Biological Rhythms

Question 1

What is a biological rhythm

Answer 1

-repeated patterns within the body

Question 2

What is a circadian rhythm

Answer 2

-occurs over a 24 hour cycle

Question 3

What is a Infradian rhythm

Answer 3

-last longer than 24 hours

Question 4

What is an exogenous zeitgeber?

Answer 4

-external changes in the environment that influence the rhythm

Question 5

What is an Endogenous pacemaker?

Answer 5

-Internal biological structures/mechanism which reg. the rhythm

Question 6

What is the exogenous zeitgeber in the circadian rhythm of sleep?

Answer 6

-light

Question 7

What is the endogenous pacemaker in the circadian rhythm of the sleep/wake cycle?

Answer 7

-the suprachiasmatic nuclei

Question 8

Explain how light regulates the sleep/wake cycle.

Answer 8

• light is detected by the eye
• relays info abt:
  
  • external levels of brightness
  • 2 SCN
  • can reset the SCN

Question 9

Explain how the SCN regulates the sleep/wake cycle

Answer 9

• receives info abt extern. levels of brightness from eye
• the SCN sends signals to the pineal gland
• increase in pro. of mel.
  
  • AT NIGHT (in response to d.)
• delays release of mel. in the day

Question 10

What are the supporting evidences for Circadian rhythms?

Answer 10

• Siffre’s Cave study

- Hughes 1977 Study

Question 11

Describe Siffre’s study?

Answer 11

• French caver Siffre spent an extensive amount of time in dark caves
• 2 examine the eff. of free-running biological rhythms
• conducted in diff. caves
• CR always spanned j above 24 hours
  
  • regular circadian rhythm

Question 12

Describe Hughes Study

Answer 12

• investigates the importance of light
• four pp in the British Antartic Station
• In Feb (end of Antartic Summer), cortisol patterns usual pattern
  
  • highest level as pps awoke
  • lowest as participants went to bed
• After 3 months: peaked at noon

Question 13

Evaluate circadian rhythms

Answer 13

SE: Siffre et al- j above 24 hour s/w cycle in the absence of light(role of endogenous pacemakers)
Hughes 1977- cortisol levels normal during summer. peaked in the morning, fell when they went to bed.
cortisol levels changed and peaked at noon after months of darkness
-EP regu. by EZ
U: Baraldo’s 2008 study- found that circadian rhythms determine when drugs best absorbed. Medical benefits.
CE: temperature may be more impt. than light in regu. (Buhr et. al)–>
-Siffre is a cave study–> lacks generalisability
-Hughes study only had 4 participants(small sample)–> low population validity

Question 14

Explain the menstrual cycle

Answer 14

• lasting for abt 28 days
• pituitary gland releases FSH
  
  • stimulates ovaries 2 pro. egg
• oestrogen lowest on first day of the MC–>increases
• Faill in progestorene and oestrogen if egg not fertilised
  
  • shedding of the womb

Question 15

What is the supporting evidence for infradian rhythms

Answer 15

• Moos et al.–> changes in menstrual symptoms (mood, sexual arousal) changed in relation to menstrual cycle–> controlled internally by infradian rhythmst
• McClintock

Question 16

What is the exogenous zeitgeber of infradian rhythms?

Answer 16

-Pheromones

Question 17

pass

Answer 17

pass