040, 041 The Autonomic Nervous System Flashcards Preview

Neuroscience and Behaviour > 040, 041 The Autonomic Nervous System > Flashcards

Flashcards in 040, 041 The Autonomic Nervous System Deck (7)
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1
Q

Why may diabetics be impotent?

A

Because they have neuropathy in smallest neurons first (sympathetic post-ganglionic neurons), resulting in less sympathetic control over organs.

2
Q

What are varicosities?

A

These are aligned along post synaptic autonomic fibres and their targets, where they release neurotransmitters.

3
Q

What is the rate-limiting enzyme for NA synthesis?

A

Tyrosine hydroxylase

4
Q

Where does the main source of sympathetic excitation to heart and vessels arise from in brain?

A

Rostral ventral lateral medulla

5
Q

Describe the pathway of the baroreceptor reflex?

A
  1. Signals travel via vagus and hypoglossal to the NTS.
  2. NTS projects to nucleus accumbens and dorsal motor nucleus of vagus.
  3. Dorsal motor nucleus of vagus projects parasympathetic fibres down.
  4. NTS also projects to CVLM, which inhibits RVLM, to reduce sympathetic transmission to heart and vessel.
6
Q

Describe the pathophysiology of autonomic dysreflexia?

A

Lesion above level of T6 results in lack of sympathetic control.

  1. Afferent stimuli below lesion e.g. full bladder causes increased sympathetic drive to vascalature
  2. Blood pressure increases, detected by baroreceptor reflex.
  3. Sympathetic drive to heart is reduced by the sympathetic drive to the vasculature below lesion unchanged.
  4. Voiding signals cannot reach parasympathetic neurons, and spinal signals to increase blood pressure.
7
Q

What is detrusorsphincter dyssynergia?

A

Urethral sphincter contracts at the same time as bladder contracts. There is impaired voiding which can lead to kidney failure.