Term
| What is an action potential? |
|
Definition
| A rapid change in membrane potential |
|
|
Term
| What is the name of the gap between two neurons? |
|
Definition
|
|
Term
| What is the relative concentration of K+ inside the axon? |
|
Definition
|
|
Term
| What is the relative concentration of K+ outside the axon? |
|
Definition
|
|
Term
| What is the relative concentration of Na+ inside the axon? |
|
Definition
|
|
Term
| What is the relative concentration of Na+ outside the axon? |
|
Definition
|
|
Term
| What is the relative concentration of Cl- inside the axon? |
|
Definition
|
|
Term
| What is the relative concentration of Cl- outside the axon? |
|
Definition
|
|
Term
| What is the relative concentration of protein inside the axon? |
|
Definition
|
|
Term
| What is the relative concentration of protein outside the axon? |
|
Definition
|
|
Term
|
Definition
| Resting Membrane Potential |
|
|
Term
| What two things maintain the RMP? |
|
Definition
1. High permeability to K+
2. Active transport of Na+ out of the axon |
|
|
Term
| What does the K+ leak channel do? |
|
Definition
| Allow K+ to diffuse out of the axon until equilibrium potential is reached |
|
|
Term
| Which Na+/K+/ATPase pump do? |
|
Definition
| Pumps out three Na+ for two K+ in by the direct hydrolysis of ATP to ADP |
|
|
Term
| What is the relative charge of the inside of the axon? |
|
Definition
|
|
Term
| What is the relative charge of the outside of the axon? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| When does K+ stop leaving the axon? |
|
Definition
| When equilibrium potential is reached |
|
|
Term
| Which equation is used to determine the equilibrium potential? |
|
Definition
|
|
Term
| State the Nernst Equation |
|
Definition
|
|
Term
| What does the R is the Nernst Equation stand for? |
|
Definition
|
|
Term
| What does the T is the Nernst Equation stand for? |
|
Definition
|
|
Term
| What does the z is the Nernst Equation stand for? |
|
Definition
|
|
Term
| What does the F is the Nernst Equation stand for? |
|
Definition
|
|
Term
| What is the equilibrium potential for K+? |
|
Definition
|
|
Term
| What is the equilibrium potential for Na+? |
|
Definition
|
|
Term
| What is the equilibrium potential for Cl-? |
|
Definition
|
|
Term
| What is the Goldman Equation? |
|
Definition
| Th equation used to work out the RMP |
|
|
Term
| What is the RMP of a nerve? |
|
Definition
|
|
Term
| Why is the RMP most close to the Eion of K+? |
|
Definition
| It is the most permeable and so has the biggest influence |
|
|
Term
| What is the order of permeability for a nerve? |
|
Definition
|
|
Term
| What is the order of an action potential? |
|
Definition
| Depolarisation, repolarisation, hyperpolarisation, refractory period |
|
|
Term
| How does a voltage gated channel protein work? |
|
Definition
| Opens when a particular voltage is reached |
|
|
Term
| What three voltage gated channel proteins are present along the axon? |
|
Definition
|
|
Term
| What is the speed in which the Na+ voltage gated channel proteins open and shut? |
|
Definition
|
|
Term
| What is the speed in which the K+ voltage gated channel proteins open and shut? |
|
Definition
|
|
Term
| At what voltage do the Na+ voltage gated channel proteins open? |
|
Definition
|
|
Term
| What part of an action potential occurs when the Na+ voltage gated channel proteins open? |
|
Definition
|
|
Term
| What part of an action potential occurs when the K+ voltage gated channel proteins open? |
|
Definition
|
|
Term
| What is the refractory period? |
|
Definition
| The period of time after an action potential that is used to restore ions to the correct side of the membrane |
|
|
Term
| What are the two types of refractory period? |
|
Definition
| Relative and absolute refractory period |
|
|
Term
| What is the relative refractory period? |
|
Definition
| The period at which another action potential can be generated if the stimulus is large enough |
|
|
Term
| What is the absolute refractory period? |
|
Definition
