Neuroendocrine function and Hypothalamic control. Neuronal regulation (e.g., of the cardiovascular system); what is the point?.
Neuroendocrine function and Hypothalamic control
Parallel pathways regulate arterial pressure, but their time constants are very different.
It’s the flow that is important
Regional blood flow is important and acute changes in it are largely regulated by the nervous system.
Both the IX and X nerves carry baroreceptor information to the brain. Other baroreceptors located throughout the body organs, but their influence is less global.
Variability of AP control without baroreceptor feedback.
Unlike an injection of NE which raises BP and HR via alpha1-AR equally, epinephrine injections act primarily on beta-AR increasing HR/contractility and thereby increasing CO. BF is increased to the skeletal muscle heart and brain but decreased to the kidney and skin. TPR is reduced as reflected in decrease in diastolic pressure. Increase in CO reflected in increased systolic arterial pressure.
Integrated Neurendocrine regulation of the CV system
Brainstem BP control pathway
Parent, Fig. 17.1
Circadian output of SCN via sympathetic nervous system
Regulates melatonin release from the pineal
Which modulates sleep and sex
B. Activating nuclei to respond to cold or stressShut down eating/peristalsisShiverRenal inhibitionVasoconstrict non-required vascular bedsIncrease blood flow to skeletal muscle
Parent, Fig. 17.20
Parent, 17.20, 17.1
Interactions of neuropeptides and other transmitters in autonomic control
Young individual can excrete up to 25 L/day about 1.2 L/hour, but when intake is increased above that level dilution will occur first in vascular space and then in extracellular and intracellular space.
Approximately 108 neurons = all spinal cord neurons
Regulate peristalsis in gut
While parasympathetic input accelerates parastalsis, sympathetic input inhibits it
The system is truly peripheral with only CNS regulation of speed