ANPH Cardiovascular System Flashcards
How much blood does the heart pump in a day?
7000-9000L
How big and how much does the heart weigh?
Approx. the size of your fist
Weights 250-300g
Where is the heart located?
Mediastinum, left of the midline, 0.5in - 1.2cm above diaphragm
Apex
Located approx. 5th intercostal space, point of maximal impulse
Maximal impulse
Occurs when the hearts apex rotates forward with systole, gently beating against the chest wall and producing pulsation
Pericardium
A protective double-walled sac around the heart composed of 2 layers (visceral and partial)
Visceral layer
Epicardium; lines the surface of the heart
Partial layer
Outer fibrous layer
What are the two layers separated by?
Approx. 25-50ml of pericardial fluid. Reduces friction as the heart beats
What does the pericardium do?
Protects and anchors the heart, prevents overfilling of the heart with blood, allows the heart to work at a relatively friction free environment
What happens if pericardial fluid is to low?
Chest pain due to friction of the 2 layers
What happens if the pericardial fluid is to high?
The pumping is restricted and not allowing as much contraction, smaller amount of blood output, heart rate increases
Most common organelle in cardiac muscle?
Mitochondria; accounts for 25% of the volume of cardiac cells, high resistance of fatigue
Why is there only one pale nucleus?
There is no need for protein synthesis as the cardiac cells do not divide and replicate.
4 heart chambers?
Two atria. Two ventricles
Atria
Superior chambers receive incoming blood, separated by inter atrial septum
Ventricle
Inferior chambers, pump blood out of the heart. Larger than the atria, separated by the inter ventricular septum
What three veins does the blood enter the atria through?
Superior vena cava, inferior vena cava, coronary sinus
Superior vena cava
Blood returning to the heart superior to the diaphragm
Inferior vena cava
Blood returning to the heart inferior to the diaphragm
Coronary sinus
Blood from the myocardium
The auricle
A small expandable muscular pouch in the upper portion of the atrium. Increases the blood capacity of the atrium
What does the 2 Atrioventricular valves do?
Lie between the atria and ventricles preventing back flow into atria when ventricles contract.
Where is the Tricuspid valve located?
Right atrium to right ventricle
Where is the bicuspid (mitral) valve located?
Left atrium to left ventricle
Chordae tendineae
White collagen cords that are attached to each AV valve which anchor the cusps to the papillary muscles protruding from the ventricle walls
What’s does the two semilunar valves do?
Allow ejection of blood from the heart into the arteries but prevents back flow into the ventricles
Where is the Pulmonary semilunar valve located?
Connects right ventricle to the aorta
Where is the aortic semilunar valve located?
Connects left ventricle to the aorta
What is the pathway of blood through the heart and lungs?
Right atrium > tricuspid valve > right ventricle > pulmonary semilunar valve > pulmonary arteries > lungs > pulmonary veins > left atrium > bicuspid valve > left ventricle > aortic semilunar valve > aorta > systemic circulation
Coronary circulation
Coronary arteries fill while the ventricles are relaxed, the aorta recoils pushing blood systemically backward into coronary arteries
Anastomoses
Connections between the arterioles
Collateral circulation
Connections between the arterioles ensure blood delivery to the heart even if major vessels are occluded
Where is the Right coronary artery (RCA) located?
The sulcus between the right atrium and ventricle
Marginal arteries
Supplies the surface of the right ventricle
Where is the left coronary artery (LCA) located?
Subdivides into the left anterior descending (LAD) and circumflex artery (CX)
What are the 5 cardiac veins?
Great cardiac vein - anterior, middle cardiac vein - posterior, small cardiac vein - right atrium/ventricle, anterior cardiac vein - anterior right ventricle, posterior cardiac vein - circumflex artery
What 3 artery’s come out of the aorta?
Brachiocephalic, carotid , subclavian
