Which one of the following endocrine glands is located in the neck region, lying close to and partly surrounding the trachea in humans?

Introduction:
The positions of different glands in the human body are frequently asked in biology and medical entrance exams. Among the endocrine glands, the thyroid has a distinctive location in the front of the neck. This question asks you to identify which gland lies close to the trachea, the windpipe, and partly surrounds it from the front and sides.

Given Data / Assumptions:
- The organ of reference is the trachea, located in the neck and upper chest. - Options include pancreas, liver, adrenal gland and thyroid gland. - We are looking for an endocrine gland in the neck region, not deep in the abdomen. - Standard adult human anatomy is assumed.

Concept / Approach:
The thyroid gland is a butterfly shaped endocrine gland located in the anterior neck. It lies just below the larynx (voice box) and wraps around the upper part of the trachea with two lobes connected by an isthmus. The pancreas is situated in the upper abdomen behind the stomach, the liver is in the right upper abdomen below the diaphragm, and the adrenal glands sit on top of each kidney. Therefore, the only gland that is close to and partly surrounds the trachea is the thyroid gland.

Step-by-Step Solution:
Step 1: Recall the location of the thyroid gland as being in the front of the neck near the Adam's apple. Step 2: Visualise a cross section of the neck, showing the trachea in the centre and the thyroid lobes on either side connected by an isthmus. Step 3: Recognise that the pancreas, liver and adrenal glands are located in the abdominal cavity, far away from the trachea. Step 4: Exclude these abdominal organs and select the thyroid gland as the one close to the trachea.

Verification / Alternative check:
Anatomy atlases show the thyroid covering the anterolateral aspects of the upper tracheal rings. Clinical procedures such as tracheostomy must consider the position of the thyroid isthmus. Thyroid enlargement, called goitre, is visibly seen in the neck surrounding the trachea. All these facts confirm that the thyroid gland is the one located near the trachea in the neck region.

Why Other Options Are Wrong:
Pancreas: Lies transversely across the upper abdomen, associated mainly with the duodenum and stomach, not with the trachea. Liver: Occupies the right upper quadrant of the abdomen, under the diaphragm; it has no direct anatomical relationship with the trachea in the neck. Adrenal gland: Sits on the superior surface of each kidney in the abdomen, much lower than the trachea, and is not near the neck region.

Common Pitfalls:
Sometimes learners mix up thyroid and thymus because both words sound similar and both are linked to the central body axis. The thymus is actually located in the upper chest in front of the heart and behind the sternum, not wrapped around the trachea in the neck. Another error is to quickly pick pancreas because it is famous for hormone production, but its anatomical site does not match the description. Focusing on body regions (neck versus abdomen) helps to avoid such mistakes.

Final Answer:
The gland present close to and partly surrounding the trachea is the Thyroid gland.