NEET Practice Questions (MCQs) with Answers & Solutions

(a) Parietal cells (or oxyntic cells) secrete hydrochloric acid (HCl) and Castle's intrinsic factor. Chief cells (or peptic cells) secrete gastric digestive enzymes as proenzymes pepsinogen and prorennin. HCl helps in converting pepsinogen to pepsin. Goblet cells secrete mucus which helps to neutralise acid in stomach and protects stomach wall against HCl action.

(a) Wharton's duct is the duct of submandibular salivary gland that opens into the floor of mouth at the junction where front of the tongue meets the mouth's floor.

Thecodont: The type of attachment in which each tooth is embedded in a socket of jaw bone. Diphyodont: This type of dentition forms two sets of teeth during life, first set of teeth being temporary or deciduous and second set being permanent or adult teeth.

Heterodont: It is the condition of having different types of teeth. For example in humans- incisors, canines, molars and premolars.

The oesophagus is a thin, long tube which leads to a ‘J’ shaped bag like structure called stomach.

The opening of the stomach into the duodenum is guarded by the pyloric sphincter because a narrow distal portion which opens into the first part of small intestine is pyloric portion.

In duodenum, brunner’s glands are present in sub-mucosal layer.

The innermost layer lining the lumen of the alimentary canal is the mucosa. This layer forms irregular folds (rugae) in the stomach.

The innermost layer lining the lumen of the alimentary canal is the mucosa. This layer forms small finger-like foldings called villi in the small intestine.

Smooth muscles, typically muscularis externa consisting of inner circular layer and outer longitudinal muscular layer, is responsible for peristaltic movement.