Lesson 13 - Endogenous Pacemakers

Question 1

What are endogenous pacemakers

Answer 1

Internal biological rhythms

Question 2

What is the most important endogenous pacemaker

Answer 2

Suprachiasmatic nuclei (SCN)

Question 3

What is SCN location + function

Answer 3

Hypothalamus + generates circadian rhythms

Question 4

How does the SCN work

Answer 4

• SCN receives info about light levels via optic nerve

• Resets built in circadian rhythm

• Nerves elsewhere controlled by SCN + sync

Question 5

SCN relationship w/ pineal gland

Answer 5

• Regulates manufacture/secretion of melatonin

• SCN signals pineal gland to increase at night + decrease with higher light levels

Question 6

(+) Case study of Kate Aldcroft

Core Body Temp

Folkard(1996)

Answer 6

• Spent 25 days in a lab w/ NO exogenous zeitgebers of light
• At end of 25 days her core temp rhythm was still 24 hours
• EZ NOT necessary for EP

Question 7

(-) Case study of Kate Aldcroft

Sleep-Wake Cycle

Folkard(1996)

Answer 7

• Her sleep-wake cycle extended to 30 hours
• EZ IS necessary for EP