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Circulatory System
Objectives
Concepts to Learn
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Compartments of heart chambers
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Components of blood pressure
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Regulation of blood pressure, heart rate and blood volume
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Regulation of cardiac output
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Cardiac action potential
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Pacemaking activity of myocardiac muscles
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Electrical activity of the heart
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Electrocardiogram
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Cardiac disorders
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Evolution of the circulatory system and heart chambers
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Open circulatory system
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Closed circulatory system
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1.1.Function and Structure of Circulatory System
Objectives
Concepts to Learn
Q&A
What are the functions of the circulatory system?
It is used to transport and deliver materials, such as O2, CO2, nutrients, hormones and drugs.
It is a forced convection system to pump materials through the system, providing a much faster rate than diffusion.
What is the lymphatic system?
The lymphatic system is continuous with the circulatory system (which carries blood), whereas the lymphatic system carries the lymphatic cells as the immune system.
Circulatory system drains into the lymphatic system (without the red blood cells).
What are the two separate circulatory systems in vertebrates?
They are the pulmonary system and the systemic system.
Pulmonary (= lung) system carries blood to the lungs while systemic system carries blood to the rest of the body. The pulmonary circulatory system obtains oxygen from the lung while the systemic circulatory system delivers oxygen to the tissues.
What is the function of the heart?
It is used to pump blood.
The heart is a pump that produces the forced circulation of blood in the blood vessels. Different animals evolved to use different number of hearts for circulation. When the different pumps in the heart are merged together into a single heart, they are called heart chambers, even though each chamber can be considered as separate pump or separate heart.
What is the definition of artery?
It is the vessel that carries blood away from the heart.
Most arteries carry oxygenated blood except pulmonary artery, which carries deoxygenated blood to the lungs. It may be counter-intuitive that the pulmonary artery carries deoxygenated blood because of the definition that arteries are blood vessels that carry blood away from the heart.
What is the definition of vein?
It is the vessel that carries blood to the heart.
Most veins carry deoxygenated blood except pulmonary vein, which carries oxygenated blood from the lungs.
What is aorta?
It is the largest artery emerging from the heart with elastic tissue to dampen the blood pressure and maintains the blood pressure.
The elasticity of the aorta prevents the blood pressure to drop to zero between beats. This aorta sustains the blood pressure even between heart beats.
What are the names of blood vessels from the heart to capillaries and back to the heart?
The names of the vessels in sequence are:
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aorta
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arteries
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arterioles
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