1. The Circulatory System

2. Some Interesting Facts
No cell is further than two cells away from a blood vessel that carries nutrients!
Your circulatory system has km of blood vessels…strung together they could circle the globe 2.5 times!
Your heart is the size of your clenched fist!
Your heart beats ~ 30 million times per year!
An adult heart pumps nearly litres of blood each day!
During an average lifetime, the heart pumps enough blood to fill two ocean tankers!
The average three year old has 1.1 litres of blood in their body; the average adult has 5 times that!

3. Purpose of the Circulatory System
Brings oxygen and nutrients to cells
Takes away wastes from cells
Relays chemical messages (hormones)
Maintains fluid levels
Important in immunity

4. Blood Flow Through the Heart

5. Types of Blood Vessels Arteries: Carry blood away from the heart
Usually at high pressure
Thick, muscular walls
Branch into smaller “arterioles”

6. Types of Blood Vessels 2. Veins: Carry blood to the heart
Less pressure
Thin, less muscular walls, and valves to prevent backflow
Branch into “venules”

7. Types of Blood Vessels

8. Types of Blood Vessels 3. Capillaries:
Carry blood from arterioles to venules
Form a fine network through cells (capillary bed)
No tissue is more than 0.1 mm away from a capillary!
1 cell thick – easy diffusion!

9. Types of Blood Vessels 4. Coronary Arteries:
Supply heart muscles with blood!

11. Components of the Blood
Blood is composed of water, plasma and blood cells (P. 319)
Plasma:
The fluid portion of the blood
55% of a blood sample

12. Components of the Blood
Red blood cells:
Contain hemoglobin (O2 taxis)
No nucleus = more hemoglobin (280 million per RBC)
Biconcave form – allows them to fit through small capillaries
44.9% of a blood sample

13. Components of the Blood
White Blood Cells:
Are less numerous than RBC’s (1:700)
Have a nucleus
Destroy invading microbes using phagocytosis
Form antibodies
0.1% of a blood sample

14. Components of the Blood
Platelets:
Are responsible for blood clotting
Are cell fragments
Stick to sharp edges in otherwise smooth vessels

15. Bone Marrow
RBCs, WBCs and platelets are all produced in the bone marrow

16. Blood Doping
See Page 323

17. Regulating Heart Beat
The S.A. (sinoatrial) node, also known as the pacemaker sends an electrical impulse to start the heart contraction.
Both atria contract
The A.V. (atrioventricular) node then tells the ventricles to contract.
Double pump
“Lub Dub” is the sound of the valves flapping shut

18. Regulating Heartbeat

19. ECG - Electrocardiogram

20. Blood Pressure 1. Systolic (top number) Normal = 120 mmHg
The pressure of blood surging through the artery, causing expansion
2. Diastolic (bottom number)
Normal = 80 mmHg
Heart rests, blood is still, pressure drops

21. The Circulatory System and Exercise
Exercise increases CO2 content in blood, which leads to higher breathing and heart rates (think HR lab).
The benefits of exercise are many:
1. Improved body system functions.
2. Improved blood supply to muscles, organs,
tissues, etc.
3. Reduced ‘bad’ cholesterol levels.
4. Improved strength, bone density and
self-esteem.
5. Improved oxygen capacity and usage!

22. Circulatory System Problems - Jigsaw
Form expert groups!
Share info!

23. Circulatory System Technology
Nitroglycerine: A drug used to treat angina by dilating the coronary arteries.
Bypass surgery: A blood vessel is removed from leg and is used to redirect blood flow around a blocked coronary artery.
Angioplasty: A small balloon is inserted through a catheter and inflated in order to reduce the narrowing of an artery.
Pacemaker: An artificial device that electrically stimulates the heart to beat

24. Bypass Operation