Endocrine Glands: Structure & Function PDF
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Uploaded by BriskPiccoloTrumpet
Taibah University
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Summary
This document introduces the endocrine system and different glands like the pituitary, thyroid, and adrenal glands. It explains their structure, function, and the hormones they produce, including clinical aspects such as pituitary adenoma and goitre. The document uses diagrams to teach about the endocrine system and how the glands work.
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Endocrine glands It is the system that includes all ductless glands in the body. It includes the following glands: 1. Pituitary gland. 2. Thyroid gland. 3. Parathyroid glands. 4. Adrenal gland. 5. Islets of Langerhans of pancreas. 6. Endocrinal parts of the ova...
Endocrine glands It is the system that includes all ductless glands in the body. It includes the following glands: 1. Pituitary gland. 2. Thyroid gland. 3. Parathyroid glands. 4. Adrenal gland. 5. Islets of Langerhans of pancreas. 6. Endocrinal parts of the ovary and testes. PITUITARY GLAND It is also termed hypophysis cerebri and master gland. It lies in the base of the brain in a depression on the upper surface of the sphenoid bone called sella turcica and covered by fold of dura mater. It is about 0.5gm in weight and one cm in diameter It is connected to the hypothalamus by infundibulum. It is divided into two parts: anterior lobe and posterior lobe Hormones of the anterior lobe 1. Growth hormone = GH. 2. Prolactin. 3. Lutinizining hormone = LH. 4. Follicle stimulating hormone = FSH B- Hormones of the posterior lobe 1. Oxytocin. 2. Vasopressin (anti- diuretic hormone) = ADH Clinical anatomy 1- pituitary adenoma May cause ballooning of sella turcica Normal pituitary Enlarged pituitary THYROID GLAND Size: 30 grams in weight. Site : It lies in the lower part of the front of the neck just below the larynx. Shape: butterfly or H- shape Structure: consists of two lobes, right and left, connected by an isthmus Function: It secrets Thyroxine Clinical anatomy Enlarged thyroid gland is called goitre PARATHYROID GLANDS Four small rounded glands embedded in the posterior surface of the thyroid gland. Secret the parathyroid hormone (PTH). ISLETS OF LANGERHANS OF PANCREAS The pancreas is a mixed gland, it has A. Exocrine portion (secrets digestive juice in its pancreatic duct) B. Endocrine portion (secrets its hormones directly in the blood). It secretes hormones Insulin: by beta cells. Glucagon: by alpha cells. ADRENAL GLANDS o It is also termed suprarenal gland. o lies on the upper pole of the kidney. o Each is small yellowish body about 2.5 cm in length and 12 grams in weight. o It is formed of outer layer called cortex and inner core called medulla. TESTES ▪ The endocrine parts of the testis are its interstitial cells of Leydig. ▪ These cells lie in connective tissue spaces between the semineferous tubules. ▪ It secrets the hormone testosterone. OVARY Its endocrine parts are the cells forming the Graffian follicles. These cells secrete estrogen and progesterone hormones.
