Endocrine systemThe glands and organs that make hormones and release them directly into the blood so they can travel to tissues and organs all over the body

endocrine system

1. Endocrine System

2. GLANDS Group of cells that produces and secretes, or gives off, chemicals. S elects and removes materials from the blood, processes them, and secretes the finished chemical product for use somewhere in the body . Some types of glands release their secretions in specific areas. For instance ,  exocrine glands , such as the sweat and salivary glands, release secretions in the skin or inside the mouth. Endocrine glands, on the other hand , release more than 20 major hormones directly into the bloodstream where they can be transported to cells in other parts of the body.

3. Definition The endocrine system is the collection of glands of an organism that secrete hormones directly into the circulatory system to be carried towards distant target organs. It regulates a number of vital functions of our body . Includes all the glands in the body. E ndocrine system is instrumental in regulating mood, growth and development, tissue function, metabolism, and sexual function and reproductive processes .

4. Functions 1 ) To maintain a stable environment within the body or homeostasis . Ex: M aintaining the blood sugar levels according to changes occurring in the body is homeostasis 2) Promoting the structural changes of the body. Ex: The permanent changes occurring in the body over the period of time like height, development of sexual organs, etc. is a part of the structural changes.

5.   M ajor glands 1 . Hypothalamus 2. Pituitary gland 3. Parathyroid gland 4. Thyroid gland 5. Adrenal glands 6. Pancreas 7. Ovaries (in female body) 8. Testes (in male body)

6. Endocrine System

7. Hypothalamus A collection of specialized cells that is located in the lower central part of the brain, it is the main link between the endocrine and nervous systems. The nerve cells of the hypothalamus control the pituitary gland by stimulating or suppressing the hormone secretions . Located above the midbrain and below the thalamus.

8. Functions of hypothalamic hormones 1. GnRH (Gonadotrophin-releasing hormone): Stimulates FSH and LH secretion 2. TRH ( Thyrotrophin -releasing hormone): stimulates thyroid stimulating hormone(TSH) secretion 3. CRH (Corticotrophin-releasing hormone): stimulates Adrenocorticotropic hormone (ACTH) secretion 4. GHRH (Growth hormone-releasing hormone): Stimulates growth hormone secretion

9. 5. PRH (Prolactin-releasing hormone): Stimulates prolactin secretion 6. GHRIH (Growth hormone-releasing inhibitory hormone or somatostatin): Inhibits growth hormone secretion 7. PRIH (Prolactin-releasing inhibitory hormone): Inhibits prolactin secretion 8. ADH (Antidiuretic hormone or vasopressin) improves renal water reabsorption and vasoconstriction 9. O xytocin produce milk ejection and uterine myometrial contraction

10. Hypothalamus

11. Hypothalamus

12. The hypothalamus is involved in different daily activities like eating or drinking, in the control of the body's temperature and energy maintenance, and in the process of memorizing and in stress control. It also modulates the endocrine system through its connections with the pituitary gland. Functions of Hypothalamus

13. Pituitary gland It is an endocrine gland about the size of a pea and weighing 0.5 g (0.02 oz.), in humans. The pituitary gland is a small gland that sits in the  sella turcica  ('Turkish saddle'), a bony hollow in the base of the skull, underneath the brain and behind the bridge of the nose.  Most important part in the endocrine system It is called master of gland.

14. Pituitary gland  Pituitary gland is divided into three parts: the anterior lobe , middle and the posterior lobe. Hormones of pituitary gland- Anterior pituitary- Growth hormone (GH), Prolactin (PL), Follicle stimulating hormone (FSH), Luteinizing hormone (LH), Thyroid stimulating hormone (TSH), Adrenocorticotropic hormone (ACTH). Posterior pituitary- Antidiuretic hormone (ADH), Oxytocin. Middle pituitary- α , β , γ Melanocyte stimulating hormone (MSH).

