Lecture 24 - Pelvic Neuroanatomy

Question 1

The inferior hypogastric plexus (IHP) is vulnerable to …

Answer 1

surgical injury

Question 2

Within the IHP there are thousands of…

Answer 2

autonomic neurons - the key to understanding

its not just tracts, its a ganglionated plexus

there is potential to damage cell BODIES

Question 3

INHP damage can damage what..

Answer 3

motor pathway:

postgangionic axons, ganglion cell bodies, preganglionic axons

Sensory pathways: lumbar and sacral sensory axons

Question 4

What does sympathetic nerves do to the bladder?

Answer 4

contraction of bladder base - continence

Question 5

What does parasympathetic nerves do to the bladder?

Answer 5

contraction of bladder dome - micturition

Question 6

What does the sympathetic input do to the reproductive organs in males

Answer 6

ejaculation - contraction of smooth muscle in prostate gland, seminal vesicle, vas, urethea

Question 7

What does the parasympathetic input do to the reproductive organs in males

Answer 7

stimulates prodction of secretions from prostate gland

vasodilation - increased uterine and penile blood flow

Question 8

Sympathetic and parasympathetic axons look __ ___ but can have different _______

Answer 8

Sympathetic and parasympathetic axons look the same but can have different distribution

Question 9

True or false

There is no easily visible synaptic junction

Answer 9

true

Question 10

True or false

there is more than one transmitter release site per axon

Answer 10

true

Question 11

True or false

IHP contains both sympathetic parasympathetic ganglion neurons

Answer 11

true

Question 12

Autonomic neurons in the IHP are sexually dimorphic, meaning…

Answer 12

there are many more neurons in the male.

Question 13

True or false

Receptors for sex steroids do not continue to be expressed in adults

Answer 13

false

they do

steroid levels or drugs that influence steroid actrivity, affect neuron strucutre and fucntion

Question 14

What are some things to consider when investigating ways to undertake safer surgical operations?

Answer 14

the extent of neuron damage - do they die?

understand the innate potential for recovery - can they regrow

Find ways to make damaged axons grow better/faster - clues from developmental neuroscience

Enhance the potential of undamaged axons - indetify compensatory mechanisms, how do we increase the amount of them?

Question 15

What is a way to identify the spinal connectivity of the nerves in the IHP?

Answer 15

microsurgical lesion of the hygogastric nerve will denervate sympathetic neurons - can then identify

can also put in retrograde tracers to trace organ connectivityi

Question 16

With identification of neurons what can then be achieved?

Answer 16

pre-labl then injure selected target-specific neurons - can then compare different types of injury and see the effects:

nerve regrowth
neural activity
drug activation of tissue
contribution of spared nerves

Question 17

the impact of injuring pelvic visceral sensory nerves is likely to be occurring in parallel with..

Answer 17

injuring autonomic nerves

Question 18

What are the potential problems of pelvic sensory nerve damage

Answer 18

loss/reduction of sensroy fucntion to initiate reflexed and tissue receovery from injury/inflammation

initiate state of visceral pain - can be chronic

Question 19

true or false

[retrograde labeling from pelvic organs simultaneously labels autonomic and sensory neurons

Answer 19

true

Question 20

The sensory innervation of pelvic organs originates from ….

Answer 20

dorsal root ganglia of two spinal levels (upper lumbar and sacral)

Question 21

The sensory nerves from pelvic organs are not just sending information about pain, but also

Answer 21

reflex information to do with normal autonomic function

Question 22

visceral sensory neurons branch profused in the SC compared to….

what does this mean for pain?

Answer 22

somatic sensroy neurons

visceral pain more diffuse, poorly localised and often referred

makes sense, the many fibres converge on other sensory fibres.