Define the lymphatic system
system of vessels, cells, and organs that carries excess fluids to the bloodstream and filters pathogens from the blood
Most "interstitial fluid" drains to blood capillaries, the remaining fluid must drain into the ______
lymphatics
What are the functions of the lymphatic system:
-drain interstitial fluid
-return leaked plasma proteins to the blood
-transport dietary fats
-protect against infection
Without the lymphatics you would gain ______ of fluid each day
6-8 pounds
Components of lymphatic system:
-lymph (interstitial fluid and lymph are basically the same, except for location)
-lymphatic vessels
-several structures and organs that contain lymphatic tissue (specialized reticular tissue containing large numbers of lymphocytes)
-red bone marrow (whic
Lymphatic capillaries are found throughout the body except where?
-avascular tissue
-the CNS
-portions of the spleen
-the red bone marrow
Lymphatic capillaries have a slightly larger diameter than blood capillaries and have "overlapping endothelial cells" which work as what?
one-way valves for fluid to enter the lymphatic capillary (like veins)
Anchoring filaments attach ________ cells to surround tissue.
endothelial
Define lacteal
a lymphatic capillary in the villi of the small intestine that transports digested fats (milky fluid called chyle) from the small intestine into blood
Lymphatic vessels begin as blind-ended lymph capillaries in ?
tissue spaces between cells
Interstitial fluid drains into lymphatic capillaries, thus forming
lymph
List principal lymph trunks
-lumbar
-intestinal
-bronchomediastinal
-subclavian
-jugular
List 2 lymphatic ducts
right lymphatic duct and thoracic duct
The thoracic duct is the main ______
collecting duct of the lymphatic system
The thoracic duct receives lymph from the:
Left side of head, neck & chest & left upper limb & entire body inferior to ribs
The thoracic duct drains lymph into the :
the venous blood via the left subclavian vein
The right lymphatic duct drains lymph from the :
upper right side of the body
The right lymphatic drains lymph into the venous blood via the :
right subclavian vein
Lymph flows as a result of the :
milking action of skeletal muscle contraction
respiratory movements
valves that prevents backflow of lymph
An excessive accumulation of interstitial fluid may be caused by:
an obstruction to lymph flow (ex. infected nodes,...radical breast surgery and radiation therapy)
Immune function is organized into what 3 phases based on the timing of their effects:
-Barrier defenses such as the skin and mucous membranes
-The rapid nonspecific innate immune response (present from birth)
-The slower but more specific and effective adaptive immune response (acquired)
Phagocytic cells :
Ingest pathogens and destroy them
Lymphocytes:
specifically coordinate the activities of adaptive immunity
Cells with granules:
help the immune responses against parasites and other pathogens
The two basic types of lymphocytes are B cells and T cells, both born in the _______, and look identical (large central nucleus surrounded by a thin layer of cytoplasm
bone marrow
B cells mature in the bone marrow and T cells mature in the :
thymus
Where are B cells and T cells found?
in the bloodstream and lymph, and in secondary lymphoid organs
B cells produce antibodies, T cells do "not"---what do T cells secret?
factors that communicate with other cells or destroy cells infected with intracellular pathogens
Plasma cells are "activated B cells" in response to what?
antigen binding" and secret antibodies
Define natural killer cells
Circulating blood cells that contain cytotoxic (cell-killing) granules in its extensive cytoplasm
What is the body's first line of defense against viruses and some types of cancer?
NK cells
The thymus gland lies between the sternum and the heart, and functions in what?
immunity as the site of T cell maturation, but is replaced by connective tissue as an adult
The thymus produces several hormones that are important to the development of what?
Functional T cells; and thus the maintenance of normal immunological defenses
Thymosins are several hormones that promote _____-
immunological defenses
Red bone marrow is a loose collection of cells where hematopoiesis occur, and the yellow bone marrow is the site of what?
energy storage, which consists largely of fat cells
One major cause of age-related immune deficiencies is ?
thymic involution
Define thymic involution
the shrinking of the thymus gland that begins at birth, at about 3 percent tissue loss per year; at that pace total loss thymic tissue and thymocytes would occur at 120 years of age
Lymph nodes are encapsulated oval structures located along _______-
lymphatic vessels
Lymph nodes contain:
Fixed macrophages, B cells, T cells
Lymph enters nodes through "afferent lymphatic vessels" and is filtered to remove damaged cells and microorganisms; it exits through _____
efferent lymphatic vessels
The spleen is largest mass of lymphatic tissue in the body and is found where
in the left hypochondriac region between the stomach and diaphragm; and has the following regions: white and red pulp
Define white pulp:
lymphatic tissue in which lymphocytes directly attack and destroy antigens in blood and produce antibodies
Define red pulp
venous sinuses and splenic cords for removing bacteria and old RBCs
Lymphatic nodules are non-encapsulated oval-shaped concentrations of lymphatic tissue which are scattered throughout the mucous membranes lining the:
GI tract
respiratory airways
urinary tract
reproductive tract
Lymphatic nodules are in the ____ of the small intestine
ileum
B cells produce _______
diverse antibodies