Neural Control of Pelvic Function 6

Question 1

What is a major region for the neural control of sexual behavior?

Answer 1

• Medial preoptic region of the hypothalamus
  
  • lesions to this area in animals diminish or abolism sexual behavior
  • stimulation here elicits sexual behavior
  • many sexual responses and sexual motivation remain after lesions
  • input from limbic, olfactory, and cortical regions
• Receptors in the medial preoptic region
  
  • for androgens
  • for estrogen
  • for progesterobne
  • allows integration of hormonal status and behavior
• A common view is that sexual function is organized at the spinal level and these responses are under mostly descending control
  
  • mostly inhibitory
  • some facilitory

Question 2

What are the neural mechanisms for male arousal?

Answer 2

• Penile vasodilation mediated by the cavernous nerve
  
  • originates in the pelvic plexus and travels alongside prostate and urethra
  • contains both sympathetic and parasympathetic postganglionic neurons
• Vasodilation is primarily mediated by nitric oxide
• Contraction of penile muscles is mediated by pudendal nerve
• Erection can be mediated by both direct genital stimulation (reflexogenic erection) or by CNS control (psychogenic erection)
  
  • genital sensory information is carried primarily by the pudendal nerve

Question 3

What are the neural mechanisms of emission in the male climax?

Answer 3

• Both sympathetic and parasympathetic mechanisms are involved in emission
• Glandular secretion is increased by stimulation of fluid production by both ACh and NE
  
  • contraction of myoepithelial cells from NE
• Ductus deferens motility is increased by both NE and ACh

Question 4

What are the neural mechanisms involved in ejaculation of the male climax?

Answer 4

• Stereotyped response mediated by a central pattern generator
• Response is elicited by a combination of genital sensory stimulation and supraspinal control
• Sensory fibers ravel in the pudendal nerve
• Pudendal nerve also mediates contractions of muscle
• Ejaculation generated in the caudal spinal cord
• Spinal pattern generator under tonic descending inhibition
• Mechanisms mediating male refractory period are unknown

Question 5

What are the neural mechanisms that are involved in the female climax?

Answer 5

• Little known of mechanism
• Likely identical to males
• Response produced by pattern generator elicted by genital and CNS stimulation