Lecture 20 - Control Of Blood Pressure : Pharmacology And The Role Of The Kidney

Question 1

What is the cause of 90% of hypertension cases

Answer 1

It is unknown

Question 2

If the cause of hypertension is unknown what type of hypertension is it

Answer 2

Primary/essential hypertension

Question 3

Hypertension that can be traced to a known condition is usually associated with

Answer 3

Renal disease or endocrine disturbances

Question 4

Hypertension that can be traced to a condition is known as what type of hypertension

Answer 4

Secondary hypertension

Question 5

What are the consequences of chronic hypertension

Answer 5

Abnormal thickening of the left wall of the ventricle and narrowing of the lumen in resistance vessels

Question 6

What is chronic hypertension a risk factor for

Answer 6

Heart failure, stroke, renal failure and myocardial infarction

Question 7

How can hypertension be managed

Answer 7

Through lifestyle modification

Question 8

What lifestyle modifications can be made to manage hypertension

Answer 8

The loss of additional weight, increase aerobic exercise, reduced alcohol intake, low salt diet and no smoking

Question 9

What drugs are used in the treatment of hypertension

Answer 9

ACE inhibitors or AT1 receptor blockers (ARBs), beta-blockers, calcium channel blockers and diuretics

Question 10

What is the stepwise treatment for hypertension in under 55 and non-black

Answer 10

Step 1 - ACE inhibitors
Step 2 - ACE inhibitors and calcium channel blockers
Step 3 - ACE inhibitors, calcium channel blockers and diuretics
Step 4 - Consider adding alpha-blockers, beta-blockers or spironolactone or additional diuretics

Question 11

What is the stepwise treatment for hypertension for over 55 and black

Answer 11

Step 1 - Calcium channel blockers
Step 2 - ACE inhibitors and calcium channel blockers
Step 3 - ACE inhibitors, calcium channel blockers and diuretics
Step 4 - Consider adding alpha-blockers, beta-blockers or spironolactone or additional diuretics

Question 12

What do B-blockers act as

Answer 12

Competitive antagonists of B-adrenoceptors

Question 13

What effects do B-blockers have

Answer 13

A reduced cardiac output, reduced MABP, reduced renin release from the kidneys and a CNS action that reduces sympathetic activity

Question 14

In what patients are B-blockers useful

Answer 14

Patients with angina or following a myocardial infarction

Question 15

What are the adverse effects of B-blockers

Answer 15

Bronchospasm, aggravation of cardiac failure, bradycardia, hypoglycaemia, fatigue and cold extremities

Question 16

What does the RAAS system play a major role in

Answer 16

The regulation of sodium excretion and vascular tone

Question 17

What activates the RAAS

Answer 17

A drop in blood pressure

Question 18

Describe the RAAS

Answer 18

A drop in blood pressure is detected by the kidneys which causes the stimulation of the granular cells to release renin. Renin interacts with angiotensinogen, produced by the liver, and converts it to angiotensin I. Ang I then travels to the lungs where angiotensin converting enzyme (ACE) converts it to angiotensin II. Ang II travels to the adrenal gland and causes the release of aldosterone. Aldosterone travels to the kidney and causes an increase in sodium chloride and water retention which causes an increase in blood pressure

Question 19

What cells are found within the juxaglomerular apparatus

Answer 19

Macula densa, granular cells and mesanglial cells

Question 20

What is the function of macula densa

Answer 20

To detect the sodium chloride concentration in the blood

Question 21

What is the function of granular cells

Answer 21

To produce renin

Question 22

What innervates the granular cells

Answer 22

The sympathetic nervous system

Question 23

What effect does RAAS have on congestive heart failure

Answer 23

A failing heart has a decreased CO and BP, the lowered BP causes the stimulation of RAAS and this increases the salt and water retention which causes the heart to fail

Question 24

Where are ACE-membrane bound enzymes found

Answer 24

On the surface of endothelial cells

Question 25

What is the function of the ACE-membrane bound enzymes

Answer 25

To convert inactive angiotensin I to angiotensin II

Question 26

What does angiotensin II inactivate

Answer 26

Bradykin

Question 27

Function of ACE inhibitors

Answer 27

They block the conversion of angiotensin I to angiotensin II

Question 28

Example of an ACE inhibitor

Answer 28

Lisinopril

Question 29

What is the function of AT1 receptor antagonists

Answer 29

To block the agonist action of angiotensin II at AT1 receptors in a competitive manner

Question 30

What do ACE inhibitors cause

Answer 30

Venous dilation so reduced preload, arteriolar dilation so reduced after load and TPR, which decreases the arterial blood pressure and cardiac load

Question 31

What do ACE inhibitors reduce the release of

Answer 31

Aldosterone

Question 32

What does a reduction in the production of aldosterone cause

Answer 32

An increase in the loss of Na+ and H2O

Question 33

What are the adverse effects of ACE inhibitors

Answer 33

A dry cough and can also cause hypotension

Question 34

What are the properties of ARBs

Answer 34

Similar to ACE inhibitors

Question 35

What conditions should ACE inhibitors and ARBs contraindicated in

Answer 35

Pregnancy and bilateral renal artery stenosis

Question 36

What are the clinical uses of ACE inhibitors and ARBs

Answer 36

Hypertension, cardiac failure and following a myocardial infarction

Question 37

What is the benefit of using ACE inhibitors and ARBs in hypertension

Answer 37

Reduced TRP and MABP and the possible suppression of proliferation of smooth muscle cells in the media of resistance vessels

Question 38

What is cardiac failure associated with

Answer 38

The inappropriate activation of the RAAS

Question 39

What do ACE inhibitors do

Answer 39

They decrease vascular resistance improving perfusion, increase secretion of Na+ and H2O and cause regression of left ventricular hypertrophy

Question 40

What do diuretics act on

Answer 40

The kidneys

Question 41

What is the function of diuretics

Answer 41

To increase excretion of Na, Cl and H2O and exert additional indirect relaxant effects on the vasculature

Question 42

What are the major classes of diuretics

Answer 42

Thiazides and loop agents

Question 43

Thiazides

Answer 43

Inhibit NaCl reabsorption in the distal tubule by blocking the Na+/Cl- co-transporter

Question 44

Example of a thiazide

Answer 44

Bendroflumethiazide

Question 45

What are thiazides widely used in

Answer 45

Heart failure, hypertension and additionally in severe resistant oedema

Question 46

What do thiazides reduce

Answer 46

MABP

Question 47

What does the loss of Na+ and H2O cause

Answer 47

Contracts blood volume and initially reduces the cardiac output

Question 48

Loop agents

Answer 48

They inhibit the the NaCl reabsorption in the thick ascending loop of henle by blocking the Na+/Cl-/K+ co-transporter

Question 49

What do thiazides and loop agents cause an undesirable loss of

Answer 49

K+

Question 50

How is the loss of K+ corrected

Answer 50

By co-administering a potassium sparing diuretic or K+ supplements

Question 51

Example of loop agent

Answer 51

Furosemide

Question 52

Loop agents are used to reduce the salt and water overload associated with

Answer 52

Acute pulmonary oedema and chronic heart failure

Question 53

How is the salt and water overload corrected

Answer 53

As a result of an absorption of extracellular fluid contributing to oedema in capillaries as a consequence of diuretic-induced reduction of blood volume