Multicellular Organisms Sub-Topic (2.2) Control and Communication Hormonal Control (b) On completion of this sub-topic I will be able to state that: Hormones are chemical messengers Hormones are released from endocrine glands into the bloodstream Hormones act on target tissues and these target tissues have cells with complementary receptor proteins for specific hormones Only tissues with the complementary receptor proteins are affected by these specific hormones Insulin is a hormone made by the pancreas Insulin converts excess glucose into glycogen and glycogen is stored in the liver and muscles The conversion of glucose to glycogen by insulin lowers blood glucose level Glucagon is a second hormone released by the pancreas which converts glycogen to glucose and so increases the blood glucose level In addition I will be able to: Describe the role of insulin and glucagon in maintaining steady blood glucose level Describe the causes and treatment of Type 1 and Type 2 diabetes Duncanrig Secondary School 2017 Page 1 of 5
Hormonal Control Hormones are usually small molecules made by a gland. They are secreted following a suitable stimulus and transported in the blood. They act as chemical messengers. Blood carries hormones to a target organ or group of cells or tissues which will recognise the hormone (this triggers a specific chemical response when the correct receptor is activated). The behaviour of the target will then change, bringing about the right response. Specific hormones need to combine with complementary receptor proteins on, or in, a target cell to have an effect. Hormone combining with specific receptor site Hormone Specific receptor site on the surface of a cell Hormones are released into the blood stream by endocrine glands. Duncanrig Secondary School 2017 Page 2 of 5
Complete the table to show the target organ and function of each hormone. Name of Hormone Produced in Target Organ Function Insulin Pancreas Liver Converts glucose to glycogen Glucagon A.D.H. (Antidiuretic hormone) Maintenance of Blood Sugar Glucose is needed by cells for respiration. It is important that the concentration of glucose in the blood is maintained at a constant level. The two hormones insulin and glucagon are responsible for controlling the concentration of glucose in the blood. Summarise the information from the diagram above into the table below: Glucose level Too high Too low Effect on pancreas Effect on liver Effect on glucose level More insulin secreted into the blood Less glucagon secreted into the blood Less insulin secreted into the blood More glucagon secreted into the blood goes down goes up Duncanrig Secondary School 2017 Page 3 of 5
Diabetes Diabetes is a lifelong condition which causes a person's blood sugar level to become too high. It is also known as diabetes mellitus. In the UK, around 2.9 million people are affected by diabetes. There are two main types of diabetes: type 1 and type 2. Type 1 Diabetes (insulin-dependent diabetes) Also known as juvenile diabetes or early-onset diabetes as it often develops before the age of 40, usually during the teenage years. This is an autoimmune condition, where the immune system (the body's natural defence against infection and illness) mistakes the cells in the pancreas as harmful and attacks them. As a result the pancreas (a small gland behind the stomach) is unable to produce insulin, the hormone that regulates blood glucose levels. Insulin usually moves glucose out of the blood and into your cells, where it is used to provide energy. However, in type 1 diabetes, there is no insulin to move glucose out of the bloodstream and into the cells. If the concentration of glucose in the blood is too high, it can seriously damage the body's organs. Without insulin, the body breaks down its own fat and muscle (leading to weight loss). This can lead to a serious short term condition where the blood becomes acidic, along with dangerous dehydration. A person with type 1 diabetes needs to take insulin injections for life. It is also necessary to make sure that blood glucose levels stay balanced by eating a healthy diet, taking regular exercise and having regular blood tests. Duncanrig Secondary School 2017 Page 4 of 5
Type 2 Diabetes (insulin resistance) Type 2 diabetes occurs when the pancreas doesn't produce enough insulin to maintain a normal blood glucose level, or the body s cells don't react to insulin i.e. they are unable to use the insulin that is produced. This is known as insulin resistance. Type 2 is far more common than type 1 diabetes. In the UK, about 90% of all adults with diabetes have type 2 diabetes. Several factors affect the risk of an individual developing type 2 diabetes. Age The risk of developing type 2 diabetes increases with age. Genetics The risk is increased if a close relative, such as a parent, brother or sister, has the condition. The closer the relative, the greater the risk. Ethnicity Some ethnic groups are more at risk. People of South Asian, African, African- Caribbean and Middle Eastern descent are more likely to develop type 2 diabetes. The condition is up to six times more common in South Asian communities than in the general UK population, and it is three times more common among people of African and African-Caribbean origin. Being overweight or obese Being overweight or obese (a body mass index of 30 or greater), gives a greater risk of developing type 2 diabetes. In particular, fat around the abdomen increases the risk. Women have a higher risk of developing type 2 diabetes if their waist measures 31.5 inches (80cm) or more, as do men with a waist size of 37 inches (94cm) or over. Reducing your body weight by about 5% and exercising regularly could reduce the risk of getting diabetes by more than 50%. Research Project (500 words) Investigate the causes and treatment of both types of diabetes. Find data on the incidence of diabetes in Scotland. Suggest ways the incidence of diabetes can be reduced in Scotland. Your project should include at least one table or graph to support your research. You must list the sources for your information. Duncanrig Secondary School 2017 Page 5 of 5