Exam 3 Flashcards
homeostasis
- process by which body achieves a stable, balanced environment
- has set points and set zone
- works in negative feedback loop (homeostasis counteracts whetever is deviating from set point)
set points vs. set zone
set points- optimal setting homeostasis is trying to avhieve (where system works best)
set zone- range within which a system can work (set point found here)
thermoregulation
- process by which body maintains an ideal temp
- in mammals: use heat-produced metabolism
- in reptiles: reliant on behavioral measures because have low metabolisms
preoptic area (POA)
- located in hypothalamus
physiological responses - shivering: heat generated through metabolic burn required for motion
- construction of blood vessels: body’s exterior reduced blood flow makes skin and fat better as insulation
- activated by osmosensory neurons and baroreceptors, which increases drinking behavior
lateral hypothalamus
behavioral regulation of temp (ex: seeking heat sources, increase surface area of body that gets exposure)
reptiles often choose heat over food
thirst and the 2 types
the homeostasis of fluid regulation
1. osmotic: less water, more salt (via urination or salt consumption)
2. hypovolemic: decrease in body fluid volume (triggered even if [salt] doesnt change)
osmosensory neurons
- detect changes in [salt]
- found in circumventricular organs
- fluid around osmosensory neurons too salty -> shrink -> opens ion channels ->depolarizes osmosensory neurons and send more action potentials
baroreceptors in blood vessels of kidneys and hearts
monitor cahnges in blood volume by detecting when walls of vessels stretch/ contract
- hypovolemic thirst
where is vasopressin hormone released from and what is the effect?
- released from pituitary gland
- tells kidneys to retain water
- will slow down water loss but not fully fix the problem
nutrients vs essential nutrients
nutrients: chemicals required for the normal maintenance and function of the body
essential: those that the body cannot manufacture and must be obtained from diet
ex: amino acids, fatty acids (omega-3), minerals
what happens when we eat?
eat -> glucose levels increase -> insulin released into blood -> lets glucoes enter muscles and liver cells to be used or converted to glycogen
what is glycogen
glucose in its short-term storage form
what does low glycogen lead to?
fats converted back to glucose
what do low glucose levels lead to?
glycogen converted back to glucose by hormone glucagon
what happens if there is more glucose than needed in the short-term?
glucose goes into long-term storage in adipose (fat) tissue
what releases insulin and what does it do?
- released into blood by pancreas
- inhibits NPY neurons, which reduces hunger
- allows glucose to enter muscles
(not required for glucose to enter NEURONS)
diabetes definition
failure of insulin to allow glucose to be taken into cells that need it
Type 1 Diabetes
- ‘juvenile onset’
- when pancreas stops making insulin (too much glucose, not enough getting used)
Type 2 Diabetes
- ‘adult onset’
- when cells no longer respond to insulin
- may lead to hyperglycemia (increase in blood pressure)
what is basal metabolism and where does energy go to?
- level of energy used when you are at rest
- where majority of energy is spent
- energy goes to: heat production, maintenance of ion gradients, life-sustaining cellular processes
metabolic adaptation
basal metabolism decreases when energy intake decreases, but could cause substantial weight gain
hunger vs satiety
hunger: motivational drive to eat
satiety: feeling of being full/ absence of hunger
what do arcuate nucleus in hypothalamus monitor?
levels of hunger and satiety-relevant hormoens
what neurons can arcuate nucleus activate?
- POMC: signal satiety when activated, which inhibits hunger and feeding
- NPY: signal hunger when activated, which promotes feeding
ghrelin
released from digestive organs and activate NPY neurons
leptin
released from fat cells and inhibits hunger
Glucagon-like peptide 1 (GLP-1)
stimulates insulin release in presence of food in the gut
semaglutide
- GLP-1 receptor agonist
- treatment for Type 2 Diabetes
what does hedic mean and what stimulates it?
- pleasure seeking
- stimulated by ultra-processed food
nucleus accumbens (NAcc)
- located in basal ganglia
- motivation
- express mu-opiod receptor
- ensures no opportunity to feed on high caloric food is missed (even if there is no homeostatic demand for energy)
bliss point
amount of an ingredient needed to make a food maximally delicious (engineered to be this way)
sensory specific satiety
the more you eat of a specific food, the less you want it
energy intake is controlled by _____ and _____ mechanisms
hedonic and homeostatic
biological rhythms definition
periodic fluctuations in normal physiological processes that occur over different timescales
circadian rhythms definition and processes that fluctuate on a cycle
- fluctuations that happen over 24 hr period
- processes that fluctuate: sleep and wakefulness, [hormones], feeding
what is evidence that the body can keep time even without external tools?
daily fluctuations in bio processes are coordinated by internal clock
Zetigebers
external env. cues that signal something about the time of day (ex: shift in light)
where is the circadian clock located?
suprachiasmatic nucleus in hypothalamus
where does SCN gets input from?
