Lung
All other parts of the body
The mammalian The mammalian circulation plancirculation plan
Double circulation in mammals
Heart BloodBlood
vesselsCirculatory
system
pulmonary circulation
systemic circulation
As blood passes through heart twice, this also known as double circulation
The human circulatory systemThe human circulatory system
The pulmonary circulationThe pulmonary circulation
2 The blood is pumped through pulmonary artery into lungs for gas exchange
3 The blood becomes oxygenated
4 The blood flows through pulmonary veins to left auricle
1 Deoxygenated blood in right ventricle
The human circulatory systemThe human circulatory system
The systemic circulationThe systemic circulation
1 Oxygenated blood in left ventricle
2 The blood is pumped through aorta to all parts of the body except lungs
3 O2 and nutrients diffuse into cells while CO2 and wastes diffuse out
4 The blood flows through inferior/ superior vena cava to right auricle
The human circulatory systemThe human circulatory system
Nutrients from the small intestine diffuse into the blood
The blood flows through hepatic vein to liver
After digestionThe blood flows through inferior vena cava back to right auricle
The systemic circulationThe systemic circulation
capillary bed
body cell
red blood cell
Formation of the tissue fluidFormation of the tissue fluid
At arterial end :
Blood pressure
Osmotic pressure
Plasma except RBC and protein are
forced out of the capillaries
arterioletissue fluid
Tissue fluid
Formation of the tissue fluidFormation of the tissue fluid
capillary bedcapillary 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 fluidFormation of the tissue fluid
capillary bed
At venous end :
Blood pressure
Osmotic pressure
somesome tissue fluid return to capillaries by osmosisosmosis.
venule
lymph
Note: Exchange of MateriNote: Exchange of Materialsals
It is carried out by diffusion through the whole length of capillaries ( not tissue fluid formationnot tissue fluid formation)
O.P. O.P.
B.P.B.P.
blood flowarteriole 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 systemThe lymphatic system
Lymphatic system
Lymph vessels Lymph
collect excess tissue fluid and return them
to vein (blood circulation) in neck
is the tissue fluid inside lymph
vessels
Lymph vesselsLymph 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?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 nodesLymph nodes
lymph node
• swellings along the lymph vessels
• presence of white blood cells – filter lymph
kill bacteria and micro-organisms
Functions of the lymphatic systemFunctions of the lymphatic system
2 Transport 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