ENDOCRINE SYSTEMS IN HUMANS - Hormonal Coordinationpptx

This highly illustrated powerpoint slides examines critically, how human system is coordinated with the hormones from the endocrine system.

1. KELECHI EMMANUEL [email protected]

2. HORMONES

3. WHAT ARE HORMONES? A hormone is a chemical substance, produced by a gland and carried by the blood, which alters the activity of one or more specific target organs Hormones are made in special glands called ENDOCRINE GLANDS ENDOCRINE SYSTEM!!!

4. ENDOCRINE GLANDS Endocrine glands have good blood supply; they have blood capillaries running through them. So when they produce hormones, they are released directly into the blood. Endocrine glands are ductless glands; they do not have ducts! once the hormone is in the blood, it dissolves in the blood plasma and is carried to ALL parts of the body HOWEVER, each hormone only affect parts of the body. These are called TARGET ORGANS. Hormones speed up, slow down or alter the activity of target organs

5. POSITION OF ENDOCRINE GLANDS IN THE BODY Pituitary gland Thyroid gland Pancreas Adrenal gland Ovary Testis

6. COMMON ENDOCRINE GLANDS IN THE BODY

7. HORMONES AND TARGET ORGANS Hormones only affect cells with target receptors that the hormone can bind to. These are either found on the cell membrane, or inside cells. Receptors have to be complementary to hormones for there to be an effect.  REGULATION OF HORMONES The liver regulates levels of hormones in the blood; transforming or breaking down any that are in excess. 

8. HORMONES

9. THE PANCREAS (DUAL FUNCTION) The pancreas is a digestive gland that secretes enzymes into the duodenum through the pancreatic duct. It is also an endocrine (ductless) gland. Most of the pancreas cells produce digestive enzymes but some of them produce hormones. The hormone-producing cells are arranged in small isolated groups called ISLETS and secrete their hormones directly into the bloodstream. One of the hormones is called INSULIN Insulin controls the levels of glucose in the blood by instructing the liver to remove the sugars and store them. This happens when levels get too high, such as after a meal rich in carbohydrate.

10. REPRODUCTIVE ORGANS The ovaries and testes produce hormones as well as gametes (sperms and ova). One of the hormones from the ovary, OESTROGEN, prepares the uterus for the implantation of the embryo, by making its lining thicker and increasing its blood supply. The hormones testosterone (from the testes) and oestrogen (from the ovaries) play a part in the development of the secondary sexual characteristics

11. ADRENAL GLANDS Secreted by the ADRENAL GLANDS - the pair of glands above the kidneys The adrenal gland has a zone called the ADRENAL MEDULLA which receives nerves impulses from the brain & produces adrenaline

12. EFFECTS OF ADRENALINE ON THE BODY Increased rate and depth of breathing. Increase in pulse rate (heartbeat) Dilation of the pupils

13. EFFECTS OF ADRENALINE CONTD

14. NERVOUS SYSTEM VERSUS ENDOCRINE SYSTEM What’s the difference? Nervous System Endocrine system Made up of nerves (neurons), brain & spinal cord Made up of endocrine glands Information carried in the form of electrical impulses Information carried in the form of chemical called hormones Impulses are transmitted along nerve fibres (axons & dendrites) Impulses carried dissolved in the blood plasma Hormones dispersed through out the body Impulses sent directly to target organs FAST Speed of transmission: SLOW Short-lived effect – until impulses stop Longer effect – until hormone is broken down ADRENALINE?? CONPONENT SPEED OF ACTION DURATION OF ACTION FORM OF TRANSMISSION PATHWAY OF TRANSMISSION