The Lymphatic The Lymphatic SystemSystem

Along with the blood circulatory Along with the blood circulatory system, mammals have a 2system, mammals have a 2ndnd circulatory system called the Lymphatic circulatory system called the Lymphatic system.system.

This is a one way system of dead This is a one way system of dead ending vesselsending vessels

These vessels collect fluid around cells These vessels collect fluid around cells and return it to the blood.and return it to the blood.

Lymph nodes are swellings in the lymph Lymph nodes are swellings in the lymph vessel, these help to fight infectionvessel, these help to fight infection

Formation of LymphFormation of Lymph Because blood in Because blood in

arteries are under arteries are under high pressure they high pressure they force out some fluid force out some fluid through the through the capillaries.capillaries.

This fluid is called This fluid is called tissue fluid and tissue fluid and surrounds all the surrounds all the cells of the body.cells of the body.

Formation of LymphFormation of Lymph Tissue fluid is similar to Tissue fluid is similar to

plasma as it contains plasma as it contains small amounts of white small amounts of white blood cells & proteins blood cells & proteins but no red blood cells but no red blood cells or platelets.or platelets.

It acts as an exchange It acts as an exchange medium whereby medium whereby materials materials entering/leaving cells entering/leaving cells must pass through.must pass through.

Formation of LymphFormation of Lymph Because it is believed that life originated Because it is believed that life originated

in the sea, it is interesting that our cells in the sea, it is interesting that our cells still need to be surrounded by water to still need to be surrounded by water to function.function.

As tissue fluid is being formed it must be As tissue fluid is being formed it must be removed & returned to the blood.removed & returned to the blood.

This prevents swelling (called oedema) This prevents swelling (called oedema) from developing in the tissues.from developing in the tissues.

Formation of LymphFormation of Lymph Tissue fluid is drained Tissue fluid is drained

away by 2 routesaway by 2 routes1.1. 90% goes back into 90% goes back into

capillaries near veins. capillaries near veins. This occurs by This occurs by osmosis.osmosis.

2.2. 10% enters dead 10% enters dead ending tubes called ending tubes called lymph vessels. This lymph vessels. This fluid is now called fluid is now called LymphLymph which contain which contain large amounts of large amounts of white blood cells, white blood cells, proteins & fatsproteins & fats

Lymph VesselsLymph VesselsFound throughout the bodyFound throughout the body Lymph (tissue fluid) is moved through Lymph (tissue fluid) is moved through

the vessels by muscular walls & general the vessels by muscular walls & general body movements pressing on the body movements pressing on the vessels.vessels.

A system of valves ensure one way flow.A system of valves ensure one way flow.

Lymph VesselsLymph Vessels 2 main vessels2 main vessels1.1. Thoracic duct on left Thoracic duct on left

side of bodyside of body2.2. Right lymphatic duct Right lymphatic duct

at the right shoulder at the right shoulder These ducts empty These ducts empty

lymph into the lymph into the bloodstream at the bloodstream at the subclavian veins subclavian veins located near the located near the collar bones at the collar bones at the shoulders.shoulders.

Lymph NodesLymph Nodes Small swellings found Small swellings found

along lymph vessels.along lymph vessels. Contain large no. of Contain large no. of

white blood cells with white blood cells with many channels the many channels the lymph can flow through.lymph can flow through.

Formed in clusters, Formed in clusters, which form glands i.e. which form glands i.e. Tonsils, adenoids, neck, Tonsils, adenoids, neck, armpits, thymus, spleen armpits, thymus, spleen & groin.& groin.

Lymph NodesLymph Nodes They fight infection in 2 waysThey fight infection in 2 ways1.1. They filter bacteria They filter bacteria 2.2. They store large no. of white blood cells They store large no. of white blood cells

called Lymphocytes. Some kill pathogens called Lymphocytes. Some kill pathogens directly while others make antibodiesdirectly while others make antibodies

When they are fighting disease they swell When they are fighting disease they swell i.e. swollen tonsils if you have a sore i.e. swollen tonsils if you have a sore throat/coldthroat/cold

If lymph vessel get blocked, swelling occursIf lymph vessel get blocked, swelling occurs

Function of Lymphatic Function of Lymphatic SystemSystem

To collect tissue fluid & return it to the blood. To collect tissue fluid & return it to the blood. To absorb & transport fats in the digestive To absorb & transport fats in the digestive

system. Lymph found in lacteals (villi in small system. Lymph found in lacteals (villi in small intestine)intestine)

To help with hearing & balance in the earTo help with hearing & balance in the ear To defend the body against infectionTo defend the body against infection

– Filtering out micro-organisms in lymph nodesFiltering out micro-organisms in lymph nodes– Maturing & storing lymphocytesMaturing & storing lymphocytes– Destroying micro-organisms by engulfing & Destroying micro-organisms by engulfing &

digesting them or anti-body productiondigesting them or anti-body production