The circulatory system consists of the heart, blood vessels, and blood. The heart is a muscular pump made of four chambers that pumps blood through two circuits - the pulmonary circuit which sends blood to the lungs, and the systemic circuit which pumps blood to the entire body through arteries and veins. Blood carries oxygen, nutrients, hormones, and waste products and helps maintain homeostasis. Some common circulatory illnesses include arteriosclerosis, thrombosis, heart attacks, and angina.

1. Unit 3.C. The circulatory
system

2. Index
Composition of the Circulatory System
2. Blood Circulation
3. The Working of the Heart
4. Some Illnesses of the Circulatory System
1.

3. 1. Composition of the Circulatory System
The human circulatory system
consists of:
1.1 Blood vessels
1.2 Heart
1.3 Blood

4. 1.1 Blood Vessels

5. Caracteristics of Blood Vessels
Arteries
have thick walls,
 no valves and
 carry blood away
from the heart

Capillaries


link arteries to veins.
Their wall is only one cell thick
and this allows substances to
pass into and out of the blood.
Veins
• have thin walls,
• valves, and
• carry blood to the heart
http://www.youtube.com/watch?v=CjNKbL_-cwA  Types of blood vessels

6. 1.2 Parts of the Heart



It is a pump that pushes the blood into the arteries.
Is made of cardiac muscle, a special kind of muscle that never
tires.
Is divided into two sides by a wall called the septum.

7. It has got four chambers:
 Atria: the two upper
chambers (singular:
atrium). They have thin
walls. They pump blood to
the ventricles.
 Ventricles: the two lower
chambers. They pump
blood out of the heart.
 right ventricle, with
thin wall, pumps the
blood to the lungs .
 left ventricle, with
thicker and stronger
wall, pumps the blood
to the body.

8. Valves
Tricuspid valve and bicuspid valve or mitral valve,
between atria and ventricles.
Semilunar valves (aortic valve and pulmonary
valve) between ventricles and arteries.
Valves
prevent the
backflow of
blood.
http://vimeo.com/5588613 ==> valves working

9. THE HEART

10. http://www.youtube.com/watch?v=jLTdgrhpDCg  Cardiac Cycle, systole and diastole

11. 1.3 The Blood
Every person has 4 to 5 litres of blood on average.
 55% of the blood is plasma
 45% consists of blood cells and platelets.
(leukocytes)
 They defend the body from infection
 coagulation
(erythrocytes)

12. Composition
of Blood
http://www.youtube.com/watch?v=CRh_dAzXuoU  blood cells

13. FUNCTIONS OF THE BLOOD

Transport of:




Nutrients
Waste products
Hormones
Oxygen and carbon dioxide

Keeping the normal temperature
of the body

Defence against disease

14. 2. Blood circulation
Blood circulation in human being is double
and complete
It has two circuits (general and pulmonary)
The blood in the veins never mixes
with the blood in the arteries

15. 3. The working of the heart

16. The movement of blood through the heart
1. Blood from the body enters the right atrium through the vena cava.
The atria contract, the blood is pushed through the tricuspid
valve, into the right ventricle.
2. When the right ventricle contracts, the blood is pumped through the
semilunar valve into the pulmonary arteries.
3. Blood goes to the lungs.
In the lungs, the blood collects up oxygen and gets rid of its carbon
dioxide.
4. It then comes back to the heart in the pulmonary vein which enters the
left atrium.
When the atria contract, the blood is pushed through the bicuspid o
mitral valve into the left ventricle.
5. The ventricles contract and this pushes the blood through the semilunar
valve to the main artery of the body, aorta.
6. Blood is pushed out to all around the body.

17. The stages of heartbeat (cardiac cycle)


Diastole: heart chambers relax.
Systole: heart chambers contract.

18. Heartbeat

19. http://www.youtube.com/watch?v=jLTdgrhpDCg

20. 4. Some illnesses of the circulatory system
Arteriosclerosis
Accumulation of substances (fats, calcium…) in the arteries, which causes them
to narrow and restricts the blood flow.
http://www.youtube.com/watch?v=qRK7-DCDKEA  atherosclerosis
(a common form of arteriosclerosis in which fatty substances form a deposit of plaque on the inner lining ofarterial walls)

21. Thrombosis
Blood clots formed in a blood vessel. It is especially dangerous in the brain
or in the heart
http://www.youtube.com/watch?v=OxY4BphpGqo  Thrombosis

22. Heart attack and angina
Arteries which carry blood to the cardiac cells
Angina: narrowing or partial obstruction of the coronary arteries.
Heart attack: total obstruction of the coronary arteries