Overview Of CNS And Baroreceptor Reflex Flashcards Preview

Cardiology > Overview Of CNS And Baroreceptor Reflex > Flashcards

Flashcards in Overview Of CNS And Baroreceptor Reflex Deck (21)
Loading flashcards...
1
Q

Sympathetic agents

A

Norepinephrine (sympathetic neurotransmitter)
- acts at effectors only

Epinephrine (sympathetic hormone)

Acetylcholine (sympathetic/parasympathetic neurotransmitter)
- acts at effectors and ganglia

Dopamine (sympathetic hormone)
-acts at effectors only

2
Q

Parasympathetic agents

A

Acetylcholine (sympathetic/parasympathetic neurotransmitter)

3
Q

What is the only location in the body that receives acetylcholine on its tissue receptors after the neuron has crossed the sympathetic trunk?
(Receives signals via the sympathetic route, but its actually acetylcholine)

A

Sweat glands

4
Q

Biosynthesis of catecholamines in the body

A

Catecholamines are dopamine, norepinephrine and epinephrine.

Begins with tyrosine substrate -> DOPA -> Dopamine -> norepinephrine-> epinephrine
- note if the body needs dopamine of norepinephrine, it will stop the conversion there .

5
Q

What receptor is consisted an autoreceptor?

A

A2
- while it also has immediate direct vasoconstriction effects, its primary purpose when activated is to block norepinephrine release. This overtime causes parasympathetic effects.

6
Q

Receptor Selectivity of catecholamines

A

NE = equal for alpha receptors, however (B1»>B2)
- therefore its clinical use is when you want a heart response, but little lung response

Epinephrine = Equal for all alpha and beta receptors

Dopamine = D»>B»>a
- causes increased renal filtration rates and a positive inotropic effect on the heart in large doses.

7
Q

Baroreflex sympathetic responses

A

In the presence of lowered blood pressure (MAP), the baroreflex will induce the following:

  • increases heart rate
  • increase inotropic effects
  • increase venous tone
  • increase preload
  • increase stroke volume
  • increase cardiac output
  • increases peripheral vascular resistance (vasoconstriction)

All of these factors work together to increase Blood pressure (MAP)

8
Q

Baroreflex parasympathetic response

A

If the blood pressure is really high, the baroreflex will stimulate a parasympathetic response which is to decrease heart rate and cardiac output

Both of these two decreases work to decrease Blood pressure (MAP)

9
Q

A1 agonist effects

A

Peripheral vasoconstriction

Increased SVR

Increases venous return

Increased Blood pressure

Modest positive inotropic effect

will induce a baro-receptor mediated reflex bradycardia

10
Q

A2 agonist effects

A

Different effects based on local vs systemic (systemic is more common)

Local = vasoconstriction of arteries and veins

Systemic = decreases sympathetic outflow due to blocking the release of NE systemically
- causes vasodilation

11
Q

B1 agonist effects

A

Increases inotropic, dromotropic and chronotropic effects

Increases renin production (increases BP)
- done via retaining volume/sodium

12
Q

B2 agonist effects

A

Vasodilation and bronchodilation

13
Q

Albuterol

A

B2 selective agonist used in the treatment of asthma and COPD
- NOT used for heart stuff or HTN

14
Q

B receptor antagonists

A

Negative chronotropic and inotropic effects

Lowers blood pressure in HTN patients
- done via decreasing cardiac output due to decreased heart rate and stroke volume

  • will acutely increase BP in non-HTN patients*
  • this is because B2 blockade results in unopposed a1 vasoconstriction

Bronchoconstriction (DONT use w/ asthmatics of COPD patients)

Inhibts lipolysis and inhibits glycogenolysis
(DONT use w/ diabetics)

Increases VLDL and decreases HDL

15
Q

What BBs have local anesthetic effects

A

Labetalol

Propranolol

Pindolol

Metoprolol

Acebutolol

16
Q

Why is sotalol a special BB?

A

It blocks B1 and B2 receptor as well as K+ channels

17
Q

Why is esmolol special?

A

Shortest half life for a BB

- 10 min

18
Q

Clinical action against HTN for BBs

A

Induces a hypotensive action

- decreases cardiac output by suppressing renin release from the kidney

19
Q

Clinical action against ischemic heart disease w/ BBs

A

Reduces angina frequency and induces a negative inotropic/chronotropic effect on the heart
- this decreases cardiac work load and oxygen demand, allow for the damaged heart to compensate

20
Q

Clinical action against cardiac Arrhythmias w/ BBs

A

Antiarrhythmic properties surround slowing and regularizing the heart rate
- BBs give a negative chronotropic effect

Note: sotalol has additional antiarrhythmic effects since it also blocks K+ channels

21
Q

A-receptor antagonist broad effects

A

Hypotension

  • mediates vasoconstriction in arteries and veins
  • this is opposed by the baroreceptors reflex and usually results in reflex tachycardia

Orthostatic hypotension