Defecationa. can be initiated by stretch of the rectum.b. can occur as a result of mass movements.c. involves local reflexes.d. involves parasympathetic reflexes mediated by the spinal cord.e. All of these characteristics are true of defecation.
Defecation
a. can be initiated by stretch of the rectum.
b. can occur as a result of mass movements.
c. involves local reflexes.
d. involves parasympathetic reflexes mediated by the spinal cord.
e. All of these characteristics are true of defecation.
The digestive system of the body is concerned with the simplification of nutrients present within the ingested food particles, the absorption of these simplified nutrients, and the excretion of the undigested food waste.
The term defecation refers to the last process of digestion in which the undigested food is expelled out of the body from the last part of the large intestine, that is, the anus. The urge to defecate occurs when the walls of the rectum is stretched, this in turn triggers the internal anal sphincter muscles to relax and the external anal sphincter muscles to contract. The faeces are pushed from the colon regions to the rectum in response to the mass movements that occur within the colon segments. The mechanism of defecation is also regulated by the autonomic reflexes that involve nerve fibers of the parasympathetic division that arose from the sacral region of the spinal cord.
Hence, the correct answer is the option ‘e.’
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