Lecture 2 Flashcards
What are the 2 primary systems in the body responsible for mental behavior?
- CNS
- Endocrine system
• Both have pathways & interact with each-other
o IE Fight or flight response (surge of norepinephrine – key neurotransmitter)
• Direct nerve running from the locus coeruleus to the adrenal glands so they respond almost instantaneously as each-other
Neurotransmitters
• Ganglia → clusters of nerve cells that work together to serve a common purpose
• Site comes from the bottom of the brain stem → locus coeruleus
o Responsible for 100% of the norepinephrine secreted into the brain
o Rule of brain → “the further down & closer to the center you go—the more primitive the fcns//// the further out & further up you go – the more sophisticated the fcns”
Norepinephrine
a neurotransmitter that is important for attentiveness, emotions, sleeping, dreaming, and learning. Norepinephrine is also released as a hormone into the blood, where it causes blood vessels to contract and heart rate to increase.
Norepinephrine plays a role in mood disorders such as manic depression.
Serotonin
contributes to various functions, such as regulating body temperature, sleep, mood, appetite, and pain.
Depression, suicide, impulsive behaviour, and agressiveness all appear to involve certain imbalances in serotonin.
Glutamate
is a major excitatory neurotransmitter that is associated with learning and memory.
It is also thought to be associated with Alzheimer’s disease, whose first symptoms include memory malfunctions.
GABA (gamma-aminobutyric acid)
is an inhibitory neurotransmitter that is very widely distributed in the neurons of the cortex. GABA contributes to motor control, vision, and many other cortical functions. It also regulates anxiety.
Some drugs that increase the level of GABA in the brain are used to treat epilepsy and to calm the trembling of people suffering from Huntington’s disease.
Dopamine
is a neurotransmitter involved in controlling movement and posture. It also modulates mood and plays a central role in positive reinforcement and dependency.
The loss of dopamine in certain parts of the brain causes the muscle rigidity typical of Parkinson’s disease.
Acetylcholine
is a very widely distributed excitatory neurotransmitter that triggers muscle contraction and stimulates the excretion of certain hormones. In the central nervous system, it is involved in wakefulness, attentiveness, anger, aggression, sexuality, and thirst, among other things.
Alzheimer’s disease is associated with a lack of acetylcholine in certain regions of the brain.
Brain Stem vs. Pre-Frontal Cortex conflict
Central principle of Freud’s psychoanalytic theory
Brain Stem = ID
Pre-frontal cortex = SuperEgo
Hyperthyroidism
“silent killer”
One of the great fakers of Major Depressive Disorder (MDD)
- Can become depressed
- Hair falls out
- trouble with temperature regulation
Note: doing a good Depression assessment will rule out chances for hyperthyroidism
(have both thyroid panel & TSH test conducted)
2 ways to occur:
1. Thyroid begins to dysfunction
2. Master gland (pituitary) secrets TSH (thyroid stimulating hormone) which tells the thyroid to secrete thyroxin
Pituitary tumor –> TSH is inadequate
Central Nervous System (CNS)
• Structure of Brain
o consists of 5 billion brain/nerve cells → Neurons
o Neurons govern fcn of brain by secreting neurotransmitters
o Neurotransmitters → turn things off or on (depending on fcn)
• Neo-cortex (counts for the complexity of human intelligence)
o emotional centers/limbic system/ amygdala (located by hippocampus –memory and emotions → governs fear)
• Mid-brain & Hind-brain / Lower Brain → can effect pre-frontal cortex
Pro-longed Stress
Major problem of human species
our bodies were not intended to experience–How children succeed
What develops intelligence levels?
• it’s not the size of the brain
• it is the interconnectivity of the neurons
o the pre-frontal cortex matures as you establish more inter-neuronal connections
o people are generally born with the intelligence they’re going to have (within 1 SD) because the DNA predicts how many connections their pre-frontal cortex will have
o Reaction range → if you don’t stimulate the brain adequately (raising in an impoverished environment) then the child may be unable to develop as many inter-neuronal connections as genetically predisposed (requires both nature & nurture)
o early stimulation of the brain. . . you can stimulate more interconnections in the pre-frontal cortex and may in turn increase IQ (high IQ 115+)
• some people with a more highly developed pre-frontal cortex may have more resources to deal with more stressors
Biological Etiology of Psychiatric Disorders
• Genetics →
o Some illnesses appear to be more or less genetically determined
• i.e. 1 form of Alzheimer’s that is determined by 1 gene → very early onset if they have gene..they will develop at about 40years of age … can be determined via genetic analysis of DNA (via blood test)
• i.e. Huntington’s
o most psychiatric disorders that have a genetic component are multi-factorial
• i.e. Schizophrenia cannot be soley determined via human genome because there appear to be multiple genes that are involved — although it is a highly genetically determined disease … family histories can be a predictor
o pre/para/natal …genes have the ability to mutate & or turn off
• Central Nervous System (CNS) →
o approx. 200 different types neurotransmitters
• only identified 40-50 types
• most common = GABA (off switch)
brain doesn’t know the difference between alcohol & GABA
o Catecholamine’s: (most psychotrophic medications are designed to increase or decrease access to this group)
• Serotonin →
first discovered in the calf muscles of the leg
• Fcn believed to provide “tone” to the muscles
SSRI’s (selective serotonin reuptake inhibitor)– didn’t come about until 1988
5 versions of molecule
5HT2 –> (serotonin molecule) goes through definitive pathways in the limbic system & to/from the frontal cortex
• promoting sense of wellness/happiness/pleasure
Could be stopped by stress or GABA (or alcohol disguised as GABA) or genetics thus leading to disorders such as depression
• norepinephrine →
• dopamine →
• Note: 3 step process of neurotransmitters (governs the fcn of the brain)
o Secretion
o reception
o up-take/re-uptake
• Stress-Diathesis
o may cause neurotransmitters to “run out”
• i.e. super stressed… produce less serotonin & thus depressed
• Endocrine Etiology
• Other Organ Systems
o 11 different systems in body (fcn & then interact with other systems)
• I.e. cardiovascular problem could lead to diminished cognitive ability due to poor diet which can diminish flow of blood (due to high fat content) which can decrease pre-frontal cortex ability
2 most common forms of dementia
• 1. Alzheimer’s
o related to the aging process (84+ = 50% of humans)
o only way to definitively diagnose → brain biopsy
• 2. Vascular
o occlusions → blockages
o hardened arteries → produced high blood pressure → rupture arteries → bleed into brain
