Cardiovascular System Flashcards
What is Darcy’s law?
Flow = pressure difference / resistance
What is the simplified version of Poiseuille’s law?
Resistance = 1/r^4
What formula connects velocity and flow rate?
Velocity = flow rate / cross sectional area
What fibrous sac surrounds the heart to protect i by providing lubrication during constant movement?
Pericardium
What is the difference between excitation-contraction reactions in cardiac and skeletal muscle?
Contraction of cardiac muscle cells is dependent on extracellular Ca^2+ rather than Intracellular Ca^2+
Can tetanic contractions occur in cardiac muscle?
No
Is cardiac muscle multinucleated?
No
What are the four layers of arteries?
• Adventitia (structural strength)
• Elastin (mechanical strength and elastic properties)
• Endothelium (filtering interface and secretes vasoactive products)
• Smooth muscle (contractile power and regulates lumen diameter)
What is active hyperaemia?
Increase in blood flow according to the metabolic needs of the tissue in question
What are the three main categories that regulate arterial diameter?
• Neural controls
• Hormonal controls
• Local controls
What are the three types of capillary endothelium?
• Continuous
• Fenestrated
• Discontinuous
What is oedema?
Accumulation of excess fluid in the interstitial spaces
What is stroke volume regulated by?
• The force by which the muscle cells contract
• The arterial pressure against which they have to eject the blood
What is the force of contraction regulated by?
- Length-tension properties of cardiac muscle cells
- Effects of hormonal influence on the contractility of cardiac muscle cells
Why isn’t MAP (mean arterial pressure) just the average of diastolic and systolic pressure?
Because the heart spends more time in diastole
