Unit 4: Lymphatic & Immune System Flashcards
What are the 3 functions of the lymphatic system?
Lipid absorption
Fluid recovery
Immunity
Describe lipid absorption by the lymphatic system
Lacteals in the small intestine absorb dietary lipids
Describe fluid recovery by the lymphatic system
Plasma proteins and interstitial fluids leak out of blood vessels into tissues, which is absorbed by lymph vessels and returned to the bloodstream
What happens if the lymphatic system’s fluid recovery is dysfunctional?
Edema
Describe immunity by the lymphatic system
Immune cells in the lymph organs can respond to foreign cells/chemicals while the fluid is being filtered
Describe lymph
Colorless, clear fluid that is similar to plasma but with less proteins
When interstitial fluid pressure builds up, what opens to let cells and bacteria into the lymph capillaries
Valve-like flaps
Describe the flow of lymph
lymphatic capillaries
collecting vessels (flow thru lymph nodes)
lymphatic trunks
collecting ducts (empty into subclavian arteries)
Where is the site of antigen challenges?
Lymph nodes
Where are surface lymph nodes located?
Axillary, inguinal, cervical regions
Where are deep lymph nodes located?
Thoracic, abdominal, and pelvic regions
What are the 4 lymphatic organs
Lymph nodes
Tonsils
Thymus
Spleen
What is the function of lymph nodes
Filter lymph
There are ____ efferent vessels in lymph nodes than ______ which causes _______
fewer efferent than afferent
slows down flow through the node
Why is flow slowed in the lymph node?
So that reticular cells and macrophages can phagocytize foreign matter
Lymphocytes respond to antigens
What are the 3 types of lymphatic cells (WBCs)
T lymphocyte
B lymphocyte
Antigen Presenting Cells (macrophages, dendritic cells, and reticular cells)
Where do T lymphocytes mature
Thymus
What are the 4 types of T cells
Cytotoxic (killer) T cell
Helper T cell
Regulatory T cell
Memory T cell
What happens when a B lymphocyte is activated?
Proliferation and differentiation into plasma cells (which produce antibodies)
What are the types of Antigen Presenting Cells
Macrophages
Dendritic Cells
Reticular Cells
What do Antigen Presenting Cells do?
Phagocytize antigens and then advertise them on surface
Where are dendritic cells located?
Epidermis, mucous membranes, and lymph organs
What are macrophages derived from?
Monocytes
Define non-specific defense
Broadly effective defenses which require no prior exposure to pathogens
Include external barriers
INNATE immunity (phagocytes, antimicrobial proteins, fever, etc.)
Define specific defense
Targeted defense against specific pathogen resulting from prior exposure
ACQUIRED immunity (B & T Cells)
What are 4 external barriers for non-specific defense?
Skin
Mucous membranes
Digestive system
Genitourinary system
How is the skin an external barrier?
Tough keratin
Dry, nutrient poor environment
Defensin proteins which attack microbes (from neutrophils)
Lactic acid mantle
How are mucous membranes an external barrier?
Sticky mucus
Lysozymes in tears and saliva which kill pathogens
How is the digestive system an external barrier?
Stomach acidity and lysozymes in saliva
How is the genitourinary system an external barrier?
Vaginal acidity
Flushing with urine
What are the 5 types of cells involved in innate immunity?
Neutrophils
Eosinophils
Basophils
Monocytes
Lymphocytes
Describe neutrophils and their function
Phagocytizes bacteria
Creates “killing zone” with defensins and respiratory bursts
Define defensins
Antimicrobial proteins
Describe respiratory burst
Toxic chemical released to attack a pathogen
Describe eosinophils and their function
Phagocytize antigen-antibody complexes and allergens
Antiparasitic by aggregating and releasing enzymes
Describe basophils and their function
Aid movement of WBCs and increase inflammation with heparin and histamine
Describe lymphocytes and their function
Usually specific, but can be nonspecific
Called natural killer cells
NK cells lyse infected host cells by releasing perforin proteins
Define complement system and the 2 types
Plasma proteins in the blood which are activated by pathogen
Opsonization and Cytolysis
Describe opsonization
Complement protein which binds to antigens to promote phagocytosis
Describe cytolysis
Membrane attack complex which punches holes in membrane
Describe inflammation and how it is innate immunity
Defense response to tissue injury which limits spread of pathogens and destroys them
Then removes debris and initiates tissue repair
Acquired immunity is _____ and has a _____
specific with a memory
What are the 2 types of specific defense?
