L1 – Overview of the Central Nervous System Flashcards
Difference between glutamate and GABA action in synapses?
Glutamate = excitatory transmitter
GABA = inhibitory neurotransmitter
List some postsynaptic receptor types for Glutamate and GABA?
All postsynaptic neurons are ion channels Glutamate: - AMPA receptor - NDMA receptor - Kainite receptor
GABA:
- Cl- ion channels
Differences in the action between GABAergic and Glutamatergic synapses?
GABA = Inhibitory postsynaptic potential = postsynaptic neuron hyperpolarization
Glutamate = Excitatory postsynaptic potential = postsynaptic neuron depolarizes
Difference between sensation and perception ?
Sensation = OBJECTIVE sensory physiology, involves interaction with sense organ, adequate stimulus at receptor for excitation, central processing for integration
Perception = SUBJECTIVE sensory physiology. Involves integration of conscious subject, subject the impression with experience, reason and personality
Explain the pathology of epilepsy at the neuron level.
Epilepsy: excitation-inhibition imbalance in motor cortex (precentral gyrus)
> > spread of abnormal synchronized cortical discharge (repetitive firing)
> > seizure, convulsion
Explain the efect of ‘angel dust’/ PCP on the brain?
phencyclidine piperidine (PCP / ‘angel dust’ = recreational dissociative drug)
> > blocks NMDA receptors for glutamate (excitatory) on neuronal membrane
> > abnormal synaptic function (no Na+, Ca2+ influx)
> > behavior mimics schizophrenia
Define the somatic senses. (4)
Touch
Body position/ Proprioception
Temp.
Pain
Define the special senses. (5)
Taste Smell Hearing Balance Vision
List the organelles responsible for the somatic senses in the skin?
Mechanical stimuli delivered to skin activate several mechanoreceptors simultaneously but to different degree
- Touch: Meissner’s Corpuscle
- Pain, temperature: free nerve ending
- Pressure: Merkel’s disk
- Vibration: Pacinian corpuscle & Ruffini’s ending
Difference between neural pathway for touch/ vibration/ position versus pathway for temp/pain?
Touch/ Vibration/ Position:
Dorsal root ganglion cells synapse at medulla at cuneate nucleus and medial leminscus
Pain/ Temp:
Dorsal root ganglion cells synapse at spinal cord
List the neural pathway for peripheral sensation?
- Receptor ending
- Afferent fiber (either mechanosensory or pain/temp)
- Dorsal root ganglion cells (either synapse at medulla or spinal cord)
- Midbrain
- Synapse at VPN complex of thalamus
- Cerebrum somatosensory cortex
What is a topographic body map?
organization of body senses into 2D cortical columns
Map around the somatosensory cortex with distorted body surface for tactile sensibility
Areas of high acuity are magnified on the body map
Difference between the control of pain withdrawal and reflexive motor control?
Pain withdrawal: does not require supraspinal control, execution at the spinal level
Reflexive: Requires supraspinal control/ central integration before motor output
Describe the pathway of ipsilateral and contralateral pain stumulus to a leg.
Ipsilateral:
Flexors contract to move foot away from painful stimulus, extensors inhibited
Contralateral:
Crosses extensor reflex: Extensors contract and weight shift to other leg, Flexors inhibited on other leg
Which reflexes involve supraspinal control?
Plantar reflex
Used to test CST function
What are the main neural areas for motor control?
Cerebellum
Basal ganglia
Cerebral motor cortex
What are the lateral and Ventromedial pathways for voluntary motor control?
Lateral: Pathway via Red Nucleus, Corticospinal tract
Ventromedial: Pathway via Reticular nuclei, Pathway via Superior colliculus and vestibular nucleus
List some surgery outcomes of Prefrontal Lobotomy?
cannot concentrate ill-tempered loss of emotional thought difficulty in planning & working towards goals personality change lowering of moral standard
List some functions of the Right hemisphere?
Left hand Musical and artistic ability Perception of space Imagination and fantasizing Body control and awareness
List some functions of the Left hemisphere?
Right hand Logical thinking Language ability Writing Science and math work
Areas of the brain involved with the limbic system? Function of the system?
Hippocampus, Amygdala
- Learning, memory
- Sleep, wakefulness
- Emotion
Pathway and difference in action between sympathetic and parasympathetic activation on: Pupil (eye)
Sym: Thoracic sympathetic chain: Dilate
Parasym: CNIII: Constrict
Pathway and difference in action between sympathetic and parasympathetic activation on: Salivation, tearing (lacrimal, salivary glands)
Sym: Thoracic sympathetic chain: Inhibit secretion
Parasym: CN VII and CN IX: Stimulate secretion
Pathway and difference in action between sympathetic and parasympathetic activation on: Blood vessels
Sym: Thoracic sympathetic chain: Constrict vessels
Parasym: CNX: Dilate (in gut)
Pathway and difference in action between sympathetic and parasympathetic activation on: Airway
Sym: Thoracic sym. chain: Relax airway
Parasym: CN X: Constrict airway
Pathway and difference in action between sympathetic and parasympathetic activation on: Heart
Sym: Thoracic sym. chain: Increase HR
Parasym: CN X: Decrease HR
Pathway and difference in action between sympathetic and parasympathetic activation on: Glucose homeostasis (Liver)
Sym: Thoracic collateral ganglia: Increase glucose production
Parasym CN X: Decrease ‘’
Pathway and difference in action between sympathetic and parasympathetic activation on: Digestion (stomach)
Sym: Thoracic collateral ganglia: Inhibits digestion
Parasym: CN X: Increase digestion
Pathway and difference in action between sympathetic and parasympathetic activation on: Pancreatic secretions
Sym: n/a
Parasym: Stimulate
Pathway and difference in action between sympathetic and parasympathetic activation on: Adrenal medulla secretions (NE)
Sym: Thoracic sym. chain: Stimulate NE release
Parasym: n/a
Pathway and difference in action between sympathetic and parasympathetic activation on: Urinary bladder
Sym: Lumbar sym. chain: Relaxes bladder
Parasym: Sacral nerves: Contract bladder
Pathway and difference in action between sympathetic and parasympathetic activation on: Reproductive organs
Sym: Lumbar sym. chain: Stimulate orgasm
Parasym: Sacral nerves: Stimulate sexual arousal
Symptoms of Alzheimer’s?
Impaired learning and memory
Disoriented time and place
Poor judgement
Language impairment
A brief overview of pathology of AD?
Extreme shrinkage of hippocampus, accumulation of Amyloid plaque and Tau fragment causing loss of brain cells
Pathology of Parkinson’s?
Apoptosis of dopamine neurons in substantia nigra > Lack of dopamine release > Disrupted firing to basal ganglia (Striatum: caudate nucleus, putamen) > Movement disorders
Action of Heroin on neurons?
Heroin acts on opioid receptors on GABAergive neurons > Inhibit release of GABA to GABA receptor on dopamine neuron
> Less conversion of tyrosine to dopamine in dopamine neuron for release to D1/D2 like receptors
> Less generation of cAMP on postsynaptic neuron
Action of cocaine on neurons?
Cocaine binds to uptake transporter on dopamine neuron > Enhance dopamine effect on D1/D2 like receptors > More cAMP production in postsynaptic neuron
