Answer:
While doing medical research on the human subject, following limitations are unavoidable:
a). Privacy: The privacy of the subject involved in the research should be maintained.
b). the subject must be allowed to the minimal exposure to risks and it must be tested on animals first to avoid deaths.
c). The risk associated with the physiological and physical well being of the subject must be considered.
d). The subject must be well instructed about all the risk and procedure involved in the research.
Pharyngeal constrictor muscles (superior, middle and inferior)
The pharyngeal constrictor muscles are a group of muscles that form the lumen of the pharynx. After you swallow, an act that you have control, it starts a involuntary contraction by these muscles to propel the bolus downwards.
