B1- Topic 2 4.0 / 5 based on 1 rating ? Biologyall of topic 2 edexcelGCSEEdexcel Created by: odionj01Created on: 19-02-16 18:40 What is homeostasis? Ability to maintain a stable internal enviroment 1 of 35 Why is sweat produced when you are too hot? when sweat evaporates, it transfers heat from skin to the surroundings, which cools you down. 2 of 35 What is vasodilation? This is where blood vessels move closer to the skin and dilate , this means more blood flow , transfer more heat 3 of 35 Why do erector muscles contract when your too cold? The hairs stand on end and trap insulating layers of air, to help keep you warm 4 of 35 What is vasoconstriction? blood vessels at surface constrict, less blood flow near surface, less heat transferred to surroundings. 5 of 35 What are hormones? They are chemical messengers sent in the blood, they are produced by the endocrine glands 6 of 35 What is a target cell? What a hormone affects because they have the right receptors to respond to the hormone 7 of 35 What is a synapse? the gap at which nuerotransmitters diffuse across. 8 of 35 What is a dendron? They are branched endings that connect with other nuerons 9 of 35 what is a nueron? a nerve cell 10 of 35 What is an axon? An electrical impulse thats passed along the cell 11 of 35 What is a mylein sheath? Acts as the electrical insulator,speeds up the electrical impulse 12 of 35 What are the main five sense organs? eyes,ears,nose,tounge 13 of 35 What do sensory nuerones do? carry nerve impulses from the receptors in sense organs to the CNS 14 of 35 What do relay nuerones do? carry nerve impulses from sensory nuerones to motor nuerones 15 of 35 What do motor nuerones do? carry nerve impulses from the CNS to the effectors 16 of 35 What are effectors? muscles or gland that respond to nerve impulses in different ways 17 of 35 What does the CNS consist of? the brain and the spinal cord 18 of 35 What does the CNS do? coordinates the response, decides what to do about the stimulus. 19 of 35 What is the purpose of a reflex? they help prevent injury 20 of 35 What does the pancreas secrete when blood glucose is too high? Insulin which turns glucose into glygogen 21 of 35 What happens when insulin is secreted? Blood glucose is reduced, insulin stops being secreted 22 of 35 Why is glycogen useful? Its insoluble so wont dissolve in the blood stream 23 of 35 What does the pancreas secrete when blood glucose is too low? glucagon 24 of 35 What turns glucagon do? makes liver turn glucagon into glucose 25 of 35 How can type 1 diabetes be controlled? avoiding foods rich in carbohydrates,injecting insulin 26 of 35 Where is insulin injected? subcataneous tissue 27 of 35 What does resistancy to insulin? body cells dont respond properly to the hormone insulin 28 of 35 How would you work out BMI? body mass divided by height squared 29 of 35 How do plants respond to stimuli? regulate their growth, by tropism 30 of 35 What is phototropism? the growth of a plant in response to light 31 of 35 What is gravitropism? the growth of plant in response to gravity 32 of 35 What happens if a plants is positively gravitropic? they grow downwards 33 of 35 what is auxin? a plant hormone that controls growth at tips of shots and roots. 34 of 35 What happens if a plants is positively phototropic? shoot tip exposed to light, more auxin accumulates the side with shade 35 of 35
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