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What do the following have in common? The Titanic The London underground A tri-athlete A London Marathon Runner Four asylum-seekers Pensioners Raymond.

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Presentation on theme: "What do the following have in common? The Titanic The London underground A tri-athlete A London Marathon Runner Four asylum-seekers Pensioners Raymond."— Presentation transcript:

1 What do the following have in common? The Titanic The London underground A tri-athlete A London Marathon Runner Four asylum-seekers Pensioners Raymond and Doreen Elsom

2 Look at the following slides and discuss why the people died?

3 Titanic – 1,502 died – WHY? It was 2:20 am on Monday 15th April The Titanic had collided with an iceberg at 11:40 pm on 14th April and had floundered 3.5 hours later. About 650 passengers were lowered in lifeboats capable of holding 1178; the remaining passengers entered the sea as the Titanic sank. Hundreds of people thrashed about in water that was less than -2 degrees, well below freezing point. It was 4:10am before another ship arrived to collect the survivors. Only 705 of the 2207 survived died. Many of the passengers had life jackets and there was a lot of debris to hang onto. It was a calm and still night. Why did they die?

4 People die on underground trains all over the world during the hot summer months – WHY?

5 An elderly couple died in bed after forgetting to switch their electric hob off in the kitchen. No fire broke out, there was no evidence of fire damage. Just two dead bodies WHY?

6 After the London Flora Marathon. Why did this man collapse?

7 Why is this tri-athlete more likely to get hyperthermia when wet?

8 Four asylum-seekers die in a tragedy. Police have discovered the bodies of four suspected asylum-seekers in a container. The four, all young men are believed to be have been Romanian. The bodies were found in a container load of tiles bound for the UK. The grim discovery was made when police noticed seals had been broken on the container and investigated. WHY did they die?

9 Homeostasis Objectives: *Define homeostasis ** Explain the concept of negative feedback *** Explain the control of blood glucose concentration in terms of negative feedback

10 Homeostasis is maintaining a nearly constant conditions in the body. Why nearly constant? Why this is necessary? Clue: metabolism, enzymes Who has the overall control of body processes? What things need controlling?

11 Homeostasis makes sure our body has the correct levels of; Temperature Carbon dioxide OxygenWater Blood sugar(glucose) pH and ions

12 What happens if you are in your living room and experience either of these two situations? Brain stimulates the body to sweat more to release more heat. Brain stimulates the production of more heat in the muscles by shivering and by increasing respiration rate in the liver. It also stimulates the body to conserve more heat by decreasing sweat production by the sweat glands. Most body heat is generated in the deep organs like liver and brain

13 How does your heating work? Nice comfortable temperature Too hot Too cold Temp. drops at nightHeating is switched on by thermostat Temp. increases during the day Heating is switched off by thermostat. This is NEGATIVE FEEDBACK What should we be controlled using negative feedback? Negative Feedback

14 Draw a negative feedback diagram of controlling temperature in an oven Reqd oven temperature Oven gets hot Thermostat switches heater off Temp falls Reqd oven temperature Temp rises Thermostat switches heater on Oven gets cold

15 The Pancreas  Insulin controls  Glucose is a sugar needed by cells for piraRestion.  It is important that the concentration of glucose in the blood is kept at a constant level. blood sugar levels in our bodies. Copy this down into your books

16 Changing glucose levels After a meal the level of glucose in our bodies [increases/decreases]? After exercise the levels of glucose in our bodies [increases/decreases]? Why do you think this happens? I think this happens because

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19 The pancreas detects the change in blood glucose concentration and releases the appropriate hormone (glucagon)

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21 Insulin and glucagon(the hormones) Stimulate liver cells to change glucose to glycogen or vice versa. Both made in pancreas. They are not enzymes so they stimulate changes to blood glucose level but do not convert one to another. The enzymes in the liver and muscle help do the conversion.


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