Lecture 14: Human and animal

Question 1

List 3 facts about the endocrine system

Answer 1

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

Question 2

Describe target cells and receptors

Answer 2

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.

Question 3

List 5 places in the body where there are glands for the release of hormones

Answer 3

Liver, pituitary gland, hypothalamus, kidney, testes.

Question 4

What is behavioural endocrinology?

Answer 4

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.

Question 5

What are the two types of stress?

Answer 5

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

Question 6

What does stress try and do?

How does chronic stress start?

Answer 6

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.

Question 7

What are the three stages of a stress response in response to a severe stressors?

Answer 7

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.

Question 8

What are the three main stress hormones?

Answer 8

Epinephrine, norepinephrine and glucocorticoids like cortisol.

Question 9

What is the HPA axis?

Answer 9

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.

Question 10

When is cortisol released?

Answer 10

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.

Question 11

Where are sex hormones released?
What are the two types?
List three sex hormones

Answer 11

In gonads and adrenal glands, mainly gonads
Androgens; masculinsing hormones
Oestrogens; feminising hormones
Testosterone, oestrogen, progesterone

Question 12

What is testosterone responsible for?

Answer 12

It’s responsible for secondary sexual characteristics, the castrati stopped the release of testosterone so that the males could sing in high pitched voices.

Question 13

When was the first endocrinology experiment?
By whom?
What did it entail?

Answer 13

1849
Berthold
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.

Question 14

Briefly describe marriage and testosterone

What about competition and testosterone?

Answer 14

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.

Question 15

What is the function of oestrogen?

Progesterone?

Answer 15

It’s involved in ovulation and maintains female’s secondary sexual characteristics.
It’s involved in bonding and the maintenance of pregnancy.

Question 16

What are the three phases of the menstrual cycle?

Answer 16

Menses
Follicular phase
Luteal phase
Each phase causes relevant psychological changes

Question 17

Describe ovulation

Answer 17

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.

Question 18

What are sexual swellings?

Answer 18

When primates’ rear swell and are red to show that they are fertile and are ready to mate.

Question 19

How do humans advertise fertility?

Answer 19

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.

Question 20

What do women prefer at different times in the menstrual cycle?

Answer 20

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.

Question 21

How does the pill work?

Answer 21

It inhibits the release of oestrogen and progesterone. It also prevents the growth of the unfertilised egg.

Question 22

Describe menopause

Answer 22

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.

Question 23

Describe cuddly hormones

Answer 23

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.

Question 24

Describe the effects of progesterone

Answer 24

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.

Question 25

Describe the effects of oxytocin and vasopressin

Answer 25

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.

Question 26

Describe oxytocin and trust

Answer 26

Kosfield 2005; Intranasal oxytocin increases the amount of money an investor is willing to offer a trustee. If this money isn’t returned by the trustee then the investor will offer less money next time to the placebo group but not to the oxytocin group.