Lymphatic System Flashcards
List the components of the lymphatic system.
- Lymphatic Organs:
- lymph nodes
- spleen
- thymus
- tonsils
- aggregations of lymphatic follicles (nodules) in the intestinal wall
- Extensive network of thin- walled lymphatic vessels that resembles veins
State the functions of the lymphatic system.
- Collects excess fluid (interstitial, extracellular) and returns it to the venous channels of the cardiovascular system
- when tissue fluid enters lymphatic vessels = lymph
- lymph filters through lymph nodes - Produces lymphocytes
- lymphocytes produce antibodies when exposed to antigens present in lymph
- important line of body defense
- Absorption of lipids from the DIG system
Differentiate lymph from interstitial (extracellular) fluid.
*lymph and interstitial fluid are essentially the same thing
Lymph: excess tissue fluid that enters lymphatic capillaries
(i.e. it’s just interstitial fluid that goes into the lymphatic vessels/capillaries)
Interstitial fluid: fluid within intercellular matrix
(i.e. it’s the fluid outside of the veins and capillaries; it surrounds everything in the body)
Explain how lymph forms by discussing and quantifying the four pressures acting on fluid in and around capillaries.
https://www.youtube.com/watch?v=ZJVUTkgYhhg
- Plasma hydrostatic pressure - physical pressure on blood as a result of contractions of the heart (37mm Hg)
(pressure is on the blood inside the capillary, going to want to move out)
- forces fluid out of capillary wall
2. Plasma osmotic pressure - pressure imparted by blood albumins (proteins); draws water in capillary wall (25mm Hg)
(pressure is from high concentrations of proteins in capillary wall, going to want fluid to move in)
- forces fluid in
3. Interstitial Fluid hydrostatic pressure - low pressure resulting from fluid present in extracellular space (outside capillaries) (2 mm Hg)
(pressure is on the fluid outside of the capillaries, going to want to move in)
- forces fluid in
4. Interstitial fluid osmotic pressure - very weak pressure due to low concentration of solutes out side of capillaries (1 mm Hg)
(pressure from concentration of proteins outside of capillaries; going to want fluid to move out of capillaries to dilute)
- forces fluid out
Net pressure: 11 mm Hg (out)
- net pressure is always out!
Compare a lymphatic capillary to a typical cardiovascular capillary.
Lymphatic capillaries are structurally similar to regular cardiovascular capillaries.
Differences:
. blind-ended (closed on one end)
. drain into lymphatic vessels instead of venules
Name the lymphatic trunks and indicate which ones drain into the thoracic duct and which three drain into the right lymphatic duct.
(look at picture on pg. 562)
Trunks:
- Left/Right Jugular Trunks
- Left/Right Subclavian Trunks
- Left/Right Bronchomediastinal Trunks
- Intestinal Trunks
- Left/Right Lumbar Trunks
All of these coalesce to form:
- Thoracic Duct:
Drains From: R/L lumbar trunk, Intestinal Trunks, L Bronchomediastinal, L subclavian, L Jugular
- Right Lymphatic Duct
Drain From: Right Jugular Trunk, Right Subclavian Trunk, and R Bronochomediastinal Trunk
Sketch and label the components of a lymph node.
Lymph node = bean shaped structure
- Has a dense irregular c.t. proper that surrounds numerous developing lymphocytes (lymphatic nodules)
- More recently formed lymphocytes in the middle of each lymphatic nodule from germinal center
- Mature, terminally differentiated lymphocytes near periphery of nodule are called plasma cells and they produce antibodies
- Trabeculae separate nodules from each other
- Afferent lymphatic vessels (incoming) pass through convex surface of lymph node
- Efferent lymphatic vessels (outgoing) pass through hilum
* because of their significant enlargement in response to some pathogens, they are important indicators of infection
Structurally differentiate the spleen from a lymph node.
- largest lymphatic organ
- in abdomen near greater curvature of stomach
- blood vessels, lymphatic vessels, and nerves attach at hilum
- contains lymphatic nodules (white pulp) and phagocytic cells (the rest is red pulp)
- Splenic phagocytes are blood “filters” and remove worn out RBC’s from circulation
- Highly vascularized and stores RBC’s
- smooth m in capsule will contract to add RBC’s to circulation in case of hypovolemic shock - 10% of population has accessory spleen
State the unusual features of the thymus and name the specialized cells of its parenchyma.
- Functions in early life to establish normal immunological competency.
- Reaches its largest size at puberty and then regresses (involutes) after
- Has a left/right lobe in a c.t. capsule
- Cells in thymus = thymocytes (derived from bone marrow and fetal liver precursor cells)
- These cells become T lymphocytes once they hit circulation
- Produces hormone thymosin which activates lymphocytes
Name the four groups of tonsils. Which of these are easiest to detect using a mirror?
- Palatine Tonsils: easily observed using a mirror, “tonsillitis” removed in tonsillectomies,, located in gullet (fauces)
- Pharyngeal Tonsils: posterior wall of nasopharynx, “adenoids”
- Lingual Tonsils: posterior aspect of tongue
- Tubal Tonsils: near pharyngeal openings of auditory tube
* aggregations of lymphatic nodules (“Peyer’s Patches and MALT) are common in large intestine and ileum
Define edema and state several causes.
Edema: when excess interstitial fluid collects in the tissues, localized or general swelling occurs
Causes:
- malnourished individuals have lowered levels of blood proteins which can result in reduced plasma osmotic pressure (excessive movement of fluids outward)
- increased permeability of capillary walls from physical trauma
- physical obstruction of lymphatic drainage
- heart failure (changes hydrostatic pressure)
Differentiate lymphadenitis from lymphangitis.
Lymphadenitis: inflammation of lymph nodes
- once enlarged they remain quite prominent for several months and may never return to former size
Lymphangitis: inflammation of lymphatic vessels, “blood poisoning”, red linear streaking visible on surface of skin
Define primary and secondary antibody response, and innate, active, and passive immunity.
Primary Antibody Response
Primary Antibody Response:
- when developing lymphocytes are first exposed to a foreign protein (antigen) they begin producing gamma gobulins (antibodies) that cross react with those proteins.
- this is a primary antibody response
- it takes several days to develop and total antibody response is low meaning it’s not effective enough to prevent the progression of the disease
ex) a vaccination - it introduces lymphocytes to the spreading disease but produces a primary antibody response. if patients are introduced to the disease in the near future, their secondary antibody response will kick in
Define primary and secondary antibody response, and innate, active, and passive immunity.
Secondary Antibody Response
Secondary Antibody Response:
- when exposed to a particular antigen (primary antibody response), a subsequent exposure will result in a secondary antibody response
- quicker production and larger antibody output are sufficient enough to prevent the disease
Define primary and secondary antibody response, and innate, active, and passive immunity.
Innate Immunity
Active Immunity
Passive Immunity
Innate Immunity - one species is simply not susceptible to certain diseases of another species
ex) canine distemper (in dogs not humans)
Passive Immunity - presence of antibodies in the bloodstream that the individuals did not produce themselves
ex) injections into people who have been exposed to an infectious disease to which they are not immune
Active Immunity - presence of circulating antibodies that individuals themselves produce in response to exposure to an antigen
ex) vaccination or clinical exposure
