Lymphatic - Functions And Characteristics Flashcards
Functions of lymphatic system?
- Transports escaped fluids from capillary’s back to blood
- essential role is body defence and resistance to disease
- Absorption of fat and fat soluble substances during digestive process
What causes fluid to move out of capillaries?
Blood pressure forces fluid and solutes out of capillaries
What causes fluid to move back into capillaries?
Osmotic pressure draws fluid into capillaries (mostly by albumin)
How much fluid goes out of capillaries and is reabsorbed per day?
20 L moves out and 17 L moves back in
How much fluid left behind?
3 L per day
What does the fluid that is left behind called?
Interstitial fluid (fluid between cells)
Where is the 3 L returned?
Returns to plasma to maintain blood volume
What happens if that 3 L a day is not returned?
Development of Edema
What does lymph mean?
Excess clear fluid (interstitial fluid that has entered the lymphatic system so now called lymph)
What do lymphatic vessels do?
Carry lymph from peripheral tissue to venous system
What is the smallest lymphatic vessels?
Lymphatic capillaries
Where are lymphatic capillaries found?
In the interstitial space
What’s the problem with lymphatic capillaries being very permeable?
Particles like cell debris, bacteria, viruses, and cancer cells can enter the lymph fluid easily
What type of valves do the capillaries have?
One way mini valves
How do the valves work?
When pressure in interstitial space is greater than inside the lymphatic capillary, the valves will open to allow fluid in and close once the pressure is higher in the capillary
Where does lymph travel from (capillary to what)?
Capillary -> vessel -> trunk -> ducts
How do lymph moves towards heart without a pump?
Smooth muscle in lymph vessels react to pulse in arteries and pushes the fluid
Squeezing of skeletal muscles which contracts throughout the day also pushes the fluid up
How do the vessels keep the lymph from sliding backwards?
Have valves inside
Where can we find lymph nodes?
Along the vessels
What do lymph nodes do?
Filter lymph before returning it back to blood
What are the defence cells in lymph nodes?
Macrophages and lymphocytes
Where are the large clusters of lymphatic nodes found in the body? (Three main areas)
- Cervical (head and neck)
- Axillary (under arm)
- Inguinal - located in groin
What is the structure of a lymph node?
Contains cortex and medulla (medulla contains the macrophages)
What causes lymph nodes to become tender and inflamed?
Sometimes large amounts of bacteria or viruses become trapped in nodes (like when you’re sick)
Can also be secondary sites for cancer
What two ducts does lymphatic drain into?
- Thoracic duct
- Right lymphatic duct
What’s lymphedema? What does it cause?
Blockage of lymphatic drainage
Causes interstitial fluid to accumulate and causes swollen and distended areas
What is lymphoid tissue?
Kind of the same as lymph nodes. They remove foreign material and are lookouts for immune system
What are the four lymphoid tissue areas?
- Tonsils
- Peyer’s patch
- Spleen
- Thymus
Where is peyer’s patch found?
In small intestine
What does the spleen filter? What does it destroy?
Filters blood instead of lymph and destroys dead RBCs returning iron to blood and RBC to liver for bile
What does the spleen store?
RBCs and platelets in case of a emergency
What is the white pulp of spleen?
Filters blood and where antibodies r made for B cells
What is the red pulp in spleen?
Destroys and recycles old RBCs
Where is the thymus located?
Between lungs, above heart
When does thymus primarily function?
During childhood and shrinks by puberty
What is the thymus responsible for?
Production of T-cells and destroying T-cells that attack the bodies own antigens
What is lymphophoiesis?
Production of lymphocytes
Where does lymphopoiesis occur?
In red bone marrow
