Lecture 6 Flashcards
brain and spinal cord purpose
analyze and interpret signals from peripheral nervous system
-generate thought, language, attention, consciousness, behaviour and memory
CNS
central nervous system - brain and spinal cord
-millions of neurons communiate through releasing neurotransmitters in synapses
Neurons
building blocks of the CNS (type of cells)
action potential
-resting potential -70mV
-depolarize membrane potential to threshold (-55 mV)
-sodium channels open, Na floods into cellfor rapid depolarization
-repolarization (Na channels close, K channels open to release potassium out of cell)
-refractory period as cell goes back to resting potential (Na channels cannot reopen during this)
Exictatory neurotransmitters (4)
glutamate
acetylcholine
epinephrine
norepinephrine
Inhibitory neurotransmitters (2)
GABA
glycine
drugs and the CNS
drugs alter neurotransmission
-can affect production, storage or release of neurotransmitters (pre-synapse)
-affect neurotransmitters metabolims
-inhibit or activate post-synaptic receptors
Stimulants definition
psychoactive drugs induce temporary improvement in mental or physical functions
caffeine
stiumulant
-relaxes smooth muscle, situmulates gastric acid secretion and increases heart contractibility
-increases alertness
-anxiety, tremours, arrhythmia
-tolerance and withdrawal
Prescription stimulants
treat ADHD (abmormal release of dopamine and norepinephrine ) or narcolepsy
Methylphenidate(Concerta, Ritalin)
blocks dopamine uptake transporter, increasing dopamine concentrations
side effects of stimulants
increased heart rate, dizziness, chest pain, fever, nervousness, cramps,
-highly addictive
three types of antidepressants
-SSRI (selective serotonin reuptake inhibitor)
-SSNRI (selective serotonin/norepinephrine reuptake inhibitors )
-TCA (tricyclic)
Methamphetamine
illicit stimulant
-inhibits reuptake of dopamine, norepinephrine and sertonin
-increases release of dopamine
-increase mood, energy, sex drive
-highly addictive
-neurotoxic
-body stops producing dopamine naturally, dopamine receptors stop being produced
-cycle of drug dependence
CNS depressants uses
pain, anxiety, muscle relaxants
Anesthesia
reversible state of CNS depression, use a concoction of drugs to produce effect
-can be used in general (whole body, loss of consciousness) or local (specific nerve pathways)
Benzodiazepines
target GABA receptor, causes hyperpolarization
-decresed action potentials and neurotransmission
-used for anxiety, sedation, anticonvulsant, seizures, muscle relazant, sleep disorders
-drowsiness, confusion-
-potential for dependence and lethal overdose with alcohol
Analgesics
pain management depressant
-pain is a complex and unpredictable neurochemical response and is subjective and therefore hard to measure
-nerve pain: anticonvulsants, antidepressants
-inflammation: NSAIDS
-chronic/severe pain: opiods (work on opioid receptor in CNS and intestinal tract)
opioid effects
-analgesia
-depresses cough reflex
-miosis (pinpoint pupils)
-euphoria
-constipation
-repiratory depression (decrease sensitivity of CO2 receptors)
-addictive - may disinhibit dopamine pathways in brain
Heroin
illicit depressant, turns into morphine in body
Alcohol
depressant, targets GABA receptors in bain
-stimulates serotonin release
-metabolized in liver
-eliminated by kidneys and lungs
-diuretic
-teratogen (causes birth defects)
-causes numerous issues when taken with drugs (nausea, vomiting, internal bleeding, heart and breathin problems)
-can make mediation less effective, or exaggerate effects
Neurodegenerative diseases
progressive loss of neurons in selected brain regions
-effects movement, cognition or both
-incurable, debilitating
Alzheimer’s disease
common neurodegenerative disease
-loss of cholinergic neurons in the nucleus basalis of Maynert (group of neurons in forebrain, rich in acetycholine and cholinergic neurons, modulate visual perception, mental capacity and learning)
-treated with acetylholinesterase inhibitors or NMDA-receptor antagonists
Acetylcholinesterase inhibitors
inhibit AchE, improves cholinergic function by dereasing Ach breakdown in functioning neurons
-modest reduction in rate of loss of cognitive function in Alzheimer’s
NMDA receptor antagaonist
-glutamate overstimulation toxic to neurons, triggers apoptosis
-neurprotection, reduce rate of memory loss
