The Heart Flashcards
(19 cards)
What is the outer layer of the heart called
Fibrous pericardium
Made of dense connective tissue
Helps protect heart and anchors it
What are the inner layers of the pericardium
Visceral pericardium inner
Outer parietal layer
What does the heart muscle wall contain
Epicardium outer layer
Myocardium middle layer composed of cardiac tissue
Endocardium inner layer of squamous epithelium tissue
What divides the heart into two sections
Septum
Where is the pulmonary semi lunar valve
Between the right ventricle and pulmonary artery, allows blood to flow from heart to lungs
Where is the mitral valve
(Bicuspid valve) between left atrium and left ventricle
Where is the aortic semilunar valve
Between the left ventricle and aorta, which carries blood from heart to rest of body
Where is the tricuspid valve
Between the right atrium and right ventricle
How does blood become oxygenated
Blood leaves the heart though the right ventricle past the pulmonary semi lunar valve into the lungs through the pulmonary artery, picks up oxygen, carbon dioxide leaves
How does blood re enter the heart after being oxygenated
Blood enters the left atrium which has lower pressure than the pulmonary vein, the atrium contracts increasing its pressure, blood passes down through the mitral valve to the left ventricle
How does oxygenated blood leave the heart
Left ventricle contracts to increase pressure, mitral valve closes to prevent backflow forcing blood to leave through the aortic semilunar valve through the aorta
How does deoxygenated blood re enter the heart
Enters through superior and inferior vena cava into right atrium, atrium contracts increasing pressure above ventricle, blood flows into ventricle through tricuspid valve
What is systole
High pressure caused by ventricular or atrial contraction
What is diastole
Ventricles relax to receive blood from atria
What do pacemaker cells do
Keep heart beating at correct rhythm and ensure each cardiac muscle cell contracts in coordination with others
What does the sino atrial node do
Acts as a pacemaker, sends action potentials across atrial walls causing contraction until they reach the av node
What does the atrioventricular node do
Signal gets delayed by av node so atria finish contracting before ventricles contract, signal moves down bundle of his
What happens to the signal at the purkyne fibres
Signal reaches bottom of heart at purkyne fibres which cause ventricles to contract from the bottom up
What is fibrillation
Uncoordinated contraction
