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

What’s wrong with him?What’s wrong with him?

capillary bed

body cellplasma

RBCTissue fluid

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

Transport of tissue fluid back into blood circulation

Lymphatic systemLymphatic system

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