export_cv pharm Flashcards
describe the formation of the dorsal aortae
mesoderm –> blood islands –> haemoblasts –> d aortae
What was the precursor of the cardiac tube?
Cardiogenic plate
What do the cranial parts of the dorsal aortae become?
internal carotid arteries
Name the two vessels which bring blood INTO the foetus
- Vitteline vein
- Umbilical vein
What creates the AV canals?
Endocardial cushions
What causes AV valves to be created?
Cavitation. Chordae tendinae and papillary m created now too
Why is the LEFT recurrent laryngeal susceptible to damage?
- hooked around 6th aortic arch
- LHS 6th and 4th remain
- –> DA and ligamentosum arteriosum
- left rec laryngeal retained more cd’lly
What is the function of the intervenous tubercle in the foetal heart?
To guide oxy blood from CD VC across foramen ovale.
Brachiocephalic trunk supplies:
Head, neck, upper limbs, & thoracic wall
Why is it important that the brachiocephalic trunk leaves Cranially to the DA?
So that oxygenated blood supplies the head, not semi oxygenated.
What leads are used to measure the mean electrical axis?
Aug unipolar
Describe the baro reflex
- Baroreceptors in vessels
- detect inc BP/stretch
- ANS –> brain –> para –> heart –> slow
- BP/stretch reduced
Describe the RAAS
- low BP detected
- red GFR (macula densa)
- JGC - renin
- renin
- ANGO I –> ANGIO II (ACE)
- vascocon Aldosterone rel (adrenal)
- Na/Water retention
What is a positive chronotrope
Increases HR, example: beta agonist
What is a positive lusiotrope?
Inc relaxation.
How do cardiac glycosides have a +ve inotropic effect?
Inhibition of the NaCa exchanger
Higher concentrations of Na within the cytoplasm leads to..
neg chronotropic effect
Name three classes of drug which would have +ve inotropic effect
- Cardiac glycosides
- Sympathomimetics
- PDE III inhibitors
What receptor do sympathomimetics target?
B-1.
What do PDE III inhibitors do?
- Inhibit cAMP (cardiac)
- phosphorylation –> Ca channels open —> influx
- Lots of Ca = stronger contraction
- Reflux is faster too
- Pos inotrope and lusiotrope!
Side effects of PDE III inhib?
Tachycard
Vasodil ( inhib of phosph of MLCK)
No oocyte maturation
Name a PDE inhib
Pimobendin, Vetmedin
Name 3 classes of negative inotropes
- Symp antagonist
- Cholinergics
- Ca-channel blockers
What class of drug are B-blockers?
Sympathetic antagonist
What four classes of drugs could be used to treat bradyarrythmmias?
- Sympathomimetics
- Anticholinergics
- Methylxanthines
- PDE III inhib
Sympathomimetics can cause a positive dromotrphy and positive chronotrophy, which receptors is its target?
B2
Dromotophy is
inc speed of conduction from AVN
4 classes of anti-dysrhythmics
Class I: Na channel Blockers
Class II: Beta Blockers
Class III: K+ channel blockers
Class IV: Ca+ channel blockers
(Class V - other)
What negative effects can tachycardia have?
- inc workload
- myocard hypertrophy
- red EDVV
- red CO
- syncope
- death
The PHARM aim to Tx tachycardia is to reduceSAN rate of fire and Slow AVN conduction. How?
- Na channel blockers:
- 1b - not permanent, prev premature beats
- 1c - remain bound longer, reduce conduction B-Blockers slow conduction Ca channel blockers - “”
I. Na channel blockers have 3 classes:
1a. Quinidine:
- rhythm conversion, horses
1b. Lidocaine: - ventric tachycard
1c. Slow through perkinje
What is the action of B-blockers?
- Slow conduction AV
* slow pacemaker pot
What class of drugs should be used to treat Supraventricular tachy?
B blockers
What is atenolol?
B1 blocker
Class III antidysrhythmics aim to:
Block K
Slow repol
Inc refractory
Name a K channel blocker
Sotalol
What is interesting about Sotalol and its isomers?
I-isomer = non-select B blocker D-isomer = K channel blocker
Ca channel blockers aim to:
shorten plateux phase
slow conduction in SAN/AVN
neg inotrope
pos lusiotrope
Name a calcium channel blocker
Amlodipine - vasodil
Diltiazem - CV effect
Nitrates are peripheral vaso______
dilators
Percutol is rubbed on laminitic fetlocks, what is it?
A BOMB!
Nitroglycerine, venodil
PDE V inhibitor are ___________
arteriodilators
What is viagra?
Sildenafil
arteriodilator
What does hydralazine do?
Relaxes arterioles, decreases BP –> reflex tachycardia and ^ renin
Indirect vasodilators will activate another system to cause vasodil for example
activate RAAS
Sympathetics agonists may cause vasodilation. Name 2:
Prazosin and Phenoxybendazine
what componants of the RAAS are vasoconstrictors?
ANG II!
Blocking action of ANG-II would cause vasodil, how can this be done?
- ACE inhib, ramipril
* ANG-II R antagonist (prevents any ANG-II acting), Telismartan
Spironolactone is both a ______ and a _____
Aldosterone antagonist and K-sparing Diuretic
Name 5 types of diuretics
- Thiazide
- Loop
- Potassium-sparing
- Osmotic
- Methylxanthines
