Heart Flashcards
Where is the heart located?
Within the thoracic cavity. The mediastinum
How many liters of blood does it pump per minute?
Approx 5.25L per minute
What is the serous membrane that covers and protects the heart?
The pericardium
What are the 3 layers of the heart?
Epicardium, myocardium, endocardium
Which layer of the heart is the thickest?
Myocardium
What are the 4 chambers of the heart?
left and right atria
Left and right ventricles
What structure separates the right and left ventricles?
The interventricular septum
What are the heart valves?
Tricuspid AV valve
Pulmonary SL valve
Bicuspid (mitral) AV valve
Aortic SL valve
Know blood flow through the heart
- Superior and inferior vena cave into R atrium
- R atrium through tricuspid valve into R ventricle
- R ventricle through pulmonary SL valve into pulmonary arch
- Pulmonary arch to pulmonary arteries
- Pulmonary arteries into lungs
- Lungs to pulmonary veins
- Pulmonary veins to L. Atrium
- L atrium through bicuspid (mitral) AV valve to L ventricle
- L ventricle through Aortic SL valve into aorta
What is systemic circulation?
Movement of blood from left side of heart to the systemic cells of the body and back to the right side of heart
What is pulmonary circulation?
Movement of blood from the right side of heart to the lungs and back to the left side of heart
How does deoxygenated blood get to the heart?
Through the superior and inferior vena cava into the R atrium
What is coronary circulation?
Circulation of blood in the blood vessels that supply the heart muscle
Where do arteries in the coronary circulation system originate from?
Ascending aorta
What area of the heart does the left coronary artery supply?
Left side of the heart
What area of the heart does the anterior interventricular branch supply?
Also known as the left anterior descending artery (LAD)
Supplies blood to the anterior of the left and right ventricle
What part of the heart does the circumflex branch arteries supply?
The lateral wall and posterior wall of the left ventricle
What part of the heart does the right coronary artery supply?
The right side of the heart
What part of the heart does the posterior interventricular branch supply?
The posterior wall of both ventricles
What part of the heart does the marginal branch arteries supply?
The lateral wall of the right ventricle
Where do veins in the coronary circulation system empty blood?
The coronary sinus, which drains into the right atrium
What area of the heart do the great cardiac veins drain?
The anterior surface of the left ventricle
What areas of the heart does the middle cardiac vein drain?
The posterior wall of both ventricles
What areas of the heart does the small cardiac vein drain?
The posterior surfaces of the right atrium and ventricle
What area of the heart does the anterior cardiac vein drain?
The anterior surface of the right ventricle
What is the coronary sinus?
A large, thin walled vein on the back of the heart that lies within the atrioventricular sulcus
Where does the coronary sinus drain into?
The heart myocardium, directly into the right atrium
What is the conduction system of the heart?
Conducting (nodal) cells
What are conducting (nodal) cells?
Autorhythmic fibers that form the conduction system of the heart. They initiate and propagate the action potential that travels throughout the heart
Where do cardiac action potentials originate, where do they travel, and what do they initiate?
- Originate in the sinoatrial (SA) node, initiates atrial contraction
- Travels to atrioventricular (AV) note, AV node depolarizes and transmits signal
- Signal travels to AV bundle (bundle of his), proceeds down AV septum and branches
- Branches to purkinje fibers and reaches papillary muscles, initiates ventricular contraction
What is an ECG?
Surface recording of electrical activity of the heart that can be used for diagnosis of irregular heart function
What is represented by each wave of an ECG?
-P wave- atrial depolarization, atrial. Atrial Contraction
-QRS Complex- ventricular depolarization. Ventricular contraction and atrial relaxation
-T Wave- ventricular depolarization. Relaxation of ventricles
What is systole?
Contraction of heart muscles, pumps blood out of chambers
Define diastole?
Relaxation of heart muscles, allows chambers to fill with blood
Define depolarization?
Muscle cells becoming electrically charged, leading to contraction
Define repolarization
Returning to the resting state, leading to relaxation of the muscle
What makes the S1 “lub” sound in the heart?
Closing of the atrioventricular valves during ventricular contraction
What makes the S2 “dub” sound?
Closing of the semilunar valves during ventricular diastole
What is cardiac output?
The volume of blood pumped by the heart per minute
What is the cardiac output equation?
stroke volume (SV) X heart rate (HR) = Cardiac output
What is stroke volume?
the amount of blood ejected by a ventricle in one contraction
What is heart rate?
number of heartbeats per minute
What factors affect stroke volume?
Preload, contractility, and afterload
define preload
The degree of stretch in the heart before contraction
define contractility
the force of contraction of the heart muscle
define afterload
The resistance the heart must overcome to eject blood
What controls heart rate?
ANS, hormones, Exercise, temperature and electrolyte levels
