Lecture 13: Autonomic nervous system Flashcards
T.M
Where is the central regulation of the autonomic NS?
Spinal cord, medulla oblongata, hypothalamus
What does the autonomic NS regulate?
Visceral functions –> functions of the hollow organs
In which 2 NS can you separate the autonomic NS and in what state do they activate + hormone involved
Sympathetic NS –> fight or flight - noradrenaline
Parasympathetic NS –> rest and digest - acetylcholine
What is allostasis? Which NS is responsible for restoration of allostasis?
Out of homeostasis. Restoration by parasympathetic NS
To what areas do these spinal cord branches go or located?
1. Sympathetic trunk
2. Prevertebral ganglion
3. Peripheral nerve
4. Dorsal root ganglion
5. Parasympathetic post ganglion
- Output to organs
- To viscera
- To blood vessels and skin
- Input to the brain
- Located in wall of end organ + viscera
Most organs have parasympathetic nerves and sympathetic input.
Which parts in the body only have sympathetic input?
Most arterial blood vessels, sweat glands, adrenal glands
NOTE: can only stop when sympathetic NS inactivates
What does the ANS control in the cardiovascular system and which NS does a specific control?
Blood pressure and heart rate.
- Sympathetic NS controls vaso constriction
What happens within the ANS when blood pressure is too high?
- Central parasympathetic NS activated
- Sympathetic NS reduced activity: heart rate decrease and lowering vaso constriction
–> After blood pressure drops within range
What happens when blood pressure is to low?
- Central parasympathetic inhibition.
- Sympathetic activation: heart rate increases and vasoconstriction takes place
–> blood pressure rises within range
What happens with the bloodpressure when a large internal bleeding occurs?
It drops
- body will increase heart rate through vasoconstriction –> gives more bleeding
What is the function of the arterial baro reflex system?
Keep main arterial blood pressure within optimal gain range
Does a transplanted heart have a baroreflex?
No, sympathetic input to blood vessels do exists
What does the Auerbach plexus of the enteric NS do and where is it located?
It lays between the muscle layers in the wall of the GI tract. Primary function is controlling muscle movement + peristalsis
What does the Meissner’s plexus of the enteric NS do and where is it located?
Located in the submucose layer. Primary function is chemical monitoring and secretion/absorption
What is the function of the nucleus of the solitary tract (NTS) in the medulla?
- Feedback to local reflexes
(via preganlgionic neurons in brainstem and spinalcord to primary motor neurons in autonomic ganglia) - Inform higher integrative centers AKA cognitive control system (via parabrachial nucleus to thalamus to insular ocrtex to medial prefrontal cortex)
- In which brain structure takes fear conditioning place?
- To which area does this structure project?
- What happens in low shock and high shock (generalized fear))
- Dorsal Raphe (serotonin production)
- Central amygdala and lateral hypothalamus
- Low shock: more cell bodies with serotonin/glutamate
High shock: more cell bodies with serotonin/GABA
How can generalized fear be blocked? (so only conditioned)
By blocking GABA
What is the primary function of the hypothalamus?
Homeostasis
What does the hypothalamus do with the received input from cortical areas?
Translates the synaptic information to hormonal signals
Through which structures does the hypothalamus get visceral input?
All ogan systems, NTS, paraventricular nucleus (PVN), lateral hypothalamus
From which parts of the brainstem gets the hypothalamus input?
- Medial forebrain bundle
(Dopaminergic via VTA, noradrenergic via locus ceoruleus, serotonergic via dorsal Raphe) - Collaterals of forebrain projections
- Multiple hypothalamic regions
Hippocampus parts that hypothalamus gets input from:
Direct input via fornix to mammilary bodies
What is the role of the amygdala input to the hypothalamus?
Expression of fear –> endocrine fear and stress response
What is the function of the chemosensitivity of the hypothalamus?
Feedback from target organs
Name 4 effector systems of the hypothalamus.
- Sleep wake cycle
- Neuroendocrine regulation
- Reproduction
- Integration of autonomic functions
- Immune and thermoregulation
- Liquid homeostasis and thirst
- Food intake
Which non-thalamic target of the optic tract IS regulated by the hypothalamus?
For what is this structure responsible?
Supra chiasmaticus, responsible for sleep wake cycle/ biological clock
Which structure are involved in neurotransmitter release in the blood?
Paraventricular nuclei via the media eminence to the posterior pituitary
What are in the context of the reproduction sytem, effector systems of the hypothalamus?
Spermatogenesis and ovulation, sexual behavior also
Where are the heat and cold sensitive neurons located in the hypothalamus?
Heat sensitive in the preoptic area. Cold sensitive in the posterior are
Where are the satiety centers in the brain?
Ventromedial hypothalamus
Paraventricular nuclei
Which structure stimulates food and water intake (feeding center)?
Lateral HT
