Classifications of HTN
1. optimal BP
3. HTN stage 1-2-3
- 140/90 (one med)
- 160/100 (one or two meds)
- 180/110 or greater
CV mortality is more closely related to SBP OR DBP?
Marked or shapr increase in DBP to 120mm Hg
- No end organ damage evident
- Can reduce BP over hours to days
- End organ damage
- BP needs decrease within several min to hours
Where are the pressure sensitive neurons located?
Aortic arch and carotid sinus
Where are the Alpha-1 receptors located?
Smooth muscle cells within walls of arterioles in skin, mucosa, viscera, kidneys and within walls of veins- causes vasoconstriction to increase BP.
Where are the Beta-1 receptors located?
Cells of SA node and AV node. Increase HR, conductivity, force of contraction and increase CO which increases BP.
3 things that stimulate Renin secretion?
- 1. Decrease in NaCl transport in the ascending limb of the loop of Henle.
- 2. Decrease pressure or stretch within the renal afferent arteriole (baroreceptor mechanism).
- 3. Sympathetic NSstimulation of renin secreting cells via B1 adrenoreceptors.
RENIN SECRETION IS INHIBITED BY THE OPPOSITE OF THE THE ABOVE FACTORS.
STEPS OF rENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM
- 1. Low BP detected by juxtaglomuerular cells in renal afferent arterioles.
- 2. Renin release by renal affernt arterioles.
- 3. Renin stimulates production of Angiotensin I.
- 4. Angiotensin I turns into Angiotensin II
- 5. ATI (brain, renal, nyocardial, vascular, and adrenal tissue) and ATII (brain, adrenal medulla, and uterine tissue) receptors stimulated.
- 6. Sympathetic stimulation of cardia system- direct vasoconstriction, increase epinephrine release from adrenal medulla, and increase in sympathetic activity.
- 7. Increased release of aldosterone which stimulates Na and K pumps in renal tubules.
- *HCTZ and metolazone
- *MOA- decreases plasma volume
- *Lowers BP 10-15 mm Hg in most pts
- *Sometimes used with vasoldilator or sympathomimetic drugs.
- *Decrease potassium, increase uric acid, increase glucose, increase lipid levels, decrease magnesium levels.
2. CLORTHALIDONE (HYGROTON)
- *Decreases potassium, increase uric acid, increase glucose, increase lipid levels, decreace mag levels
- * 1-2 times more potent than HCTZ for BP