Environment (Light) and Breast Cancer - Final Exam Flashcards
How much wavelength is needed to create serotonin?
480nm
How much wavelength of UVB is needed to make vitamin D?
295nm
What has to be absent in order to make serotonin?
Melatonin
What inhibits the production of melatonin?
Light
Can you make vitamin D inside?
No
What 2 factors effect duration and intensity of light source?
- Different seasons
2. Geography
What are circadian rhythms?
Are physical, mental and behavioural changes that follow a roughly 24hr cycle
What does the circadian rhythm respond to?
Light and darkness in an organisms environment
Where can you find circadian rhythms?
- Animals
- Plants
- Many tiny microbes
- -> most living things
What is the study of circadian rhythm called?
Chronobiology
What is light?
An influential environmental agent
What 2 pathways does light act on the body with?
- Primary optic tract
- -> governs visual perception and responses - Retinohypothalamic tract
- -> governs circadian, endocrine and neurobehavioral
What light is retinohypothalamic tract most sensitive to? What is its wavelength?
Blue light
- 459-485nm
What does light signal through?
Melanopsin protein that undergoes a chemical change when exposed to light received by intrinsically photosensitive retinal ganglion cells in the back of the eye
What are 10 acute biological/ behavioural effects on the retinohypothalamic tract?
- Melatonin secretion
- Body temperature
- Cortisol secretion
- Heart rate
- Alertness
- Cognitive performance
- Psychological performance
- Brain bloodflow
- EEG responses
- Clock gene expression
What are 2 long term biological/ behavioural effects on the retinohypothalamic tract?
- Circadian regulation
2. Light therapy
What are 10 health effects of circadian clock deregulation?
- Insomnia and sleep disorders
- Reduced alertness
- Poor cognitive and motor function
- Depression, bipolar disorder and seasonal affective disorder
- Cardiovascular disease
- Altered hormone levels
- Obesity
- Early onset diabetes
- Altered immune function
- Cancer –> breast, prostate and colon
What are 6 hormones relating to breast cancer and the hypothalamus exposure to light?
- GnRH
- Estrogen
- Progesterone
- Melatonin
- Serotonin
- Vitamin D
What is melatonin known as?
The hormone of darkness
Where is melatonin produced?
Pineal gland
When is melatonin secreted?
At night
What is melatonin’s precursor?
Serotonin
What inhibits the production of melatonin?
Light
When are melatonin levels high and low?
High = night Low = day
What kind of body temp helps with melatonin production?
Low body temperature
–> this is why your circadian rhythm drops you body temperature at night so you can sleep
SCN
Suprachiasmatic nucleus
What does SCN do?
Works like a clock that sets off a regulated pattern of activities that affect the entire body
What does the SCN do once exposed to light? (2)
- Increases body temperature
- Releases stimulating hormone
- eg) cortisol
What does the SCN delay?
Production of melatonin
What 2 things is serotonin considered to be?
- Neurotransmitter
2. Hormone
Where is most of serotonin produced?
In the gut
Where is the rest of serotonin produced?
Central nervous system
What does serotonin regulate after its been synthesized in the CNS? (4)
- Mood
- Appetite
- Memory
- Sleep
What is a major action of many anti-depressants?
Modulation of serotonin levels