Environment (Light) and Breast Cancer - Final Exam Flashcards
(87 cards)
1
Q
How much wavelength is needed to create serotonin?
A
480nm
2
Q
How much wavelength of UVB is needed to make vitamin D?
A
295nm
3
Q
What has to be absent in order to make serotonin?
A
Melatonin
4
Q
What inhibits the production of melatonin?
A
Light
5
Q
Can you make vitamin D inside?
A
No
6
Q
What 2 factors effect duration and intensity of light source?
A
- Different seasons
2. Geography
7
Q
What are circadian rhythms?
A
Are physical, mental and behavioural changes that follow a roughly 24hr cycle
8
Q
What does the circadian rhythm respond to?
A
Light and darkness in an organisms environment
9
Q
Where can you find circadian rhythms?
A
- Animals
- Plants
- Many tiny microbes
- -> most living things
10
Q
What is the study of circadian rhythm called?
A
Chronobiology
11
Q
What is light?
A
An influential environmental agent
12
Q
What 2 pathways does light act on the body with?
A
- Primary optic tract
- -> governs visual perception and responses - Retinohypothalamic tract
- -> governs circadian, endocrine and neurobehavioral
13
Q
What light is retinohypothalamic tract most sensitive to? What is its wavelength?
A
Blue light
- 459-485nm
14
Q
What does light signal through?
A
Melanopsin protein that undergoes a chemical change when exposed to light received by intrinsically photosensitive retinal ganglion cells in the back of the eye
15
Q
What are 10 acute biological/ behavioural effects on the retinohypothalamic tract?
A
- Melatonin secretion
- Body temperature
- Cortisol secretion
- Heart rate
- Alertness
- Cognitive performance
- Psychological performance
- Brain bloodflow
- EEG responses
- Clock gene expression
16
Q
What are 2 long term biological/ behavioural effects on the retinohypothalamic tract?
A
- Circadian regulation
2. Light therapy
17
Q
What are 10 health effects of circadian clock deregulation?
A
- 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
18
Q
What are 6 hormones relating to breast cancer and the hypothalamus exposure to light?
A
- GnRH
- Estrogen
- Progesterone
- Melatonin
- Serotonin
- Vitamin D
19
Q
What is melatonin known as?
A
The hormone of darkness
20
Q
Where is melatonin produced?
A
Pineal gland
21
Q
When is melatonin secreted?
A
At night
22
Q
What is melatonin’s precursor?
A
Serotonin
23
Q
What inhibits the production of melatonin?
A
Light
24
Q
When are melatonin levels high and low?
A
High = night Low = day
25
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
26
SCN
Suprachiasmatic nucleus
27
What does SCN do?
Works like a clock that sets off a regulated pattern of activities that affect the entire body
28
What does the SCN do once exposed to light? (2)
1. Increases body temperature
2. Releases stimulating hormone
- eg) cortisol
29
What does the SCN delay?
Production of melatonin
30
What 2 things is serotonin considered to be?
1. Neurotransmitter
| 2. Hormone
31
Where is most of serotonin produced?
In the gut
32
Where is the rest of serotonin produced?
Central nervous system
33
What does serotonin regulate after its been synthesized in the CNS? (4)
1. Mood
2. Appetite
3. Memory
4. Sleep
34
What is a major action of many anti-depressants?
Modulation of serotonin levels
35
When are the levels of serotonin levels the highest ?
In the afternoon
36
What is needed to initiate the production of serotonin?
Blue light (450-480nm) derived from tryptophan
37
What is vitamin D essential for?
The formation of normal bones and teeth
38
How does vitamin D create formation of bones and teeth? (2)
1. By maintaining normal blood levels of Ca and P
| 2. Cell differentiation and development
39
What are 3 other names for vitamin D?
Fat soluble vitamines
1. D1
2. D2
3. D3
40
What is the active form of vitamin D called?
Calcitriol
41
What is an example of a non true vitamin?
Vitamin D
42
What is vitamin D considered to be and why?
- Considered to be a hormone
- Because we make most of it ourselves from a metabolite of cholesterol that is present in the skin when exposed to UV light
43
What percentage of vitamin D do we make ourselves?
90%
44
Where is vitamin D further processed? (2)
1. Liver
| 2. Kidney
45
What percentage of vitamin D do we eat?
