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27 Cards in this Set
- Front
- Back
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Sympathetic nervous system activation causes Increased HR and contractility in the heart, and Vasoconstriction of the blood vessels. What is the effect on the kidney? Describe the cascade.
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Stimulates renin release from the kidney. Renin cleaves angiotensinogen to angiotensin I.
Angiotensin I is converted to Angiotensin II via ACE Angiotensin II causes further constriction of blood vessels. It also stimulates the AC to release Aldosterone which acts on the kidneys to retain Na and H20. |
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Name the 4 major cardiovascular pathologies requiring pharmacological intervention.
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Hypertension
Heart Failure Arrhythmia Reduced vascular blood flow |
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What is the formula for BP?
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BP = CO x TPR
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What is the formula for CO?
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CO = HR x SV
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Name the 2 ways that antihypertensives work?
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They either decrease CO or decrease TPR
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What two main factors influence HR?
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Sympathetic/Parasympathetic stimulation
Neuro-hormonal substances (angiotension II, vasopressin) |
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What two main factors influence SV?
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Venous return
Myocardial contractility |
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Vascular Resistance is regulated mostly by this
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SNS
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This regulates both vascular resistance and cardiac output
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SNS, PNS
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Name the 5 phases of a cardiac action potential.
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0 = Rapid Depolarization
1 = Partial Repolarization 2 = Plateau 3 = Repolarization 4 = Pacemaker depolarization |
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What is measured in an ECG?
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Body surface potentials induced by cardiac electrical activity.
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What does the P wave represent?
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Atrial Depolarization
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What does the QRS complex represent?
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Ventricular Depolarization
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What does the T wave represent?
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Ventricular repolarization
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What is the PR interval?
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The area that spans from the P wave (initial atrial depolarization) to the beginning of the Q wave.
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What is the QT interval?
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The area that spans from the beginning of the Q wave to the end of the T wave. Represents the entire interval of ventricular depolarization and repolarization.
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What is the ST segment?
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The area that extends from the end of the S wave to the beginning of the T wave
The period during which the ventricles are depolarized (plateau of action potential) |
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What does Poiseuille's equation measure? What is the equation?
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Measures TPR
TPR = (L x n)/r^4 n = viscosity of the blood |
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What portion of this equation has the greatest effect on TPR?
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blood vessel radius
**70% of TPR is controlled by arteriole sphincters. This is a major target of drug treatment. |
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Describe blood velocity from arteries
to veins |
Highest in arteries. Decreases in capillaries and increases in veins
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Describe blood pressure from arteries to veins
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Highest in arteries. Decreases in capillaries and stays decreased in veins.
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Describe the Total area from arteries to veins
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Lowest in arteries. Increases in capillaries and decreases in veins.
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When is renin released from the kidney? What is its function?
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In response to reduced blood pressure or blood volume
Converts angiotensinogen to angiotensin I |
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What is the function of ACE?
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Converts Angio I to Angio II in the lungs
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What are the 4 actions of Angiotensin II?
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Intense vasoconstriction
Aldosterone release Negative feedback on renin release CNS: stimulates thirst and sympathetic outflow |
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Describe the anatomy of the Nephron
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Glomerulus
PCT LH (thin descending, ascending thin limb, thick ascending limb) DCT (macula densa, juxtaglomerular apparatus) CD (CCD, OMCD, IMCD) |
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Myocardial Oxygen demand is a function of what 2 things?
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Preload
Afterload |