| The period where no action potential can ever be generated |
|
|
Term
| During the absolute refractory period what is the status of the ion channels? |
|
Definition
| Na+ voltage ion channels are inactive |
|
|
Term
| During the relative refractory period what is the status of the ion channels? |
|
Definition
| Na+ volatage gated ion channels have recovered and K+ channels are still open |
|
|
Term
|
Definition
|
|
Term
|
Definition
| The part of the nerve cell that an action potential travels across |
|
|
Term
|
Definition
| The point of the axon where the action potential is first generated |
|
|
Term
| Which section of a neuron contains many voltage gated Na+ channel proteins? |
|
Definition
|
|
Term
|
Definition
| The sections of the axon that are depolarised to pass on the action potential |
|
|
Term
| What prevents the action potential moving backwards? |
|
Definition
| The absolute refractory period |
|
|
Term
| What two factors affect the velocity of an action potential? |
|
Definition
| Membrane resistance and axon diameter |
|
|
Term
| What is the relationship between axon diameter and velocity? |
|
Definition
| The wider the axon the more room for action current flow in current loops and so an increase in velocity |
|
|
Term
| What is the relationship between membrane resistance and velocity? |
|
Definition
| The higher the membrane resistance the less current is lost due to leaks of the membrane and so an increase in velocity |
|
|
Term
| What cell aids membrane resistance? |
|
Definition
| Schwann cells that form a myelin sheath |
|
|
Term
| What is a node of ranvier? |
|
Definition
| A gap in the myelin sheath where depolarisation can occur |
|
|
Term
| How frequent are nodes of ranvier? |
|
Definition
|
|
Term
| How wide are nodes of ranvier? |
|
Definition
|
|
Term
| What ion channels are present in a higher density at the nodes of ranvier? |
|
Definition
| Na+ voltage gated channel proteins |
|
|
Term
| What is saltatory conduction? |
|
Definition
| Jumps of the atcion potential from node to node |
|
|
Term
| In myelinated neurons what other factor effects velocity? |
|
Definition
| The dstance between the nodes of ranvier |
|
|
Term
| What is Multiple Sclerosis? |
|
Definition
| I neurodegenerative disease where demyelination occurs in the myelinated neurons resulting in a gradual loss of motor control |
|
|
Term
|
Definition
|
|
Term
| What is the synaptic cleft? |
|
Definition
| The space between two neurons |
|
|
Term
| What is the neurotransmitter present at NMJ's? |
|
Definition
|
|
Term
| Outline the mechanism that occurs at an NMJ? |
|
Definition
1)Depolarisation from the axon potential causes an influx of Ca2+ ions from Ca2+ voltage gated ion channels.
2) This causes vesicles containing Acetylcholine to be released into the synaptic cleft
3)Acetylcholine binds to receptors on the sarcolema to cause an influx of Na+ from Na+ ligand gated ion channels
4)K+ ions also leave the sarcolema
5)This causes a depolarisation of the sarcolema |
|
|
Term
| How long does it take for the Ach molecules to diffuse across the cleft? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| What EPP is required for a muscle contraction? |
|
Definition
|
|
Term
|
Definition
| A smaller EPP that is randomly generated by the nerve at rest |
|
|
Term
| What is the smallest mini-EPP? |
|
Definition
|
|
Term
| What is the purpose of the mini-EPP? |
|
Definition
| One mini-EPP requires the release of one vesicle, so approximately 100 vesicles need to be released for an full EPP |
|
|
Term
| How many Ach molecules are in one vesicle? |
|
Definition
|
|
Term
| What enzyme breaks down Ach? |
|
Definition
|
|
Term
| What is Ach broken down into? |
|
Definition
|
|
Term
| Which product of the breakdown of Ach is reabsorbed by the neuron? |
|
Definition
|
|
Term
| What is the purpose of acetylcholine esterase? |
|
Definition
| Breaks down Ach to prevent the constant stimulation of the muscle |
|
|
Term
| How does the Curare poison work? |
|
Definition
