Hormones & Pheromones

• A hormone is a chemical secreted by the endocrine glands into the blood stream, which distributes it around the body. The pituitary gland regulates the secretion of all hormones
• Hormones act slowly unlike neurotransmitters and may take years to fully have an effect (puberty involves slow release of testosterone and estrogen which control primary and secondary sexual characteristics)
• The pituitary gland is located at the base of the hypothalamus
• Hormones can have different effects on the body and on behavior depending on the hormone's nature.
• Testosterone is the male sex hormone that regulates fertility, muscle mass, fat distribution, sperm production etc. testosterone levels rise during puberty when secondary sexual characteristics start showing
• Females also produce testosterone but at much smaller volumes
• Testosterone has been linked to behaviors like aggression and competitiveness
• Oxytocin is a hormone made in the hypothalamus. It's known as the cuddle hormone and is associated with feelings of trust, bonding, and security.
• Oxytocin is secreted during childbirth and breastfeeding so it's thought to have evolved for allowing the mother and baby to bond
• Pheromones are chemicals secreted by glands to act outside the body, unlike hormones that are secreted internally from the endocrine glands. Research has shown that animals use pheromones for mate selection and territoriality, as pheromones communicate signals to members of the same species
• Mammals detect pheromones nasally (VNO), the VNO is is a collection of neurons deep in the nose that transmit signals via the accessory olfactory bulb to the hypothalamus. There is no real evidence to show that the VNO or bulb exist in humans, though both are present in the developing fetus
• There may be some validity that a pheromone nerve exists in humans, also known as the terminal nerve. It's a pair of nerves that run from the nose into the brain in front of the olfactory nerve.