Sexual Motivation and the Neurobiology of Arousal

Flashcards about sexual behavior, pheromones, hormones and the nervous system's impact on human sexuality.

What are the two stages of sexual behavior?

Appetitive behaviors and consummatory behaviors

Define appetitive behaviors.

Behaviors aimed at finding the right conditions and target for motivational behavior (e.g., foraging for food, motivation to have sex).

Define consummatory behaviors.

The motivated behavior itself (e.g., eating, having sex).

What usually triggers sexual motivation?

External stimuli, often related to the opposite sex or specific to one's sexual orientation.

What are pheromones?

Species-typical molecules that work across organisms, triggering behaviors related to copulation.

How do pheromones function in mammals?

They are usually a mix of molecules detected by the vomeronasal organ, influencing mating behavior.

What is the vomeronasal organ?

An organ located within the nose and mouth cavity that detects pheromones in most mammals.

What evidence suggests pheromones might exist in humans?

T-shirt smelling studies indicate that men rate women's t-shirts worn during the fertile phase as more attractive.

What is androstadienone?

A molecule found in male sweat that can improve mood and sexual arousal in women while worsening mood in men.

What is the significance of underarm and groin hair in the context of pheromones?

The hairs increase the surface area from which chemical information might be dispersed.

What are MHC genes?

Major histocompatibility complex genes are immune-related genes that women may unconsciously detect in men's smells.

Why might women be attracted to men with dissimilar MHC genes?

Children would have a wider range of immune molecules, potentially increasing their survival chances.

What is copulins?

A molecule found in female urine during the third trimester of pregnancy that some believe may be a pheromone, though this is debated.

Besides pheromones, what else affects sexual motivation?

Learned associations and individual preferences.

How do hormones influence sexual motivation?

Male sex hormones (androgens) are relevant to sexual drive.

How does testosterone affect sexual motivation in individuals?

Within an individual, higher testosterone levels correlate with increased sexual motivation, and vice versa.

What are the four stages of arousal described by Masters and Johnson?

Excitement, plateau, orgasm, and resolution.

What part of the nervous system controls the excitement and plateau phases?

The parasympathetic nervous system.

What is the autonomic nervous system?

The system that controls bodily functions, including the parasympathetic and sympathetic nervous systems.

What neurotransmitter is used by both sets of parasympathetic nervous system neurons?

Acetylcholine.

What are the effects of the parasympathetic nervous system?

Increases somatic function, relaxation, digestion, and decreases heart rate.

How does the parasympathetic nervous system facilitate erection?

It releases acetylcholine, causing smooth muscle relaxation in blood vessels, allowing blood to fill cavities in the genitals.

How does Viagra (sildenafil) work?

It blocks the PDE5 enzyme, preventing the breakdown of cyclic GMP, which maintains smooth muscle relaxation and sustains an erection.

What is the role of sensory input in sexual arousal?

Stimulation of sensory neurons in the genitals activates a spinal cord circuit, leading to parasympathetic nervous system activation and erection.

How does the brain influence the spinal cord circuit involved in sexual arousal?

The brain provides both excitatory and inhibitory inputs, enhancing or suppressing the reflex arc based on circumstances.

What role does the sympathetic nervous system have on sexual function?

The sympathetic nervous system controls orgasm.

What is smooth muscle?

Muscles of organs that we can't control voluntarily, such as those surrounding blood vessels.

Why are men more likely to report ED (erectile dysfunction)?

It is physically impossible for men to have sex without an erection.