The Endocrine System and HormonesMany changes in your body are due to the Endocrine System.The Endocrine System regulates, coordinates and controls:- Growth and development.- Male and female development.- How your body uses energy.- Levels of salts and sugars in your blood.- The amount (volume) of fluid in your body.- Appetite.- Many other body functions.Endocrine Glands- The Endocrine Glands are the organs of the Endocrine System.- They produce and secrete (release) Hormones.- They are located all over your body.Functions of the Endocrine System- Controls the processes involved in movement and physiological equilibrium- Includes all tissues or glands that secrete hormones into the blood- Secretion of most hormones is regulated by a negative feedback system- The number of receptors for a specifichormone can be altered to meet the body’s demandSome Endocrine Glands and What they Regulate- Pituitary - “Master Gland” that regulates all other Endocrine Glands, also releases growth hormone - Thyroid - Metabolism, body heat, bone growth - Parathyroids - Use of Calcium and Phosphorous - Hypothalamus - Links nervous systemto endocrine system - Adrenal - Response in emergency or stressful situations, metabolism, blood pressure, salt balance - Pancreas - Blood sugar - Ovaries - Production of eggs; female characteristics - Testes - Production of sperm; male characteristics - Thymus - Parts of the immune systemPoint out that there are more endocrine glands, this is just a sample of some.Hormones are chemical messengers that are secreted (released) from glands into the bloodand affect cells in another part of the body. Because they are in the blood, hormones can get transported to the organs (genitals, brain, blood vessels, etc.)Target Cells- Hormones only work on certain cells, called target cells.- The target cells have special receptorsthat “recognize” the hormones and allow them to influence that cell.What controls the Hormones?External stimuli- by way of nerves from the sensory organs in the nervous systemInternal stimuli- by way of nerves and other hormones from inside the bodyNerves and various hormones act on the brainto affect the what the brain does. Such action can affect both behavior and certain control functions of the brain on the body (including feedback control on the level of hormones). External stimuli through the sense organs can also act on the brain to affect what it does.Brain reacts by way of secretions from neurons in hypothalamus (neurohormones).Brain also reacts by way of nerves from hypothalamus and brainstem.The hypothalamus controls the many gland cells in the pituitary by way of secretions fromthe hypothalamus that get carried by venous blood into the pituitary. Various hormones from the pituitary control many other organs that make hormones. That is why the pituitaryis called the “master gland” of the body. The hypothalamus and some neurons in the brainstem supply peripheral nerves that provide automatic and subconscious control over many vital functions, such as blood-vessel diameter, rate and strength of heart beat. This system also can “turn on” the adrenal gland to make adrenalin, a true hormone that raises blood pressure, increasesheart rate and strength of contraction.Stimulus:- You hear a loud noise- A large dog runs toward you, growling and barking- You eat a large candy bar- You have not eaten in six hours- You have strep