The circulatory system consists of the lymphatic and blood circulations. The blood circulation transports nutrients, oxygen, and waste throughout the body via arteries, veins, and capillaries driven by the heart. Blood is composed of plasma and blood cells including red blood cells, white blood cells, and platelets. The heart pumps blood through two circuits - pulmonary circulation to exchange gases in the lungs and systemic circulation to exchange substances in tissues throughout the body.

1. Circulatory System

2. Circulatory System
• The circulatory system is made up of two chains of
vessels
• Lymphatic circulation
• Drains interstitial fluid (in which cells of tissues are immersed)
• A liquid called lymph circulates through the vessels and
transports interstitial fluid, and moves without the help of any
organ
• Blood circulation
• Is responsible for transporting nutrients, oxygen, and waste.
• The liquid, blood, circulates through the blood vessels, which
are called arteries, veins, and capillaries
• The movement of blood is driven by the heart

3. Blood
• Blood is the liquid that circulates through the blood
vessels
• Made up of a liquid part called plasma, as well as:
• Red blood cells – Most abundant. They are in charge of
transporting oxygen molecules combined with the hemoglobin
molecules they have inside
• White blood cells – These cells belong to the immune system
and use the blood circulation because blood vessels reach every
part of the body and it is fast
• Platelets - Cellular fragments produced in the bone marrow.
Their purpose is to contribute to the formation of clots which
cover wounds

4. Blood Vessels
• Three types of blood vessels
• Veins – These transport blood from the organs and parts of
the body to the heart
• Arteries – These transport blood from the heart to the
organs and parts of the body
• Capillaries - The arteries divide into arterioles as the
blood vessel branches off
• Capillaries are the exchanging areas between the blood and the
tissues
• The capillaries begin to join together again in venules which
join others and return to the heart

5. Heart
• The heart is a muscle divided into four chambers, two on the
left, two on the right, joined vertically
• The upper chambers are called atria (singular: atrium) and and
the lower chambers called ventricles.
• The right atrium is connected to the right ventricle through the
tricuspid valve. The left atrium is connected to the left ventricle
through the mitral valve
• Pericardium – The membrane that covers external surface
of the heart and protects it
• The heart has two basic movements:
• Contraction (systole)
• Relaxation (diastole)

6. Heart

7. Cardiac Cycle
• Both atria contract to finish filling their corresponding
ventricles
• This movement is called atrial systole
• The ventricles contract and push blood through the main
vessels leading from the heart (called ventricular systole)
• These are the aorta artery, which starts the circuit of taking
blood to the body, and pulmonary artery, which transports
blood to the lungs to take oxygen and release carbon
• All the cardiac muscle relaxes and all four cavities fill with
blood again (called general diastole)
• To prevent the blood that has just left the heart from returning,
the aorta and the pulmonary artery have semilunar valves

8. Blood Circulation
• Pulmonary circulation
• Blood returns from the tissues of the entire body through the
two main veins, the superior vena cava and the inferior
vena cava.
• The blood goes to the right atrium and then the right
ventricle, and from there, goes out the pulmonary artery to
exchanges gases (Carbon dioxide to oxygen)
• Once oxygenated, the blood returns to the heart through the
pulmonary vein, which takes blood to the left atrium

9. Blood Circulation
• Systemic circulation
• The blood in the left atrium goes to the left ventricle during
atrial systole, and then gets distributed throughout the body
through ventricular systole
• Exchange of substances in the tissues
• The capillaries are the little branches that reach the tissues
• The blood plasma leaves the capillaries and mixes with the
interstitial liquid.
• Then the cells take the oxygen and nutrients contained in the
plasma
• The capillaries take back the liquid exiting the tissues and
join the venules, and return to the heart

10. Blood Circulation
• Systemic circulation
• The blood in the left atrium goes to the left ventricle during
atrial systole, and then gets distributed throughout the body
through ventricular systole
• Exchange of substances in the tissues
• The capillaries are the little branches that reach the tissues
• The blood plasma leaves the capillaries and mixes with the
interstitial liquid.
• Then the cells take the oxygen and nutrients contained in the
plasma
• The capillaries take back the liquid exiting the tissues and
join the venules, and return to the heart