10%
46
What kinds of food gives us vitamin D? (6)
Fortified foods like ...
1. Milk
2. Margarine
3. Breakfast cereal
4. Fatty fish
- -> salmon, tune, mackerel, or oil
5. Cheese
6. Egg yolk
47
What vitamin D suppliment can you take every day, and how much?
- D3
| - 1000 IU/day
48
What structure is vitamin D related to?
Steroids
49
What does vitamin D (in the context of it being a vitamin) do?
Uses some type of high affinity of nuclear receptors to affect transcription as steroids and levels regulate
50
Where can you find vitamin D receptors? (5)
1. Bones
2. Kidneys
3. Immune cells
4. Testis
5. Breasts
51
Why is vitamin D important in cancer?
Vitamin D acts as an anti-proliferation signal
52
What does natural exposure to light control? (3)
Natural body levels of...
1. Serotonin
2. Melatonin
3. Vitamin D
53
What has breast cancer found to be associated with? (3)
Low levels of...
1. Serotonin
2. Melatonin
3. Vitamin D
54
What causes an increased risk of chronic disease like cancer?
Endocrine disrupting compounds are chemicals in the environment that disrupt our hormones
55
What is a way that our hormones get altered?
Disruption of biological rhythm
56
What is one of the major components of disrupting to our environment that can contribute to cancer risk?
Is our new built in environment which alters our exposure to natural sunlight an darkness and exposes us to artificial light
57
What are 2 factors that effect our light exposure?
1. Geographical location
- -> different latitudes
2. Population differences
- -> Living is cities vs rural areas
58
LAN
Light at night
59
Exposure to light at night is correlated with what 2 things?
1. Breast cancer
| 2. Prostate cancer
60
What affects the biological rhythm?
Changes in human exposure to environmental light
61
What does exposure to light alter? (6 examples)
Metabolism of key hormones
1. Gonadotropin releasing hormone
2. Estrogen
3. Progesterone
4. Testosterone
5. Vitamin D
6. Melatonin
62
What 2 neurotransmitters does exposure to light alter?
1. Serotonin
| 2. Dopamine
63
What micronutrient does exposure to light alter?
Iron
64
What could be a result from decrease natural daytime light exposure and increase to LAN?
Increase in breast cancer
65
What does melatonin regulate? (2)
1. Estrogen receptors
| 2. Estrogen production
66
What is part of the rate limiting step in melatonin biosynthesis?
Serotonin precursor
67
What enzyme takes part in the serotonin precursor?
Serotonin-N-acetyltransferase
68
What enzyme is associated with tryptophan?
Tryptophan-5-hydroxylase
69
What enzyme is associated with melatonin?
N-acetyl-5-hydroxytryptaime
70
What time of day is melatonin produced in?
Between 2am and 5am
71
When is serotonin produced?
In the day
72
What does vitamin D follow?
A circadian rhythm
73
When does vitamin D peak?
After mid day
74
What kind of hormone is vitamin D?
Secosteroid hormone
75
Where is 25-(OH)-D3 produced?
In the liver
76
What are 3 things vitamin D regulates?
1. Ca absorption
2. Cell longevity
3. Immune functions
77
Where are low serotonin levels found ?
In depression
78
SSRI
Selective serotonin re-uptake inhibitors
79
What do SSRIs do?
They block the reabsorption of the neurotransmitter serotonin in the brain
80
What does the changing the balance of serotonin levels do?
It seems to help brain cells send and receive chemical messages
--> this can boost the mood
81
What do SSRI patents have a reduced risk of?
Breast cancer
82
SAD
Seasonal affective disorders
83
Where is serotonin levels low?
In the plasma of those who have SAD
84
What percentage of patients with breast cancer experience a depressive disorder with low serotonin levels?
25%
85
What does vitamin D activate?
The transcription of the initial serotonin synthesizing gene tryptophan hydroxylase int eh brain at a vitamin D response element
86
What 2 factors down-regulate estrogen signalling and what is an outcome?
1. Melatonin
2. Vitamin D
- Outcome = decreases breast cancer risk
87
What does low levels of vitamin D, serotonin and melatonin lead to?
Increase in estrogen signalling
