:L Flashcards
what are major classes of antihypertensive agents? (5)
1. angiotension converting enzyme inhibitors (ACE inhbitors): block conversion of angiotension I to II
2. angiotension II receptor blockers
3. dihydropyridine calcium channel blockers:
4. thiazide diuretics: inhibit Na-Cl contransporter in DCT = natriuresis
5. loop diuretics: Inhibit Na-K-Cl cotransporter in loop of Henle = natriuresis
how do loop diuretics work? / mechanism of action?
what does this mean regarding K scerection in urine?
- inhibit the luminal Na-K-2Cl contransporter in thick ascending limb of LoH
- get increased delivery of Na to distal tubule, enhances K secretion into urine
good for acute response, more research needed for long term reduciton in hypertension
how do calcium channel blockers work?
what are the two major types? & mech of action for each
- block Ca entry to vascualr smooth muscle and myocardial cells: interrupt excitation-contraction coupling
types:
- dihydropyridine CCBs: vasodilate dominately. reduced systemic vascular resistance
- non dihydropyridine CCBs: reduce HR, contractility, conduction. may worsen heart failure tho
what is angina and how do u treat?
angina - restricted blood supply to heart
what is effect of nitroglycerin (and glyceryl trinitrate) in low doses and high doses?
low dose:
- *- decreases preload
- decrease myocardial o2 demand**
high dose:
- *- decreases afterload
- decreaese myocardial o2 demand**
Q
what is MOA for beta blockers for treating angina?
Beta Blockers
- B1 receptor antagonist:
- causes reduced HR (@ SA node)
- decrease in o2 demand at SA node
- negative inotropic effect
- decrease BP
- decreased myocardial oxygen demand
what are the two MOA for calcium channgel blockers?
- intracellular Ca2+ influx stopped
i) Left ventricle and HR decrease: less o2 consumption in myocardium
_ii) vascular smooth muscle contraction inhibitio_n: coronary artery dilation = coronorary BF increaeed, o2 supply in myocardium increased
decreases angina
what are three types of drugs used for drugs in heart failure?
- positive inotropic drugs
- vasodilators
- misceallaneous drugs for chronic failure
what is ejection fraction?
what is normal, borderline and reduced ejection fraction?
ejection fraction: compares the measurement of the percentage of blood leaving your heart each time it contracts to the amount of blood pumped oiut
normal ejection fraction: 50-70% (50/70% of blood is pumped out every cardiac cycle)
borderline ejection fraction: 41-49%
reduced ejection fraction: <40%
what 3 movements happen (how) when inhalation occurs?
- *pump handle movement:**
- during inhalation, get elevation of the ribs: ribs move superior and anterior (increasing diameter)
- occurs at costal-vertebral joints (ribs & Tvert)
- *bucket handle movement:**
- during inhalation: increase lateral diameter of thorax
- *diaphragm:**
- during inhalation: flatttens
name 5 chest muscles that involved in inhalation [5]
serratus anterior
pectoralis major
pectoralis minor
external intercostal muscles
sternocleidomastoid
describe path of trachea -> alveolar sacs
trachea -> main bronchus -> lobar bronchus -> segmental bronchi -> conduncting bronchioles -> terminal bronchioles -> respiratory bronchioles-> Alveolar ducts -> alveolar sacs
where is sensor for the hormonal control of BP?
sensor: juxtaglomerular apparatus of the distal tubule of the kidney
which two systems does the juxtaglomerular apparatus of the distal tubule of the kidney control?
- GFR
- hormonal blood pressure
effect of angiotension II on afterload? why?
- angiotension II is a potent vasoconstrictor of smooth muscle of systemic arterioles: raises afterload and therefore BP
what is liddle syndrome / disease?
- enac channels undergo ubiquitination
- this causes inappropriately elevated sodium reabsorption in the distal nephron
- this makes have too much water retention and hypertension
what is a different way that renin can be released?
describe how positive feedback can occur because of this alternative renin release xx
Renin can also be released by sympathetic stimulation; there are sympathetic nerves to the kidney, and beta receptors on the cells of the juxtaglomerular apparatus.
This raises the possibility of positive feedback; sympathetic stimulation increases renin release, angiotensin then increases noradrenaline release which in turn increases renin release leading to hypertension
what does activation of AT1 receptors cause to occur? [3]
AT1:
i) GCPR which increases Ca entry into smooth muscle & constriction to occur
ii) stimualtes noradrenaline release from sympathetic nerve terminlas (can increase BP via SNS too)
iii) found in cells of adrenal cortex: secretes aldosterone
what is bradykinin & how do ACE inhibitors interact with them?
- bradykinin: 9 amino acid peptire
- ACE inhibitors: increase bradykinin levels by inhibiting its degradation
- causes a dry cough in patients who take ACE inhibitors (why people often stop taking them)
- can cause angioedema - occurs 5x higher in African descent: which is why ACE inhibitors are not the first line of drugs for treating hypertension
the airway tree divides how many times? into what two subparts?
The airway tree divides 23 times:
- first 16 divisions make up the conduction airways
- the last 7 are the respiratory zone