Lymphatic & Immune system Flashcards
What is the lymphatic system
The lymphatic system is associated with the immune system to such a degree that the two systems are virtually indistinguishable.
Lymphatic system is the system of vessels, cells, and organs that carries excess fluids to the bloodstream and filters pathogens from the blood
What is the function of the lymphatic system?
Blood hydrostatic pressure
Drain body fluids and return them to the bloodstream
What causes leakage of fluid from the capillaries, resulting in the accumulation of fluid in the interstitial space?
Blood pressure
How much plasma is released into the interstitial space of the tissues each day due to capillary filtration
20 litres
What is lymph?
Term used to describe interstitial fluid once it has entered the lymphatic system
What is the inappropriate accumulation of fluid referred to as?
What can it lead to?
Lymphedema may lead to serious medical consequences
What is the purpose of lymphatic vessels?
Convenient avenues for transporting the cells of the immune system
Transport of dietary lipids and fat-soluble vitamins absorbed in the gut also uses this system
What is a lymph node?
One of the small, bean-shaped organs located throughout the lymphatic system
Where are the most lymph nodes found?
high concentration of lymph in the groin, armpits, and neck
How do lymph vessels begin?
Begin as open-ended capillaries (don’t form a circular route) they feed into larger and larger lymphatic vessels
eventually empty into the bloodstream by a series of ducts
How does lymph travel?
Travels through the lymph nodes, which are commonly found near the groin, armpits, neck, chest, and abdomen
Flow of lymph?
What is the function of the immune system?
Immune system is a collection of barriers, cells, and soluble proteins that interact and communicate with each other in extraordinarily complex ways
Immune function is organized into three phases based on the timing of their effects
What are the 3 immune system protection responses?
Barrier defenses
Innate immune response
Adaptive immune response
What is the barrier defense?
- skin and mucous membranes
- act instantaneously to prevent pathogenic invasion into the body tissues
What is the innate immune response?
rapid but nonspecific
consists of a variety of specialized cells and soluble factors
What is the adaptive immune response?
slower but more specific and effective
involves many cell types and soluble factors
primarily controlled by white blood cells (leukocytes) known as lymphocytes
help control immune responses
What are the different types of WBC and their protective functions?
Natural killer cells: attack to cancer cells, or infected cells
T-cells: respond to antigens/ adaptive immune response
Plasma cells: humoral immunity
B-cells: humoral immunity
What are the cells of the immune system?
phagocytic cells
lymphocytes
cells containing cytoplasmic granules
What is the function of phagocytic cells?
Ingest pathogens to destroy them
What is the function of lymphocytes?
Specifically coordinate the activities of adaptive immunity
What is the function of cells containing cytoplasmic granules?
Help mediate immune responses against parasites and intracellular pathogens such as viruses
Describe lymphocytes:
primary cells of adaptive immune responses
Identical morphologically with a large central nucleus surrounded by a thin layer of cytoplasm
Distinguished from each other by their surface protein markers as well as by the molecules they secrete
What are the 2 basic types of lymphocytes?
B cells and T cells
Where do B cells mature?
B cells mature in red bone marrow
Where do T-cells mature?
T cells mature in the thymus
Where do B cells and T cells initially develop?
bone marrow
What cell have the ability to distinguish self and nonself?
T cells
Describe B-cells:
Immune cells that function primarily by producing antibodies
What are antibodies?
Any of the group of proteins that binds specifically to pathogen-associated molecules known as antigens
What are antigens?
Chemical structure on the surface of a pathogen that binds to T or B lymphocyte antigen receptors
What happens once a B cells is activated by binding to an antigen?
Differentiate into cells that secrete a soluble form of their surface antibodies
What are activated B cells are known as?
plasma cells
Describe plasma cells?
Differ in morphology from standard B and T cells in that they contain a large amount of cytoplasm packed with the protein-synthesizing machinery known as rough endoplasmic reticulum
What is the function of T cells?
Performs a variety of functions in the adaptive immune response.
Different T cell types have the ability to either secrete soluble factors that communicate with other cells of the adaptive immune response or destroy cells infected with intracellular pathogens
Describe natural killer cells:
Circulating blood cell that contains cytotoxic (cell-killing) granules in its cytoplasm
Shares this mechanism with the cytotoxic T cells of the adaptive immune response.
NK cells are among the body’s first lines of defense against viruses and certain types of cancer
What are the primary lympoid organs?
Bone marrow
Thymus
What are secondary lymphoid organs?
Naïve lymphocytes are fully functional immunologically, but have yet to encounter an antigen to respond to. In addition to circulating in the blood and lymph, lymphocytes concentrate in secondary lymphoid organs, which include the lymph nodes, spleen, and lymphoid nodules
Function of lymph nodes?
remove debris and pathogens from the lymph,
“filters of the lymph”
Function of spleen
Spleen is sometimes called the “filter of the blood” because of its extensive vascularization and the presence of macrophages and dendritic cells that remove microbes and other materials from the blood, including dying red blood cells
The spleen also functions as the location of immune responses to blood-borne pathogens
Lymphoid nodules?
Consist of a dense cluster of lymphocytes without a surrounding fibrous capsule. These nodules are located in the respiratory and digestive tracts, areas routinely exposed to environmental pathogens.
Function of Tonsils:
Tonsil located at the back of the throat, the pharyngeal tonsil, is sometimes referred to as the adenoid
Swelling is an indication of an active immune response to infection
Mucosa-associated Lymphoid Tissue (MALT):
Consists of an aggregate of lymphoid follicles directly associated with the mucous membrane epithelia
MALT makes up dome-shaped structures found underlying the mucosa of the gastrointestinal tract, breast tissue, lungs, and eyes
Peyer’s patches
Peyer’s patches, a type of MALT in the small intestine, are especially important for immune responses against ingested substances
Peyer’s patches contain specialized endothelial cells called M (or microfold) cells that sample material from the intestinal lumen and transport it to nearby follicles so that adaptive immune responses to potential pathogens can be mounted
Bronchus-associated Lymphoid tissue (BALT):
Consists of lymphoid follicular structures with an overlying epithelial layer found along the bifurcations of the bronchi, and between bronchi and arteries.
Less-organized structure of other lymphoid nodules
Effective against inhaled pathogens
What is Adaptive Immunity?
Adaptive immunity is part of the third line of defense consisting of lymphocytes
Two different classes of lymphocytes involved
What are the 2 different classes of lymphocytes involved in adaptive immunity?
B-cell mechanisms are considered antibody-mediated immunity
T-cell mechanisms attack pathogens more directly (cell-mediated immunity)
What are the 2 strategies of the adaptive immunity?
Describe the activation of lymphocytes:
Lymphocyte
- Signal 1: Antigen & Antigen receptor
- Signal 2: Molecule form infected/ injured cell or from microbe
Activated immune cells
