The Heart Flashcards
Describe the structure and function of the heart
“double pump” with 4 chambers–2 atria and 2 ventricles; right side pumps into the pulmonary circuit and left side pumps into the systemic circuit
What are veins?
Low-pressure vessels that carry blood back to the heart
What are arteries?
High-pressure vessels that carry blood away from the heart
Describe the pressure gradient of the circulatory system
Blood flows from high-pressure to low pressure; artery pressure lessens the further it gets from the heart, lessens in the capillary bed, and lessens even more in veins
Describe distribution of pressure in the heart
Least pressure in the body where receiving blood from veins; highest pressure in the body where pushing blood into arteries
Why is there less muscle on the right side of the heart than the left?
The pulmonary circuit requires less pressure from the heart for blood to flow; the left side of the heart needs to create immense pressure to pump blood throughout the body
What chambers pump blood out of the heart?
Ventricles
Describe the path blood takes through the heart/circuits
Deox. blood flows into right A, down into right V, pumped into pulmonary trunk and into lungs via pulmonary arteries; oxygenated at pulmonary capp, carried back via pulmonary veins into left A, down into left V, pumped into aorta and into arteries to body; returned through veins into inf/sup vena cava into right A
What is the aorta?
Structure of the heart where ALL systemic arteries branch from
How does the heart receive blood TO THE CARDIAC MUSCLE?
capillaries!
Does gas exchange occur in the chambers of the heart?
NO! It has its own blood supply through coronary circulation
Describe coronary circulation
Special branch of the systemic circuit that supplies blood to the cardiac muscle–coronary artery carries blood from the aorta to the heart itself, gas exchange happens in capillaries of the heart, cardiac veins carry blood to coronary sinus that drains into vena cava
What causes coronary artery disease?
Blockage of the coronary arteries
What causes angina (chest pain)?
Lack of oxygen to the heart when it needs to work harder (i.e. during physical activity)
What causes myocardial infarction (heart attack)?
Damage to the cardiac muscle, usually from lack of oxygen
What is the pericardium?
Connective tissue membranes that surround the heart
Identify the layers of the pericardium
Parietal pericardium is the outer layer in contact with the tissues of the body; visceral pericardium is the inner layer in contact with the cardiac muscle
What is the pericardial fluid?
Fluid found in between the layers of the pericardium; reduces friction between the cardiac muscle and tissues of the body
What are the valves of the heart?
structures that separate areas of the heart
What do the atrioventricular valves do?
separate atria and ventricles
What do the semilunar valves do?
separate ventricles from circulation; found at the base of the pulmonary trunk and aorta
What are the chordae tendinae?
“heart strings” that hold the AV valves in place
What is another name for the right AV valve and why?
Tricuspid valve; three flaps
What is another name for the left AV valve?
Bicuspid; two flaps–also mitral valve (less common for purpose of this class, more common in caridology)
Why are there no cordae tendinae on the semilunar valves?
Pressure is less here than at the ventricles, so “blowout” of the valves backwards is unlikely
Describe the arrangement of muscle fibers in the heart
A sort of figure 8, creates a wringing motion that squeezes blood up and out
What is the fibrous skeleton of the heart?
Connective tissue rings that surround the AV valves, separating atria from ventricles
