Question

Read the following statements and select the correct option.
Statement 1: Deglutition starts as a reflex and then continues by voluntary action.
Statement 2: Oesophagus has smooth muscles in the beginning and striated muscles In the rest of its wall.
A) Both statements 1 and 2 are correct.
B) Statement 1 is correct but statement 2 is incorrect
C) Statement 1 is incorrect but statement 2 is correct
D) Both statements 1 and 2 are incorrect.

Answer 1

Hint: Oesophagus is a muscular tube which connects the mouth to the stomach and deglutition can be defined as the process of swallowing

Complete answer:
Statement 1It is incorrect because deglutition is the process of swallowing during which the bolus enters from the mouth into the stomach. The process of swallowing is supported by the coordination of muscles of mouth, pharynx, larynx and esophagus, which are regulated by the cranial nerves.

The three stages of deglutition are, oral stage (mouth to pharynx, voluntary), pharyngeal stage (oropharynx to esophagus, involuntary), esophageal stage (esophagus to stomach, involuntary).

Swallowing, is a complex reflex mechanism by which food is pushed from the oral cavity into the esophagus and then pushed to the stomach. This movement of food from the oral cavity onto the esophagus and stomach by pushing is called propulsion, and it is an important part of the digestive process.

The pharynx leads into oesophagus. Glottis is the opening of the windpipe. A cartilaginous flap called epiglottis prevents the entry of food into the glottis during swallowing.

Statement 2:It is incorrect because oesophagus have two types of muscular layers.The upper third of the esophagus contains striated muscle, the lower third contains smooth muscle, and the middle third contains a mixture of both.

Thus, the correct option is D) Both statement 1 and statement 2 is incorrect.

Note:The oesophagus is a thin,long tube which extends posteriorly passing through the neck, thorax and diaphragm and leads to a J shaped bag-like structure called stomach. The opening of oesophagus into the stomach is regulated by a muscular gastro-oesophageal sphincter.