Lecture 13: Autonomic nervous system

Question 1

Where is the central regulation of the autonomic NS?

Answer 1

Spinal cord, medulla oblongata, hypothalamus

Question 2

What does the autonomic NS regulate?

Answer 2

Visceral functions –> functions of the hollow organs

Question 3

In which 2 NS can you separate the autonomic NS and in what state do they activate + hormone involved

Answer 3

Sympathetic NS –> fight or flight - noradrenaline
Parasympathetic NS –> rest and digest - acetylcholine

Question 4

What is allostasis? Which NS is responsible for restoration of allostasis?

Answer 4

Out of homeostasis. Restoration by parasympathetic NS

Question 5

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

Answer 5

1. Output to organs
2. To viscera
3. To blood vessels and skin
4. Input to the brain
5. Located in wall of end organ + viscera

Question 6

Most organs have parasympathetic nerves and sympathetic input.
Which parts in the body only have sympathetic input?

Answer 6

Most arterial blood vessels, sweat glands, adrenal glands
NOTE: can only stop when sympathetic NS inactivates

Question 7

What does the ANS control in the cardiovascular system and which NS does a specific control?

Answer 7

Blood pressure and heart rate.
- Sympathetic NS controls vaso constriction

Question 8

What happens within the ANS when blood pressure is too high?

Answer 8

• Central parasympathetic NS activated
• Sympathetic NS reduced activity: heart rate decrease and lowering vaso constriction
  –> After blood pressure drops within range

Question 9

What happens when blood pressure is to low?

Answer 9

• Central parasympathetic inhibition.
• Sympathetic activation: heart rate increases and vasoconstriction takes place
  –> blood pressure rises within range

Question 10

What happens with the bloodpressure when a large internal bleeding occurs?

Answer 10

It drops
- body will increase heart rate through vasoconstriction –> gives more bleeding

Question 11

What is the function of the arterial baro reflex system?

Answer 11

Keep main arterial blood pressure within optimal gain range

Question 12

Does a transplanted heart have a baroreflex?

Answer 12

No, sympathetic input to blood vessels do exists

Question 13

What does the Auerbach plexus of the enteric NS do and where is it located?

Answer 13

It lays between the muscle layers in the wall of the GI tract. Primary function is controlling muscle movement + peristalsis

Question 14

What does the Meissner’s plexus of the enteric NS do and where is it located?

Answer 14

Located in the submucose layer. Primary function is chemical monitoring and secretion/absorption

Question 15

What is the function of the nucleus of the solitary tract (NTS) in the medulla?

Answer 15

• 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)

Question 16

• 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))

Answer 16

• 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

Question 17

How can generalized fear be blocked? (so only conditioned)

Answer 17

By blocking GABA

Question 18

What is the primary function of the hypothalamus?

Answer 18

Homeostasis

Question 19

What does the hypothalamus do with the received input from cortical areas?

Answer 19

Translates the synaptic information to hormonal signals

Question 20

Through which structures does the hypothalamus get visceral input?

Answer 20

All ogan systems, NTS, paraventricular nucleus (PVN), lateral hypothalamus

Question 21

From which parts of the brainstem gets the hypothalamus input?

Answer 21

• Medial forebrain bundle
  (Dopaminergic via VTA, noradrenergic via locus ceoruleus, serotonergic via dorsal Raphe)
• Collaterals of forebrain projections
• Multiple hypothalamic regions

Question 22

Hippocampus parts that hypothalamus gets input from:

Answer 22

Direct input via fornix to mammilary bodies

Question 22

What is the role of the amygdala input to the hypothalamus?

Answer 22

Expression of fear –> endocrine fear and stress response

Question 23

What is the function of the chemosensitivity of the hypothalamus?

Answer 23

Feedback from target organs

Question 24

Name 4 effector systems of the hypothalamus.

Answer 24

• Sleep wake cycle
• Neuroendocrine regulation
• Reproduction
• Integration of autonomic functions
• Immune and thermoregulation
• Liquid homeostasis and thirst
• Food intake

Question 25

Which non-thalamic target of the optic tract IS regulated by the hypothalamus?
For what is this structure responsible?

Answer 25

Supra chiasmaticus, responsible for sleep wake cycle/ biological clock

Question 26

Which structure are involved in neurotransmitter release in the blood?

Answer 26

Paraventricular nuclei via the media eminence to the posterior pituitary

Question 27

What are in the context of the reproduction sytem, effector systems of the hypothalamus?

Answer 27

Spermatogenesis and ovulation, sexual behavior also

Question 28

Where are the heat and cold sensitive neurons located in the hypothalamus?

Answer 28

Heat sensitive in the preoptic area. Cold sensitive in the posterior are

Question 29

Where are the satiety centers in the brain?

Answer 29

Ventromedial hypothalamus
Paraventricular nuclei

Question 30

Which structure stimulates food and water intake (feeding center)?

Answer 30

Lateral HT