CVS Flashcards
Maximum blood flow during exercise
25 l/min
Minimum blood flow
5 l/min
What are the Venae Comitantes
3 vessels (2v 1a) wrapped in one sheath. Pulsing of artery promotes venous return.
3 examples of venae comitantes
Brachial, Ulnar, Tibial
What is pericarditis?
Inflammation of the pericardium.
Rubbing sound on auscultation.
What is pericardial effusion?
Accumulation of fluid that compresses the heart.
Right cardiac hypertension.
What is isovolumetric relaxation?
Relaxation of ventricles when all valves closed.
What is rapid filling phase?
Opening of AV valves so high pressure blood in atrium enters into ventricle.
What is isovolumetric contraction?
Contraction when all valves closed. This causes a massive increase in ventricular pressure.
What is the rapid ejection phase?
Outflow valves open and isovolumetric contraction ended.
What is splitting?
Valves do not close at the same time.
What is stenosis?
Narrowed valve.
What is incompetence?
Valve not closing correctly.
What is acyanotic congenital heart defect?
Shunting of blood from left to right (oxygenated).
What is cyanotic congenital heart defect?
Deoxygenated blood shunted from right to left side of the heart. Deoxy blood enters circulation.
What are chromaffin cells?
Receive ACh and release adrenaline into blood stream. Found in adrenal medulla.
Define flow
Volume of fluid passing given point per unit time
Define velocity
Rate of movement of fluid particles along tube.
At fixed flow what is the relationship between velocity and cross sectional area?
Inversely proportional
With fixed pressure, what is the relationship between velocity and cross sectional area?
Directly proportional
With fixed pressure, what is the relationship between velocity and viscosity?
Inversely proportional
Mean velocity x cross sectional area = ?
Flow
Flow x Resistance = ?
Pressure
How is overall resistance calculated in series?
R1 + R2
How is overall resistance calculated in parallel?
(R1 x R2)/(R1 + R2)
What is pulse pressure?
Systolic - Diastolic
How is average pressure calculated?
Diastolic + 1/3 Pulse Pressure
Define stroke volume
End Diastolic Volume - End Systolic Volume
Define contractility
Slope of Starling Curve
What is the relationship between TPR and the body’s need for blood?
Inversely proportional
Normal pulmonary artery pressure
12-15 mmHg
Normal pulmonary capillary pressure
9-12 mmHg
Pulmonary vein pressure
5 mmHg
Optimal ventilation/perfusion ratio
0.8
Effect of hydrostatic pressure in Starling’s Forces
Push fluid out of vessel and into interstitial fluid.
Effect of oncotic pressure in Starling’s forces.
Large molecules in blood draw fluid into vessel.
Describe the effect of myogenic autoregulation
Increased BP causes vasoconstriction (vice versa).
In cerebral circulation.
Describe the effects of metabolic concentrations in cerebral circulation.
Hypercapnia causes vasodilation (hypo causes constriction).
Describe the effects of hyperventilation concerning cerebral circulation.
Hyperventilation causes hypocapnia. This employs cerebral vasoconstriction leading to dizziness or fainting.
What is Cushing’s Reflex?
Rigid cranium prevents brain expansion. Impaired blood flow to vasomotor control regions causes increase in arterial BP to maintain cerebral blood flow.
Action of Class I arrhythmia drugs
Block open or inactivated Na+ voltage-gated channels
Action of Class II arrhythmia drugs
β-adrenoreceptor antagonists
Action of Class III arrhythmia drugs
Blocks K+ channels
Action of Class IV arrhythmia drugs
Block Ca2+ channels
Action of adenosine in arrhythmia
α 1 Receptor agonist
Define heart failure
Chronic failure of the heart to provide sufficient output to meet the body’s requirements
What does ACE stand for?
Angiotensin Converting Enzyme
Define central venous pressure
Pressure in the great veins
Define venous return
Return of blood from the body
