Human Biology - immunity

Immunity lecture 4

define pathogen?

A pathogen is any microorganism, such as bacteria, viruses, fungi, or parasites, that can cause diseases

define infection

invasion of the body tissues by pathogens

define disease

any harmful change from the normal structure and function of the body.

define immunity

Immunity is the body's ability to resist or fight off infection and disease through specific defenses, such as antibodies or immune cells.

what are the two types of immunity

innate defence

adaptive defence

what is the difference between innate defence (non-specific) and adaptive (specific)defence

Innate defense refers to the body's initial, non-specific response to pathogens, including physical barriers and immune cells, while adaptive defense involves a targeted immune response that develops over time, creating memory of specific pathogens for faster responses in the future.

what does non specific innate defence consist of? how many line of defence are there and what is in those line of defence?

first line of defence is the Skin

second line of defence is the inflammatory response and phagocytic cells.

what is phagocytosis?

A process where immune cells, such as macrophages and neutrophils, engulf and digest pathogens and cellular debris to help eliminate infections and maintain tissue health.

what is the process of phagocytosis?

it varies with different types of cells

step one

The virus and the cell need to come into contact with each other.

step two

The virus binds to the cell surface receptors on the macrophage.

step three

The macrophage engulfs the virus, forming a phagosome.

step four

The phagosome fuses with a lysosome, forming a phagolysosome, which contains enzymes that digest the virus.

step five

The digested materials are expelled from the cell through exocytosis.

what are antigens?

any substance that is recognised as foreign and triggers the immune response