Test 2 RT Flashcards
Tell me about the hearts pump system.
The heart is a 2 pump system. The small pump on the right side of the heart pumps blood to the lungs and back to the heart and the larger stronger pump on the left pumps blood throughout the remainder of the body. Also it is a closed system.
What is the passage of blood in the heart starting from the body?
From the BODY through the superior vena cava to the RIGHT ATRIUM to RIGHT VENTRICLE to the LUNGS via the pulmonary arteries then back into the heart to the LEFT ATRIUM then the LEFT VENTRICLE to the body from the aorta
What is are the muscular cells of the heart called?
Myocardial
What is afterload?
Pressure that the ventricles must create to eject the blood out of themselves into the aorta or pulminary artery
What happens if an animal has hypertension?
Arteries are smaller
Harder to push blood into the vessels
Little pressure and more force
What are examples of sodium channel blocker antiarrhythmic drugs?
Lidocaine, Quinidine, Procainamide
LQP
Talk to me about Lidocaine
Lidocaine selectively decreases firing of ectopic focus cells without significantly depressing the function of the normal conduction system.
Cats should be given this at lower dosages as they are more sensitive to the side effects
What trade name works similar to lidocaine but can be given orally?
mexiletine
Talk to me about Quinidine and Procainamide
They control both ventricular ectopic foci and atrial flutter or fibrillation, Injectable procainamide may be seen in small animals occasionally.
Quinidine may be seen in use to control artial fibrillation in horses
What are antiarrhythmic beta blockers?
drugs that block beta 1 sympathetic nervous system receptors on the heart leading the parasympathetic nervous system effects to dominate
They basically calm down the heart from beating too fast.
overtime we will see upregulation where the animal becomes resistant to the effects of the drug
Examples of antiarrhythmic beta blockers.
Propranolol - non selective
Atenolol - hypertension, feline cardiomyopathy
Carvedilol - general
Metoprolol - cardiomyopathy in cast
Esmolol - short acting
PACME
Pacmen
What two antiarrhythmic beta blockers are used to treat cardiomyopathy in cats?
Atenolol and Metoprolol
What are example of calcium channel blockers?
What are they used to treat?
What is the problem with them?
Verapamil and Diltiazem.
Treatment of supracenticular tachycardia, atrial fibrillation and atrial flutter
The problem is they decrease the strength of heart muscle contraction
VD view to see calcium channel blockers
What do positive inotropes do?
They increase the strength of contraction of a weakened heart.
What is an example of a vasoldilator and positive inotropic drug? What is its purpose?
Pimobendan: Vetmedin
it increases calcium binging with the contractile elements resulting in a more effective contraction of cardiac muscle cell
What is the purpose of vasodilators?
These drugs are used to relieve some of the cardiac workload
o Opening constricted sphincters
o Decreasing resistance to flow
o Making it easier for the heart to pump blood through vessels
Also most of them work by blocking the renin-angiotensin-aldosterone system
What are the three classification of Vasodilators?
Arterial, Venous, and Mixed
What are examples of Arterial Vasodilators and what do they do?
Amlodipine
- hypertension in dogs and cat (secondary to kidney disease)
Hyralazine
- mitral valve disease
What are examples of Venous Vasodilators and what do they do?
Nitroglycerin
- primarily relaxes blood vessels on the venous side of circulation. It treats pulmonary edema secondary to heart failure
- wear gloves with this one
Ignore my brain
Venous is venomous so wear gloves with nitroglycerin
What are example of Mixed Vasodilators and what do they do?
Nitroprusside
- short term use to help stabalize dogs and cats
- potent
Ace inhibitors such as Enacard (enalapril), Fortekor (Benazepril), Prilium
List three ace inhibitors and their trade names
Enalapril - trade name: Enacard
Benazepril - trade name: Fortekor
tradename prilium
either end or start with pril?
What is an ARB?
Angiotension Receptor Blocker
example is Semintra (what buddy takes)
- used to used to treat arterial hypertension and reduce proteinuria in cats
its used for hypertension in cats
Discuss vasoconstriction.
Vasoconstriction is a protective mechanism. It happens in a small part of the circulatory system aka the arterioles (small arteries which are located between the arteries and the capillaries).
