9/26b ANS & Neural Control of CVP Function (Biomedical Sciences) Flashcards
Central autonomic network
- systems working in parallel, but controlled by the -central autonomic network.
- Receives input from multiple different brain regions
- function is deduced from its connections
- Receives afferent and efferent information
Afferent information in the central autonomic network
- Cerebral cortex
- Cingulate cortex and Amygdala - regulate emotions, parts of the limbic system, helps regulate your mechanisms that could be influenced by all the different systems
- Basal forebrain - at the base of the forebrain, that helps in general arousal
- Midbrain - nucleus of tractus solitaries (helps get information about the blood pressure or the blood pH), periaqueductal grey matter
- Nucleus of tractus solitaries, periaqueductal grey matter
- Spinal cord
- Hippocampus - part that helps process memories
- Retina
Efferent information in the central autonomic network
Hypothalamic nuclei
- cingulate cortex and amygdala
- basal forebrain
- midbrain
- hippocampus
- spinal cord
Hypothalamus
control/transit center that regulates multiple physiologic, emotional/limbic, memory, conscious control, and decision making systems to essentially help your action
Deficits in the central autonomic nervous system
patient with TBI may be able to do all physical ADLs, but may not be able to come back to their everyday life (mentally)
How does the ANS work?
- Controls BP and HR
- Controls body temperature
- Controls glucose and energy
Role of cardiovascular and respiratory systems?
- maintain oxygen supply to the viral organs, through:
- -maintaining oxygen saturation of the blood
- -maintaining perfusion (blood flow) to the organs
Regulation of BP
-Cardiac Output = stroke volume x HR
-TPR/perfusion
-Maintenance is done through complex reflexes with:
afferent input to processing centers then get an efferent response
Efferent control/supply to the heart
- Sympathetic stimulation
- Parasympathetic stimulaton
- higher autonomic levels of cardiac regulation
- control of peripheral vasculature
what is the effect of efferent sympathetic stimulation on the heart?
- T1-T4 go to heart SA node and AV Node (preganglionic neurons > paravertebral chain > post gang neuron supplies heart)
- Activation of the sympathetic nerves to the heart yields:
- -increases HR (positive chronotropy)
- -increases contractility (positive chronotropy)
- -> thus increasing SV
what does efferent activation of the parasympathetic nerves do to the heart?
- Craniosacral region in the brainstem (medulla - dorsal motor nucleus of vagus) to parasympathetic ganglia (very close to the heart) and then goes to supply the SA node and AV node
- Activation of dorsal nucleus of vagus yields:
- -decrease HR
- -decrease SV
- -decrease BP
Cardiac accelerator center
- sits in the medulla
- facilitates/activates SNS through spinal cord
Cardiac inhibitory center
- sits in the medulla
- activates PNS and calms heart down through brainstem
control of peripheral vasculature
- No PNS innervating the peripheral vasculature, in general (there are a few exceptions)
- If we want to vasoconstrict, increase SNS
- If we want to vasodilate, decrease SNS
afferent control of the heart
sensory receptors:
- baroreceptors
- chemoreceptors
baroreceptors
- sense pressure changes
- in aortic arch and carotid bodies
- relationship between receptor firing rate and MAP (as receptor firing rate increases, BP increases)
chemoreceptors
sense changes in PO2 and PCo2
MAP
mean arterial pressure: 1/3(sbp - dbp) + dbp
change in integrated receptor firing rate means:
they have detected a change in bp that then stimulates the autonomic NS to act based on the change
-basic reflexes for involuntary control