1. Transport in Living Organisms

2. Importance of a transport system
Organisms can be:
Unicellular - made up of one cell
Multicellular - made up of many cells.
Substances pass easily through the bodies of unicellular organisms by diffusion and osmosis so a transport system is not needed.
As organisms get bigger and are made up of many more cells, it gets more difficult for substances to get to all the cells so a transport system is needed.

3. The ratio of SUPPLY (of substances) compared to the DEMAND (amount of substance needed by the organism) is called the SURFACE AREA:VOLUME ratio.
Unicellular organisms have a high SA: V ratio
Multicellular organisms have a low SA: V ratio

4. The Circulatory System

5. Blood Transport liquid carried in blood vessels. Transports
Oxygen
Carbon Dioxide
Other solutes e.g. Food Substances, Urea, Hormones
Heat
Defence against disease
Blood Clotting

6. Blood Red blood cells (Erythrocytes) Biconcave, slightly elastic discs
No nuclei
Contain red haemoglobin that transports oxygen (oxyhaemoglobin) and carbon dioxide (carboxyhaemoglobin)
Formed in bone marrow of pelvis, scapula, ribs sternum
Destroyed in the liver, spleen

7. Blood White blood cells (Leucocytes) Formed in red bone marrow
Phagocytes engulf bacteria
Lymphocytes produce antibodies which are specific to antigens on bacteria.
Bacteria clump and are destroyed

8. Phagocytosis
Phagocyte
Lymphocyte

9. Blood Platelets (Thrombocytes) Small cell fragments with no nucleus
Formed in bone marrow of long bones
Assist in blood clotting.

10. Blood Clotting

11. Blood Plasma a watery liquid Contains :
Nutrients
Proteins (albumin and globulin)
Gases (Carbon dioxide)
Hormones
Waste
Heat
Blood cells
Transports substance from where they are made or enter the body to their destination.

12. Blood Vessels
Tube like structures that carry blood around the body. There are 3 types:
Arteries: take blood away from the heart to organs
Veins: take blood to the heart from organs
Capillaries: takes blood to individual cells in organs
Muscular Walls

13. Arteries Veins Receive blood at high pressure from the heart
Thick muscular walls withstand pulsing blood at high pressure
Maintain the blood pressure to all parts of the body
Carry oxygenated blood (except pulmonary artery)
Veins
Return blood at low pressure to the heart from the tissues
Wide lumens reduce resistance of blood flow
Reduced pressure and smooth blood flow allow for thin walls
One way flow is maintained by pocket valves
Carry deoxygenated blood (except pulmonary vein)

14. Capillaries Smallest vessels Smooth blood flow
Blood becomes deoxygenated along length of capillaries
Exchange materials between the blood and the cells through their walls
Walls are only one cell thick
Permeable to small particles eg. Molecules of gas, nutrients and waste.
Capillaries branch repeatedly to form a network within tissues

15. Lymphatic System A system of thin tubes that run throughout the body
Carries a colourless liquid called ‘lymph’
circulates around body tissues and contains a high number of lymphocytes (WBC) and plasma that leak out of the capillaries (Tissue fluid).
drains into the lymph vessels.
Lymphatic system eventually rejoins the circulatory system and its contents are returned

16. Formation of Tissue fluid

17. Formation of Tissue Fluid
Tissue Fluid (Interstitial Fluid)

18. Lymph nodes
In armpits               
In groin (at the top of your legs)                
In neck
Lymph nodes that cannot be felt
Abdomen                          
Pelvis          
Chest 
Other organs that are part of the lymphatic system
Spleen        
Thymus        
Tonsils

19. The Heart
A muscular organ that pumps blood around the body at different speeds and pressures
Made of cardiac muscle
contracts and relaxes continuously
Divided into:
Two upper chambers called Atria
Two lower chambers called Ventricles
Left and right sides are separated by a septum
Valves (bicuspid and tricuspid) keep blood flowing in one direction

20. How the Heart Works
Left atrium receives oxygenated blood from the lungs in the PULMONARY VEIN.
Right atrium receives deoxygenated blood from the rest of the body in the VENA CAVA (vein).
Blood
flows from the two atria into the ventricles.
is then pumped out of the heart through the AORTA (artery) on the left side and the PULMONARY ARTERY on the right side.
is transported around the body in the aorta and to the lungs by the pulmonary artery.

21. The Heart Beat Heart Problems
When the cardiac muscles contract and relax this causes a heart beat.
As the muscle contracts to squeeze out the blood, it is called a SYSTOLE.
When the muscle relaxes to receive blood this is called a DIASTOLE.
Heart Problems

22. Circulatory System Summary

23. Thank you!!