Lung All other parts of the body The mammalian circulation plan Double circulation in mammals Heart Blood Blood vessels Circulatory system pulmonary circulation systemic circulation As blood passes through heart twice, this also known as double circulation

The human circulatory system The pulmonary circulation 2The blood is pumped through pulmonary artery into lungs for gas exchange 3The blood becomes oxygenated 4The blood flows through pulmonary veins to left auricle 1Deoxygenated blood in right ventricle

What’s wrong with him? capillary bed body cell plasma RBC Tissue fluid

The human circulatory system The systemic circulation 1Oxygenated blood in left ventricle 2The blood is pumped through aorta to all parts of the body except lungs 3O 2 and nutrients diffuse into cells while CO 2 and wastes diffuse out 4The blood flows through inferior/ superior vena cava to right auricle

The human circulatory system Nutrients from the small intestine diffuse into the blood The blood flows through hepatic vein to liver After digestion The blood flows through inferior vena cava back to right auricle The systemic circulation

capillary bed body cell red blood cell Formation of the tissue fluid At arterial end : Blood pressure  Osmotic pressure Plasma except RBC and protein are forced out of the capillaries arteriole tissue fluid Tissue fluid

Formation of the tissue fluid capillary bed tissue fluid Tissue fluid is similar to blood plasma but NO plasma proteins and red blood cells Too large to be forced through capillary wall

Formation of the tissue fluid capillary bed At venous end : Blood pressure  Osmotic pressure some osmosis some tissue fluid return to capillaries by osmosis. venule lymph

Transport of tissue fluid back into blood circulation Lymphatic system Lymphatic system

Note: Exchange of Materials not tissue fluid formation It is carried out by diffusion through the whole length of capillaries ( not tissue fluid formation) O.P. B.P. blood flow arteriole end venule end (B.P. > O.P.) substance pressed out to the tissue cells (O.P. > B.P.) substances diffused into the blood capillary O.P.= osmotic pressure B.P.= blood pressure

The lymphatic system Lymphatic system Lymph vesselsLymph collect excess tissue fluid and return them to vein (blood circulation) in neck is the tissue fluid inside lymph vessels

Lymph vessels lymph capillary tissue fluid enters valve closed Lymph capillaries collect excess tissue fluid in the capillaries beds. Lymph capillaries from different parts of the body join to form lymph vessels. Eventually, lymph is returned to the blood.

How lymph moves within lymph vessels? Do you remember how blood flows inside veins ? Lymph flows in similar way Skeletal muscles surround the vessels contract Valves to prevent backflow of lymph

lymph nodes group of lymph nodes Lymph nodes lymph node swellings along the lymph vessels presence of white blood cells –filter lymph kill bacteria and micro-organisms

Functions of the lymphatic system 2Transport of fats absorbed from lacteals in intestinal villi into the blood 3 As a bridge for the exchange of materials between capillaries and the tissue cells (tissue fluid) 4 As a site for body defence (lymph nodes) 1 Transport of tissue fluid back into blood circulation