Immune system Flashcards
function of the immune system
to protect the body against infection and disease by producing white blood cells and making antibodies
important structures of the lymphatic system
tonsils, thymus gland, spleen, lymph nodes, skin and bone marrow
tonsils
located at the back of the pharynx and is typically the first site of infection (alert system)
thymus gland
found between the chest and backbone just above the heart
- responsible for producing T-lymphocytes, a specialized white blood cells
spleen
located on top of the pancreas and stomach: produces macrophages
lymph nodes
found in the neck, armpits, and groin: responsible for producing white blood cells
skin
impenetrable barrier of protection against microorganisms
bone marrow
a deep reddish brown, pulpy substance found in the bone
- contains stem cells that produce white and red blood cells
first line of defense
Skin
Forms impenetrable barrier
Sweat contains salts that are poisonous to many invaders
Mucus
Traps inhaled invaders and contains digestive enzymes the destroy cell walls of many bacteria
Cilia
Trapped invaders are expelled by coughing and sneezing
Tears
Invaders that enter the eyes are attacked by enzymes \
Anything that gets by the eyes is caught by mucus in the nasal cavity
Stomach
Strong acids in the stomach kill many invaders
second line of defense
The system contains lymph fluid. Lymph is a translucent fluid that contains white blood cells (leukocytes)
Fever
The body increases temp in an attempt to destroy an invading microbe (mst likely a virus)
Inflammation
Tissue damage results in swelling, redness, heat, and pain
Tissue damage is from injury or from attack of infected cells by leukocytes
Leukocytes
Work together to destroy foreign invaders
They have the ability to identify infected cells from your healthy cells and destroy them
Unable to divide and reproduce
Two types produced in the bone marrow and modified in lymph nodes and spleen
neutrophils
- first WBC to reach the site of infection
attracted to chemical signals given off by cells that have been inffected and damaged by mictobes - they use phagocytosis to engulf the microbe and release lyosomal enzymes to digest the microbes as wll as the leukocyte itsself
- pus is the dead remains of the difested invader and the neutrophil
(granulocyte: contains cytoplasmic granules)
monocytes
- use phagocytosis to engulf and digest invading microbes in a phagosome (to seperate themselves from the invader)
- present microbe antigens on the outside of the leukocyte
third line of defense
Lymphocytes
Originate in the bone marrow
B-cells
Create antibodies (fit the antigen on the invader)
Helper T-cells
Activate B-cells to make antibodies
Identifies invader antigens presented on the membrane of the macrophages
Cytotoxic T-cells
Killer T-cells or natural killer cells
They kill cells that have been infected by puncturing their cell membrane
Suppressor T Cells
Stop the immune response once the foreign invaders have been eliminated
antibodies
Once b cells are activated by helper t cells, they divide into plasma and memory cells
Plasma cells produce antibodies
Antibodies are y-shaped proteins produced on the outside of the cell membrane of the plasma cells
Each antibody matches with a specific antigen
Antibodies bind to the antigen and disable the microbes infection ability (altering the shape)
Memory cells remember the antigens on the invader in case of future invasion
allergies
- Occur when your immune system mistakes harmless cells for harmful invaders
-Cells that believe they are in danger release a chemical messenger called bradykinin which stimulates the release of another chemical called histamin
- Histamine leads to increased tissue swelling , skin rendering, mucus secretion and constricted air passages
- Epinephrine and antihistamines can reduce the effects
