Biological Rhythms

Question 1

What does endogenous mean?

Answer 1

Something that’s built in

Question 2

What does exogenous mean?

Answer 2

Something that affects us on the outside (environment)

Question 3

How often does a circadian rhythm repeat itself?

Answer 3

Every 24 hours

Question 4

How often does a ultradian rhythm repeat itself?

Answer 4

More than once in 24 hours

Question 5

How often does a infradian rhythm repeat itself?

Answer 5

In a period over 24 hours

Question 6

Why did Siffre spend 2 months in a dark cave?

Answer 6

Wanted to see whether the sleep wake cycle depends mainly on exogenous or endogenous factors

Question 7

What happened to Siffre in the cave?

Answer 7

No clear pattern was established initially but after a while he settled to a clear 25hr pattern

Question 8

What can we conclude from siffre’s study?

Answer 8

Proves we get affected by exogenous factors as when they were changed (dark cave) his s/w cycle changed

Question 9

What is entrainment?

Answer 9

When our biological and environmental factors are in line with one another

Question 10

Why was Siffre’s study not universal?

Answer 10

Can’t apply it to other as it could be affected by individual differences. For example as Siffre AGEd his clock slowed

Question 11

What is the SCN?

Answer 11

The main pacemaker for circadian rhythms

Question 12

What does the SCN do?

Answer 12

Controls levels of melatonin via the pineal gland

Question 13

Support for the SCN’s role in the SWC comes from hamsters

Answer 13

Transplant SCN of mutant 20hr cycle hamsters to normal hamsters, ‘normal’ hamsters adapted to that cycle and returned back to normal when replaced with the original

Question 14

What is an exogenous zeitgeber?

Answer 14

Factor outside our body which may trigger biological rhythms

Question 15

Siffre found that an important exogenous zeitgeber is…

Answer 15

Light

Question 16

What does siffre’s research suggest about zeitgebers?

Answer 16

They’re needed to keep our rhythms in sync

Question 17

Outline how Miles’ study highlights the deterministic nature of biological rhythms

Answer 17

Told 12 students, for 3 weeks, to sleep at 11:45 and wake at 7:45. He sped this up so they only had a 22hr cycle, 1 followed but the rest stuck to their 24hr cycle. Shows how speeding up a cycle doesn’t affect everyone

Question 18

Evidence that we can ‘will’ our biological rhythms come from where?

Answer 18

When told to wake earlier than usual we have an increase in the stress hormone ACTH which makes us wake earlier

Question 19

DeCoursey outlines the adaptive reasons why rhythms are determined, explain this

Answer 19

Bio rhythms allow animals to justify daily environmental events. Chipmunks SCN removed - most died after 80 days as they remained awake at night and so weasels could hear them

Question 20

Why can you justify the ethical implications of DeCoursey’s research?

Answer 20

It has lots of real-life application so testing on animals is not too bad