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| Frage | Antworten |
| topic 4 | the nervous system and hormones |
| nerves and hormones are involved in sensing and responding to changes in the environment | nerves and hormones have very different characteristics... |
| nerves: *fast *electrical *travel along nerve cells *specific actions | hormones *slow *chemical *travel in blood *travel to a target organ |
| animal nervous system: *receptor - a receptor is stimulated - something must trigger them *coordinator (which is the brain and spinal cord [CNS] ) - information is sent for the receptor which determines what response is required *effector - produces a respose (usually a muscle or a gland) | hormones: hormones are chemical proteins that are released from glands. they travel in the blood to a target organ. hormones cannot be taken orally as the protease in the stomach will break it down into amino acids. |
| insulin: *helps to lower blood glucose level *release from pancreas into the blood | when blood glucose levels are high, insulin causes glucose to be converted into glycogen in the live. it increases the rate of respiration in cells (to use up glucose). causes more glucose to enter cells. |
| when blood glucose levels are low, less insulin is released so glycogen is converted into glucose in the liver. the rate of respiration is decreased. it causes less glucose to enter cells. | Diabetes is a medical condition caused by too little insulin being released or the cells dont respond to insulin |
| most common symptoms are: *high blood glucose levels *glucose in the urine *constant thirst *frequent toilet visits *irritability and confusion | long term dangers: *kidney damage *eye damage *stroke *heart disease |
| plant hormones plants like animals respond to stimuli as light. plants grow towards the light, this is called phototropism. the hormones responsible for this are auxins | *auxins are produced in the tip of the plant *light spread evenly will cause plant to grow evenly *if light is shone from one side auxins move to the shaded side *this causes the plant to grow and elongate on one side - making it bend towards the light * this allows for max photosynthesis and growth |
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