Biology - Hormones

• Hormones are chemical messengers released by glands into the blood and carried to a target organ or organs.
• The nervous system is a body system that includes the brain, spinal cord and nerves.
• Hormones are much slower and act over a longer period compared to the nervous system.
• Homeostasis is the body maintaining a constant internal environment for the proper functioning of cells and enzymes.
• Insulin is a hormone produced in the pancreas that decreases blood glucose levels, controlling blood glucose concentrations.
• Anti-diuretic hormone (ADH) is a hormone produced in the brain that controls the amount of water reabsorbed by the kidneys, controlling the water content of the body, referred to as osmoregulation.
• Insulin and blood glucose are hormones that affect the body's metabolism.
• Diabetes is a condition where blood glucose levels are too high due to the body's inability to produce or use insulin.
• Osmoregulation is the process by which water moves in and out of cells from a high concentration to a low concentration.
• The pancreas continually monitors the level of glucose in the blood.
• Insulin acts in the liver to reduce blood glucose concentration by increasing glucose absorption from the blood by the liver and muscles, converting excess glucose to glycogen, and increasing respiration in the liver.
• Normal blood glucose concentration is restored when blood glucose concentrations are low, less insulin is produced and the above processes do not take place or slow down, which helps to raise the concentration of glucose in the blood.
• Symptoms of diabetes include glucose in the urine, high blood glucose levels, being thirsty, the need to go to the toilet a lot, and lethargy.
• Type 1 diabetes, which usually develops early in life, is characterized by the pancreas stopping the production of insulin.
• Type 2 diabetes, which usually develops in older people and is a progressive disease linked to poor diet, lack of exercise, and obesity, causes the pancreas to gradually produce less insulin and insulin to become less effective.
• Treatment for diabetes includes controlling carbohydrate intake, increasing exercise, and injecting insulin.
• The number of sufferers of diabetes is increasing due to an increase in obesity and becoming more common in young people.
• Complications of diabetes include eye damage/blindness, heart disease, stroke, and kidney damage.
• These complications are due to high blood glucose concentrations damaging the capillaries, which are small, permeable blood vessels present in the organs of the body that allow the diffusion of substances like oxygen and glucose.
• Homeostasis is the ability of the body to maintain a constant internal environment, such as temperature and blood glucose concentration.
• Osmoregulation is the process that controls the amount of water in body fluids, such as blood.
• Poor control of osmoregulation can lead to osmotic close osmosis, the process by which water moves in and out of cells from a high concentration to a low concentration, potentially causing cell damage.
• Hormones are involved in osmoregulation.
• Osmoregulation is a form of homeostasis which controls the volume of water in the body by bringing the volumes back into balance.
• During hot weather or exercise, the kidney produces a large volume of dilute urine, retaining more water and increasing body water levels.
• To compensate for this loss, the kidney produces a small volume of concentrated urine, making us thirsty and increasing the water brought into the body.
• During hot weather or exercise, the body loses more water as sweat, leading to a decrease in body water levels.
• Hormones also play a role in the excretory system.
• Hormones are found in plants as well as animals.
• The kidney works by filtering out liquid and many dissolved substances in the cortex, reabsorbing some of these substances back into the blood in the medulla, and passing the rest into the urine.
• The function of the kidneys is to remove waste from the body and control the volume of water in the body.
• ADH is produced by the part of the brain that monitors water levels in the blood.
• ADH is then carried in the blood to its target organ – the kidneys.
• When the brain detects lower than normal water levels in the blood, ADH is produced.
• In the medulla, ADH causes more water to be reabsorbed from the urine back into the blood, producing a lower volume of more concentrated urine and returning blood water levels to normal.
• When the brain detects higher than normal water levels in the blood, less or no ADH is produced.
• In the medulla, less water is reabsorbed back into the blood, producing a larger volume of dilute urine and returning blood water levels to normal.
• Plants respond to stimuli such as light, heat, sound, gravity, smell, taste, or temperature.
• These changes in the environment are detected by receptors in an organism.
• Roots grow towards water.