Hormones and Behaviour

Question 1

What are hormones?

Answer 1

Chemical substances, formed in a specialised gland or group of cells, released into the blood that affect target cells in another organ.

Question 2

What parts of the body do hormones reach?

Answer 2

All parts of the body but only target cells that have receptors for that hormone.

Question 3

What are neurotransmitters?

Answer 3

substances released by neurons and are received by adjacent neurons & alter their membrane potential.

Question 4

What are pheromones?

Answer 4

Substances released by an individual as scent signals for others.

Question 5

What does the endocrine system do?

Answer 5

Refers to a set of glands that produce chemical messengers called hormones.

Question 6

Where do the hormones from the endocrine system go to?

What do they help with?

Answer 6

The brain and other tissues.

Coordinate and integrate complex physiological functions.

Question 7

Modes of hormone action: what are activational effects?

When does this occur?

Answer 7

Short-term, reversible effects that occur in the fully developed organism e.g., alteration of transmission in neural networks that respond to certain aspects of the environment.

Can occur at any time in lift.

Question 8

Modes of hormone action: What are organisational effects?

When does this occur?

Answer 8

Long term, irreversible effects on tissue differentiation and development e.g., brain, overt, that can either directly (brain) or indirectly (ovary) influence behaviour.

Occur mostly at a critical stage of development (before birth in humans)

Question 9

What are the 2 major hormones that the endocrine glands produce?

Answer 9

1. Protein hormones

2. Steroid hormones

Question 10

What is a protein hormone?.

Answer 10

These comprise of amino acids. They exert their effect by binding to the membrane receptor of the target cell.

Question 11

What is a steroid hormone?

Answer 11

These are derived from cholesterol from the diet and exert their effects in 2 ways.

Question 12

What 2 ways do steroid hormones exert their effects?

Answer 12

1. They bind directly to membrane receptors.
2. As they are fat soluble they pass through cell membranes where they attach to receptors in the cytoplasm. Here they determine gene expression.

Question 13

What are the 3 steps of protein hormones in action?

Answer 13

1. Binding with receptors
2. Beginning a transduction pathway.
3. The transaction pathway ends with transcription factors being activated in the nucleus, and protein synthesis beginning.

Question 14

What are the different types of protein hormones?

Answer 14

Protein hormones that are only several amino acids long are called peptide hormones.

Larger protein hormones are Called polypeptide hormones.

Insulin: Made in the pancreas

Glucagons: made in the pancreas .

Leptin: produced by the fat cells.

Question 15

What does insulin do?

Answer 15

increases the entry of glucose into the cells, and regulates fat storage.

Question 16

What do glucagon do?

Answer 16

responsible for increasing the conversion of stored fats to blood glucose

Question 17

What does leptin do?

Answer 17

Informs the brain how much fat is contained by the body

Question 18

what happens when leptin levels are high?

Answer 18

appetite is decreased

Question 19

What happened when leptin levels are low?

Answer 19

appetite is increased ad bodily activity is decreased.

Question 20

What happened to mice who inherit 2 copies of the defective gene re leptin?

What reduces their food intake?

Answer 20

unable to produce leptin so they overeat.

Leptin injection.

Question 21

How do steroid hormones exert their effects?

Answer 21

1. they bind directly to the membrane receptors.

2. as they are fat soluble, they pass through cell membranes where attach to receptors in the cytoplasm.

Question 22

What is the process of steroid hormones attaching to receptors in cytoplasm?

Answer 22

1. Entering a cell
2. binding to a receptor in the cytoplasm
3. the hormone-receptor complex enters the nucleus and triggers gene transcription.
4. This starts protein synthesis.

Question 23

What are the different types of steroid hormones: corticoids:

Answer 23

• Glutocorticoids: (principally cortisol), are released by the adrenal glands in response to stress. They increase the breakdown of fats and proteins into glucose to trigger escape or defence.
• Mineralocorticoids (e.g., aldosterone) are also produced by the adrenal glands and reduce salt secretion in the kidneys.

Question 24

What are the different types of steroid hormones: sex steroids?

Answer 24

Released mainly by the ovaries and testes but also by the adrenal glands.

• Androgens: testosterone is produced in large quantities.
• Estrogens: estradiol is produced in large amounts in females.
• Progesterone: prepares uterus and breasts for pregnancy and regulates the stages of pregnancy.

Question 25

Are sex steroids specific?

Answer 25

No, both males and females produce androgens and oestrogen's.

Question 26

Do individual differences in behaviour and physiology reflect differences in hormone concentration?

Answer 26

No! even though concentration is important, it is just as important, the receptivity of the hormone. A high hormone concentration will have little effect if it lacks cell receptivity. e.g., androgen insensitivity syndrome.

Question 27

What 2 structures in the brain control hormone release?

Answer 27

Hypothalamus and Pituitary gland.

Question 28

Where is the hypothalamus?

Answer 28

Base of the brain and consists of several interconnected nuclei.

Question 29

Where is the pituitary gland?

Answer 29

Controls several hormone glands. Just above the bridge of the nose. Size of a pea.

Question 30

What is the hypothalamus' main function(s)?

Answer 30

To maintain homeostasis i.e., keep the human body in a stable, constant condition.

Question 31

Why signals does the hypothalamus respond to?