- glutamate from ganglion cells in retina that carry info about phase shifts in light levels
- cells are light sensitive (especially to blue light)
where does SCN send info to and what does that do?
to pineal gland and releases melatonin
what are EEGs used for?
differentiate the different stages of waking and sleep
awake on EEG
- desynchronized activity across cortex
- high frequency and low amplitude
when is synchronized waking activity seen?
seizures
non-REM sleep
- 3 phases with distinct wave patterns
- early: low heart rate and muscles relax
- final: slow-wake sleep, high amplitude, non-seizure synchronization of activity across cortex
REM sleep
- brain activity highly similar to awake
- complete loss of muscle tension
- most likely to report that you were dreaming if awakened here
- cortical activity during waking and REM sleep is associated with conscious experience
80% of sleep in ____ and 20% in ____
80% non-REM
20% REM
biological functions of sleep
- developmental
- memory
- growth hormones released during slow-wave sleep
- immune function
- clearance of metabolites by increased for of CSF through extracellular space
narcolepsy
- overwhelming sleepiness occurs suddenly and unpredictably
- have low orexin neurons
sleep paralysis
brief inability to move before/after waking
dorsal pons- loss of muscle tension during sleep
REM behavior disorder
- no loss of muscle tension during REM sleep
- people can act out their dreams while remaining asleep
Locationist Definition of Emotion
- psychological state, triggered by an external stimulus of situations
- Different parts of the brain are activated for emotion
- discrete emotions
Plutchik core emotions
4 pair of opposites that produce different variations on the same emotion depending on intensity
Limbic system
- interconnected group of forebrain structures important for emotion and memory
- Contains: anterior cingulate cortex, hippocampus, amygdala, and hypothalamus (all emotion)
Amygdala
- emotional processing (stimulation here during surgery produces fear)
- Patient with destroyed amygdala: limited fear of spiders or scary scenes. Also overly trusting
- Information about threatening stimuli can reach the amygdala directly from sensory significance of complex stimuli
Kluver-Bucy syndrome
removal of the monkey amygdala induces bizarre emotional and motivational responses
1. Reduced fear and aggression-monkeys became strongly docile
2. Strange food consumption behavior- non-food items consumed
Constructionist Definition of Emotion
- emotions are NOT psychological states, but instead a mix of other more fundamental psychological components
- Core affect: combination of psychological processes and emotion: emotion is a value that your brain assigns to help you understand your reaction to a situation
- emotions are NOT discrete
Evidence for the constructionist approach
regions that tend to be active in fMRI studies of ANY emotion
abulia
- damage to anterior cingulate cortex (ACC)
- Powerful apathy that leaves individual incapable of of basic decisions
- show diminished emotional reactions, reporting less intense feelings, and reduced physiological response to emotional stimuli
- Demonstrates that without them our ability to make basic choices is lost
facial expressions controlled by
- superficial facial muscles: create subtle movements in skin of face (ex: wrinkling nose)
- deep facial muscles: create larger movements (ex: opening your mouth)
what are facial muscles controlled by?
facial and trigeminal nerves
stress definition
The physiological response to aversive/ threatening stimuli
hypothalamus-pituitary-adrenal axis (HPA)
- regulates hormones
- Controls release of cortisol from adrenal gland (increases glucose levels for when we need energy in emergency)
Sympathetic nervous system
- activated by stress
- Increase availability of metabolic energy (glucose) while also increasing utilization of that energy by muscles
- Adrenal gland releases epinephrine (facilitates energy mobilization and use)
- activation of it inhibits parasympathetic system
acute stress
an emergency
Yoked control design
- master controls what happens to both. Master and yokes get the same stressor but masters are in control (learned helplessness)
- Control reduces stress response and can make master resilient against future stressors
- Control over stressors activates medial prefrontal cortex (mPFC)- inhibits activity in amygdala and thus dial down the stress response
Mood
baseline affective/ emotional state that persist across situations
Mood disorders
disruptions or distortions in mood that significantly impair normal life activity
anhedonia
inability to take pleasure in previous pleasurable things
what does PET scan measure?
glucose uptake
Evidence for strong genetic component in depression
- ** Identical (monozygotic twins)**: if one, both 60% of the time
- Fraternal (dizygotic twins): if one, both 20% of the time
Vulnerability to repression is polygenic (related to about 269 genes)
102 patterns
15 sets or functionally related genes implicated in depression
Sugnenual cingulate in depression
takes up less glucose
sleep disruption in depression
- eduction in slow-wave sleep (stage 3 non-REM) (most restorative- may produce effects on memory)
- REM sleep can occur immediately
____ levels of cortisol in depression
higher
HPA dysregulation
dexamethasone (similar to cortisol) does NOT suppresses normal cortisol release through negative feedback (as it would in a healthy individual)
hippocampus categories and effects on depression
- hippocampal gyri
- dentate gyri (subgranular zone has dividing neural progenitor cells that give rise to newborn neurons)
hippocampus volume decreases in patients with depression
Depression drugs
- work on monoamine neurotransmitters (block reuptake to prolong the action of the neurotransmitter in the synapse)
SSRIs
MAOIs: inhibit enzyme monoamine oxidase, which breaks down serotonin, norepinephrine, and dopamine (Prevent enzymatic degradation and increase monoamines in synapse)
Neurogenesis
- some areas (hippocampus) get new neurons throughout life
- Cortisol inhibits neurogenesis, while monoamines promote it
- theory: depression tamps down neurogenesis and neurogenesis increases [monoamine]
CBT
- help develop antidepressant cognitive strategies
- Premise: cognition can be used to alter mood
ECT
- electroconvulsive therapy treatment of refractory depression
- Patient anesthetized and administered muscle relaxants, Similar to shock therapy
- Nonstandard treatment for refractory depression
novel/experimental treatments for depression
- Ketamine: psychedelic drug that blocks NMDA glutamate receptor
- Vagus nerve stimulation- electrical stimulation inhibits sympathetic nervous system, which may balance out dysregulated stress response in depressed individuals
- Deep brain stimulation- intracranial electrode implanted to stimulate specific limbic system regions (like cingulate cortex)
Vagus nerve
primary parasympathetic nerve of the body
