Cardiovascular physiology Flashcards
Layers of the heart
• pericardium (sac around the heart)
• epicardium (outer surface)
• myocardium (heart muscle)
• endocardium (inner lining)
Properties of a cardiac muscle
•rhythmicity
• excitability
• contractility
• conductivity
Cardiac Action Potential
0 = Na+ (in)
1 = K+Cl (out)
2 = Ca2 (in)
K+ (out)
3 = K+ (out)
4 = resting potential
Cardiac output - Stroke volume
Volume of blood pumped by each ventricle in one contraction. Approx. 70ml
What is Cardiac Output (CO)
Amount of blood pumped by the heart in one minute.
CO = (heart rate [HR] x stroke volume [SV])
Blood pressure during cardiac output
BP = (cardiac output [CO] x Total peripheral resistance [TPR])
Which heart chambers does blow flow into on its return from the rest of the body?
Right atrium, into Right Ventricles
Name the heart valves between:
Right atria and Right Ventricle
Right Ventricle and Pulmonary artery
Left Atria and Left Ventricle
Left Ventricle and Aorta
Tricuspid
Pulmonary (Semilunar)
Mitral
Aortic (Semilunar)
What is the anatomical landmark for auscultation of the aortic valve
Right sternal border, second intercostal space
What is the relative voltage of the cardiac cell membrane at rest?
-90mV
What changes the action potential of cardiac cells?
Movement of positively charged ions into the cell until it increases to -40mV
Describe the path of electrical impulses through the heart?
Starts at the sinoatrial node, through the atria, to the atrioventricular node, down the left and right bundle branches, to the perkinje fibres
ECG:
What electrical action does the P wave relate to?
Atrial Depolarisation
ECG:
What does the QRS complex relate to?
Ventricular depolarisation
ECG:
What does the T Wave represent?
Ventricular Repolarisation
