CIRCULATION APPLE

• What are common changes in the ageing heart related to blood vessels?

  Common changes in the ageing heart include thickening of blood vessel walls, narrowing of the lumen, and reduced elasticity in the vessels.
• What are the layers of the heart responsible for its structure and function?

  The heart consists of three main layers - the epicardium (outer layer), myocardium (middle layer responsible for contraction), and endocardium (inner lining).
• What is the primary function of the epicardium in the heart?

  The epicardium serves as the protective outer layer of the heart, providing a protective barrier and contributing to the lubrication of the heart.
• What role does the myocardium play in cardiac function?

  The myocardium is the muscular middle layer responsible for the contraction and pumping action of the heart, ensuring blood is circulated throughout the body.
• What is the primary function of the endocardium?

  The endocardium is the inner lining of the heart, contributing to a smooth surface that allows for efficient blood flow while preventing clotting within the heart chambers.
• What is the primary function of blood related to oxygen, and how long does this process take?

  Blood carries oxygen with hemoglobin, and these cells have a lifespan of approximately 120 days.
• How does blood contribute to the body's defense against infections, and how long does this proces take?

  Blood fights infection, and this process takes approximately 12-20 days.
• What role does blood play in preventing excessive bleeding through clotting, and how long does this process take?

  Blood facilitates clotting, preventing excessive bleeding, and this process takes approximately 6 days.
• What is the approximate volume of blood in the human body, and how is it often measured?

  The human body contains approximately 5 liters or 10 units of blood, often measured in units during medical procedures.
• What proportion of the body weight does blood constitute?

  Blood makes up about 10% of the body weight.
• What does the term "Cardiomegaly" refer to in medical context?


  Cardiomegaly is a medical condition characterized by the enlargement of the heart.

  
  

  Which can be caused by various underlying factors such as hypertension, heart valve disease, or cardiomyopathy.
• What does the term "Poiesis" signify in medical terminology?

  "Poiesis" refers to the creation or formation of a particular substance or cell type.
• What does the term "Penia" signify in medical terminology?

  "Penia" refers to a decrease or deficiency of a particular substance or cell type.
• What does the term "Cytosis" signify in medical terminology?

  "Cytosis" refers to an increase in the number of cells of a specific type.
• What is the role of the myocardial pump in the cardiovascular system, specifically regarding the right and left sides?

  The right side of the myocardial pump sends blood to the pulmonary circulation, while the left side pumps blood to the systemic circulation.
• How do baroreceptors contribute to overall blood pressure control?

  Baroreceptors continuously monitor blood pressure and play a crucial role in maintaining homeostasis by initiating appropriate responses to deviations, whether it's high or low blood pressure, to ensure optimal cardiovascular function.
• How do baroreceptors respond to high blood pressure?

  Baroreceptors detect high blood pressure and initiate responses such as:

  
  

  1. vasodilation (widening of blood vessels)

  
  

  2. decreased heart rate, and other mechanisms to reduce blood pressure.
• What is the role of baroreceptors in response to low blood pressure?

  Baroreceptors detect low blood pressure and trigger responses such as:

  
  

  1. vasoconstriction (narrowing of blood vessels)

  
  

  2. increased heart rate, and other mechanisms to raise blood pressure.
• Can heart valves be repaired or replaced, and why might this be necessary?

  Yes, heart valves can be repaired or replaced.

  
  

  This may be necessary due to conditions like valve stenosis or regurgitation, where the valve is narrowed or leaky, affecting blood flow.
• Name two heart valves commonly requiring repair or replacement.

  The Mitral Valve and the Aortic Valve are two commonly repaired or replaced heart valves.
• What events coincide with the sound "LUB" (S1) in the cardiac cycle?

  "LUB" (S1) corresponds to the closure of the atrioventricular (AV) valves, marking the end of diastole.
• What events coincide with the sound "DUB" (S2) in the cardiac cycle?

