The Human Circulatory System: Heart, Blood Vessels, and Blood Flow, Lecture notes of Cardiology

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CARDIOVASCULA

R SYSTEM

NOTES BY

ELIASPARAMEDIC

Cardiovascular System

Circulatory Overview The circulatory system transports substances including food, hormones, metabolic wastes, and gases (oxygen, carbon dioxide) to and from cells responding to changing demands by diffusion (from high to low concentration along concentration gradient).

Structure  (^) Humans have a closed circulatory system.  (^) Blood is pumped through a system of vessels  (^) (In an open system, blood flows in vessels and sinuses/gills)  (^) Sometimes the circulatory system is also called the “cardiovascular system” because:  (^) Cardio = heart  (^) Vascular = vessels  (^) The human circulatory system consists of:  (^) The heart: pumps or pushes blood through body  (^) A series of blood vessels: routes blood travels  (^) Blood: carries important “ *stuff ” through body

Where the Heart is located

Aorta Superi or vena cava

Chambers of the Heart

• (^) Human heart has 4 chambers  (^) 2 Atria

 Superior = primary receiving chambers, do not

actually pump

 Blood flows into atria

 (^) 2 Ventricles

 Pump blood

 Contraction = blood sent out of heart + circulated

Chambers are separated by septum…  (^) Due to separate chambers, heart functions as double pump

Blood Flow through the heart  (^) Deoxygenated blood returns from the top of the body through the superior vena cava and from the bottom of your body through the inferior vena cava to the right atrium.  (^) Deoxygenated blood is pumped from the right atrium through the tricuspid valve to the right ventricle.  (^) Deoxygenated blood leaves the right ventricle through the pulmonary valve to the pulmonary arteries.  (^) The pulmonary arteries pump blood to the lungs to absorb oxygen and release carbon dioxide.  (^) Blood leaves the heart in arteries, and blood returns to heart in veins.  (^) Oxygenated blood returns from the lungs through the pulmonary veins to the left atrium.  (^) Oxygenated blood is pumped from the left atrium through the mitral valve to the left ventricle.  (^) Oxygenated blood leaves the left ventricle through the aortic valve to the aorta, which is the largest artery of the body.  (^) The aorta branches into various arteries pumping blood through ther body.

Pathway of Blood Flow Through the Heart

Pulmonary Circulation  (^) Pulmonary = Deoxygenated Blood  (^) Involves Right Side of Heart  Pathway:

1. Superior / Inferior Vena Cava
2. Right Atrium  Tricuspid Valve
3. Right Ventricle  Pulmonary Semilunar Valve
4. Left Pulmonary Artery
5. Lungs

Systemic Circulation  (^) Systemic = Oxygenated Blood  (^) Involves Left Side of Heart  (^) Pathway:

1. Left Pulmonary Vein

2. Left Atrium  Bicuspid Valve

3. Left Ventricle  Aortic Semilunar Valve

4. Aorta

5. All Other Tissues