18: Lymphatic System Flashcards
What is lymph?
Name given to interstitial fluid once it enters the lymphatic system
What lymphatic structure is crucial to the small intestines ability to transport dietary lipids/lipid-soluble vitamins?
Lacteals, lymphatic capillaries in the small intestine
What is chyle?
A milky fluid formed in lacteals by combining dietary triglycerides and other lipids. It eventually enters the bloodstream
What are the 4 lymphatic structures that drain into each other, from smallest to largest?
Lymphatic capillaries, vessels, trunks, and ducts
The lymph from the upper right side of the body drains into the _______ via the __________
Right subclavian vein
right lymphatic duct
Lymph from the body (besides the upper right portion) drains into the _______ via the ________.
Left subclavian vein
Thoracic duct
The thoracis duct begins just beneath the diaphragm in the ______ that receives lymph from the lower abdomen, pelvis, and lower limbs
Cisterna chyli
Within the lymphatic system, what is the bone marrow and thymus gland? Why do they fit this category?
Primary lymphoid (lymphatic) organs
They are organs where lymphocytes proliferate and mature
What does the cortex of the thymus contain?
Large numbers of immature T cells
What does the medulla of the thymus contain?
T cells that are ready to be released into circulation
What are the secondary lymphoid (lymphatic) organs? What do they do?
Lymph nodes and spleen
Organs that store naive lymphocytes
The cortex and medulla of the lymph nodes contain large numbers of macrophages. Why?
Lymph nodes function to remove debris and pathogens from lymph
What is the difference between afferent and efferent lymphatic vessels?
Afferent is TOWARDS a lymph node
Efferent is AWAY from a lymph node
What are the two types of pulp in the spleen?
Red pulp (mostly RBCs)
White pulp (mostly WBCs)
What is the function of lymphoid nodules?
Screen for and attack foreign antigens by mounting the immune response
What are the adenoids?
Pharyngeal tonsils
What is MALT? Where is it?
Mucosa-associated lymphoid tissue
Aggregates of lymphoid tissue directly associated with the mucous membrane epithelia (GI tract, respiratory tract, urinary tract, etc.)
What happens in phagocytosis?
A phagocyte takes a pathogen in itself, essentially eating it
What are the two major types of phagocytes?
Macrophage and dendritic cell
What makes macrophages and dendritic cells “antigen presenting cells?”
Once they digest a pathogen, they will display certain parts of it, the antigens, on their cell membrane. The lymphocytes recognize these antigens and mount an immune response
What are the 3 major families of lymphocytes? Where do they mature?
b cells, t cells, and natural killer cells
b and natural killers mature in bone marrow
t cells mature in the thymus
What do b lymphocytes do?
Produce antibodies
What do helper t cells do?
Function as cytokines that stimulate other immune cells
What do cytotoxic t cells do?
Kill target cells by breaking apart their cell membrane
What do regulatory t cells do?
Suppress other t cell immune responses
What are memory t and memory b cells?
Proliferated t and b cells that stay in the body and are ready to act in case of a second, similar infection
What are natural killer cells?
They are like t and b cells, but they can attack more than one type of antigen (unlike t and b)
What is lymphoma?
Cancer in which masses of malignant t and/or b lymphocytes collect in lymph nodes, the spleen, liver, and other tissues.