  "DUB" (S2) corresponds to the closure of the semilunar valves, marking the end of systole.
• What is the role of the coronary artery in the heart, particularly concerning oxygen and nutrient supply?

  The coronary artery supplies oxygen and nutrients to the myocardium, ensuring the heart's optimal functioning.
• During which phase of the cardiac cycle does perfusion occur in coronary artery circulation, and why is this significant?

  Perfusion occurs during diastole (rest) in the cardiac cycle, ensuring that the heart muscle receives the necessary oxygen and nutrients for its metabolic needs.
• What is the primary function of systemic arteries, and what type of blood do they generally carry?

  Systemic arteries carry blood away from the heart. Typically, all arteries carry oxygenated blood except for the pulmonary arteries.
• How would you describe the pressure characteristics of systemic arteries?

  Systemic arteries operate within a high-pressure system.

  
  

  facilitating the efficient distribution of oxygenated blood throughout the body.
• What is the primary function of systemic veins, and what type of blood do they generally carry?

  Systemic veins carry blood towards the heart. Typically, all veins carry deoxygenated blood except for the pulmonary veins.
• How would you describe the pressure characteristics of systemic veins, and what mechanisms do they rely on for efficient blood flow?

  Systemic veins operate within a low-pressure system.

  
  

  They rely on valves and the contraction of surrounding muscles to facilitate the return of deoxygenated blood back to the heart.
• How is Cardiac Output calculated, and what is the average value in a resting adult?

  Cardiac Output is calculated by multiplying Heart Rate by Stroke Volume.

  
  

  In a resting adult, the average Cardiac Output is approximately 4-6 liters per minute.
• What does the term "Stroke Volume" refer to in the context of cardiac physiology?

  Stroke Volume represents the amount of blood ejected by the left ventricle of the heart in one contraction or heartbeat.
• What does "preload" refer to in cardiac physiology, and when does it occur in the cardiac cycle?

  Preload is the ventricular stretch that occurs at the end of diastole (rest), representing the filling of the ventricle when the heart is relaxed.
• How does an increase in preload affect the cardiac output?

  An increase in preload (ventricular stretch) generally leads to an increase in stroke volume, contributing to higher cardiac output.
• What conditions are associated with high and low preload?

  1. High preload may be seen in conditions like heart failure (volume overload)

  
  

  2. Low preload may occur in hypovolemia (low volume or decreased venous return).
• Can an increase in preload contribute to an increase in myocardial oxygen demand?

  Yes, an increase in preload can potentially increase myocardial oxygen demand, especially when the heart is working harder to pump a higher volume of blood.
• What is "afterload" in the context of cardiac physiology?

  Afterload is the resistance the heart must overcome to eject blood from the ventricles.
• What factors contribute to afterload?

  It is influenced by vessel diameter, valves, and blood viscosity, often referred to as the "3 V's."
• How does an increase or decrease in afterload affect the cardiac output, and what conditions are associated with high and low afterload?

  An increase in afterload (increased resistance) can reduce stroke volume and cardiac output.

  
  

  High afterload may be seen in conditions like hypertension or aortic stenosis, while low afterload may occur in distributive shock conditions such as sepsis or anaphylaxis.
• Can an increase in afterload contribute to an increase in myocardial oxygen demand?

  Yes, an increase in afterload can potentially increase myocardial oxygen demand, especially when the heart is working harder against increased resistance to eject blood.
• How do changes in preload and afterload influence Stroke Volume and Cardiac Output?

  An increase in preload generally increases Stroke Volume and Cardiac Output, while an increase in afterload may reduce Stroke Volume and Cardiac Output.
• What is the role of preload and afterload in cardiac physiology, and how do they collectively affect Cardiac Output?

  Preload, the ventricular stretch at the end of diastole, and afterload, the resistance the heart overcomes to eject blood, both influence Stroke Volume.

  
  

  The cumulative effect of these factors determines Cardiac Output, representing the volume of blood pumped by the heart in one minute.