cv - lymphatic system Flashcards
what makes up the lymphatic system
Network of organs, vessels and tissues
describe the accessory fluid
return route to the blood
the lymphatic system is vital to what other system in the body
immune system
it is complementary to what other body system
Cardiovascular system
what is lymph
Fluid of the system (clear, pale yellow) ~interstitial fluid; 32L/day drained into system; returns lost plasma proteins to bloodstream in lymphatic vessels
what is lymphatic tissue
Structures and organs containing lymphatic tissue – a specialised connective tissue that contains large numbers of lymphocytes
what is bone marrow
Stem cells develop into RBC & WBC
whats the 3 functions of lymphatic system
Drain tissue spaces of excess interstitial fluid and return it to the cardiovascular system.
Transport dietary lipids and lipid-soluble vitamins (A, D, E & K) from the GI tract to the blood
Protect the body from foreign cells, microbes and cancer cells through immune responses.
what are the smallest lymphatic vessel
lymphatic capillaries
explain lymphatic capillaries
Slightly larger than blood capillaries, closed-ended
Pressure in tissues will force fluid into them
Overlapping endothelial cells, like a one-way valve, so fluid not flow out
Found throughout body except in CNS, bone marrow, portions of spleen and avascular tissues.
lymphatic capillaries merge to form what
form larger vessels: lymphatic ducts
- Thin walled and more valves than veins
lymphatic vessels periodically have what
lymph nodes
explain lymph nodes
Lymphocytes in capsular structure
The left thoracic duct—-> Left subclavian vein at junction with jugular
Right lymphatic duct —> Right subclavian vein
explain lymph flow
Unlike cardiovascular, system has no pump
Muscle contraction
1-way valves,
Respiratory pressure
Smooth muscle contraction in lymph vessel wall.
lymphatic organs can be divided into what
primary and secondary organs
what are the primary lymphatic organs
Thymus
Red bone marrow
- Provide appropriate environment where stem cells divide & mature into B & T cells
what are the secondary lymphatic organs
Lymph nodes
Spleen
Lymphatic nodules
secondary lymphatic organs are the sites where most what occurs
most immune responses occur
explain the thymus structure
Two lobed organ
Between lungs, above heart
what are the cells in the thymus
immature T cells
mature T cells
explain immature T cells in thymus
migrate from bone marrow to cortex of thymus where multiply and mature
explain mature T cells of thymus
then enter blood and populate lymph nodes, spleen and other lymphatic tissues.
what are lymph nodes structure and how many and where located
~600 bean-shaped organs along lymph vessels
Scattered throughout the body
- Concentrated near mammary glands, axillae (armpits) & groin
explain cells in lymph nodes
Contain plasma cells, mature B-cells, T-cells, dendritic cells and macrophages
what do lymph nodes do
Filter lymph,
trap foreign substances
Macrophages & lymphocytes destroy most foreign substances
explain germinal centres in lymph nodes
Aggregations of B lymphocytes
Rapidly proliferating and differentiating upon stimulation with antigen.
explain the spleens shape and location
Oval, largest single mass of lymphoid tissue
On LHS between stomach & diaphragm
name the 2 tissue types of the spleen
Two types of parenchymal tissue:
white pulp
red pulp
explain the white pulp parenchymal tissue of the spleen
lymphatic – lymphocytes & macrophages surrounding central arteries
explain the red pulp parenchymal tissue of the spleen
blood-filled venous sinuses and splenic cords with RBC, macrophages, lymphocytes, plasma cells & granular leukocytes
- Destroys worn or defective blood cells & platelets
- Stores platelets
- Production of blood cells in foetal life
Remove if ruptured as severe i.p. (intraperioneal) haemorrhage & shock; red bone marrow & liver can take over functions.
describe lymphatic nodules
Egg-shaped masses of lymphatic tissues
NOT surrounded by capsule
Mucosa-associated lymphatic tissue (MALT) found is in what
GI tract
Urinary tissue
Reproductive tissue
Respiratory tissue
Some in large aggregates e.g., tonsils, Peyer’s patches (in ileum).
how much of the fluid exchange across walls of capillaries goes to lymphatics
1/10 volume
describe Fluid exchange across walls of capillaries
hydrostatic pressure out
osmotic pressure into capillaries
