hormones and behaviour

Question 1

describe how the pineal gland influences biological rhythms?

in birds or reptiles
in humans

Answer 1

unpaired structure (not 2 of them)
brids and reptiles can sense light directly through skull

acts via cervical ganglia in mammals
phasic (bursts) secretion of hormones and other chemicals in cyclic patterns
melatonin important in regulating cyclical function (released by pineal gland and amine hormone)

Question 2

describe melatonin?

Answer 2

released almost exclusively at night

provides signal to track changing daylength and season

controls timing of onset of sleep

breeding condition in seasonally breeding animals

Question 3

describe breeding condition in hamsters?

Answer 3

senses longer nights

prolong nocturnal secretion of melatonin

hypothalamus sensitive to negative feedback effects of gonadal steroids

less GnRH released

gonads atrophy (not in breeding condition)

Question 4

describe ghrelin?

Answer 4

peptide secreted by cells in stomach epithelium

stimulates feeding as appetite stimulant (rise before meal and drop after meal) and release of growth hormone from pituitary

ghrelin-secreting neurons in brain involved in control of feeding

Question 5

describe ghrelin levels in obese people?

Answer 5

lower ghrelin before eating

following a meal levels don’t drop (unresponsive to feeding) so no reduction in appetite

Question 6

describe the mammalian oestrous cycle in women?

pro-oestrus?
oestrus?

Answer 6

cyclic pattern of gonadotropin secretion (FSH and LH) prompted by surge in GnRH above tonic levels from hypothalamus

pro-oestrus - follicular development and ovulation

oestrus - fertilisation most likely to lead to pregnancy

Question 7

what did Beall and Tracy find regarding reproductive behaviour?

Answer 7

asked females what colour top they were wearing while competing the survey

asked when last had period

pink/red shirt when fertile

ovulation not completely concealed

Question 8

what did Miller et al find regarding reproductive behaviour?

Answer 8

recorded tips received by lap dancers

received largest tips when fertile

ovulation not completely concealed

Question 9

describe functions of oxytocin?

Answer 9

peptide hormone that acts on the CNS

associated with uterine muscle contraction at birth and milk letdown

governs prosocial behaviours

Question 10

describe the role of oxytocin in parental care?

Answer 10

rats had more oxytocin receptors in amygdala when high levels of maternal behaviours

higher oxytocin receptor density in nucleus accumbens

blocking oxytocin receptors inhibits maternal beh.

Question 11

describe role of oxytocin in alloparental care?

Answer 11

looking after young of others

injected with oxytocin less likely to attack

reduced levels of alloparental care if injected with oxytocin alloparental care

Question 12

what did Madden and Clutton-Brock find in regards to meerkat’s social behaviour?

Answer 12

condition injected with oxytocin produced more prosocial behaviours
e.g feeding, closeness, communal digging and guarding

and lower amount of aggression compared to control

Question 13

describe role of oxytocin in pair bonding?

Answer 13

oxytocin injections promote pair bonding in monogamous voles

have dense collection of vasopressin receptors compared to those who are polygamous

Question 14

what did Kosfeld and Zak et al find in regards to oxytocin and trust in humans?

Answer 14

played trust game (double-blind in Kosfeld case)

oxytocin condition were more generous with monetary transfers

Question 15

what did Marsh et al find regarding oxytocin and social sensitivity?

Answer 15

oxytocin condition were more sensitive to positive emotional expressions

Question 16

describe relationship between oxytocin and orgasms?

Answer 16

plasma oxytocin increases during orgasm

oxytocin evokes feelings of contentment and security around mate

sex promotes pair bonding then

Question 17

diference between the endocrine and nervous system?

and what they both have in common?

Answer 17

nervous

• localised communication between cells so targeted effect (pre and post-synaptic)
• action potential along nerve fibre
• digital all-or-nothing signal
• fast response but short lived
• voluntary control

endocrine

• diffuse effects across body
• chemical substance in blood stream
• analogue signal (graded)
• slow response and long lasting
• no voluntary control

BOTH: communication and control systems
take inputs and effect outputs
influenced by prior exposure

Question 18

describe the neuroendocrine system?

Answer 18

used when need fast response but prolonged action if required

enables regulation/control of homeostasis
- CNS, ANS, PNS and PSNS