#18 Lymphatic and Immune System Flashcards
lymph
the term used to describe interstitial fluid once it has entered the lymphatic system
where does lymph come from?
(Tissues) interstitial fluid
what does lymphatic system do with lymph
deposited in vessels, taken back to Venus system back in blood through veins
components of the lymphatic system
Lymphatic vessels
Lymphatic organs
Lymphatic cells
functions of the lymphatic system
Return leaked plasma (interstitial fluid) to the bloodstream
Screen lymph for foreign substances (antigens)
House lymphocytes that generate the immune response
Transport dietary lipids
Flow of Lymph
Lymphatic capillaries
Series of lymphatic vessels & lymph nodes
Lymphatic trunks
Lymphatic ducts
Venous circulation
primary lymphatic organs
bone marrow and thymus
bone marrow
Hemocytoblasts create lymphoid stem cells
Lymphoid stem cells that differentiate and mature in the bone marrow become B cells and the natural killer cells
thymus
Some lymphoid stem cells migrate to the thymus to mature. These cells become T cells
Each lobe of the thymus contains a cortex (containing immature T cells) and medulla (containing mature T cells)
secondary lymph organs
Lymph nodes and spleen
separated by connective tissue capsule
Structure: lymphatic tissue that ARE surrounded by a connective tissue capsule
Contain macrophages, dendritic cells, and lymphocytes
anatomy of lymph nodes
Afferent and efferent vessels
Cortex and medulla
Macrophages, dendritic cells and lymphocytes
functions of lymph nodes
Screen lymph for foreign antigens
Initiate immune response
locations of lymph nodes
Axillary (armpit)
Inguinal (groin)
Cervical (neck)
Scattered throughout the body
white pulp
Contains lymphocytes and macrophages
Monitors blood for foreign antigens, initiates an immune response when antigens are found
red pulp
Functions as a blood reservoir
Hemolysis (phagocytosis of old erythrocytes and platelets)
Remove debris from blood
spleen
Largest lymphatic organ
Upper left quadrant of the abdomen
lymph nodule structure
Oval clusters of lymphatic tissue NOT surrounded by a connective tissue capsule
Contain macrophages, dendritic cells, and lymphocytes
lymph nodule function
Screen for and attack foreign antigens
locations of lymph nodules
Tonsils: pharyngeal (adenoids), palatine, and lingual
Mucosa-Associated Lymphoid Tissue (MALT)
Gastrointestinal, respiratory, genital and urinary tracts
phagocytes include
Macrophages and dendritic cells:
Phagocytosis of foreign substances
Antigen presentation to lymphocytes to initiate immune response
lymphocytes
Most abundant cell type in lymphatic organs & nodules
B-lymphocytes, T-lymphocytes, and Natural Killer cells
Migrate through the lymphatic system searching for foreign antigens
Mount the immune response when activated
T lymphocytes include:
cytotoxin T cells (CD8+), Memory cells, helper T cells, regulatory T cells
cytotoxin T cells (CD8+)
activated Tc cells are cloned and destroy infected cells in the body, destroy cells with virus in it
memory cells
T cells are produced and are activated if this antigen is encountered again, helps body to get rid of pathogen more quickly
Helper T cells (CD4+)
orchestrate an effective immune response by secreting cytokines, chemical signals that bind to and activate other immune system cells
regulatory T cells
suppress the immune response to keep it under control and turn it off after the infection is over
B lymphocytes include:
plasma cells memory B cells
plasma cells
Produce immunoglobulins (antibodies)
Antibodies bind to antigens, tagging them for destruction
Most B lymphocytes become plasma cells
memory B cells
Patrol body after an attack
Easily activated if infected again
Natural killer cells
NK cells can respond to multiple antigens
Each B and T cell can only respond to a single antigen
NK cells can kill a wide variety of infected cells and some cancerous cells
lymphoma
Cancer of lymphatic cells
Often presents as a swollen lymph node
hodgkins lymphoma
Presence of Reed-Sternberg cell
-If caught early prognosis is good
non-hodgkin’s lymphoma
Variable prognosis, depending on the type
Lymphedema
Edema due to lymph node obstruction
surgical removal of nodes scar tissue within nodes
Malignant tumors of nodes
Parasitic infection of nodes
Extreme cases: elephantiasis
Lymphedema is NOT operable or curable
HIV
Human Immunodeficiency Virus
Passed through intimate contact with infected body fluids
Targets helper T cells
AIDS
Acquired Immunodeficiency Syndrome
An HIV infection is diagnosed as AIDS when helper T cell count drops below 200 cells/mm3
Drug cocktail can stop disease from progressing but must be taken for life
