circadian rhythms

Question 1

what is the duration of circadian rhythms

Answer 1

around 24 hours

Question 2

what are 2 examples of circadian rhythms

Answer 2

sleep wake cycle

core body temeprature

Question 3

what is the puprose of circadian rhythms

Answer 3

to regulate a number of body processes

Question 4

how do exogenous zeitgebers affect our sleep-wake cycle

Answer 4

they make us drowsy at night and alert during the day

Question 5

what is the sleep wake cycle governed by

Answer 5

the suprachiasmatic nucleus (SCN) which is an endogenous pacemaker

Question 6

where is the suprachiasmatic nucleus (SCN)

Answer 6

above the optic chiasm

Question 7

what does the suprachiasmatic nucleus (SCN) do

Answer 7

provides information from the eye about light

Question 8

what can reset the suprachiasmatic nucleus (SCN)

Answer 8

exogenous zeitgebers

for example: LIGHT

Question 9

explain the case study of SIffre that links to circadian rhythms

Answer 9

Siffre is a caveman who spends long periods underground to study the effects of his own biological rhythms

He was deprived of exposure to light and sound with access to food and drink

He resurfaced in mid september 1962 after 2 months in the alps
A decade later he repeated it for 6 months in a Texan cave

his rhythm settled down to 25 hours and he continued to fall asleep and wake on a regular schedule

Question 10

State the procedure of Aschoff and Weaver’s study on circadian rhythms in 1976

Answer 10

they convinced a group of participants to spend 4 weeks in a WW2 bunker deprived of natural light

Question 11

what were the findings of Aschoff and Weaver’s study on circadian rhythms in 1976

Answer 11

all participants displayed a circadian rhythm between 24 and 25 hours

except ones who’s sleep/wake cycle extended to 29 hours

Question 12

what does both Siffre’s and Aschoff + Weaver’s studies suggest about the sleep wake cycle

Answer 12

natural sleep/wake cycle may be longer than 24 hours

but we shouldn’t overestimate the influence of exogenous zeitgebers on our internal clock

Question 13

when there are low levels of light what happens to production of melatonin

Answer 13

the SCN stimulates the pineal gland to produce higher levels of melatonin which causes you to feel more sleepy

Question 14

when there are high levels of light what happens to the production of melatonin

Answer 14

the SCN stimulates the pineal gland to produce lower levels of melatonin which causes you to feel more awake

Question 15

when is the core body temperature at it’s lowest and what temperature is it at

Answer 15

lowest at 4.30 am at 36 degrees celcuis

Question 16

when is the core body temperature the highest and what temperature is it at

Answer 16

highest at 6pm at 38 degrees celcuis

Question 17

what happens to your core body temperature before and during sleep

Answer 17

core body temperature drops before sleep and starts to rise again in the last few hours of sleep which promotes alertness

Question 18

why do we often feel sleepy in the afternoon

Answer 18

there is a small drop in core body temperature at around 2-4pm (after lunch)