PS111 - Resting potentials/action potentials 0.0 / 5 ? PsychologyBrain and behaviourUniversityNone Created by: Steff06Created on: 27-10-16 10:23 What would be the result if the membrane was non-permeable? The electric potential would remain static. 1 of 21 What do protein channels in the cell membrane allow? Allow ions to enter or leave the cell. 2 of 21 How are the concentration gradient and electrical gradient balanced? They work in opposite directions to balance each other. 3 of 21 Which ions are transported in/out of the cell? 3Na+ ions transported out of the cell and 2K+ ions into the cell. 4 of 21 What causes ion-specific channels in the cell membrane to open? Open either by chance or in response to stimulation. 5 of 21 What causes the membrane to depolarise? Depolarises if positive ions enter or negative ions leave the cell - inside = less negative. 6 of 21 How does the membrane hyperpolarise? Hyperpolarises if negative ions enter/positive ions leave the cell - insude is more negative. 7 of 21 Describe electro-tonic transmission Passive process where ions move inside the cell along the electrical gradient. 8 of 21 What happens to the signal as time goes on? The signal will decay. 9 of 21 Where is an action potential generated and where does it travel? Generated at the axon hillock and travels down the axon towards the terminal buttons. 10 of 21 What causes Na+ channels to open or close? Electrical changes at the membrane. 11 of 21 What happens once the membrane has depolarised? Na+ channels open and Na+ ions enter the cell. 12 of 21 What is the effect of Na+ ions entering the cell? The membrane depolarises further to -50mV and the threshold potential is reached. 13 of 21 What happens if the threshold potential is reached? All the Na+ channels in the depolarised area open simultaneously, generating an action potential. 14 of 21 What are the effects of depolarisation? Na+ channels close, so no more Na+ ions enter the cell. K+ channels open, so K+ ions rush out of the cell. 15 of 21 When do the K+ ion channels close? Close when the resting potential is restored. 16 of 21 What then happens for a short period? Hyperpolarisation - there are less K+ ions inside the cell than outside. 17 of 21 What are the properties of action potentials? Doesn't decay during transmission. Fast, all-or-nothing, cannot be produced continuously. 18 of 21 What is a benefit of neurons being myelinated? Results in much faster transmission. 19 of 21 What is the myelin interrupted by and what is this for? Nodes of Ranvier which allow the action potential to 'jump' from node to node. 20 of 21 How can we tell if an input is strong? Causes the neuron to send signals out more quickly. 21 of 21
Comments
No comments have yet been made