?

specialized white blood cells that protect the body by engulfing and destroying harmful bacteria, foreign invaders, dead cells.

Peptide bonds

Chemical links to join amino acids tgt to make proteins.

Bacteria

Single celled organisms, can reproduce independently, treatable w/ antibiotics.

Viruses

Not living, require host cells, hijacks machinery to reproduce.

Fungi

Yeasts and molds, opportunistic infections.

Protozoa

Microscopic, single celled, inside the body often in blood, tissues, or intestinal tract, multiply rapidly.

Helminths

Large, multicellular, worm-like organisms that live inside intestinal tract+internal tissues, visible to the eye as adults, producing eggs that pass out.

Ectoparasites

Multicellular bugs, insects, and arachnids (such as ticks, fleas, lice, and mites) that attach themselves to the skin surface to feed.

Prions

Misfolded proteins associated with neurodegenerative disease.

Innate (nonspecific) system

Prevents entry+spread; makes up the 1st and 2nd lines of defense.

Adaptive (specific) system

Targeted response system that takes longer to develop; constitutes the third line of defense.

Humoral immunity

A type of adaptive immunity involving antibodies in the body’s fluids (blood, lymph).

Lymph

Clear/pale fluid that leaks out of blood vessels into body tissues, collects waste, and fights germs.

Cellular immunity

A type of adaptive immunity where cells themselves act as the defense.

Keratinized epithelium

Tough, outer layer of skin tissue filled w/ hard protein called keratin; it is dead, dry, and helps protect against damage.

Mechanical cleansing

Process in the blink reflex which flushes away foreign bodies, microbes, and unwanted fluids to the tear system.

Physical shielding

Involuntary closure of eyelids that prevents unwanted objects from touching the cornea.

Cilia

Hair-like cells found inside the outer lining of lungs, beating in coordinated waves to sweep unwanted mucus and dust out of the body.

Mucociliary escalator

Self-clean system in the respiratory tract that pushes unwanted particles out using mucus and cilia.

Peristalsis

Squeezing of muscles that push food and waste through the body.

Acid mantle

Slightly acidic secretion of the skin to prevent bacterial growth.

Lysozyme

Enzyme in saliva, respiratory mucus, and tears that kills bacteria.

Mucin

A substance that forms mucus to trap microorganisms and wash them out.

Defensins

Specific type of antimicrobial peptides that control bacteria and fungi.

B-cells (B-lymphocytes)

Immune cells that produce antibodies to recognize and bind to specific pathogens for destruction; they originate in the bone marrow.

Helper T cells (CD4+)

T-cells that activate and coordinate other immune cells.

Cytotoxic T cells (CD8+)

T-cells that kill infected or abnormal cells directly.

Antigen

Any foreign object your immune system recognizes to trigger a defense response.

Di-sulfide linkages

Strong covalent chemical bonds that combine 2 identical heavy protein chains and 2 light protein chains in a B-cell.

Variable region

Specific tip of the Y-shaped antibody that binds to antigens by changing its own shape.

Somatic hypermutation

Mutation of the B cell's variable region when activated to find the best antigen fit.

Affinity maturation

The process of finding the best antigen fit through somatic hypermutation.

Constant region

Base of the antibody used for macrophages to recognize and activate downstream destruction pathways.

Macrophages

Large white blood cells that eat germs, dead cells, and unwanted trash; called "big eater" in Greek.

Cytokines

Small proteins secreted by cells that act as chemical messengers to signal which isotype the cell should produce.

Plasma cell

Transformation of an activated B cell that acts like a small factory, releasing large numbers of targeted antibodies into the blood and lymph.

Opsonization

Process where an antibody tags pathogens to become a sign for phagocytes to eat them.

Phagocytosis

The process of a cell (a phagocyte cell) engulfing large particles like bacteria, dead tissue, and foreign matter.

Neutrophils

A more common type of white blood/phagocytic cell involved in the process of phagocytosis.

Agglutination

When antibodies clump pathogens together to remove their ability to function and allow them to be filtered out.

Neutralization

The binding of antibodies to pathogens to prevent the infection of a host cell.

Memory B cells

Long-lived cells that remain in the body after an infection is cleared for long-term protection and fast response upon re-exposure.

Describe the Immune system process

1. first line: skin+mucus are physical barriers to stop germs from entering the body, as well as mechanical barriers like blink reflex.

2. second line: Innate system that you are given with since birth. such as acid mantle, mucin, etc

3. Third line: adaptive system that is highly specific and relies on long lasting defense through B and T cells.

What does Immune Memory rely on?

This relies on the prescence of a small sample of B and T cells in the body even after infection.

What is Antigen Recognition?

 immune cells detect specific molecular markers on pathogens, allowing for precise targeting. They are developed before any encounter with the pathogen as the immune system generates billions of unique T and B cell receptors prior to any contact. This ability is established during lymphocyte maturation. 

Name three types of Phagocytic cells

neutrophilis, macrophages, dendritic cells