BACKGROUND
A 30cm length of distal small intestine, attached to a short length of colon, is surgically resected from a human patient undergoing surgery for a cancerous tumour in the right colon. The small intestine is separated from the rest of the excised gut and placed in an organ bath filled with warmed, oxygenated Krebs solution, which effectively replaces the blood supply and keeps the tissue alive and active for several hours.
(i). The physiologist pushes a soft wad of cotton wool (2cm diameter, 3 cm long) into the proximal end (i.e: oral end) of the tubular specimen of small intestine. It is big enough to slightly distend the gut. After a delay of a few seconds, the gut starts to produce a squeezing movement, which propels the cotton wool bolus slowly along the intestine until, a few minutes later, it is pushed out of the other (aboral/anal) end of the preparation.
(ii). The physiologist then pushes the wad into the other (aboral/anal) end of the specimen. It remains still for a minute or two, then is expelled from the aboral/anal end, without being propelled along the tubular intestine: the gut has rejected it.
Q: Describe how different types of neurons in the specimen (sensory neurons, interneurons, inhibitory motor neurons, excitatory motor neurons) are activated in neural pathways to give rise to this distinctive motor pattern in (i) including why the wad of muscle moves. Name which division of the autonomic nervous system these neurons belong to. (4 MARKS)
Answer :)
The distinctive motor pattern observes in gut are through afferent neurons, efferent neurons, and interneurons. These make two types of plexus: the myenteric plexus that helps to regulate digestive tract motility and the submucous plexus that regulates gastrointestinal blood flow and controls epithelial cell function.
Answer i)
Within the myenteric plexus, motor neurons regulate peristalsis and mixing of intestinal contents. These motor neurons regulate by sympathetic nervous system.
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BACKGROUND A 30cm length of distal small intestine, attached to a short length of colon, is...
i have a med assignment to do. this is the background and the questions. 100% rating if all parts are answered, make sense and are relevant. i just need to make sure my answers are correct (hence why im posting it here!) BACKGROUND A 30cm length of distal small intestine, attached to a short length of colon, is surgically resected from a human patient undergoing surgery for a cancerous tumour in the right colon. The small intestine is separated from...