nervous system Flashcards
What are the two main divisions of the nervous system?
The central nervous system (CNS), consisting of the brain and spinal cord, and the peripheral nervous system (PNS), which includes sensory and motor neurons.
What are the two functional divisions of the peripheral nervous system?
The somatic nervous system (controls voluntary movements) and the autonomic nervous system (ANS) (controls involuntary functions like heart rate and digestion).
What are the two branches of the autonomic nervous system (ANS)?
The sympathetic nervous system (SNS) (“fight or flight”) and the parasympathetic nervous system (PNS) (“rest and digest”).
What is the primary neurotransmitter of the sympathetic nervous system?
Norepinephrine (and to a lesser extent, epinephrine).
What is the primary neurotransmitter of the parasympathetic nervous system?
Acetylcholine (ACh).
What are the two main types of adrenergic receptors, and where are they found?
Alpha receptors (α1 and α2) are found in smooth muscles and blood vessels. Beta receptors (β1, β2, and β3) are found in the heart, lungs, and adipose tissue.
What are the two main types of cholinergic receptors, and where are they found?
Muscarinic receptors (found in parasympathetic target organs) and nicotinic receptors (found in the autonomic ganglia and skeletal muscle).
What are sympathomimetic drugs?
Drugs that mimic the effects of the sympathetic nervous system by stimulating adrenergic receptors.
What are sympatholytic drugs?
Drugs that inhibit the sympathetic nervous system by blocking adrenergic receptors or reducing norepinephrine release.
What are cholinergic agonists?
Drugs that mimic acetylcholine and stimulate cholinergic receptors, enhancing parasympathetic activity.
What are anticholinergics?
Drugs that block acetylcholine from binding to muscarinic receptors, reducing parasympathetic activity.
How do beta-blockers work in the nervous system?
Beta-blockers inhibit β-adrenergic receptors, decreasing heart rate and contractility, commonly used in hypertension and anxiety.
What is the mechanism of action for benzodiazepines in the CNS?
Benzodiazepines enhance the effect of GABA at GABA-A receptors, increasing inhibitory neurotransmission and causing sedation or anxiolysis.
What is the pharmacological basis for using SSRIs in depression?
Selective serotonin reuptake inhibitors (SSRIs) block the reuptake of serotonin in synapses, increasing serotonin levels in the brain.
What drug class is used to treat Parkinson’s disease, and what is its mechanism?
Dopaminergic agents (e.g., Levodopa) increase dopamine levels or mimic its effects to compensate for the loss of dopamine in the CNS.
How do antiepileptic drugs work?
They reduce neuronal excitability by enhancing GABAergic inhibition, inhibiting sodium channels, or blocking calcium channels.
What is the role of acetylcholinesterase inhibitors in treating Alzheimer’s disease?
They prevent the breakdown of acetylcholine, enhancing cholinergic neurotransmission and temporarily improving cognitive function.
How do local anesthetics work on the nervous system?
Local anesthetics block voltage-gated sodium channels, preventing nerve impulse conduction and producing localized numbness.
What are the main adrenergic receptor subtypes and their effects?
- α1: Vasoconstriction, pupil dilation.
- α2: Inhibits norepinephrine release (feedback inhibition).
- β1: Increases heart rate and contractility.
- β2: Bronchodilation, vasodilation in skeletal muscles.