| Blocks Ach receptors and causes paralysis |
|
|
Term
| How does the Botullinum Toxin work? |
|
Definition
| Prevents release of Ach and causes paralysis |
|
|
Term
| What product is Botullinum Toxin present in? |
|
Definition
|
|
Term
| What causes Myasthenia Gravis? |
|
Definition
| An autoimmune response that destroys Ach receptors and so cant produce EPP's and so die of paralysis |
|
|
Term
| What is the treatment given to patients with Myasthenia Gravis? |
|
Definition
| Inhibitors of Acetylcholine esterase |
|
|
Term
| Muscles are made up of what? |
|
Definition
|
|
Term
| Muscles fibres are made up of what? |
|
Definition
|
|
Term
| Myofibrils are made up of? |
|
Definition
|
|
Term
|
Definition
| The area of myosin and actin |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| The limits of each sarcomere |
|
|
Term
| How does the A-band change when contraction occurs? |
|
Definition
|
|
Term
| How does the I-band change when contraction occurs? |
|
Definition
|
|
Term
| How does the H-zone change when contraction occurs? |
|
Definition
|
|
Term
| How does the z-lines change when contraction occurs? |
|
Definition
| The distance between them decreases |
|
|
Term
|
Definition
| The center of a sarcomere |
|
|
Term
|
Definition
| The thick filament with 100's of heads |
|
|
Term
| What is a mysoin filament? |
|
Definition
| A thin protein with a head and a tail region |
|
|
Term
| What three proteins make up the thin filament in muscles? |
|
Definition
| Actin, troponin and tropomyosin |
|
|
Term
| What is the G-actin molecule? |
|
Definition
| It makes up the F-actin double helix |
|
|
Term
| What does tropomyosin do? |
|
Definition
| It wraps around the F-actin filament |
|
|
Term
|
Definition
| Proteins with three subunits that bind to actin, tropomyosin and Ca2+ |
|
|
Term
| How many binding sites does troponin have? |
|
Definition
|
|
Term
| What does the T-subunit of troponin bind? |
|
Definition
|
|
Term
| What does the I-subunit of troponin bind? |
|
Definition
|
|
Term
| What does the C-subunit of troponin bind? |
|
Definition
|
|
Term
| What happens to troponin when Ca2+ binds? |
|
Definition
| Conformational change that exposes the myosin binding site |
|
|
Term
|
Definition
| Invaginations of the sarcolema |
|
|
Term
| Where is the Ca2+ store in muscles? |
|
Definition
| In the terminal cisternae of the sarcoplasmic reticulum |
|
|
Term
|
Definition
| A t-tubule with a sarcoplasmic reticulum either side |
|
|
Term
| Outline the mechanism that releases and bind Ca2+? |
|
Definition
1)Depolarisation of sarcolema travels down t-tubules to depolarise the triads and the sarcoplasmic reticulum
2)Terminal cisternae release Ca2+ from the sarcoplasmic reticulum
3) Ca2+ binds to troponin which exposes the actin myosin biding site |
|
|
Term
| Outline the mechanism involved in a muscle contraction? |
|
Definition
1)Myosin hydroylses ATP to ADP and Pi and becomes in a state of high energy
2)Mysoin binds to actin myosin binding site and rotates pulling the actin filament in
3) ATP binds to myosin breaking off the cross bridge and releases ADP and Pi
4)Repetition until all Ca2+ is used up |
|
|
Term
| What is the name given to the 'ratchet movement' of myosin? |
|
Definition
|
|
Term
| How many myosin heads does a typical muscle fibre have? |
|
Definition
|
|
Term
| How is Ca2+ removed from the muscle? |
|
Definition
| Using a Ca2+/ATPase pump to pump it back into the sarcoplasmic reticulum |
|
|
Term
| What happens if an individual has Rigour Mortis? |
|
Definition
| The myosin heads remain bound to actin |
|
|
Term
| What does the CNS stand for? |
|
Definition
|
|
Term
| What does the PNS stand for? |
|
Definition
| Peripheral Nervous System |
|
|
Term
| Outline the order of neurons involved in a simple reflex? |
|
Definition
| Sensory -> intergratory -> motor |
|
|
Term
| Which neuron/s are involved in the CNS? |
|
Definition
|
|
Term
| Which neuron/s are involved in the PNS? |
|
Definition
|
|
Term
| Which is the efferent neuron? |
|
Definition
|
