Cardiac and Vascular Physiology Flashcards
What type of circulatory system do vertebrates have?
Vertebrates have a closed circulatory system, where the blood is enclosed in specialized vessels and circulates through a multi-chambered heart with complex valves
What are the primary differences between atrial and venous circulation?
Atrial circulation carries oxygenated blood from the heart to the rest of the body.
Venous circulation returns de-oxygenated blood back to the heart.
What is the function of the atrioventricular valves in the heart?
The atrioventricular valves (mitral on the left and tricuspid on the right) are located between the atria and ventricles. They ensure proper blood flow from the atria to the ventricles and prevent backflow.
What is the role of the coronary arteries in cardiac perfusion?
The coronary arteries supply blood to the myocardium (heart muscle), ensuring the heart receives the oxygen and nutrients it needs to function effectively.
How does cardiac output (CO) relate to heart rate and stroke volume?
Cardiac Output (CO) is the volume of blood pumped by one ventricle per minute and can be calculated as: Cardiac Output (ml/min) = Heart Rate (beats/min) x Stroke Volume (ml/beat)
What is the significance of the sinoatrial (SA) node in the heart’s electrical conduction system?
The sinoatrial (SA) node is the initiating region for electrical impulses in the heart. It sets the rhythm of the heart, acting as the natural pacemaker.
How does blood pressure relate to systolic and diastolic pressure?
Systolic pressure is the measure of the contractile force when the heart pumps blood.
Diastolic pressure is the measure of the pressure when the heart is at rest between beats.
Pulse pressure is the difference between systolic and diastolic pressures.
What are the key differences between arteries and veins in terms of structure?
Arteries have a well-defined tunica media with smooth muscle cells and elastin, which allows for high pressure and blood flow.
Veins have a poorly defined tunica media and large lumens with thin walls, as well as valves to prevent backflow of blood
What is the function of capillaries in the cardiovascular system?
Capillaries form a network between arteries and veins and allow for the transfer of nutrients, gases, and waste products between the blood and tissues.
How does the lymphatic system complement the cardiovascular system?
The lymphatic system consists of vessels that carry lymph, which includes tissue fluid, fats, and cells. These vessels help return excess fluid from tissues back towards the heart and aid in immune function.
What is the formula for calculating Mean Arterial Pressure (MAP)?
The Mean Arterial Pressure (MAP) is calculated as: MAP = Diastolic Pressure + (0.3333 x Pulse Pressure) For a normal individual, MAP is typically around 93.3 mmHg.
How does exercise affect cardiac output?
During exercise, venous return increases, leading to a greater preload. The cardiac muscle contracts with greater force, resulting in a larger stroke volume, which increases cardiac output.
What factors influence blood pressure?
Factors that can influence blood pressure include:
Arterial constriction (increased resistance)
Venous return (affecting cardiac output)
Sympathetic nervous system activity (vasoconstriction)
Total peripheral resistance, which is the main determinant of arterial blood pressure.
What are the three types of capillaries, and what is their function?
The three types of capillaries are:
Continuous capillaries - Allow for the exchange of gases and small molecules.
Fenestrated capillaries - Have pores that allow for the exchange of larger molecules.
Sinusoid capillaries - Allow for the passage of larger cells and molecules, important in the liver and spleen.
How is blood flow regulated in the vascular system?
Blood flow is regulated by:
The force of blood generated by heart contraction.
The size of the vessels and the action of smooth muscle cells in the vessel walls.
One-way valves in veins that prevent backflow and ensure blood moves in one direction.
What is the role of the Purkinje fibers in the heart’s electrical conduction system?
The Purkinje fibers are specialized cardiac myocyte-like cells that translate electrical impulses into contractile force, helping to ensure the coordinated contraction of the ventricles.
How does the heart’s electrical conduction system ensure coordinated contraction?
The heart’s electrical conduction system, including the sinoatrial (SA) node, atrioventricular (AV) node, bundle branches, and Purkinje fibers, ensures coordinated contraction by transmitting electrical impulses that regulate the timing of atrial and ventricular contractions, maintaining efficient blood flow.
What is the significance of the intraventricular septum in the heart?
The intraventricular septum is the dividing wall between the two ventricles. It plays a crucial role in separating oxygenated blood in the left ventricle from deoxygenated blood in the right ventricle, ensuring proper blood flow to the lungs and the rest of the body.
What is the function of the semilunar valves in the heart?
The semilunar valves (aortic and pulmonary valves) are located in the arteries leaving the heart. They ensure that blood flows in the correct direction, preventing backflow into the ventricles after the heart pumps blood into the arteries.
