Flashcards in Exam #2: Regulation of Blood Pressure II Deck (24):
What is the NTS?
Nucelus tractus solitarius=
- Bilateral structure
- Receives all input from sensory receptors
- Sends projects to cardio-inhibitory center & vasomotor center
What is the RVLM?
Rostroventral Lateral Medulla
- Vasoconstrictor center
- Sympathetic outflow stops here on its way out of the spinal cord
*Excitation leads to vasoconstriction via the SNS
What is the CVLM?
Caudoventral Lateral Medulla
- Vasodilator center
- Inhibits the RVLM
*Excitation leads to vasodilation by inhibiting the RVLM
What two nuclei form the cardio-inhibitory center? Which division of the ANS are these two nuclei associated with?
1) Dorsal motor nucleus of the vagus (DNMV)
2) Nucleus ambiguus
PNS; thus, excitation leads to slowing the heart rate
Draw the overview of the reflex arcs.
Outline the steps in the PNS reflex arc in response to an increase in HR.
1) Increased heart rate
2) Sensory input
4) DMNV & NA
6) Decreased HR
Outline the steps in the SNS reflex arc.
1) Sensory input
6) Sympathetic Chain
Where are sensory receptors located?
1) Aorta (pressure and oxygen saturation)
2) Carotid arteries (pressure & oxygen saturation)
Baroreceptors detect changes in pressure
Chemoreceptors detect changes in oxygen saturation
What are the reflexes that control blood pressure?
1) Arterial baroreflex
2) Cardiopulmonary baroreflex
What are the characteristics of the arterial baroreflex?
Activated by HIGH pressure
Sensors are in the carotid sinus & aortic arch
What are the characteristics of the cardiopulmonary baroreflex?
Activated by LOW pressure i.e. low volume
Sensors in the atria & pulmonary vessels
What are the characteristics of the chemoreflex?
Central & peripheral receptors
Chemosensitive (O2, Co2, & pH)
- Peripheral input changes sympathetic tone & vasoconstriction
- Central also leads to changes in sympathetic tone/ vasoconstriction BUT also changes hemodynamics in the brain i.e. CO to brain (arteriole resistance)
Draw the arterial baroreflex in regards to the SNS & an increase in blood pressure.
1) Stretch vessel wall
2) Increase BR firing
3) Signal to NTS (via vagus or glossopharyngeal)
4) Inhibition of vasoconstrictor center & activation of cardioinhibitory center
5) Vasodilation of vessels, decrease HR, decrease contractility
Draw the arterial baroreflex in regards to the PNS & and increase in blood pressure.
1) Increased blood pressure sensed
2) Efferents stimulate NTS
3) DMNV & NA activated
4) Increased vagal outflow
5) Decreased heart rate
6) Decreased CO
What happens to the arterial baroreflex in HTN?
Draw the chemoreflex arch.
1) Decreased arterial blood pressure
2) Decreased O2, increased CO2, & increased H+ sensed
3) Increased CR firing
4) Signal to CNS
5) Activation of vasoconstriction center
6) Vasoconstriction of blood vessels
Note that the brain has its own chemoreceptors that will affect these.
Draw the Cardiopulmonary reflex.
1) Decreased blood volume
2) Decreased stretch on atria
3) Increased firing to CNS
Resp oscillations in blood pressure
How is blood pressure regulated in the long-term?
How do the kidneys regulate blood pressure?
What is pressure diuresis?
What is pressure natriuresis?
Draw the renal output curve.