BIOPSYCH ( ENDOGENEOUS PACE MAKERS & EXOGENEOUS ZEITGEBERS)

Question 1

Outline definition of endogenous pacemakers , the main pace maker and it’s role

Answer 1

Endogenous pacemaker - Internal mechanisms that govern biological rhythms, particularly the circadian rhythm ( sleep/wake cycle)

Main pacemaker - Suprachiasmatic nucleus ( SCN) located in hypothalamus , receives info about light from the optic nerve , even when our eyes are shut.

Role of the SCN : send signals to pineal gland which controls secretion of melatinon ( hormone inducing sleep) . At night melatonin levels rise , promoting sleep /wake cycles , during daylight they fall encouraging wakefulness.

Question 2

Evaluate endogenous pacemakers

Answer 2

Supporting animal research : SCN lesion study in chipmunks shows the importance of endogeneous pace makers for survival and daily rhythms.

Limitation - ethical concerns in harming animals and hard to generalise findings fully to humans

Question 3

Outline the definition of Exogenous zeitgebers , the main zeitgeber

Answer 3

Definition : external environment cues that help regulate biological rhythms.

Light as the main zeitgeber : cues are detected by light-sensitive cells in the retina that send messages to the SCN to reset the clock . Helps keep the circadian rhythm synchronised with the 24hr day.

Social cues as zeitgebers : mealtimes , routines , social interactions entrain biological rhythms if light cues are weak or unavailable

Question 4

Evaluate exogeneous zeitgebers

Answer 4

Strengths :

supporting human study
Siffre lived in a cave with no natural light , his sleep/wake cycle extended to around 25hr , showing influence of internal clocks , confirming the interaction between endogenous pacemakers and exogeneous zeitgebers.

Understanding endogenous and exogeneous influences has led to developments in treatment for sleep disorders , jet lag and shift work , by manipulating light exposure and melatonin

Limitations:

Overemphasis on light - although light is important other zeitgebers like temperature , food and routine significantly influence rhythms

Reductionism : This explanation may be biologically reductionist as it isolates components like SCN or light rather than looking at the complex interaction of multiple systems an environmental factors.