Chapter 1 TRANSPORT

The Lymphatic system

Subtitle that we study last lesson

How blood pressure is regulated The circulatory system in human ,

fish and amphibiansThe necessity for blood clotting

Blood clotting

Problem related to blood clotting

The lymphatic systemFormation and composition of interstitial fluid

The pressure is enough to cause fluid to leak from the blood into the space between the cells.

The fluid is known as interstitial fluid.

Important for the exchange of materials between blood and cell

Question……What consists in the Interstitial fluid?

Interstitial fluid consists of water, dissolved nutrients,

hormones,waste product from blood.

Does not contain R.B.C and platelets----too large to pass through capillaries ,but contain W.B.C can immersed through the openings between capillary cells.

About 85%of the fluid that leaves the blood at arterial end of the capillary re-enter at the venous end.

The interstitial fluid must returned to the circulatory system to maintain the normal blood volume.

About 15% of the fluid that still remains in the interstitial space.(4 litre fluid lost each day)

The fluid loss is returned to the blood through the lymphatic system.

Area of high blood pressure

Area of lower blood pressure

The Lymphatic SystemLymphatic system is a one –way

system consisting lymph capillaries, larger lymphatic vessels and lymph nodes.

Lymph capillaries are blind-ended tubes that locates in the spaces between the cells.

The interstitial fluid that has not been reabsorbed into the bloodstream goes into the lymph capillaries.

Once inside the lymph capillaries ,the fluid is known as lymph.

Lymph capillaries converge into larger lymphatic vessels . Lymphatic vessels contain valves to prevent the backflow of the lymph.

Lymph nodes located along that lymphatic vessels .

They produce and store lymphocytes to protect the body against infection.

Lymphatic vessels drains into one of the two main channels that are thoracic duct and right lymphatic duct.

Question …Where the thoracic duct and right

lymphatic duct receive lymph?

The thoracic duct receive lymph from the left side of the head ,neck and chest.

The right lymphatic duct from the right arm, shoulder area, and the right side of the head and neck.

Thoracic duct empties its lymph into the left subclavian vein while the right lymphatic duct empties into the right subclavian vein.

The lymph moves to the subclavian veins with the help of

(a)one–way valves(b)contraction of the surrounding skeletal

muscles(c) intestinal movement (d)Change in the pressure occur during

inhalation and exhalation

The role of the lymphatic system in transportLymphatic system helps maintain the fluid

balance in the body. If the excess fluid is not returned to the

bloodstream ,the body tissues become swollen because too much of fluid.

Excessive accumulation of interstitial fluid in the spaces between the cells is known as oedema.

Oedema may cause by a blocked lymphatic vessels.

Water and nutrient diffuse from blood capillaries into the surrounding body tissues.

Lymph capillaries that transport droplets of lipids and fat-soluble vitamins to the bloodstream are called lacteals(in the villi of the small intestine).

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