Cardiology: Vasculature Flashcards by Jennifer Steen

What is your central venous pressure?

The pressure in your right atrium

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What g protein acts in smooth muscle?

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What does activation of the CPCR in smooth muscle cause?

Opening of L type calcium channels
Increased calcium into cell
Calcium binds to calmodulin
Activates MLCK
Phosphorylates myosin LC
CONTRACTION

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How does vascular smooth muscle relax?

Increased cGMP
Activates Myosin LC phosphatase
Dephosphorylates myosin LC
RELAXATION

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Describe the formation of NO in endothelial cells.

Vasodilating substances act on CPCR which open calcium channels
Increase in calcium
Binds to calmodulin
Forms eNOS
Catalyses the formation of NO from Larginine and oxygen

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What happens when NO diffuses into the smooth muscle?

NO activates Calcium dependant activated K channels
Efflux of potassium–>relaxation
NO also activates guanylate cyclase which concerts GTP to cGMP
cGMP acts of protein kinase G
RELAXATION

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What is the effect of organic nitrates?

Metabolise to form nitric oxide- relaxes all types of smooth muscle

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What effect does organic nitrates have on the vasculature?

Venorelaxation
Arteriolar dilation
Increased coronary blood flow

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How are organic nitrates beneficial in angina?

Decrease preload and afterload

Improve perfusion to the ischaemic areas ( by opening collaterals)

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Name two organic nitrates used to treat angina.

GTN (short acting)
Isosorbide Mononitrate (longer acting)

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Name two unwanted effects of organic nitrates.

Tolerance

Headaches (initially)

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What substances will switch on genes for endothelin production?

Adrenaline A
Andgiotensine II
ADH

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What substances will switch off genes for endothelin production?

Nitric oxide

Shear stress

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What receptor does endothelin activate?

ETa receptorq

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What g protein is activated by endothelin?

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What does the activation of g proteins by endothelin cause?

Intracellular calcium increases- contraction

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What are antagonists of the ETa receptor used to treat?

PULMONARY hypertension

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Name two ETa antagonists

Bosentan

Ambrisentan

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What do ACE inhibitors do?

Block ACE- an endothelial enzyme which catalyses the formation of angiotensin II from angiotensin I

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Name an ACE inhibitor.

Lisinopril

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What do AT1 receptor antagonists do?

Block the action of angiotensin II on the AT1 receptors

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Name an ARB

Losartan

What drug should not be used in conjunction with ACE inhibitors or ARBs?

Rennin inhibitors eg aliskiren

Give the adverse affects of ACE inhibitors.

Hypotension

Dry cough

What is the main difference between ACEI and ARBs

ARBS do not inhibit the metabolism of bradykinin | Do not get a dry cough

Are ACEI and ARBs safe in pregnancy?

Name three uses of ACEI and ARBS

hypertension cardiac failure following an MI

Why do ACEI give you a dry cough?

They do not allow the break down of bradykinin which irritates sensory nerve fibres triggering the cough reflex

What effect do beta blockers have on the kidney?

Decrease renin release

What happens to RAAS during heart failure?

It is inappropriately activated

What do calcium antagonists do?

Prevent the opening of L-type channels and decrease calcium concentration of result in relaxation

Where can calcium antagonists act?

The Heart | Smooth muscel

Name a calcium antagonist the works solely of the heart.

Verapamil

Name a calcium antagonist that works manly on the smooth muscle?

Amlodipine

Name a calcium antagonist that works with intermediate selectivity?

Diltiazem

How can calcium antagonists be used to treat hypertension?

Arteriolar dilation- reduces MAP Coronary vasodilation Indicated for patients soley with systolic hypertension

Give the adverse effects of calcium antagonists

Hypotension Dizziness Flushing Swollen ankles

How can calcium blockers be used in angina?

Arteriolar dilation decreases preload | Coronary vasodilation

When should verapamil not be used?

In heart failure | With a beta blocker

How do potassium channel openers work?

Antagoniste intracellular ATP redulting in opening of K channels and hyperpolarisation which switches of Ca channels RELAXATION

Name two potassium channel openers.

Minoxidil | Nicorandil

When is minozidil used?

Last resort hypertension | Can cause reflex tachycardia and water retention

WHen is nicorandil used>

Last resort angina

Name two alpha adrenoceptor antagonsits

Prazosin Doxazosin can cause postural hypertension

How do diuretics work?

They act on the kidney to increase the excretion of Na, Cl and water

Name the two types of diuretic

Thiazide | Loop

Where do thiazide diuretics limit absoprtion

In the distal tubules | Moderate diuresis

Where so loop diuretics limit absorption

Loop of henle | Strong diuresis

What is the adverse affect of diuretics?

Hypokalaemia

Name a thiazide

Bendroflumethiazide

When is bendroflumethiazed used?

Mild hear failure Hypertension Severe resistan oedema (combined with Loop)

Name a loop diuretic

Furosemide

When is furosemide used?

Acute pulmonary oedema | chronic heart failure