Cardiovascular System Notes: The Heart

The human heart creates enough pressure to squirt blood 30 feet. Interesting Cardiovascular System Facts The human heart creates enough pressure to squirt blood 30 feet.

Review What are the 3 parts of the cardiovascular system? heart – blood – blood vessels What do arteries do? Take blood AWAY from the heart What are the 3 layers of an artery? Tunica externa /connective tissue (elastin) – tunica media/smooth muscle – tunica intima/endothelium What do veins do? Bring blood TOWARD the heart What do veins have that arteries don’t? VALVES – (veins & arteries both have the same layers except the muscular layer is smaller)

What exchanges material between blood and the body’s cells? CAPILLARIES How big are they? microscopic in size

NOTES – THE HEART Location: cavity between the lungs, 2/3 left of midsagittal roughly the size of a fist

Heart Anatomy PERICARDIUM outer membrane of the heart 2 layers 1. Parietal pericardium: external (outer) layer 2. Visceral pericardium (epicardium): part of the heart wall

Functions: protection – physical barrier anchors heart to other structures provides lubrication to reduce friction – allows the heart to beat easily

THE HEART WALL 3 layers 1. Epicardium: outer portion (visceral pericardium) EPICARDIUM

2. Myocardium: middle layer consists of twisted cardiac muscle THIS IS THE LAYER THAT ACTUALLY CONTRACTS MYOCARDIUM

3. Endocardium: inner layer made of epithelial tissue

HEART CHAMBERS 4 chambers Atrium (left/right atria) divided by the INTERATRIAL SEPTUM Function of Atria: receives blood from veins (pig heart)

RIGHT ATRIA receives blood from superior & inferior vena cava blood that’s been used oxygen poor – high in CO2

LEFT ATRIA receives blood from pulmonary veins coming from lungs rich in oxygen

Ventricles (left/right) muscular pumps – divided by INTERVENTRICULAR SEPTUM (pig heart)

RIGHT VENTRICLE receives blood from the right atria (O2 poor) pumps blood to the lungs through the PULMONARY ARTERIES

LEFT VENTRICLE receives blood (O2 rich) from the left atrium pumps blood to the body through the AORTA

Systemic Circulation heart – lungs – heart – body – heart

HEART VALVES (4) allow for “one way” circulation 2 Atrioventricular Valves (AV valves) 1. Tricuspid Valve: between right atria and right ventricle

2. Bicuspid or Mitral Valve: between left atria and left ventricle heavier & stronger of the two

CHORDAE TENDINAE and papillary muscles stop valves from being folded backwards

3. Pulmonary Semilunar Valve: between the pulmonary artery and right ventricle

4. Aortic Semilunar Valve: between aorta and left ventricle