The arterioles contain one or two layers of smooth muscle that can squeeze the vessels
What is the trade name for Acetylaicylic Acid?
Aspirin
What is the trade name for Acetylaicylic Acid? What does it do?
Aspirin
It inhibits the formation of prostaglandins and thromboxanes
It also reduced the aggregation of platelets
Use with caution with cats (48-hour dose interval to allow for metabolization
What do diuretics promote and reduce?
Diuretics promote the reduction of preload through the process known as ‘diuresis’
They reduce the harmful effects of pulmonary edema, ascites, and increased cardiac work
What are Ancillary drugs?
Bronchodilators
These drugs increase the size of lung passageways to allow more efficient oxygenation of blood
What are the type of renal / urinary drugs?
Diuretics, blood pressure lowering, urinary incontinence and urolith treatment
What do Diuretic do?
They will increase urine formation (volume of urine) and promote water loss from tissues, as well as decrease edema and lower blood pressure
or
Diuretics are drugs used to remove excess extracellular fluid by increasing urine flow and sodium excretion and by reducing hypertension
How do diuretics work in the kidneys.
Diuretics block the reabsorption of sodium and chloride ions while making urine. The sodium then has nowhere to go but out of the kidneys and into the urinary bladder. This will promote water to follow the sodium
When you eat something salty you need water to wash it down
What are the clinical effects of Diuretics?
Increased volume of urine excreted by kidneys & promote release of water from the tissues
Lower fluid volume in tissues – decreasing edema and lower blood pressure
Reduce udder edema in cattle & promote voiding to enhance toxin removalT
What are the types of Diuretics
Loop, osmotic, Thiazide and Thiazide-like, potassium-sparing, carbonic anhydrase inhibitor, and methyzanthines
What diuretic is the most potent?
Loop diuretics
What do loop diuretics do?
Prevent the reabsorption of sodium and chloride from the Loop of Henle
This retention of sodium in the forming urine osmotically retains water in the urine – preventing water reabsorption back into the body and results in a water loss as urine
How does loop diuretic not result in sodium loss?
Because sodium is so important to the body, the distal convoluted tubule has an active transport mechanism by which sodium is reabsorbed and potassium is excreted in exchange for the sodium
Common loop diuretics examples
Furosemide: LASIX®
- exercise induced pulmonary hemorrhage
- Pulmonary edema , CHF , hypertension
How do Osmotic Diuretics work?
Retains water in the renal tubules by its physical presence
It is freely filtered into the Bowman’s capsule BUT POORLY reabsorbed from the renal tubule …this provides a solute that ‘osmotically’ retains water in the renal tubular lumen.
Sodium , Chloride , Potassium , Water: are excreted
DIURESIS BEGINS WITHIN 15-30 MINUTES AND LASTS 3-4 HOURS BECAUSE IT IS HYPEROSMOLAR IT CAUSES WATER TO MOVE OUT OF CELLS AND INTO THE VASCULAR SPACE THIS CAN CAUSE A CIRCULATORY OVERLOAD and IT SHOULD NOT BE USED IN PATIENTS WITH HEART FAILURE.
SOMETIMES USED TO PROMOTE THE RENAL ELIMINATION OF TOXINS
Example of Osmotic Diuretics
Mannitol which increases renal medullary blood flow and decreases intracranial intraocular pressure
Discuss Thiazide Diuretics
Acts directly on the distal convoluted tubule to block sodium reabsorption (and promote chloride ion excretion)
Long term thiazide use causes excessive potassium excretion leading to Hypokalemia and Cardiac dysfunction
Examples Hydrodiuril
Discuss potassium sparing diuretics
The site of action is in the distal convoluted tubule and collecting ducts to, promote sodium-ion excretion (and water excretion), and retain potassium (therefore hyperkalemia possible)
Sometimes referred to as aldosterone antagonists
Example Aldacton (Spironolactone)
What is an acetazolamide? What does it promote?
Carbonic anhydrase inhibitor
Promote the excretion of sodium, potassium, bicarbonate and water
decrease the production of aqueous humor therefore reduce intraocular pressure= used for Glaucoma
What is used to treat ‘spinal cord bladders’ where there has been damage to the nerves which control relaxation of the urinary bladder outflow sphincters? Can you name an example?
cholinergic agents
Bethanechol