Cellular immunity
Humoral immunity
Describe cellular immunity
Cell mediated by T Cells
Describe humoral immunity
Antibody mediated by B Cells
What are the 4 types of acquired immunity?
Natural active
Artificial active
Natural passive
Artificial passive
How do you get natural active immunity?
Natural exposure to an antigen causes you to produce your own antibodies or T Cells (which have memory)
How do you get artificial active immunity?
Vaccination which causes you to produce your own antibodies or T Cells (which have memory)
How do you get natural passive immunity?
Gain non-self antibodies thru natural methods (thru placenta and breast milk)
Don’t produce memory cells so immunity is temporary
How do you get artificial passive immunity?
Gain non-self antibodies thru artificial methods like treatments for snakebite, rabies, tetanus, etc.
Don’t produce memory cells so immunity is temporary
Describe clonal selection
Only the T or B lymphocytes that are activated by the antigen exposure will proliferate, which THEN differentiate and specialize against antigen
Acquired cellular immunity involves
T Cells
What do cytotoxic T cells do
Carry out the attack
What do helper T cells do
Help promote T and B cell actions and also nonspecific defense mechanisms
What do regulatory T cells do
Control cell-mediated attacks
What do memory T cells do
Provide immunity from future exposure to a specific antigen
Acquired humoral immunity involves
B cells
After T helper cell stimulation, B cells …
proliferate and differentiate into plasma cells which produce antibodies
Describe how antibodies initiate destruction of an antigen
Antibody binds to antigen, disables it (“net”), and tags it for destruction by a phagocyte
Describe neutralization in the humoral attack phase
Antibodies block pathogenic region of an antigen like a net
Describe complement fixation in the humoral attack phase
When an antigen binds to an antibody it initiates complement protein binding
Describe agglutination in the humoral attack phase
Binds to multiple enemy cells and causes clumping which immobilizes them
Describe opsonization in the humoral attack phase
When an antigen binds to an antibody it promotes phagocytosis
Describe Lymphatic Filariasis
Cause?
Symptoms?
Risk group?
Tropical parasitic disease that affects the lymph nodes and vessels
Causes swelling and thickening of body parts, especially legs
Spread by mosquitos in tropical zones, long term exposure leads to condition
Describe AIDS
Cause?
Symptoms?
Risk group?
Treatment?
HIV virus attacks T Cells which makes you vulnerable to opportunistic infections and cancer
Asymptomatic or flu-like in beginning
Long term effects vary depending on which infections/ cancers are acquired, can lead to memory loss
Classified as chronic illness, antiretroviral drugs given to help immune system
Describe Hodgkins Lymphoma
Cause?
Symptoms?
Risk group?
Treatment?
Cancer of lymphocytes, usually starting in B Cells
Indicated by abnormal cells called Reed-Sternberg cells
Swelling lymph nodes, fever, lethargy, and weight loss
Highly curable cancer, treated with chemo, radiation, and bone marrow transplant
Describe Non-Hodgkins Lymphoma
Cause?
Symptoms?
Risk group?
Treatment?
Cancer of B Cells (only sometimes T cells)
Elderly, caucasian, insecticides and drugs, exposure to radiation, suppressed immune system, some viral infections
Swollen lymph nodes, fever, abdominal pain
Chemo, radiation, and stem cell transplant
