Lesson 3: endocrine system

• endocrine glands are Glands which produce hormones which are released to blood stream and distributed to body cells
• hormones Is a substance that acts on certain target cells and tissues to produce a specific response                                    
• Estrogen and testosterone are examples of steroid hormones.
• steroid hormones can diffuse through the plasma membrane of target cells because they are soluble in lipids.
• steroids hormones Work by causing the target cells to initiate protein synthesis
• amino acids hormones Initiates a biochemical pathway causing the cells to produce the desired response
• amino acid hormones must bind to receptors on the plasma membrane of target cells. because they are soluble in water which means they cannot diffuse through the plasma membrane
• insulin and growth hormones are example of amino acid hormones
• another name for amino acid hormones is non-steroid hormones.
• The hormone and the receptor that are bound together binds to DNA in the nucleus, which activates specific genes.
• Feedback mechanisms can either encourage (positive feedback) or discourage (negative feedback) internal processes.
• Negative feedback systems typically manage conditions that stay stable over long periods, thereby stabilizing the system.
• A target cell is a body cell that has receptors specific to a certain hormone.
• Communication in the body takes place mainly through the nervous and endocrine systems
• The endocrine system includes all the glands that secrete hormones—pituitary, thyroid,

  parathyroid, adrenal glands, pancreas, ovaries, testes, pineal gland, and the thymus gland.
• Pituitary Gland is located at the base of the brain
• pituitary gland is also called the "Master gland" because it regulates so many functions
• pituitary gland is the Most important endocrine gland- not only regulate many body functions but also regulates other endocrine glands such as thyroid, adrenal, testes and the ovaries.
• human growth hormone (hGH) regulates the body’s physical growth by stimulating cell division in muscle and bone tissue.
• Thyroid gland produce hormone thyroxine and calcitonin
• Thyroxine causes cells of the body have a higher rate of metabolism
• Calcitonin help for regulation of calcium
• Parathyroid gland produce hormone parathyroid hormone
• Parathyroid hormone also help for regulation of calcium
• Parathyroid hormone (PTH) and calcitonin (CT) regulate the level of calcium in the blood.
• The pancreas plays a crucial role in the production of enzymes that digest carbohydrates, proteins, and fats.
• the pancreas secretes the hormones insulin and glucagon, which work together to maintain homeostasis.
• the pancreas Secretes 2 hormones ... Insulin & glucagon
• Insulin lowers blood glucose level
• insulin Give signal to liver and muscle cells to covert glucose to glycogen
• Glucagon increases blood glucose level
• glucagon Give signal to liver to convert glycogen to glucose and release to blood
• Adrenal Glands is located just above the kidney
• The outer part of the kidney, called the cortex, produce steroid hormones- aldosterone and glucocorticoids
• Aldosterone give signal to kidney to reabsorb more sodium
• Cortisol raises blood glucose level and reduces inflammation
• the inner part of the kidney produce two hormones adrenaline and Noradrenaline
• they kidney produce Fight or flight response in a stressful situation to produce more energy. Increases heart rate, breathing rate, blood pressure and sugar levels, all of which are important for increasing the activity of body cells