Define transcription and translation
- transcription: DNA is read by transcriptional factors that bind to DNA strands, ultimately producing mRNA
- translation: mRNA read in triplets which gives code to put together amino acids necessary for prod of proteins
What is the promotor region of a gene
- marks start of gene where transcription factor will bind
DNA methylation is an _____ process of long-term ___ that involves attaching a methyl group to cytosines in the promoter region of a gene
epigenetic; gene silencing
What are 3 hormones that have transcriptional effects?
- cortisol
- GH
- testosterone
**all act in nucleus
What is homeostasis
ability to maintain optimal conditions in the body
(T/F) there is always an external trigger for stress
FALSE, can be internal
What are the 3 main categories of sources of stressors?
- environmental factors
- physiological factors
- psychosocial factors
Stress can be defined as any significant _____
disturbance of homeostasis
What are the 2 key components of the stress response
- epinephrine from adrenal medulla
- glucocorticoids from adrenal cortex
current stress research focusses mainly on ___
psychological features of stress (mainly degree of control individual has over situation)
Who discovered the non-specificity of the stress response and what does this mean?
- Hans Selye (rats injected w saline vs hormone had similar stress responses–probs due to manipulation)
- epinephrine and glucocorticoids are released in response to almost any stressor
What are the 3 stages of the General Adaptation Syndrome?
- Alarm Reaction Stage (fight or flight, low stress resistance)
- Stage of Resistance (body adapts to restore homeostasis)
- Stage of Exhaustion (can no longer cope w stressor, can even lead to death!)
What are 2 key limitations to the homeostatic concept of stress?
- does not address issue that psychological stressors can evoke full physiological stress response
- does not account for individual differences in perception of stressors (ex sky diving)
What are the 3 elements of the modern definition of stress?
- condition in which indiv is aroused by aversive stimuli
- must perceive stimuli as aversive
- lack of perceived control over aversive stimuli
Within seconds of exposure to a stressor, the ____ secretes ____ and then the ______ secretes ______
sympathetic NS secretes norepinephrine; adrenal medulla secretes epinephrine
The effects of (epinephrine/norepinephrine) are 6x stronger than (epinephrine/norepinephrine)
epinephrine 6x stronger than norepinephrine
Within the short-term stress response, epinephrine and norepinephrine lead to what 6 symptoms?
- increased HR
- increased BP
- liver converts glycogen to glucose and releases it into blood
- dilation of bronchioles
- decreased digestive system activity and reduced urine output
- increased metabolic rate
How is the HPA axis involved in the stress response?
- after release of nor/epinephrine
- HYPOTHALAMUS releases corticotropin-releasing hormone
- stimulates release of adrenocorticotropin hormone from anterior PITUITARY gland
- within minutes ADRENAL cortex begins to secrete glucocorticoids
In the long-term stress response, what are 2 impacts of mineralcorticoids and 3 impacts of glucocorticoids?
Mineralcorticoids:
- retention of sodium and water by kidneys
- increased BP and volume
Glucocorticoids:
- proteins/fats converted to glucose or used for energy
- increased blood glucose
- suppression of immune system
(T/F) glucocorticoids are only involved in the long-term stress response
FALSE, also act on metabolic pathways within minutes to replenish energy reserves
The fact that predators and prey experience similar acute stress responses is an example of ____
nonspecificity of the stress response
The implication of a hormone in behaviour requires evidence of _____
hormonal signaling in the CNS
Why are glucocorticoids good candidates for mediating behavioral effects of stress (3)?
- released in response to numerous stressors
- can easily diffuse past blood-brain barrier (so act on CNS unlike epinephrine which struggles to pass through)
- there are glucocorticoid receptors in several brain regions
How does corticotropin releasing hormone (CRH) mediate the stress responsein the hypothalamus and the amygdala?
- in hypothalamus: regulation of HPA axis
- in amygdala: mediating anxiety response
