Lymphatic System Flashcards
Why does fliud leak from capilarries?
high pressure in arterionles as large amount of blood being forced inside , therefor fluid tends to leak out into the tissue surrounding it
What are the two functions of the system?
- collect fluid that escapes from blood and returns it to circ. system
- part of the bodys internal defense system against pahogenic organism
what type of system is it in terms of movement?
one way
Define lymph
extracelluar fluid entered into lymphatic system
define lymph capillaries
open ended vessels within tissues
what are the differences between lymph and normal capilaaries?
lymph- bigger-
More permiable
both takes in more fluid
What are lymph nodes?
small bodies situated along lymph vessels that filter lymph
Outline the structure of a lymph node
- each surrouned by a capsul of connective tissue that extends into node, forming a framework
- within frame, masses of lymphoid tissue contianing cells like lymphocystes, macrophages
- spaces between cells are criss crossed by network of fibres
- lymph filters through the spaces
Explain the steps of the lyphatic system as a drainage system
1) high pressure causes leak
2) most fluid osmosises into cells, remainder drains into lymph
3) drains due to to fluid constantly moving in vessel therefor contentration gradient constant
4) now called lymph, fluid pushed along lymph vessels by squeezing action of skeletal muscles, aslo valves
5) lymph pushed back to system- in vein as less pressure
What happens to the large particles trapped in the mesh ?
macrophages destroy by phagocytosis
where are the lymphocytes found and their purpose?
lymph nodes, digest debris and particles
what happens when there is a infection?
lymph nodes swell due tot lymphocytes increasing in number to fight infection
What happens during minor clots?
plateltes will stick to the jagged edges and repair itself
what happens during major clots?
1) platelets try to clog, though high pressure will push platelets out
2) platelets change shape to become spiky and stick to each other and jagged edges
3) clotting factors turn fibrinogen into fibrin which forms a mesh over platelets to hold in place
4) clot retraction- threads tightening, pull closer together- serum leaks out and clot dries and forms a scab
Describe how fluid leaves the cappilaries and baths the body cells
Increase in pressure from arteriole to cappilaries causes plasma (fluid in blood) to be forced through capillary wall.
Dissolved molecules go with plasma while larger one and formed elements left in capillary
