Question

Given below is an outline of the human body showing the important glands.

1. Name the glands marked 1 to 5.
2. Name the hormone secreted by part 2. Give one important function of this hormone.
3. Name the endocrine part of the numbered 3.
4. Why is the part labeled 1 called the master gland? Which part of the forebrain controls the gland labeled 1?
5. Name the gland that secretes the ‘emergency hormone’.

Answer 1

1. Identification of the glands in the diagram

Pituitary gland:

1. The pituitary gland also called the master endocrine gland, is attached to the hypothalamus at the base of the brain.
2. It secretes tropic hormones like somatotropin, ACTH, FSH, etc.

Thyroid gland:

1. The thyroid gland is situated in the front of the neck region above the trachea and below the larynx.
2. It controls the metabolism of the body.

Pancreas:

1. The pancreas is located in the abdominal region behind and slightly inferior to the stomach.
2. It is a heterocrine gland that performs exocrine (secrete pancreatic juice) and endocrine (secrete insulin and glucagon) functions.

Adrenal gland:

1. The adrenal glands are present above each kidney. They appear yellowish and are divided into an outer cortex and an inner medulla.
2. The cortex secretes corticosteroids whereas the medulla secretes adrenaline and noradrenaline.

Ovaries:

1. The ovaries are a pair of oval-shaped organs that are situated in the pelvic region. They are the female gonads.
2. They secrete estrogen and progesterone that regulate various aspects of the female reproductive system.

2. The hormone secreted by the thyroid gland (Part -2)

1. The thyroid gland secretes thyroxine.
2. Secretion of thyroxine is dependent on the levels of iodine and is under the control of thyroid-stimulating hormone (TSH) released by the anterior lobe of the pituitary gland.
3. Thyroxine hormone helps in controlling the basal metabolic rate (BMR) and temperature of the body.

3. Endocrine part of Pancreas (Part-3)

1. The endocrine function in the pancreas is performed by the islets of Langerhans which are present as small patches.
2. It comprises alpha and beta cells. The beta cells secrete insulin whereas the alpha cells glucagon.

4. The master gland

1. Part 1 is the pituitary gland. It is also called the master gland.
2. The pituitary gland secretes hormones that control the functioning of other glands and their secretions. Such hormones are called tropic hormones.
3. Adrenocorticotropic hormone, thyroid-stimulating hormone, gonadotropic hormone, etc. are released by the pituitary gland that controls the functioning of adrenal glands, thyroid gland, and gonads respectively.
4. The functioning of the pituitary gland is under the control of the hypothalamus. The pituitary gland is directly attached to the hypothalamus of the forebrain.

5. Emergency hormone

1. Adrenaline or epinephrine is called the emergency hormone.
2. It helps in responding to fright, flight, and fight situations.
3. Adrenaline is secreted by the adrenal medulla (inner region) of the adrenal gland.