NEUROHUMORAL CONTROL STUDY GUIDE Flashcards
1
Q
- Which sympathetic nerve receptor predominantly causes vasoconstriction?
A
alpha 1
2
Q
- Which sympathetic nerve receptor predominantly causes increased contractility?
A
Beta 1
3
Q
- Know the definition of the following terms: chronotropy, inotropy, dromotropy, and lusitropy.
A
- Chronotropy – Heart Rate
- Inotropy – Contractility
- Dromotropy – Conduction Velocity
- Lusitropy – Relaxation
4
Q
- What are some of the major differences between the sympathetic and parasympathetic nervous systems?
A
Sympathetic (Thoraco-lumbar) • Increased HR • Increased chronotropy • Increased dromotropy • Increased arterial & venous resistance • Increased venous capacitance
Parasympathetic (Cranio-sacral) • Decreased HR • Decreased chronotropy • Decreased dromotropy • Decreased arterial & venous resistance • Decreased venous capacitance
5
Q
- Does the sympathetic nervous system primarily stimulate or inhibit the heart?
A
Stimulate
6
Q
- What is the “second messenger” that is involved with sympathetic stimulation of a cardiac muscle cell?
A
- cAMP
* adenylyl cyclase activation allows ATP to change to cAMP (allows greater Ca influx in the sarcolemma)
7
Q
- Which catecholamine does the adrenal gland predominantly release with sympathetic stimulation?
A
epi 80%
norepinephrine 20%
8
Q
- What is the Baroreceptor Reflex? Where are the receptors for this reflex located?
A
- Sensors and buffers changed in BP
* Located in the Carotid SINUS (NOT carotid body) and Aortic Arch
9
Q
- How does the Baroreceptor Reflex help with blood pressure regulation?
A
- Helps reduce daily variation in BP
- Helps with postural changes in BP
- Helps to rapidly changing pressure
10
Q
- During what surgery does Baroreceptor Reflex activation frequently cause hemodynamic changes?
A
• Carotid endarterectomy – pushing on carotid sinus (body thinks high BP) so you get profound hypotension.
11
Q
- What is the Bainbridge Reflex? Where are the receptors for this reflex located?
A
• Infusion of volume causes an increase in heart rate due to activation of atrial stretch receptors which causes medullary center activation of sympathetic output to the SA node
- Vena Cava – right atrial junction
- Pulmonary vein – left atrial junction
12
Q
- In addition to receptor activation what also contributes to the heart rate changes seen with the Bainbridge Reflex?
A
- Infusion of volume can increase HR
- Baroreceptor reflex often changes BP in opposite direction
• A small portion of the heart rate increase is d/t stretch of the SA node
13
Q
- The Baroreceptor Reflex responds to changes in arterial blood pressure or to changes in blood volume?
A
• Arterial blood pressure
14
Q
- The Bainbridge Reflex responds to changes in arterial blood pressure or to changes in blood volume?
A
• Blood volume (stretch)
15
Q
- What are some of the effects of Atrial Stretch Receptor activation?
A
- Decreased sympathetic activity to the kidneys - increases urine output
- Decreased vasopressin – increase urine output & decrease water reabsorption/BP
- Increased Atrial Naturetic Peptide – increased urine output/ Natriuresis & decreased BP