The Circulatory System

1. The Circulatory System About the system Blood Heart Vessels

2. About the circulatory system • Heart • Blood vessels – arteries and veins • Blood

3. Functions of the circulatory system • Transportation of gases, nutrients, ions and waste • Transports oxygen, carbon dioxide • Transports glucose, fats, amino acids • Transports hormones • Regulation of body temperature • Defense against disease – clotting and immunity http://greenfield.fortunecity.com/rattler/46/blood.htm

4. Use this information to complete the table in your worksheet A few nights working in a trauma center would tend to convince one that the body is just a huge bag of blood. In fact, an "average" 70 litre human body contains only about 5 litres of blood, or 7% by volume. In the normal state, blood has no business anywhere except in the confines of the heart and blood vessels and in the sinusoids of the marrow, liver, and spleen. Of the average 5 L of blood, only 2.25 L, or 45%, consists of cells. The rest is plasma, which itself consists of 90% water (by weight) and 10% solids (mostly proteins, the greatest proportion of which is albumin). Of the 2.25 L of cells, only 0.037 L (1.6%) are leukocytes. The entire circulating leukocyte population, if purified, would fit in a bartender's jigger. The total circulating platelet volume is even less -- about 0.0065 L -- or a little over one teaspoonful.

5. Composition of Blood • Plasma 55% • Blood Cells 45% http://www.medicine.mcgill.ca/physio/vlabonline/bloodlab/hemat.htm

6. Blood plasma – 55% • 55% of the blood • slightly alkaline fluid • typical yellowish color • 90 % water, 10% dry matter • organic substances – glucose, lipids, proteins • dissolved minerals

7. Blood cells – 45% • Red Blood Cells 99% • White Blood Cells <1% • Platelets http://www.bayinsider.com/shared/health/adam/ency/imagepage/9123.000571.html

8. Blood cells – 45%

9. Red Blood Cells = Erythrocytes • Most numerous blood cells • No nucleus • Biconcave shape • Rich in haemoglobin … a protein which can bind oxygen • Last 120 days then recycled

10. White blood cells = Leukocytes • Less than 1% of blood cells • Vital for defense against disease • Many different types Neutrophils Basophils Eosinophils Monocytes Lymphocytes

11. Cells in the blood Erythrocytes Lymphocytes Monocyte Platelets http://www.mybloodyourblood.org/sFRwhitecells.htm

12. How blood cells are made

13. Platelets The main function of plateletsis to stop the loss of blood from wounds. To this purpose, theyaggregate and release factors which promote the blood coagulation. • reduce the diameter of damaged vessels • slow down blood flow in that area • trap cells to form the clot. Even if platelets appears roundish in shape, they are not real cells.

14. The Heart http://www.jdaross.cwc.net/heart.htm • Size of a clenched fist • Approximately 300 g • 5-35 litres per minute • 70 beats/minute

15. Blood vessels Heart Arteries Veins Arterioles Venules

16. The whole system

17. Sickle cell anaemia http://k14education.uams.edu/SickleCell/about.html

18. References http://www.neosoft.com/~uthman/blood_cells.html http://www.funsci.com/fun3_en/blood/blood.htm#0 http://www.bayinsider.com/shared/health/adam/ency/imagepage/9123.000571.html