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23 Cards in this Set
- Front
- Back
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Where are hormones produced and where do they go?
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They are produced in the glands and secreted directly into the blood stream.
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What carries the hormones? And where to?
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The blood plasma carries the hormones to the target cells which have receptors on the outer cell membrane that are complimentary to the hormone.
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How effective are hormones?
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Very effective in small quantities, with the effects often being widespread and long lasting.
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There are two ways in which hormones function. Name the one mechanism involved in the regulation of blood glucose.
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Second messenger model.
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Describe the second messenger model.
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The hormone is the first messenger. It binds to the specific receptor to form a hormone-receptor complex. This activates an enzyme in the cell which results in a chemical being produced which works as a secondary messenger. This causes a series of chemical changes to create the desired bodily change.
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What is the role of the pancreas?
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To produce enzymes for digestion and hormones for regulating blood glucose.
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What are the digestive enzymes that the pancreas create?
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Protease, amylase and lipase.
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What are the hormones that the pancreas create which aid in regulating blood glucose?
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Insulin and glucagon.
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What is the cell structure of the pancreas?
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The majority are cells that produce digestive enzymes but there are clusters of cells that produce hormones. The clusters are called islets of Langerhans.
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What are the two types of cells found in the islets of Langerhans?
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α cells - these are larger and produce glucagon.
β cells - these are smaller and produce insulin. |
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Why is it essential to regulate blood glucose?
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Glucose is the main substrate for respiration, especially in the brain where it can only use glucose. If there is too much it will create water potential issues, and if there is too little the body will not have enough energy.
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What is the normal level of blood glucose?
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90mg per 100cm³ of blood.
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What three sources does glucose come from?
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- Directly from the diet - carbohydrates and starch taken in can be broken down into glucose.
- Glycogenolysis. - Gluconeogenesis. |
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What is glycogenolysis?
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The break down of glycogen which is stored in the liver and muscle cells. Opposite is glycogenesis.
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What is gluconeogenesis?
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This is the production of new glucose from sources other than carbohydrates. For example, the liver can make glucose from glycerol and amino acids.
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What do the β cells do?
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Detect rises in glucose level and secrete insulin accordingly.
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What initial effect does insulin have on the body?
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It binds to almost all body cells which causes glucose transport channels to open to allow more glucose into cells. It activates enzymes that change glucose to glycogen and fat. It increases the number of carrier molecules in the cell surface membrane.
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How does insulin lower blood glucose levels?
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- Increasing rate of absorption of glucose in cells.
- Increasing the respiratory rate of cells, using more glucose up. - Increasing the rate of glycogenesis (conversion of glucose into glycogen). - Increasing the rate of conversion of glucose to fat. |
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What do the α cells do?
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Detect a fall in blood glucose and respond by secreting glucagon.
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Which cells respond to glucagon?
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The cells in the liver are the only ones to have receptors so they are the only ones to react.
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How does the liver respond to glucagon?
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- Activates an enzyme that converts glycogen to glucose.
- Increases gluconeogenesis (conversion of amino acids and glycerol into glucose). |
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How does adrenaline increase blood glucose?
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- Activates the enzyme that breaks down glycogen to glucose.
- Inactivating an enzyme that synthesises glycogen from glucose. |
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What system are both insulin and glycagon part of?
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A negative feedback loop.
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