Motivation of Sexual Behaviours Flashcards
How is the urogenital system differentiated?
Based on the Sry gene (either on Y, on X, or absent/ dysfunctional)
What steroids are higher in females?
Estrogens such as estradiol, estrone, estriol, and estetrol
What steroids are higher in males?
Androgens such as testosterone and dihydrotestosterone
How do steroids work?
Steroids are hormones which are lipophilic, meaning they can enter cells or neurons through the cell membrane. They were primarily thought to exert their effects slowly by way of gene expression
What are the two pathways for steroids to exert effects?
The genomic pathway and the non-genomic pathway (through steroid receptors on the cell membrane)
Which brain regions are sexually dimorphic?
The preoptic area (POA) (in the anterior hypothalamus), Ventromedial hypothalamus (VMH), Medial amygdala (MeA), and Spinal nucleus of the bulbocavernosus (SNB)
What are the organizational effects of steroids?
To guide the organization of the brain, endocrine glands, and behavior during hormone-sensitive “critical periods” or epochs of fetal and postnatal life
What are the activational effects of steroids?
At puberty and afterward, to generate the growth of secondary sex characteristics, to activate endocrine systems involved in sperm and egg production, to mature neuroendocrine systems required for pregnancy, and to stimulate sexual behaviors
What is masculinization?
An active process of acquiring “male-typical” anatomy, physiology, and behavioural functions. The process involves testosterone being converted to estradiol
What is feminization?
Default or “passive” process in mammals of acquiring “female-typical” anatomy, physiology, and behavioural functions
How can masculinization be disrupted and restored?
Cyclooxygenase-2 (COX-2) inhibitors disrupt SDN formation and the display of masculine sexual behaviour after puberty. However, the replacement of Prostaglandin E2 (PGE2) in perinatally castrated males can restore those processes
Why does the female brain not masculinize if estradiol is the masculinizing hormone?
Alpha-fetoprotein is secreted by the liver and was thought to either facilitate or inhibit estrogen from reaching neural tissue. α-fetoprotein gene loss results in partial masculinization of the brain
What is the role of Gonadotropin-releasing hormones (GnRH)?
When GnRH is released from the hypothalamus, it induces the release of gonadotropins (Luteinizing hormone, Follicle-stimulating hormone) from the pituitary gland
How does progesterone relate to ovulation?
Progesterone peaks just prior to ovulation, it is a critical hormone for signalling the upcoming time of ovulation
What is the Dual Control Model?
Sexual behaviours are regulated through the balance of inhibitory neuromodulators (opioids, serotonin) and excitatory neuromodulators (dopamine, norepinephrine, melanocortins). Neuromodulators play a large role in regulating mating behaviours
