Module 2C: Neuroanatomy of the Digestive System Flashcards
(78 cards)
What are the two types of innervation traced from the CNS to the Stomach and Spleen?
Sympathetic and parasympathetic innervation
These innervations are crucial for understanding the autonomic control of these organs.
What is the function of the sympathetic nervous system in relation to the gastrointestinal organs?
Reactions to stress, increased heart function, bronchodilation, decreased digestive function, pupillary dilation, vasodilation in skeletal muscle, vasoconstriction in other vessels
The sympathetic system is often referred to as the ‘Fight or Flight’ response.
What is the function of the parasympathetic nervous system in relation to the gastrointestinal organs?
Recovery of rest, decreased heart function, increased digestion, pupillary constriction, managing bowel and bladder emptying
The parasympathetic system is often referred to as the ‘Protective Regulation’ response.
Where do sympathetic preganglionic neurons originate?
Intermediolateral Nucleus (IML) T6-L2
This region of the spinal cord is responsible for sympathetic output.
Where do parasympathetic preganglionic neurons originate for the abdominal organs?
Dorsal Motor Nucleus of X (DMX) for the transverse colon and Sacral Parasympathetic Nucleus (SPN) of S2-4 for distal organs
This indicates different origins for pelvic and abdominal organ innervation.
What are the sympathetic splanchnic nerves and their corresponding ganglia?
Greater splanchnic nerve: T6-9 to celiac ganglion
Lesser splanchnic nerve: T10-11 to superior mesenteric ganglion
Least splanchnic nerve: T12 to inferior mesenteric ganglion
Lumbar splanchnic nerves: L1-2 to inferior hypogastric ganglion
Sacral splanchnic nerves: L1-2 to inferior hypogastric ganglion
These nerves provide sympathetic innervation to the abdominal viscera.
What is the role of the pelvic splanchnic nerve?
Parasympathetic input from S2-4 to pelvic ganglion
This nerve is essential for innervating the lower gut and bladder.
True or False: The vagus nerve provides parasympathetic innervation to the entire gastrointestinal tract.
False
The vagus nerve innervation ends at the transverse colon; distal regions receive input from the sacral cord.
What neurotransmitter is involved in the sympathetic system’s excitatory response to sphincter activity?
Norepinephrine (NE), Alpha-1 (α-1)
This indicates how the sympathetic system can control sphincter function.
What neurotransmitter is involved in the parasympathetic system’s excitatory response to glandular secretion?
Acetylcholine (ACh), M1/3 +
This highlights the role of ACh in stimulating digestive processes.
Fill in the blank: The sympathetic system is primarily _______ to gut function.
inhibitory
This is crucial for understanding the contrasting roles of the sympathetic and parasympathetic systems.
What is the primary pathway for the sympathetic innervation of the spleen?
Greater splanchnic nerve to celiac ganglion, via the splenic plexus to the spleen
This indicates the sympathetic control over spleen function, particularly during stress.
What are the high threshold and low threshold GVA pathways associated with sympathetic and parasympathetic systems?
High threshold GVAs follow the sympathetic pathway; low threshold GVAs follow the parasympathetic pathway
This differentiation is important for understanding sensory innervation.
What is the primary function of parasympathetic input in the gastrointestinal system?
Enhances and supports digestion
This is key to the physiological processes involved in digestion.
What is the role of the intramural ganglia in the autonomic innervation of the stomach?
Postganglionic parasympathetic cell bodies are located in the organ (intramural)
This emphasizes the unique nature of parasympathetic innervation in digestive organs.
What are the two types of visceral afferent fibers based on their threshold?
High threshold GVAs follow the sympathetic pathway; low threshold GVAs follow the parasympathetic pathway
High threshold fibers are typically involved in pain signaling, while low threshold fibers are related to physiological functions.
What regulates carbohydrate and lipid metabolism in the body?
Multiple organ systems including the ANS and endocrine functions
The link between the ANS and endocrine systems is crucial for metabolic regulation.
What is the role of CCK in gallbladder function?
CCK initiates gallbladder contraction and has a positive feedback to the DMX via low threshold chemoreceptors in the duodenal wall
CCK is released in response to the presence of fatty foods in the gut.
Trace the pathway of sympathetic innervation of the liver and gallbladder.
Preganglionic sympathetic fibers originate from T6-9 IML, travel via the greater splanchnic nerve to the celiac ganglion
This pathway is essential for sympathetic control of liver and gallbladder functions.
Trace the pathway of parasympathetic innervation of the liver and gallbladder.
Preganglionic parasympathetic fibers originate from the DMX and travel through the vagus nerve to the celiac ganglion
This pathway supports the body’s rest and digest functions.
What are the cell body locations for high and low threshold GVA?
High threshold GVA cell bodies are in T6-9 DRG; low threshold GVA cell bodies are in the Nodose Ganglion of X
The dorsal root ganglia (DRG) and the Nodose ganglion are critical for sensory input to the CNS.
What neurotransmitter is involved in gallbladder release of bile?
ACh (Acetylcholine) at M1 receptors
ACh plays a key role in the contraction of gallbladder smooth muscle.
What is the effect of VIP in gallbladder function?
VIP is co-released with ACh and is inhibitory to sphincteric contraction
This inhibition helps facilitate bile flow from the gallbladder.
True or False: GLP-1 actions on the liver include increased gluconeogenesis.
False
GLP-1 actions decrease gluconeogenesis and insulin resistance.
