Section 3 Flashcards
What is the distribution of cardiac output?
Refers to the amount of blood (%) in the arterial and venous system and a given time.
Typically, 30-35% of total blood resides in arterial system, whereas 60-65% resides in the venous system.
What does pulmonary circulation function to do?
- Carries deoxygenated blood from the heart to the lungs for oxygenation (gas exchange)
- Returns oxygenated blood back from the lungs to the heart
What does systemic circulation function to do?
- Carries oxygenated blood from the heart to other organ systems/tissues of the body, EXCEPT the lungs
- Deoxygenated blood from the tissues returns to the heart
What is the anatomical position/shape of the heart?
- the heart resides in the mediastinum (a space between the lungs in the thorax)
- as a result, the heart has different borders and surfaces depending on the areas that it comes into close contact with
- the shape of the heart resembles an inverted pear fruit
- the most inferior and lateral portion of the heart on the left is known as the apex
What is the pericardium of the heart?
The heart has various layers on top of it, referred to as covering, or the pericardium of the heart.
What are the types of layers of pericardium?
- Fibrous pericardium is the most external covering
- Serous pericardium, is further divided into parietal and visceral pericardium. Between these two layers, there is pericardial space filled with pericardial fluid. Pericardial fluid decreases friction between the two layers when the heart beats
Altogether, the pericardium consists of THREE layers
What are the chambers of the heart?
- Right atrium
- Left atrium
- Right ventricle
- Left ventricle
Where is the interatrial septum of the atria?
- it is the wall between the left and right atria where the fossa ovalis is found
Where is the fossa ovalis of the atria?
- it is a depression in the interatrial septum of the right atrium
- it is an embryological remnant of the fetal foramen ovale, an opening which allowed movement of blood from the right to the left atrium during fetal life
Where are the auricles of the atria?
- they are extensions or pouches that project above the chambers of the left and right atria
- they increase the capacity of each atrium
Where is the atrioventricular groove?
- it is the depression between the atria and ventricles encircling the heart, AKA the coronary sulcus
- it separates the atria from the ventricles
- also houses the coronary vessels
What is are the functions of the ventricles of the heart?
- The right ventricle pumps blood to the lungs to become oxygenated
- The left ventricle pumps oxygenated blood to the rest of the body
Where is the interventricular sulcus of the ventricles?
- it is a groove on the external surface of the heart that separates the right ventricle from the left ventricle
- it sits above the interventricular septum
Where is the interventricular septum?
- it is the wall between the left and right ventricle
Where is the trabeculae carneae?
- they are the irregular muscular ridges on the internal walls of each ventricle
- formed by the large ventricular muscles
Where are the papillary muscles?
- they are smaller muscular projections on the internal walls of the ventricles that attach to the valves of the heart
What are the valves of the heart?
Tricuspid valve, bicuspid valve, aortic semilunar valve, and pulmonary semilunar valve
What is the tricuspid valve?
- located between the right atrium and right ventricle
- AKA the right atrioventricular valve
- has structures known as chordae tendinae which are thin strands of collagen fibres that attach to the papillary muscles
- controls the blood flow from the right atrium into the right ventricle
What is the bicuspid valve?
- located between the left atrium and the left ventricle
- AKA the atrioventricular or mitral valve
- has chordae tendinae that anchor it to the left ventricle
- controls the flow of blood from the left atrium into the left ventricle
What is the aortic semilunar valve?
- located between the left ventricle and aorta (a major vessel of the heart)
- controls the blood flow from the left ventricle into the aorta
What is the pulmonary semilunar valve?
- located between the right ventricle and the pulmonary trunk (a major vessel of the heart)
- controls blood flow from the right ventricle into the pulmonary trunk
What do pulmonary veins (left and right) do?
- drain oxygenated blood from the lungs to the left atrium
What does the superior vena cava do?
- drains deoxygenated blood from the upper body to the right atrium
What does the coronary sinus do?
- drains deoxygenated blood from the coronary circulation to the right atrium
What does the inferior vena cava do?
- drains deoxygenated blood from the lower body to the right atrium
What are the great vessels that drain blood into the heart?
- pulmonary veins (left and right)
- superior vena cava
- coronary sinus
- inferior vena cava
What are the great vessels pumping blood away from the heart?
- ascending aorta
- pulmonary trunk
- pulmonary arteries (right and left)
What does the ascending aorta do?
- conducts oxygenated blood from the left ventricle to the body
What does the pulmonary trunk do?
- conducts deoxygenated blood from the right ventricle to the pulmonary arteries
What do the pulmonary arteries do?
- conduct deoxygenated blood from the pulmonary trunk to the lungs
What is the order of blood flow, through vessels and chambers?
- Superior and inferior vena cava and coronary sinus
- Right atrium
- Tricuspid valve
- Right ventricle
- Pulmonary semilunar valve
- Pulmonary trunk
- Pulmonary arteries
- Lungs
- Pulmonary veins
- Left atrium
- Bicuspid valve
- Left ventricle
- Aortic semilunar valve
- Aorta
What two main vessels is the heart supplied by?
The right and left coronary arteries
Describe venous drainage of the heart
- there are tributaries of the venous drainage of the heart that return deoxygenated blood to the right atrium
(coronary sinus –> these carry blood into the coronary sinus: small cardiac vein, great cardiac vein, middle cardiac vein)
Patients presents with symptoms of heart attack (chest pain, shortness of breath, fatigue). Through testing it is found that the left coronary artery is blocked.
- What part of the coronary blood flow is affected? In other words, what areas of the heart would stop receiving blood?
- If the ____________ is affected, how will this affect the rest of the body?
- The left ventricle would have the most significant damage by this blockage. The anterior portion of the interventricular septum, and the left atria would also be impacted by this block.
- If the left ventricle is affected, which pumps oxygenated blood to the body, the rest of the body will not receive as much oxygenated blood and would not function to the same extent
