THE CARDIOVASCULAR SYSTEM
What is the Cardiovascular System?
● Composed of heart and blood vessels
● Functions to deliver oxygen and nutrients to tissues and remove wastes products
from the body
● Also known as the circulatory system
Anatomy
● Heart - fist sized organelle mode of muscle that pumps blood theough out the
body
● Blood Vessels
○ Arteries - muscular blood vessels that carry oxygenated blood away from
the heart to the tissues of the body
○ Veins - vessels the contain valves that return deoxygenated blood to the
heart
● Mediastatium - the medial section of the thoracic cavity where the hear is located
● Apex - inferior point of the heart
● Pericardium - 3 membranes that enclose the heart
○ Fibrous pericardium - superficial covering of the heart that protects and
anchors the heart to the structures around it
○ Serous pericardium - slippery layer deeper to the fibrous pericardium
○ Visceral pericardium - deepest layer, a part of the walls of the heart
■ Aka epicardium
● The wall of the heart is composed of 3 layers
○ Epicardium - most superficial layer
○ Myocardium - the wall of the heart
■ The actual layer that contracts
■ arrangement of ring like bundles
○ Endocardium - the deepest layer
● The heart is composed of 4 hollow chambers:
○ 2 atria - singular “atrium”
○ 2 ventricles
● Atria
○ Superior smaller chambers that receives blood
○ Not responsible for pumping blood
● Ventricles
○ Inferior larger, thick walled chambers
○ responsible for the actual pumping of blood to the rest of the body
● Septum - dividing the right and left sides of the heart
● Blood Vessel
, ○ Arteries - muscular blood vessels that carry oxygenated blood away from
the heart
■ These branch into arterioles
○ Capillaries - smallest vessels, the site of oxygen exchange
■ Drains into venules (smallest veins)
○ Veins - vessels that contain valves that return deoxygenated blood to the
heart
■ Contain thinner walls but larger lumen, interior of vessel, to equal
that amount of blood being pumped by the arteries
■ Contain valves to prevent back flow of blood
■ Surrounding skeletal muscle helps move blood through veins
○ Precapillary sphincter - regulates blood flow to capillary beds
○ Vascular shunt - directly connects arteriole and venule, skipping capillary
bed
■ I.e.why your finger go numb when it is cold
○ Vasoconstriction - narrowing of the blood cells
■ Conserves heat
○ Vasodilation - the widening of the blood vessels
■ Helps release heat
● Aorta - largest artery, supplies oxygen rich blood to the entire body
● Vena Cave - largest vein divided into superior and inferior vena cava
● Atrioventricular (AV) valves - located between the atria and ventricles on each
side
○ Mitral Valve - aka bicuspid valve, located on the left side, 2 flaps
○ Tricuspid valve - valve on the right side, 3 flaps
○ Open during heart relaxation and closed during ventricular contraction
● Semilunar valves - consists of 3 flaps that guard the base of the 2 large arteries
○ Aortic semilunar valve
○ Pulmonary semilunar valve
■ Closed during heart relaxation and forced open during ventricular
contraction.
● Chordae teninae - tendons that anchor valves to the walls of the ventricles
● As the ventricles fill with blood the pressure against the walls of the hart force the
AV to close
● Flow of blood
○ Pulmonary circuit - oxygen poor blood leaves the right ventricle the pump
travels to the lungs and then back to the right atrium (receiving chamber)
○ Systemic circuit - oxygen rich blood leaves left ventricle through the aorta
the body tissues and back to the right atrium
What is the Cardiovascular System?
● Composed of heart and blood vessels
● Functions to deliver oxygen and nutrients to tissues and remove wastes products
from the body
● Also known as the circulatory system
Anatomy
● Heart - fist sized organelle mode of muscle that pumps blood theough out the
body
● Blood Vessels
○ Arteries - muscular blood vessels that carry oxygenated blood away from
the heart to the tissues of the body
○ Veins - vessels the contain valves that return deoxygenated blood to the
heart
● Mediastatium - the medial section of the thoracic cavity where the hear is located
● Apex - inferior point of the heart
● Pericardium - 3 membranes that enclose the heart
○ Fibrous pericardium - superficial covering of the heart that protects and
anchors the heart to the structures around it
○ Serous pericardium - slippery layer deeper to the fibrous pericardium
○ Visceral pericardium - deepest layer, a part of the walls of the heart
■ Aka epicardium
● The wall of the heart is composed of 3 layers
○ Epicardium - most superficial layer
○ Myocardium - the wall of the heart
■ The actual layer that contracts
■ arrangement of ring like bundles
○ Endocardium - the deepest layer
● The heart is composed of 4 hollow chambers:
○ 2 atria - singular “atrium”
○ 2 ventricles
● Atria
○ Superior smaller chambers that receives blood
○ Not responsible for pumping blood
● Ventricles
○ Inferior larger, thick walled chambers
○ responsible for the actual pumping of blood to the rest of the body
● Septum - dividing the right and left sides of the heart
● Blood Vessel
, ○ Arteries - muscular blood vessels that carry oxygenated blood away from
the heart
■ These branch into arterioles
○ Capillaries - smallest vessels, the site of oxygen exchange
■ Drains into venules (smallest veins)
○ Veins - vessels that contain valves that return deoxygenated blood to the
heart
■ Contain thinner walls but larger lumen, interior of vessel, to equal
that amount of blood being pumped by the arteries
■ Contain valves to prevent back flow of blood
■ Surrounding skeletal muscle helps move blood through veins
○ Precapillary sphincter - regulates blood flow to capillary beds
○ Vascular shunt - directly connects arteriole and venule, skipping capillary
bed
■ I.e.why your finger go numb when it is cold
○ Vasoconstriction - narrowing of the blood cells
■ Conserves heat
○ Vasodilation - the widening of the blood vessels
■ Helps release heat
● Aorta - largest artery, supplies oxygen rich blood to the entire body
● Vena Cave - largest vein divided into superior and inferior vena cava
● Atrioventricular (AV) valves - located between the atria and ventricles on each
side
○ Mitral Valve - aka bicuspid valve, located on the left side, 2 flaps
○ Tricuspid valve - valve on the right side, 3 flaps
○ Open during heart relaxation and closed during ventricular contraction
● Semilunar valves - consists of 3 flaps that guard the base of the 2 large arteries
○ Aortic semilunar valve
○ Pulmonary semilunar valve
■ Closed during heart relaxation and forced open during ventricular
contraction.
● Chordae teninae - tendons that anchor valves to the walls of the ventricles
● As the ventricles fill with blood the pressure against the walls of the hart force the
AV to close
● Flow of blood
○ Pulmonary circuit - oxygen poor blood leaves the right ventricle the pump
travels to the lungs and then back to the right atrium (receiving chamber)
○ Systemic circuit - oxygen rich blood leaves left ventricle through the aorta
the body tissues and back to the right atrium
