Intro to Nerohemoral Transmission and the Autonomic Nervous System Flashcards
Components of the Autonomic Nervous System
- Afferent
- Efferent
- Central
Functions of the ANS
- regulation of heart and cardiac contractility
- visceral and cutaneous blood flow distribution
- gastrointestinal motility and digestion
- urogenital processes
The efferent component of ANS is also known as?
General Visceral Efferent
(GVE)
the General Visceral Efferent is subdivided into 2 primary branches
- Parasympathetic Nervous System
- Sympathetic Nervous System
Organs regulating the Sympathetic Nerve Signals
- Hypothalamus
- Brainstem
Activated in response to critical emergencies, to elicit a “fight or flight” response
SNS regulation
The Parasympathetic Nervous System originates from?
cell bodies in the brainstem and sacral sections of the spinal cord, synapses in ganglia
Primary functional profile of the Parasympathetic Nervous System (PSNS)
- Initiating and sustaining energy conservation and homoestasis durign periods of relative physiological rest
- Reduction of heart rate, stimulation of gastrointestinal secretions and peristalsis, contraction of the urinary bladder, modulation of immune function
Organs that have both SNS and PSNS innervation. Has antagonistic effects or stimulation by either of the two.
Dual ANS Innervation
Controlled by the enteric nervous system together with the SNS and PSNS
Gastrointestinal System
What stimulates gastrointestinal function, more dominant?
Parasympathetic Nervous System (PSNS)
The modulatory effect sympathomimetics are not prominently used in the GIT
Sympathetic Nervous System (SNS)
Provides neural information regarding the internal physiological environment. Provides neural information regarding the internal physiological environment.
Afferent (Sensory) Component
Components of the ANS
- Suprasinal (Brain)
- Spinal (Vertebral Column)
- Peripheral (Efferent and Afferent Components)
The efferent components of both branches of the ANS uses ________ for conveying information between nerve cells and from postganglionic neurons to target cells and tissues
Chemical Neurotransmitters
Types of neurons in the ANS
- Adrenergic (SNS)
- Cholinergic (PNS)
- Non-adrenergic-Noncholinergic (NANC)
Sites controlling the CNS (regulates the level of SNS activity)
Forebrain, Brainstem, Spinal neural circuits
The principal integration and control center of the ANS
Hypothalamus
Located in the intermediolateral cell column of the thoracic and cranial lumbar spinal segments
Sympathetic Preganglionic Neurons
Predominantly released from postganglionic SNS neurons at target organ sites (primarily binds to and activates adrenergic receptors)
Norepinephrine (Noradrenaline)
Fibers that synthesize and release Norepinephrine
Adrenergic Fibers
Released by some postganglionic neurons, metabolic precursor to NE, (released by dopaminergic neurons)
Dopamine
Analagous to ganglionic neurons, innervated by preganglionic SNS fibers and contains Nn receptors, releases epinephrine and (EPI) and NE
Chromaffin Cells of the Adrenal Medulla
A subgroup of postganglionic SNS neurons that releases ACh as a neurotransmitter, binds to and activates muscarinic receptors
Postganglionic Sympathetic-Cholinergic Fiber
Identified as a co transmitter along with NE in sympathetic nerves. Mediates respomses via activation of purigenic receptors that’s as identified as adenosine (P1) receptors and P2X and P2Y receptors
Adenosine Trphosphate (ATP)
Released with NE from sympathetic nerves, an agonist at neurokinin receptors. Modulates sympathetic neurotransmission at both pre- and postsynaptic sites.
Neuropeptide Y (NYP)
Involved in parasympathetic integration and control, nuclei communicates with the brain stem autonomic centers
Hypothalamus or Brain Stem
Location of the cell bodies
- Brainstem Nuclei
- Intermediolateral cell column of the sacral spinal cord
Exits the brrainstem with their respective cranial nerves, exits the spinal cord in association with sacral spinal nerve, terminates and synapse in ganglia
Parasympathetic Preganglionic Axons
Neurotransmittersof the PSNS
- Preganglionic
- Postganglionic
Preganglionic neurotransmitters are?
Acetylcholine-nicotinic receptors
Post-ganglionic neurotransmitters are?
Acetylcholine-muscarinic receptors
Fibers that synthesize and release Ach
Cholinergic Fibers
Are released along with Ach from many postganglionic PSNS fibers at target tissues and organs
Cotransmitters
Reeases ATP as cotransporter
parasympathetic nerves innervating the UB
Vasoactive intestinal polypeptide
Salivary glands
Nerves that does not exhibit the histochemical characteristics of cholinergic and adrenergic fibers. Plays an important role in the physiological regulation of the GI tract, genitourinary tract, and select blood vessels
Nonadrenergic-Noncholinergic Neurons (NANC)
Synthesized and released by NANC nerves and endothelial cells, important contributor to penile erection
Nitric Oxide (NO)
Regulates the complex physiological processes associated with GI physiology
Enteric Nervous System
Location of Enteric Nervous System
wall of the Gastrointestinal Tract
Transmits information to the sympathetic ganglia and can modulate postganglionic sympathetic nerve outflow
Sensory fibers
Extensively innervsted by NANC nerve fibers
Enteric Nervous System
Enteric Nervous System is innervated by
- Preganglionic PSNS nerve fibers
- Postganglionic SNS nerve fibers
Protein in the cholinergic neurons that play a critical role in aligning Ach-containing vesicles with functional release sites in the inner neuronal cell membrane and initiating neurotransmitter release
Vesicle-Associated Membrane Protein
Release sites on the presynaptic plasma membrane contain _______, interacts with VAMPs to facilitate vesicle-plasma fusion and subsequent neurotransmitter release
Synaptosomal nerve-associated membrane proteins (SNAPs)
Synthesizes Ach from acetyl-coA and choline in the cytoplasm of cholinergic nerves
Choline Acetyltransferase (ChAT)
Synthesized in the mitochondria located in the nerve endings
Acetyl-CoA
Block/inhibit the choline transport into the cell
hemicholiniums
Initiates processes essential for the vesicle membrane fusion with neuronal membrane (leads to exocytotic discharge of ACh into the synaptic cleft)
Calcium
Receptors in the ganglionic sites in the Autonomic Nervous System
nicotinic receptors
Cells and tissues at the target sites innervated by post ganglionic nerves
Muscarinic receptors
Muscarinic receptor antagonist/blocker
Atropine and other alkaloids
Nicotinic receptor antagonist/blocker
Chlorisondamine