biopsychology: endogenous pacemakers and exogenous Zeitgebers

Question 1

define the term endogenous pacemakers

Answer 1

internal body clock that regulate biological rhythms such as sleep/wake cycle

Question 2

name 2 endogenous pacemakers and state where they are located (3)

Answer 2

1. SCN - in hypothalamus
2. The Pineal gland

Question 3

describe the function and action of the SCN (3)

Answer 3

• known as one of our “internal body clocks”
• recieves info about light even when our eyes are closed
• can do this bcs it is located just above nerves that lead to visual area

Question 4

describe the function and action of the pineal gland (6)

Answer 4

• works with the SCN
• contains light sensitive cells
• secretes the hormone melatonin
• when light lvls fall melatonin production increases
• inhibits brain mechanisms that promote awake state
• light decreases melatonin production activating brain mechanisms = be awake

Question 5

define the term exogenous zeitgebers (1)

Answer 5

external factors that affect our biological rhythms such as sleep/wake cycle

Question 6

give 2 examples of exogenous zeitgebers (2)

Answer 6

1. light
2. social cues

Question 7

describe the role of light as an exogenous zeitgeber (2)

Answer 7

• can reset body’s internal clock over time (SCN)
• can also indirectly influence hormone production and circulation

Question 8

descirbe the roles of social cues as exogenous zeitgebers (3)

Answer 8

• affects sleep wake cycle
• schedules imposed by parents (meal times + bed times)
• time zones when travelling long distances

Question 10

what are the three evaluation points for endogenous pacemakers and exogenous zeitgebers

Answer 10

✅ supporting research for role of SCN as endogenous pacemaker:
- SCN connections destroyed in brains of 30 chipmunks
- found that sleep wake/cycle had completely disapeared
- and many were eaten by predators as were awake when shouldn’t have been

❌ CA: UNETHICAL + ANIMALS STUDY

✅ research evidence - light as exogenous zeitgeber:
- 15 ppnts woken up and light pad shone at back of their knees
- deviated usual sleep/wake cycle by up to 3 hrs
- light very powerful ex zeit as can be detected by skin receptors on body

❌CA: 15 ppnts only