Chapter 8-9 Flashcards
Uses only two primary neurotransmitters, acetylcholine and norepinephrine .
ANS
Contains powerful networks of inhibitory neurons that are constantly active in modulating the rate of neuronal transmission
CNS
How do neurons in the CNS and ANS function similarly?
Both involve the release of neurotransmitters that diffuse across the synaptic space to bind to specific receptors on the postsynaptic neuron.
What triggers intracellular changes in neurons?
The recognition of the neurotransmitter by the membrane receptor of the postsynaptic neuron.
What is a major difference between the CNS and ANS?
The circuitry of the CNS is much more complex than that of the ANS.
How does the number of synapses in the CNS compare to that in the ANS?
The number of synapses in the CNS is far greater than in the ANS.
Neurotransmitters can be classified a either ____ or ____ depending on the nature of the action they elicit
Excitatory or inibitory
Stimulation of this neuron causes the release of neurotransmitter molecules such as glutamate or acetylcholine
Excitatory neurons
footnote
Stimulation of excitatory neurons cases a movement of ions that results in a depolarization of the postsynaptic membrane.
The stimulation of this neurons cases movement of ions that resultss in a hyperpolarization of the postsynaptic membrane
Inhibitory neurons
When glutamate or acetylcholine bind to receptors what happens
Causes transient increase in the permeablity of Na+ ions
footnote
Influx of ions causes weak depolarization or EPSP that moves the postsynaptic potential towards its firing threshold
Generating an allor-none action potential
Stimulation of inhibitory neurons releases what neurotransmitters
GABA or glyciine - which binds to receptors
footnote
When binded this causes a transient increase in the permeability or ions like K+ and Cl+
Influx of Cl+ and efflux of K+ causes a
Weak hyperpolarization
What are some of he neurodegenerative diseases of the CNS?
Parkinson’s disease
Alzheimer’s disease
MS
ALS
footnote
These illnesses are characterized by the progressive loss of selected neurons in discrete brain areas, resulting in characteristic disorders of movement, cognition, or both
A progressive neurological disorder of muscle movements, characterized by tremors, muscular rigidity, bradykinesia and postural and gait abnormalities
Parkinsonism
footnote
Postural and gait abnormalities refer to deviations from normal walking patterns and body alignment
Slowness in initiating and carrying out voluntary movements
bradykinesia
Part of the extrapyramidal system, the source f dopaminergic neurons that terminate neostriatum
Substantia nigra
Is connected to the substantia nigra by neurons that secrete the inhibitory tranmitter GABA
neostriatum
Destruction of cells in the substantia nigra results in the degeneration of the nerve terminals that secrete dopamine in the neostriatum
Parkinson’s disease
What drugs may produce parkinsonian symptoms (also called pseudoparkinsonism)
Drugs such as phenothiazines ad haloperidol
Major pharmacological action of these drugs is the blockade of dopamine receptors in the brain
Is a metabolic precursor of dopamine
Levidopa
- It ennhance the synthesis of dopamine in the surviving neurons in the substantia nigra restoring dopaminergic neurotransmission in the neostriatum
- an extremely short life which causes fluctuations in plasma concentration
-shoulld be taken 30 mins b4 meal
Levidopa is greatly enhanced by
Carbidopa
A dopamine decarboxylase inhibitor that does not cross the blood brain barrier
carbidopa
An efficacious drug regimen for the treatment of parkinson’s disease
Levidopa carbidopa
Reduces the severity of symptoms for the first few years of treatment.
Some of the adverse effects of levodopa
Anorexia
Nausea
vomiting
Positive reaction to coombs test
Saliva and urine are brownish
Mydriasis
Mood swings
Depression
anxiety