biopsychology
hypothalamus
Stimulates and controls the release of hormones from the pituitary gland and is the control system which regulates the endocrine system
endocrine system
Provides a chemical system of communication via the bloodstream, specifically the blood plasma and secretes hormones which are required to regulate many bodily functions
glands
Pituitary gland-Control controls and stimulates the release of other hormones (oxytocin)
Pineal gland-Releases melatonin, Responsible for important biological rhythms
Thyroid gland-Secretes thyroxine, Responsible for regulating metabolism
Adrenal gland- Adrenal Medulla: Adrenaline and noradrenaline, stimulates SNS adrenal cortex: Cortisol, provides energy
hormones versus neurotransmitters
Hormones: Released by endocrine glands, Part of endocrine system, Travel through blood plasma, effects are Slower to build but long lasting
Neurotransmitters: Released by nerve cells, Part of the nervous system, Diffuse across synapses, effects are fast to act but shorter lasting
fight or flight response
Amygdala is activated-Send a distress signal to the hypothalamus
SNS is activated
Hypothalamus activates sympathomedullary pathway (SAM)
SNS stimulates the adrenal medulla
Adrenal medulla secretes adrenaline and Noraadrenaline into the blood plasma
Adrenaline causes a number of physiological changes to prepare the body for fight or flight
changes for fight or flight
heart rate increases-increases blood flow to organs
Sweating increases-Regulates temperature
breathing right increases-Increases oxygen intake
after fight or flight response
Parasympathetic nervous system is activated to return the body back to its normal resting state
fight or flight response ao3
Strength-Real life implications: Fight or flight response is a maladaptive response in modern day life, High levels of stress continuously activate SNS which increases blood pressure and causes damage to blood vessels and leads to heart disease-suggests the response is maladaptive
Limitation: In dangerous situations, our reaction isn't limited to fight or flight-Initial freeze response humans are hypervigilant while deciding the best course of action
endogenous pacemakers and exogenous zeitgebers
Internal factors/internal body clocks e.g. scn
External factors e.g. light
circadian rhythms
Light (exogenous zeitgeber) Is detected by the eye and sends a signal to the suprachiasmatic nuclei (scn)(endogenous pacemaker)
e.g. sleep-wake cycle
scn
part of hypothalamus in the limbic system
scn Located on the optic nerve junction (optic chiasm)
Light is detected by SCN - inhibits production of melatonin-less sleepy
decoursey et al. (2000) -chipmunks
control group- 20 chipmunks (has scn)
experimental- 30 chipmunks (scn destroyed)
observed for 80 days
more of experimental were killed by weasels
suggests damage to scn affects sleepwake cycle
siffre (1962) caves
2 months in cave- no sunlight, no clocks
removed exogenous zeitgeber (light)
maintained 25 hour sleepwake cycle
planned to finish sep 14
he thought it was aug 20
circadian rhythms strength
siffre (1962)- lack of external cues make him believe 1 day was longer than it was
research support- aschoff+weber (1962)- patrucipants live in bunker with only artificial light. sleepwake cycles were 25-27 hours. suggests that humans use natural light to regulate 24 hour circadian rhythm
circadian rhythm limitations
considaration of individual differences: duffy et al. (2001)- morning people rise and go bed early, evening people rise and go bed later, innate individual differences in circadian rhythms
the role of artificial light: czeisler et al (1999) critised siffre due to artificial light- can act as an exogenous zeitgeber to our sleepwake cycle+ undermine our findings
exogenous zeitgeber
(can include social cues such as meal times)
scn contains receptors that are sensitive to light- used to synchronise bodys internal organs and glands
melanopsin (protein in eye) sensitive to light + carries signals to the scn to set the 24 hour daily body cycle