Hypertension Flashcards
What BP reading characterizes HTN?
> 140/90 mmHg
What are the 3 types of HTN?
- Essential (primary) HTN
- Secondary HTN
- Malignant HTN
Essential (Primary) HTN
A. 90% of HTN individuals
B. Cause unknown (triggered by drugs)
C. Controlled with antihypertensive agents
Secondary HTN
A. 10% of HTN individuals
B. Cause - renal or endocrine problem
C. Cured by removing cause of HTN
Malignant HTN
A. Condition of VERY hight BP
B. May rapidly lead to retinal or renal damage
C. Treated aggresively
Systolic arterial pressure
Peak pressure (at beginning of cardiac cycle)
Diastolic arterial pressure
Lowest pressure (at resting phase of cardiac cycle)
What physiological mechanismscan reduce BP?
- Reduce sympathetic activity
- Directly relax smooth muscles of vasculature
- Decrease Na retention by the kidney
What factors influence BP?
- Cardiac output (HR, stroke volume)
2. Peripheral vascular resistance (degree of dilation or constriction of BV, blood volume)
T/F: The smaller the volume, the more constricted the arteries
True (higher BP)
T/F: If we dilate (relax) the arteries, the volume is increased
True (lower BP)
What drugs lower BP by decreasing sympathetic activity?
- Clonidine
- Mecamylamine
- Prazosin
- Beta adrenergic receptor antagonists (Beta blockers)
Instrinsic sympathetic activity (ISA) of drugs
Produce less cardiac depression and are preferred agents in pts with diminished cardiac reserve, bradyarrhythmias, and vascular disease. Results from partial agonist activity at adrenergic receptors in addition to the antagonist activity
An individual suffering from diabetes and hypertension is more likely to be prescribed a beta-blocker with which activity?
A selective B1 adrenergic receptor antagonist
avoid B2 activity in these individuals
What drugs directly relax the vascular smooth muscle to decrease BP?
- Hydralazine
- Minoxidil
- Sodium nitroprusside
- Ca channel blockers (Dihydropyridines)
What drugs change Na and H2O balance by the kidney?
- Thiazide diuretics (Chlorothyazide and Hydrochlorothiazide)
- Angiotensin converting enzyme (ACE) inhibitors
- Losartan
What is Renin?
An enzyme that cleaves to angiotensinogen and makes peptide angiotensin I
- juxtaglomerula cells release of renin
Where is Renin released?
Kidneys (under conditions of low blood volume and low NaCl levels. Relsease is controlled by SNS (B1-adrenergic receptors)
What does angiotensin II do?
Increase BP (want to decrease Angio II activity)
Aldosterone
Steroid hormone that increases Na+ balance via action in the kidney (increased Na+ volume leads to increased fluid volume)
Decreased levels of Angiotensin II has what effect on blood pressure?
Decreased BP
