Intro to Autonomic Pharm Flashcards
- What are the structural divisions of the Nervous System?
- What are the functional divisions of the Nervous System?
- The nervous system is divided structurally into the:
- Central Nervous System (the brain and spinal cord)
- Peripheral Nervous System (neurons outside the brain and spinal cord).
- The Nervous System is divided functionally into the:
- Somatic Nervous System
- Autonomic Nervous System.
Describe the anatomy of the Autonomic Nervous System.
Anatomically, the ANS is divided into the:
- Sympathetic (Thoracolumbar) division
- Parasympathetic (Craniosacral) division
Describe the locations of the cell bodies of the neurons.
Each part of the ANS consists of two neuron chains.
- The cell body of the first neuron is in the brain or spinal cord
- The cell body of the second neuron is in an autonomic ganglion outside the CNS
The ONLY EXCEPTION to the two-neuron arrangement is the innervation of the adrenal medulla, which secretes catecholamines.
Compare and contrast the anatomy of the sympathetic and parasympathetic divisions of the autonomic nervous system.
Describe the main functions of the SNS and the PNS.
The Sympathetic Nervous System is mainly functional in response to stressful situations such as Trauma, Fear, Hypoglycemia, Cold and Exercise
The Parasympathetic Nervous System is mainly functional during rest, digestion and elimination of wastes. It usually acts to ooppose or balance the effects of the sympathetic system.
Classify autonomic nerves based on the primary neurotransmitters released from their terminals.
Autonomic nerves release either Acetylcholine or Norepinephrine as primary neurotransmitters.
- Cholinergic fibers synthesize and release acetylcholine:
- All preganglionic efferent autonomic fibers
- All parasympathetic postganglionic fibers
- All somatic motor fibers to skeletal muscle.
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Adrenergic fibers synthesize and release norepinephrine:
* Most postganglionic sympathetc fibers are adrenergic
EXCEPTIONS:
- The sympathetic fibers supplying the sweat glands release acetylcholine.
- The adrenal medulla releases epinephrine and norepinephrine
- Dopamine is released by some sympathetic fibers
Describe the synthesis, storage, release and inactivation of acetylcholine.
Describe the synthesis, storage, release and inactivation of norepinephrine.
Describe the location and function of cholinergic receptor subtypes and the signaling mechanisms associated with them.
Cholinergic receptor subtypes are Nicotinic (Ion-channel linked) and Muscarinic (G-protein linked).
1. Nicotinic receptors can be either the muscle type (NM) or the neuronal type (NN).
- NM receptors are found at the skeletal neuromuscular junction (NMJ)
- NN receptors are found in autonomic ganglia and in the brain
2. Muscarinic receptors can be either M1 (Gq), M2 (Gi) or M3 (Gq). These receptors are located
- On the plasma membranes of cells in the CNS
- In organs innervated by parasympathetic nerves
- On some tissues that are nt innervated by these nerves eg Endothelial cells
- On tissues innervated by cholinergic postganglionic sympathetic nerves
Describe the location and function of adrenergic receptor subtypes and the signaling mechanisms associated with them.
Adrenergic receptor subtypes are alpha-adrenoceptors, beta-adrenoceptors and Dopaminergic receptors. They are all G protein linked.
- Å-1 and ß-1 receptors are located near adrenergic nerve terminals, so that they are activated during stimulation of such nerves.
- Å-2 and ß-2 receptors may be located at sites remote from adrenergic nerve terminals
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ß-2 has a higher affinity for epinephrine (released from adrenal medulla) over norepinephrine
*
Explain what tone is, and apply knowledge of predominant tone to the regulation of dually-innervated organs.
Predominant tone is a knowledge of the branch of ANS that is predominant in an effector organ that allows you to predict the actions of drugs that mimic or block the actions of these nerves.