|
Term
| Which is the afferent neuron? |
|
Definition
|
|
Term
| What three things are special about neurons? |
|
Definition
| Do not undergo mitosis, have a longlife and a high metabolic rate |
|
|
Term
| What is a graded potential? |
|
Definition
| A small depollarisation which if reaches threshold will become and action potential |
|
|
Term
| Where do graded potentials occur? |
|
Definition
| In the axon hillock, cell body or dendrites |
|
|
Term
| Where do graded potentials not occur? |
|
Definition
|
|
Term
| What is a depolarising graded potential called? |
|
Definition
|
|
Term
| What does EPSP stand for? |
|
Definition
| Excitatory Post-Synaptic Potential |
|
|
Term
| Which ion/s causes EPSP's? |
|
Definition
|
|
Term
| What is a hyperpolarising graded potential called? |
|
Definition
|
|
Term
| What does IPSP stand for> |
|
Definition
| Inhibitory Post-Synaptic Potential |
|
|
Term
| Which ion/s causes IPSP's? |
|
Definition
|
|
Term
| What happens when the graded potential reaches the axon hillock? |
|
Definition
| If it is at threshold value it will generate an action potential |
|
|
Term
| How does a neuron transmit information about the strength and duration of a stimulus? |
|
Definition
| By increasing the frequency and space between each action potential |
|
|
Term
| What is the relationship between the strength stimuli and the release of neurotransmitter? |
|
Definition
| The stronger the stimuli, the more frequent the action potentials, the more neurotransmitter released |
|
|
Term
| Why do nerves use frequency to show strength? |
|
Definition
| They are clearer as they are less prone to noise |
|
|
Term
|
Definition
| One neuron synapsing with many neurons |
|
|
Term
|
Definition
| Many neurons synapsing to one neurone |
|
|
Term
| What is spatial summation? |
|
Definition
| Many neurons converging but at different parts of the final neuron |
|
|
Term
| What is temporal summantion? |
|
Definition
| Many neurons converging but releasing their action potentials at seperete times to the final neuron |
|
|
Term
| What is Postsynaptic inhibition? |
|
Definition
| Where neurons converge but the final neuron is still subthreshold |
|
|
Term
| What is pre-synaptic modulation? |
|
Definition
| Contributions of other neurons at the axon terminal before the action potential is passed to the other neurons |
|
|
Term
| Name the most common neurotransmitter? |
|
Definition
|
|
Term
| Name three amine neurotransmitters? |
|
Definition
| Adrenaline, dopamine and histamine |
|
|
Term
| Name three amino acid neurotransmitters? |
|
Definition
| GABA, glycine and glutamate |
|
|
Term
| Name two purine neurotransmitters? |
|
Definition
|
|
Term
| Name a gas neurotransmitter? |
|
Definition
|
|
Term
| Name two polypeptide neurotransmitters? |
|
Definition
| Cholecystokinin and Enkephallins |
|
|
Term
| What is an example of an intropic receptor? |
|
Definition
| Ligand-gated ion channels |
|
|
Term
| What is an example of a metabotrophic receptor? |
|
Definition
| G-Protein linked receptor |
|
|
Term
| Which type of receptor gives a fast response? |
|
Definition
|
|
Term
| Which type of receptor gives a slow response? |
|
Definition
|
|
Term
| Which types of neurotransmitters are used in intropic receptors? |
|
Definition
| Amino acids, ions, amines and acetylcholine |
|
|
Term
| Which type of neurotransmitters are used in metatropic receptors? |
|
Definition
|
|
Term
| What is synaptic plasticity? |
|
Definition
| The variations of electrical responses and activity that allow us to have memory and learn |
|
|
Term
|
Definition
|
|
Term
|
Definition
| Repetitive stimulation that results in a learning pathway |
|
|
Term
| Which neurotransmitter is used mainly in LTP? |
|
Definition
|
|
Term
| Outline the mechanism of LTP? |
|
Definition
1)Glutamate is released continuously
2)Mg2+ leaves and opens Ca2+ channel proteins which makes the neuron more sensitive to glutamate
3)Faster response to glutamate |
|
|
Term
| How can LTP be inhibited? |
|
Definition
|
|