Answer 31

From the internal and external environment including body temp, hunger, feelings of being full up, BO and level of hormones in circulation.

Question 32

What does the hypothalamus respond to / control?

Answer 32

Repsonds to stress and controls our daily bodily rhythms like the night time secretion of melatonin from the pineal gland and the changes in cortisol (stress hormone) and body temp.

Question 33

What do the hypothalamic nuclei do?

Answer 33

Synthsise releasing hormones that either stimulate or inhibit the release of hormones form the pituitary gland.

Question 34

What does the hypothalamus secrete?

Answer 34

Oxytocin and vasopressin

Question 35

Where does oxytocin and vasopressin from the hypothalamus travel to?

Answer 35

The posterior pituitary gland. This then releases them into the bloodstream in response to certain neural signals.

Question 36

What are the 2 structures in the pituitary gland that produces hormones?

Answer 36

1. Posterior pituitary | 2. Anterior pituitary

Question 37

What does the posterior pituitary do?

Answer 37

Stores and released the hormones created by the hypothalamus,. These hormones are then released directly into the blood stream. - Anti-diuretic hormone: causes water reabsorption at the kidneys. - Oxytocin stimulates contraction of the uterus in childbirth and is important for breastfeeding.

Question 38

What does the anterior pituitary do?

Answer 38

Hormones form the hypothalamus reach the anterior pituitary gland via a network of blood vessels that run down through the pituitary stalk. Hormones produces here are refereed to as 'tropic; as they stimulate various processes such as; gonads, production and regulation of growth hormone, control of milk production etc.

Question 39

What feedback system does the hypothalamus have?

Answer 39

Negative feedback system.

Question 40

What does dimorphic mean?

Answer 40

Humans are dimorphic - exist in 2 forms.

Question 41

How many pairs of chromosomes are in each cell nucleus? What are the first 22 pairs called? What is the 23rd pair called?

Answer 41

23. Autosomes. Allosomes.

Question 42

What do autosomes consist of?

Answer 42

Contain the same genes in same order along their chromosomal arms.

Question 43

What do allosomes contain?

Answer 43

Sex chromosomes consisting of 2 X chromosomes in women and XY in men.

Question 44

Which chromo is the sex determining one?

Answer 44

Y chromo

Question 45

In mammals, what gene does the Y chromo contain?

Answer 45

Gene SRY

Question 46

Why does the gene SRY trigger?

Answer 46

The development of testis.

Question 47

When a foetus is developing, what primitive gonads are there intially?

Answer 47

Tesitis and ovary Cortex - potential to be an ovary Medulla - potential to be a testis.

Question 48

If the chromo is XY what does the SRY gene on Y trigger? What if there is no SRY protein present?

Answer 48

The synthesis of the SRY protein. Cortex develops into an ovary.

Question 49

Both sexes begin with 2 sets of reproductive ducts - what are they?

Answer 49

Wolffian system (male) and Mullerian system (female)

Question 50

What does the Wilffian system contain?

Answer 50

Seminal vesicles, vas deferens.

Question 51

What does the Mullerian system contain?

Answer 51

Uterus, vagina, Fallopian tubes.

Question 52

When does the differentiation of ducts happen?

Answer 52

Third prenatal month.

Question 53

what is the process of the differentiation of ducts?

Answer 53

- Testes produce testosterone and Mullerian-inhibiting substance. - Wolffian system develops, Mullerian degenerates, testes descend. - No testes = no testicular hormones. - Mullerian system develops, Wolffian degenerates.

Question 54

What happens in the absence of sex hormones at early differential stages?

Answer 54

The mammal becomes a female. Addition of testosterone shifts development towards male. Estradiol and other oestrogen modify the development of the brain and other internal sexual organs.

Question 55

What specific areas in the brain do sex hormones bind to in early life?

Answer 55

Receptos in specific areas of the hypothalamus, amygdala and other brain areas. E.g., the anterior hypothalamus is larger in males than in females and affect the male sexual behaviour.

Question 56

What do early hormones affect in the brain?

Answer 56

The cerebral cortex, some areas are larger in males while others are larger in females.

Question 57

According to Halpern, 2004, what do girls do better in than boys? According to Halari et al., 2005, what do boys do better in than girls?

Answer 57

Reading (on average). Mental rotation and line orientation tasks (on average).

Question 58

In adulthood what do sex hormones activate? How?

Answer 58

Sexual behaviours. Partly by facilitating activity in the medial prep-tic area (region of the hypothalamus) and anterior hypothalamus. Hormones prime cells to release dopamine in response to sexual arousal. Dopamine release evokes effects of addictive drugs.

Question 59

What does hormones being released around the time of giving brith facilitate?

Answer 59

Maternal behaviour in females.

Question 60

What hormones do females secrete late in pregnancy?

Answer 60

Estradiol, prolactin and oxytocin.

Question 61

What is prolactin necessary for?

Answer 61

Milk production.

Question 62

What is oxytocin associated with?

Answer 62

Maternal behaviour and social attachment.

Question 63

What does the brain do later in pregnancy?

Answer 63

Increases its sensitivity to estradiol in areas responsible for maternal behaviour, but not for sexual behaviour. The hormonal changes increase the attention of the mother to the young after birth. hormones also increase activity in the medial prep-tic area and the anterior hypothalamus.