Motivation & Internal Regulation

Question 1

Sleep

Answer 1

All multicellular organisms sleep.
Animals have rythms (of sleep and wake) corresponding to their functional activities.

Question 2

Biological clock

Answer 2

Animals have internal mechanism that generates rhythm (of sleep and wake).

Question 3

What is endogenous gradian rhythms ?

Answer 3

Internally controlled cycles (last 1 day)

Question 4

How do we know endogenous rhythms are internally generated?

Answer 4

Animals kept in darkness still keep to 24 hour cycle
Humans can’t synchronise in 18 hour cycle— slip back to 24 hour cycle
Blind + death animals generate near normal circadian rhythms

Question 5

Where is the biological clock?

Answer 5

Suprachiasmatic nucleus (SCN)&raquo_space; part of hypothalamus

Question 6

Damage to SCN results in:

Answer 6

Damage to circadian rhythms

Question 7

Proof the SCN generates rhythms automatically :

Answer 7

1. Remove SCN and keep its tissue culture, continues to produce 24h rhythms of action potentials
2. SCN of Hamsters with mutant gene coding (20h cycle) removed and put in normal hamsters. They them start to like 20h cycle

Question 8

How does the SCN work?

Answer 8

Control pineal gland
Then releases melatonin — makes us sleepy

Question 9

Upsetting the biological clock:

Answer 9

Clock = internal, but still responds to environment
Feedback system between our clock and world allows us to adapt to change
Light= crucial for periodically resting time - buy circadian rhythms can exist without
Stimulus that changes clock= zeitgeber

Question 10

What is a zeitgeber?

Answer 10

TIME GIVER

Dominant zeitgeber for most land mammals= light
We also respond to exercise, noise, temperature + meals
In Scandinavian countries, ppl become insomniac during winter— very little sun a day

Question 11

Stimuli that can disrupt biological clock?

Answer 11

JET LAG

Disrupts rhythms by crossing time zones
Sleeping at wrong time, depression
Mistmatch between bio clock ad environmental stimuli
Can raise cortisol levels&raquo_space; stressful
Delaying sleep= easier than sleeping early&raquo_space; travelling from Uk -USA = easier

Question 12

Thirst:

Answer 12

Animals have evolved diferent mechanisms to get/ retain water.
Eg. Gerbils- may never drink, dry faeces. Beavers, drink lots, urinate lots.

Question 13

Ther are flexible strategies depending on circumstances for thirst. What happens if water is scarce?

Answer 13

Puitotary gland secretes vasopressin (ADH, makes urine more concentrated)&raquo_space; blood vessels then constrict&raquo_space; radishes blood pressure + compensates for low fluid volume

Question 14

What is vasopressin?

Answer 14

Antidiuretic hormone (ADH)
Makes urine more concentrated by causing kidneys to re absorb fluid from urine

Question 15

Why do hangovers make us thirsty?

Answer 15

Drinking alcohol blocks production of vasopressin by putuitary glands
Prevent kidneys re absorbing water
Makes urine more diluted

Question 16

Hunger, how do we know what to eat?

Answer 16

Combo of learnt and unlearned behaviour
- learned from peers +culture
-innate taste= is serial
- likeness of sweet food

Question 17

Hunger: how do we know when to eat?

Answer 17

Way brain decided to eat= complicated
- centres around hypothalamus
- has neurons sensitive to hunger and feeling ill
- many areas involved&raquo_space; can make many errors&raquo_space; but other areas can compensate

Question 18

Eating Disorders:

Answer 18

1. Obesity
   - cultural influence
   - social aspect of eating
   - native diabetics&raquo_space; Native Americans introduced to new foods caused diabetes
   - rooted in our biology to like fatty food
2. Anorexia
   - unwilling to eat
   - perception of fatness, even when thin
   - body can deteriorate > muscle wasting
3. Bulimia
   - extreme dieting mixed with binge
   - erratic causes or can be caused by imbalance of hormones
   - similar to drug addiction&raquo_space; rat sugar drink test> drank more sugar when had been deprived of food> drinking this in feeding tike released dopamine
   - when sugar deprived= withdrawal

Question 19

How does sex affect out behaviour? Evolutionary theory:

Answer 19

We = predict of successful strategies, so we inherit those successful strategies
Men + women subject to different selection pressures— so exhibit different traits

Question 20

Main wats men and women differ:

Answer 20

1. Sexual strategies- reproductive behaviour
   - mate choice : men have numerous sperm > potential to father much offspring
   -women have few immobile eggs> o more choosy with mate
   - testosterone+ adrenal gland both create sex drive, removal of testes> still production of sex drive in brain
   -
2. Cognition
   - cognitive skills rooted in different reproductive + survival strategies