Class 8 Neurotransmitters PDF

Class 8 - Neurotransmitters 2024-09-24 1:05 PM The Bodies Chemical Messengers - Manufactured in brain - Released into synaptic cleft from the axon terminal of the sending neuron - Crosses synapse and binds to appropriate receptors on dendrites or cell body of receiving neuron - Like a...

Class 8 - Neurotransmitters 2024-09-24 1:05 PM The Bodies Chemical Messengers - Manufactured in brain - Released into synaptic cleft from the axon terminal of the sending neuron - Crosses synapse and binds to appropriate receptors on dendrites or cell body of receiving neuron - Like a lock and key (neurotransmitter fits into particular receptor sites based on shape) - When developing medicine, they try to mimic neurotransmitters -- pharmacologists synthetically copy their shape for decrease/increase of dopamine or serotonin - Influences cell either to fire or not to fire Multitalented Chemical Couriers - Neurotransmitters and other substances - our body creates endogenous substances (internally made) - They are just one part of a complex system that participates into cognitive abilities → Hormones influence our behaviour just like neurotransmitters Acetylcholine - Role in learning and memory - Slows down the heart muscles when beating too fast by exciting the skeletal muscles - Decrease in Alzheimer's - doesn't operate the same to those people - Botox - the lack of muscle tension - responsible for motor control between nerves and muscles - it inhibits the release of acetylcholine Dopamine - Excites and inhibits learning, attention, movement, motivation, reward - Dopamine reward system : when engaging in behaviours you enjoy - dopamine levels are increased - provides motivation to continue with that behaviour → Problematic: also participates in addiction - highjacks the dopamine system by obsessively needing to get dopamine levels up - Decrease amount in Parkinson's disease Norepinephrine - Affects eating habits, alertness, wakefulness - Predominant in fear → Fight or flight response - A lot of allergy medications release norepinephrine - Very little is released during sleep Glutamate - Excitatory, involved in memory - Getting too much glutamate: headaches, seizures → Can be controlled through diet to avoid oversupply: MSG avoidance Serotonin - Plays role in emotional states, sleep, impulsivity, aggression, appetite - Low levels linked to depression - Used to treat OCD and some anxiety disorders by manipulating serotonin levels GABA Gamma amino butyric acid - Main inhibitory neurotransmitter - Controls anxiety in humans - Distributed throughout the central nervous system - In the part of the brain that responds to opiates (opium, morphine, heroin) -- activate it - Opiates can be very valuable for pain control in health industry Endorphins - Help feel natural sense of pleasure/enjoyment - Reduce pain - Released in physical activities (runners high, strenuous activities) There's a left central lobe and a right one (hemispheres) → Left controls right side of body and vice versa - Left : processing language, speech - Right: visual and special tasks, nonverbal memory, spatial awareness Frontal lobes - Front of brain extends to top center of skull - Voluntary body movement, speech production, thinking, motivation, planning for the future, impulse control, emotional responses → Phineas cage case (affected area) Motor cortex ► Wilder Penfield - Strip of tissue at rear of frontal lobes - Controls voluntary body movement w During brain surgery patient has to be awake -- to make sure that they don't do anything to damage parts of the brain that control certain functions → Give local anesthetic to not feel removal of skull cap Penfield study helped discover a more accurate mapping od the motor cortex -- like where memory is actually stored, the areas of the brain responsible for Somatosensory cortex → Fine motor movement in hands and face: they have a larger share of the motor cortex → Applicable to touch as well Parietal lobes - Contains somatosensory cortex - Responsible for body awareness and spatial orientation - Tested in sobriety tests The Sensory Area of the Cortex Somatosensory cortex - Responsible for sensory information detection through temperature, touch, texture, pain, etc. Greater area = more sensitivity (like the mouth is very good at detecting hot/cold and sensations) Occipital and temporal lobes Occipital lobes : primary visual cortex interpretation of visual information (to see) Temporal lobes: primary auditory cortex where hearing registers Wernicke's area (left lobe): areas for interpreting auditory information Brain waves EEG (electroencephalograph) uses electrodes placed on the scalp to record and measure waves of electrical activity of brain Amplitude: height of wave - High waves but low frequency = low brain activity Scanning techniques CT scan - Rotating X-ray, high speed computer analysis - Produces slice-by-slice, cross sectional images of the structure of the brain - Patients are injected with radioactive glucose or inhales oxygen that is laced with low level radioactivity - Reveals structure MRI - Diagnostic scanning technique - Produces high resolution images structures of brain - Magnetic image created is safe - doesn't expose you to X rays ○ X rays are radiation that are carcinogen - Reveals structure FMRI - Functional - Measures changes in blood flow to determine activity of parts of brain PET scan - Functional - Brain imaging technique - Reveals activity in various parts of brain amount of oxygen and glucose consumed