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Blood Vessels and the Heart

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Presentation on theme: "Blood Vessels and the Heart"— Presentation transcript:

1 Blood Vessels and the Heart

2 Blood Vessels Three Types Arteries: carry blood away from the heart
Thick walled, smaller vessels are called arterioles Veins: carry blood towards the heart Thin walled, smaller vessels are called venules Contains valves Capillaries: connect the arteries to the veins Smallest of the blood vessels RBC’s travel single file through capillaries Branch like system to increase surface area for diffusion Site of gas exchange


4 Arterial System Transports blood under pressure.
Blood moves in a pulse-like wave. Contraction & relaxation of arterioles is the major determinant of the overall blood pressure.

5 Venous System Thinner walls, larger diameters & less muscle than arteries. Contains 70% of total blood volume. Most veins work against gravity. Valves allow one-way flow. Contraction of skeletal muscles pushes blood toward heart.

6 Pathways of Blood Pulmonary Circuit Systemic Circuit
Right side of heart. Low-pressure system. Takes deoxygenated blood to the lungs and back to the heart Systemic Circuit Left side of heart. High-pressure system. Takes oxygenated blood to the body and returns deoxygenated blood back to the heart


8 Pulmonary Circuit Right atrium receives oxygen-poor blood from:
Superior vena cava. Inferior vena cava. Blood flows through the tricuspid valve or the right atrioventricular (AV) valve to the right ventricle. Blood from body Blood from body

9 Pulmonary Circuit Blood flows through the pulmonary semi-lunar valve & enters the pulmonary trunk, which divides into the left & right pulmonary arteries. Divides into capillaries where external gas exchange (respiration system) occurs. Oxygenated blood enters the left & right pulmonary veins, returning blood to the left atrium.

10 Systemic Circuit Blood flows through the left AV-valve or bicuspid (mitral) valve to the left ventricle. Left ventricular walls are two times thicker than in the right ventricle. Blood travels through the aortic semi-lunar valve to the aorta.

11 Systemic Circuit Aorta branches into smaller systemic arteries, which branch into arterioles & then capillaries. Internal gas exchange occurs. Capillaries rejoin as venules & then veins. Deoxygenated blood returns to the right atrium via the superior & inferior vena cava.

12 Coronary Circulation Delivers oxygenated blood to the heart muscle.
Consists of the left & right coronary artery.

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