What are the three hormones released by the adrenal gland?
- Cortisol, adrenaline, noradrenaline
- (epinephrine, norepinephrine)
What is the endocrine system?
Glands that secrete hormones
What is immunosupression?
Immune system supression
Due to stress: directly due to cortisol; stress hormones too high in blood stream, can shut down/effect activeness of immune system over time
Due to cognitive effects: dampens immune system, more prone to getting sick
Mental state has an effect on levels of stress
How does the HPA axis work?
External stimuli triggers the hypothalamus
Hypothalamus secretes hormones into Pituitary gland
Pituitary gland releases hormones to Adrenal gland
Adrenal gland releases hormones into the blood stream
What is negative feedback loop?
When peak hormone level is reached in the blood stream, cortisol sends a signal to the hypothalamus to shut off
What is exaptation
When a species takes existing components and forms a new function with those components
What is a stressor?
Anything that triggers mental or physical stress
What is homeostasis?
Regulation of body temperature/function, keeps body at equilibrium
What is allostasis?
Homeostasis related to stress and bringing stress levels back to normal
How is negative feedback an example of allostasis?
Negative feedback regulates stress hormones by turning off the hypo campus when cortisol blood levels are too high
What are peptide ulcers caused by?
What are peptide ulcers?
Tears in stomach lining
What are the glucocorticoids?
Cortisol, adrenaline, noradrenaline
What is stress immunization?
Building an immunity to the effects of stress on your body
What did the rat pup study conclude about stress?
Rat pups were stressed when they were picked up and calmed when the mother licked them.
Rat pups who were not licked did not calm down and stayed stressed for much longer after being put down
Rat pups who were licked after they were picked up learned to not be afraid of being held.
What is epigenetics?
How DNA code is expressed
How was stress researched in the 1950's?
Biologically- physicians treated the body like an engine
Bioengineers helped contribute to what we know about stress
What was the paradigm shift in the research of stress after the 1950's?
Stress research began to include psychology
If there were no psychological factors involved, studies were not considered valid.
Research looked at stress less from a biological perspective and more from the perspective of cognition and response to experiences.
What is the correlation between ulcers and stress in rats?
More stress= more ulcers
How does social support effect stress?
People experience stress in different situations:
higher stress around strangers but lower stress around family and friends
What is the effect on rats if they have something to chew on?
Lower levels of stress
Lower # of ulcers
Outlets for frustration equal more stress or less stress?
What was the baboon social support study and what did it conclude?
Tracked cortisol/ulcer correlation
Lower ranking baboons experienced more stress than higher ranking baboons.
Stability of the hierarchy-more stress when the hierarchy was less stable, less stress when the hierarchy was stable
Higher # of friends led to a lower level of cortisol
More social grooming led to lower levels of cortisol
What did the human social support study conclude about stress?
More friends= lower cortisol levels
More social isolation= more active SNS response
Social isolation creates 5 times higher risk for cardiovascular disease
disconnection from the community= higher stress
people in communities of other ethnic groups= higher stress
What were the 2 studies on the predictability of stress in rats and what did they conclude?
1. Rats were shocked without warning, cortisol levels increased
When rats were given a warning bell before shock, cortisol levels decreased
2. Feeding time was randomized, cortisol levels increased (randomness became the stressor)
Less structure = less predictability= higher stress
Both: predictability leads to a lower level of stress
What were the 2 human studies on the predictability of stress and what did they conclude?
1. Dental exams- telling the patient when/how many times the doctors going to drill decreases stress levels
2. Military jumping from planes- more training leads to lower stress levels because they are used to it
Both: predictability helps us handle stress and lowers stress levels
What was the rat study on control over stress and what did it conclude?
Rats were shocked
When they were given a lever to avoid shocks: their stress decreased and # of ulcers decreased
When the lever was removed: stress increased and # of ulcers increased
When the lever was returned but didn't work: stress decreased and # of ulcers decreased
Conclusion: when a control mechanism is introduced, stress goes down whether or not the mechanism works
What was the human study on control over stress and what did it conclude?
Stress was induced through high noise and levels of cortisol increased
Given a button to press to avoid sound: cortisol levels decreased
Take button away: cortisol levels increased
Return button but button doesn't work: Cortisol levels were decreased
Conclusion: Even if the control mechanism doesn't work, cortisol levels will decreased if there is perceived control over a situation
What is adaptation?
A species ability to change to fit its environment
What is randomness
Only certain animals in a species are born with the necessary adaptations to survive.
What is mutation?
When a species DNA changes abnormally (usually to adapt to an environment)
What are primates and when did they first appear on Earth?
Primates are monkeys and Great Apes.
Monkeys: new world and old world
Great Apes: orangutans, gorillas, chimps, bonobos
First appeared: 14 million years ago
What did unicellular organisms have that neurons have today?
GABA and glutamate
Pores (Channels) like axon terminals
What has changed in the brain over the last 2 million years?
higher level motor, visual and language skills, teamwork and other social skills
What are the cognitive requirements of tool making?
High visual acuity
High tactile sense
fine motor coordination
What is the ratchet effect?
When a species invents something and then continues to improve on that invention
What is the triune brain model?
- Cortex: advanced cognitive processing
- Neomammalian complex
- Limbic system: Basic mammalian functions
- Paleomammalian complex
- Brain stem: Basic survival instincts
- Oldest part of the brain- reptilian complex
What are the primary aging changes?
Decrease in motor coordination
Change in sleep patterns (less sleep at lower quality)
- Cognitive deficits
- Lower short term memory
- Lower long term memory
- Lower visuospatial skills
- Lower verbal fluency
What is brain atrophy?
Breakdown of brain tissue
When does the brain start to atrophy?
Around age 20-70
Is the metabolism in the brain stable throughout life?
By how much does the brain decrease in size per year?
.2% until 70
What are the causes of Alzheimers disease?
- Genetic causes-
- Down syndrome
- genetic markers
- Other causes-
- Parkinson's disease
- History of Alcoholism
- Serious infection
- Brain tumors
- Vitamin deficiencies
- Metabolic disorders
What are the symptoms of Alzheimers?
- 1. Behavioral-
- Memory deficit (explicit LTM)
- Decreased appetite
- 2. Brain Atrophy-
- lower overall volume of cortex
- lower volume of hippocampus
3. Lower acetylcholine
4. Plaque formations= neuronal damage
5. Formation of tangles
What happens when the brain produces too much amyloid plaque?
Plaque begins to accumulate in the synapse and blocks neuronal transmission
How are tangles formed?
Tau proteins build up inside the neuron
The clumps begin to unravel the microtubules
microtubules tangle= the nueron cannot communicate with itself
Neuron starts to malfunction
What are some treatments for Alzheimers?
No real cure
- 1. Current attempts
- boosting acetylcholine levels
- curcumin- lowers amyloid plaque and tau damage
- 2. Future possibilites
- Substance to bind amyloid plaque (render it uneffective)
- Lower amyloid plaque production