Higher Human Biology Unit 2 Physiology & Health KEY AREA 8: Blood Glucose Levels and Obesity

Higher Human Biology We are going to build on the knowledge and skills that you developed during N5 and will learn about the following Physiology & Health key areas : - Key Area 1 – Reproductive Organs Key Area 2 –Hormonal Control of Reproduction Key Area 3 – Biology of Controlling Fertility Key Area 4 – Ante- and Postnatal Screening Key Area 5 – Structure and Function of Arteries, Capillaries and Veins Key Area 6 – Structure and Function of the heart Key Area 7 – Pathology of Cardiovascular Disease (CVD) Key Area 8 – Blood Glucose Levels and Obesity

N5 Revision - What is Homeostasis? Homeostasis controls water concentration in the blood (osmoregulation). This prevents cells from bursting or shrinking due to osmosis Homeostasis controls body temperature (thermoregulation). This ensures enzymes are working at an optimum temperature Homeostasis controls glucose concentration in the blood. This ensures that cells receive the correct levels of glucose required for respiration Homeostasis is the control of the internal environment in the body Homeostasis is important so that body cells can function properly

Physiology & Health Learning Intentions KEY AREA 8 – Blood Glucose Levels and Obesity a)Chronic Elevated Blood Glucose Levels b)Obesity linked to CVD and Diabetes

8a) Regulation of blood glucose levels

8b) Controlling Blood Glucose Levels The pancreas monitors the concentration of glucose in the blood Receptor cells in the pancreas detect changes in blood glucose concentration When blood glucose INCREASES(above the norm) -Pancreatic receptor cells release the hormone insulin -Insulin travels in the blood to the liver -The liver then converts the glucose to glycogen (an insoluble storage carbohydrate) -Blood glucose concentration decreases(returning to the norm) When blood glucose DECREASES (below the norm) -Pancreatic receptor cells release the hormone glucagon -Glucagon travels in the blood to the liver -The liver converts glycogen to glucose -Blood glucose concentration increases (returning to the norm)

8c) Diabetes Diabetes is a condition whereby sufferers are unable to control their blood glucose levels If untreated, blood glucose levels can rise to 10-30mmol/l compared with the normal blood glucose concentration of around 5mmol/l There are 2 types of diabetes - Type 1 Diabetes and Type 2 Diabetes Type 1 DiabetesType 2 Diabetes % of all cases of diabetes5-10%90-95% First occurrenceChildhood/Early teensAdulthood Ability of pancreatic receptors to produce insulin ABSENTPRESENT Sensitively of cells to insulin Sensitive Cells have normal number of insulin receptors on their surface & respond to insulin Less Sensitive Cells have a decreased number of insulin receptors in the liver leading to a failure to convert glucose to glycogen TreatmentInsulin and careful diet Exercise, weight loss & diet (insulin in some cases) Test Urine test for glucose

8d) Obesity linked to CVD & Type 2 Diabetes Obesity is a major risk factor for Cardiovascular Disease and for Type 2 Diabetes Obesity is characterised by excess body fat in relation to lean body tissue (muscle) A body mass index (weight divided by height squared) greater than 30 is used to indicate obesity BMI does not take in account muscle mass so some people are wrongly classified when using this method Accurate measurement of body fat requires the measurement of body density Body composition can be measured by:- Densitometry Skin-fold thickness Bioelectrical impedence, Waist/Hip ratio

8e) Treatment of Obesity Genetic, psychological, environmental, metabolic and diet all contribute to obesity, with the most common factor being high fat diets along with a lack of physical activity Treatment of obesity involves reducing energy intake and increasing energy expenditure The energy intake in the diet should limit fats (as fats have a high calorific value per gram) and free sugars (as they require no metabolic energy to be expended to digest them) Exercise increases energy expenditure and preserves lean tissue Exercise can help to reduce risk factors for CVD by:- - keeping weight under control - minimising stress - reducing hypertension - improving HDL blood lipid profiles

Physiology & Health Questions KEY AREA 8 – Blood Glucose Levels & Obesity 1.Testing Your Knowledge 1Page 195 Q’s What you should knowPage195Q’s Applying knowledge & SkillsPage196Q’s 1- 10