Flashcards in Lecture 14: Human and animal Deck (26):
List 3 facts about the endocrine system
1. It's a slow communication system
2. It involves a collection of glands that secrete hormones directly into the bloodstream, which is the circulatory system
3. The hormones are secreted in small amounts and are transported to cells that have the specific receptors for it
Describe target cells and receptors
A target cell is the cell with the specific receptor that the hormone will bind to. The hormone is transported all over the body but only influences the cells with the receptors.
List 5 places in the body where there are glands for the release of hormones
Liver, pituitary gland, hypothalamus, kidney, testes.
What is behavioural endocrinology?
The research of the relationship between behaviour and hormones. They both influence each other, however, hormones do not cause behavioural change but they do change the probability of the behaviour being expressed.
What are the two types of stress?
Eustress, this is positive stress that releases adrenaline and can help you complete goals and achievements.
Distress, this is negative stress and can be harmful to the mind and body
What does stress try and do?
How does chronic stress start?
It tries to restore your body to homeostatic balance and prepares organisms for a fight/flight response or physical harm. Chronic stress starts if you continuously anticipate that you will be knocked out of homeostatic balance, even though you won't. Stress in humans is usually because of psychosocial reasons.
What are the three stages of a stress response in response to a severe stressors?
1. Alarm reaction; Your body is mobilised to defend, this is thanks to the SNS
2. Resistance stage; Your arousal remains high as your body tries to defend against and adapt to the stressor, this is thanks to the release of cortisol
3. Exhaustion stage; Your resources become limited and your ability to resist can collapse.
What are the three main stress hormones?
Epinephrine, norepinephrine and glucocorticoids like cortisol.
What is the HPA axis?
It's a response that releases the stress hormones. It begins with the hypothalamus, which signals the pituitary gland. The pituitary gland then signals to the adrenaline glands in the kidney to release the three main stress hormones.
When is cortisol released?
It increases in response to stress, this was shown from Chatterton's study in 1997, he found that when men skydive, their cortisol levels dramatically increase. Cortisol is also released in response to social hierarchy, Abbott 2003 found that subordinate primates have more cortisol released, the lower down on the hierarchy, the more cortisol. This is because they're exposed to more stressors and have less social support.
Where are sex hormones released?
What are the two types?
List three sex hormones
In gonads and adrenal glands, mainly gonads
Androgens; masculinsing hormones
Oestrogens; feminising hormones
Testosterone, oestrogen, progesterone
What is testosterone responsible for?
It's responsible for secondary sexual characteristics, the castrati stopped the release of testosterone so that the males could sing in high pitched voices.
When was the first endocrinology experiment?
What did it entail?
He did a naturalistic observation to change the behaviour and appearance of roosters. He castrated 6 of them and re-implanted a testes in two of them. He also transplanted testes from another bird into two of them. He left the last two to develop into capons (fattened for eating). They were castrated at a young age. Only the ones left castrated didn't fully develop, they were weaker, weren't interested in females, had smaller combs and had a weaker crow.
Briefly describe marriage and testosterone
What about competition and testosterone?
Men in relationships have lower testosterone levels and they're even lower if the man is a father.
Men are more likely to commit violent crimes and when men win things, their testosterone increases. However, there are mixed results with fairness and cooperation.
What is the function of oestrogen?
It's involved in ovulation and maintains female's secondary sexual characteristics.
It's involved in bonding and the maintenance of pregnancy.
What are the three phases of the menstrual cycle?
Each phase causes relevant psychological changes
It's the target of most studies about the menstrual cycle. Other mammals have stereotyped sexual receptivity and human ovulation is considered cryptic. It occurs once a month and is regulated by hormones.
What are sexual swellings?
When primates' rear swell and are red to show that they are fertile and are ready to mate.
How do humans advertise fertility?
They don't advertise it as much as other primates but there are still psychological and physiological changes. There is evidence that women are more interested in sex during the peak of their fertility, this has been shown via clothing preferences, Durante's study 2008. Fertility usually peaks at ovulation.
What do women prefer at different times in the menstrual cycle?
When ovulating, women prefer more masculine faces
They only prefer slightly masculine faces when not ovulating. Women with a lot of oestrogen show stronger shifts in the ovulation cycle.
How does the pill work?
It inhibits the release of oestrogen and progesterone. It also prevents the growth of the unfertilised egg.
It's the cessation of menstruation and is associated with a number of symptoms.
For hormone replacement therapy, there is a timing hypothesis, this is more beneficial for younger women but isn't very effective for older women, however, hormone replacement therapy is to relieve the symptoms of menopause.
The one theory as to why menopause exists is the grandmother hypothesis; an evolutionary strategy to stop childbirth as there is high risk of death during birth at an older age.
Describe cuddly hormones
Progesterone and oxytocin can also act as cuddly hormones. Progesterone is released in anticipation of and during pregnancy. Oxytocin is a trust hormone and increases monogamy and bonding.
Describe the effects of progesterone
It's produced by men and women. It counteracts stress by acting as a sedative. It's associated with a need for affiliation and need for affiliation in response to rejection increases progesterone.
Describe the effects of oxytocin and vasopressin
If affects monogamy. For example prairie voles are monogamous for life and the mountain voles are promiscuous. The prairie voles have more oxytocin receptors, if these are blocked via drugs then the voles ditch their partners. If meadow voles are made to express vasopressin receptors, they develop a preference for their mate.
Genes that code more vasopressin receptors in men is associated with relationship satisfaction. A gene that's associated with lower pair bonding in males is also associated with autism deficits.
Intranasal vasopressin in men; this stimulates antagonistic facial expressions to unfamiliar faces and it decreases the perception of friendliness.
Intranasal oxytocin in men; these men are better at classifying emotions.
Intranasal vasopressin in women; this stimulates affiliative facial motor patterns and increases the perception of friendliness.
Intranasal oxytocin; this increases the perception of facial attractiveness and trustworthiness.