CB7 - Control and homeostasis (Homeostasis & glucose)

• What is homeostasis

  Homeostasis is the regulation of conditions inside the body to maintain a stable internal environment in response to changes in both internal and external conditions.
• Why is it important to maintain a stable environment in the body?

  ~ Cell function in optimal conditions.

  ~ Enzyme activity in optimal conditions
• Name three internal conditions that homeostasis regulates.

  ~ Temperature

  ~ Glucose levels

  ~ Blood pH
• What is negative feedback?

  A response to a change in the body that counteracts or opposes the initial change.
• When does negative feedback occur?

  Negative feedback occurs when conditions change from the ideal or set point and it returns conditions to this set point
• What happens when the conditions of something rises or falls from a set point?


  Negative feedback switches on control systems to rise it back to that set point or has to lower it to its set point, reversing any changes that change the conditions from the norms.
• What is an example of negative feedback?

  Insulin response to high blood sugar. If blood sugar rises, insulin is released to lower blood sugar.
• What is glucose?

  A sugar and source of energy
• Why is glucose important?

  ~ Its the source of all energy for the cell's activities in the body.

  ~ Essential for respiration.
• What would happen to glucose levels following a meal?

  They would increase due to eating carbs.
• What would happen to glucose levels after not eating anything or doing exercise?

  They would decrease due to a high demand for energy.
• What is insulin and where is it produced?

  ~ Insulin is a hormone which converts glucose into glycogen (when blood sugar levels are too high)

  ~ Its produced in the pancreas.
• What is glycogen?


  It is a stored formed of glucose/energy manufactured by the liver.
• What happens when the glucose levels increase?

  1. After a meal rich in carbohydrates glucose levels rise.

  2. This is sensed by the pancreas so it secretes insulin.

  3. The insulin binds to cell receptors like the muscles and it triggers them to take in glucose.

  4. It then triggers liver cells to store excess glucose in the form of glycogen as storage.

  5. Now the concentration of glucose in the blood returns to normal levels.
• What happens when glucose levels decrease?

  1. After exercise or not enough food glucose levels decrease.

  2. This is sensed by the pancreas so it secretes glucagon, another hormone.

  3. The glucagon triggers the liver cells to convert the glycogen cells back to glucose.

  4. The glucose is then released into the blood, bringing levels back to normal.
• What is the control of glucose also an example of?

  A negative feedback loop as it rises and lowers glucose levels through processes.
• What happens when theres too much glucose in the body?

  It can lead to organ damage as organs like the kidneys could be sensitive to glucose concentrations..
• Whats the main effect of diabetes?

  ~ Blood glucose cant be regulated

  ~ Insulin system is messed up
• When does type 1 diabetes develop?

  During childhood or adolescence, but can develop during adulthood. Its lifelong.
• What causes type 1 diabetes?

  ~ The body's immune system mistakely attacks insulin-producing beta cells in the pancreas.

  ~ This leads to the pancreas producing little to no insulin, causing glucose levels to rise.

  ~ Type 1 diabetes can be inherited but there's a chance you dont get it.
• How can type 1 diabetes be treated?

  ]~ Insulin injections before or after meals - allows glucose to be converted into glycogen.

  ~ Limiting carbohydrate intake.

  ~ More exercise
• How much does the insulin you need to inject depend on?

  ~ How much the person eats (more)

  ~ How much the person exercises (less)
• What causes type 2 diabetes?

  ~ Body cells become resisitant to insulin, so cells dont respond to insulin.

  ~ So cells wouldn't take in glucose from the bloodstream.

  ~ Happens to people who had unhealthy diets for long periods of time.
• How can type 2 diabetes be treated?


  ~ Following a carefully-controlled diet

  ~ Doing regular exercise

  ~ Losing weight

  ~ Use of drugs which increase insulin production and effectiveness
• How does obesity correlate with type 2 diabetes?


  ~ Obesity is a major risk factor for Type 2 diabetes - obese individuals have an increased risk of developing the condition compared to non-obese individuals.

  ~ This is probably because a person who is obese is likely to consume a diet rich in carbohydrates which causes an over-production of insulin resulting in the development of insulin resistance.
• How is obesity measured?

  Body Mass Index (BMI)

  
  

  Mass / Height^2
• Why is waist:hip ratio measured?

  Individuals with excess fat in this area have an increased chance of getting diabetes. If its high its very risky.