15. Function of pituitary hormone Posterior pituitary 1. Antidiuretic Hormone (ADH/vasopressin) - Cause the kidney to retain water, thus increasing the water content of the body - High concentration causes constriction of the blood vessel throughout the body and elevates the blood pressure. 2. Oxytocin Acts on smooth muscle - milk release from mammary glands - uterine contractions

16. Anterior Pituitary 1. Growth Hormone (GH) - regulates body growth - increases protein synthesis, fat use, CHO storage - bone growth 2. Prolactin (PL) - development of mammary glands during pregnancy - milk production 3. Follicle-stimulating Hormone (FSH) - production of sperm, testosterone - production of ovum, estrogen, progesterone 4. Luteinizing Hormone (LH) - production of sperm, testosterone - production of ovum, estrogen, progesterone 5. Thyroid-stimulating hormone (TSH) - stimulates thyroid gland to produce thyroxine & tri-iodothyronine 6. Adrenocorticotropic hormone (ACTH) - stimulates adrenal gland to secrete adrenocortical hormone

17. Pituitary gland

18. Thyroid gland The thyroid gland (butterfly shape) lies in the front of   neck just below the Adam's apple . It is situated below the larynx and above the trachea. It plays a major role in the metabolism, growth and development of the human body. It helps to regulate many body functions by constantly releasing a steady amount of thyroid hormones into the bloodstream. Thyroid hormone- Thyroxine (T 4 ), Tri-iodothyronine (T 3 ), Calcitonin.

19. Thyroid gland

20. Parathyroid gland These glands, located behind the thyroid  gland at the bottom of neck , are about the size of a grain of rice.  Parathyroid gland secrete parathyroid hormone   which regulates calcium levels in the blood, largely by increasing the levels when they are too low. It does this through its actions on the kidneys, bones and intestine. Bones – parathyroid hormone stimulates the release of calcium from large calcium stores in the bones into the bloodstream .

21. Parathyroid gland Back view of Thyroid gland

22. Adrenal glands The adrenal glands are triangular-shaped glands located on top of each kidney. The adrenal glands are made up of two parts. The outer part is called the adrenal cortex, and the inner part is called the adrenal medulla. Hormones of adrenal gland- Adrenal cortex- Mineralocorticoids (Aldosterone), Glucocorticoids (cortiso l), Sex hormone. Adrenal medulla- Norepinephrine (20%), Epinephrine (80%).

23. The adrenal cortex produce - Cortisol, which regulate metabolism - Aldosterone which maintain the balance of salt and water in the body - Sex hormone maintain sexual function. The adrenal medulla, produces catecholamines (ex: adrenaline, noradrenaline). These hormones help the body cope with physical and emotional stress by increasing the  heart rate and blood pressure. Adrenal glands

24. Pancreas The pancreas is located behind the stomach in the upper left of the abdomen . The pancreas has digestive and hormonal functions. As exocrine   gland, pancreas secretes pancreatic enzymes for breaking down of protein, lipids, carbohydrates present in food. As endocrine gland, pancreas secretes hormones called insulin  and  glucagon. These hormones regulate the level of  glucose  (sugar) in the blood.

25. Pancreas

26. Ovaries (in female body) The female gonads, or ovaries, are paired organs located on either side of the uterus within the broad ligament below the uterine (fallopian) tubes in female reproductive system. S ecrete female sex hormones, estrogen and progesterone, which helps to produce eggs. Moreover , they are also responsible for the physical changes that occur during puberty, besides it also regulates the menstrual cycle.

27. Ovaries (in female body)

28. Testes (in male body) The male gonads, called the testes, are located in the scrotum of male reproductive system. T estes  are responsible for making testosterone, the primary male sex hormone. Testosterone influence changes related to physical and sexual development, secondary male sex characteristics like growth of pubic and facial hair, change in voice, etc. Testosterone also assists in sperm production.

29. Testes (in male body)

30. Information There are almost 30 hormones on our body that are being produced by various glands of the endocrine system . The pineal gland located in brain induces sleep in our body. It produces a hormone named melatonin which controls the sleep cycle of our body . The behavior and the characteristic of a person is largely influenced by the endocrine system.