The thyroid gland lies in the lower part of the neck. It is a highly vascular gland, brownish red in colour and surrounded by a fibrous capsule. It consists of two lobes lying one on either side of the trachea and joined together by a strip of thyroid tissue called the isthmus or the thyroid.
The pituitary gland lies in a bony hollow at the base of the brain. It is approximately 15 mm long and 5 mm across. It is attached to the brain by a stalk or nerve fibers, which is continuous with the hypothalamus above, behind the optic chiasm.
The glands which have internal secretion and without any ducts but they release their secretions directly into the blood stream and transported to distant part of the body to act upon target cells.
The term pituitary was given by Vesalius. This gland appears like a small pen nut structure situated at the base of the brain in the sella turcica of sphenoid bone of the cranium (brain box). It remains attached to the floor of the third ventricle by a stalk called pituitary stalk. Average weight of pituitary is 0.57 gm.
The digestive system of cockroach consists of alimentary canal and digestive glands. One of the peculiarity of the digestive system is that the system although mainly involved in the process of digestion, it also takes part in excretion being associated with Malpighian tubules which open into the alimentary canal at the junction of midgut and hind gut.
The endocrine glands in human body are: pituitary gland, pineal gland, thyroid gland, parathyroid gland, thymus gland, islets of Langerhans, adrenal gland, ovary and testis.
It is a small cone-shaped gland (8 mm in length, 4mm in breadth) attached by a hallow stalk to the roof of the dorsal surface of the diencephalon. Pineal gland secretes melatonin hormone.
It is a large, bilobed gland (2cm x 2 cm x 2cm) behind the larynx (voice –box) in the neck. Human thyroid weighs 25 g. Between the lobes is a connecting isthmus. It secretes thyroxine and thyrocalcitronin hormones.
Parathyroid are small glands in two pairs. They are buried in the thyroid gland on its dorsal-posterior part. This gland secretes parathormone which serves to increase the blood calcium by taking the latter out of the bone.
This gland is situated on the kidney. Each kidney has an adrenal gland placed on it. Internally, the adrenal gland is divisible into an outer Cortex and an inner medulla. The outer cortex secretes three different hormones: