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163 Cards in this Set
- Front
- Back
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what is metabolism defined by? |
the sum of all chemical reaction in the cell |
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What is an activation energy? (enzymes) |
the energy required to go through the transition state of a reaction |
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What four things dictate the rate of chemical reactions? |
1) concentrations of substrates 2) enzyme activity (inherent catalytic rate of the protein) 3) enzyme concentration 4) the affinity of the enzyme for the substrate ** also temp and pH but to a lesser extent |
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how do enzymes alter the rate of reaction? |
they are not themselves catalyzed - the reactant is bound to the enzyme (substrate) and it speeds up the process |
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can enzymes catalyze forward and reverse reactions? |
yes, they only have limitations considering the specific substrate they will bind to |
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what is allosteric modulation |
a connection between substrate and enzyme that isnt a covalent bond |
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What are two ways through which enzymes can be regulated? |
1) allosteric modulation 2) covalent modification (e.g. phosphorylation) |
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What are three sources of atp production in our bodies? in which order are they used? |
carbs, lipids, proteins |
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What two general processes involving enzyme catalyzed reactions support ATP production and maintain cellular homeostasis? |
1) substrate-level phosphorylation (occurs in absence of O2, such as anaerobic glcolysis 2) oxidative phosphorylation (depends on supply of O2 for oxidation reactions in mitochondria. This is the primary mode of ATP production in most cells) |
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What are the steps of glucose oxidation? |
1) glycolysis 2) Linking step, pyruvate --> acetyl CoA 3) Krebs cycle 4)oxidative phosphorylation |
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Describe what happens in glycolysis and the linking step |
-breaks down glucose and produces two molecules of pyruvate -occurs in the cytosol -pyruvate enters mitochondria, linking step converts to acetyl CoA --> all together makes 2acetyl-CoA, NADH and ATP |
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What are the products of the krebs cycle? |
3 NADH2, 1 FADH2, 2 CO2, 1 ATP |
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Describe the steps of oxidative phosphorylation |
NADH and FADH2 donate electrons to ETC, they are oxidized to NAD+ and FAD.. the elctrons reduce O2 to h2O and the energy released is used to pump protons out of the mitochondrial matrix. The protons then move back down the concentration gradient through ATP synthase to make ATP |
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What process of energy metabolism is used in the absence of oxygen? |
Lactate production, yeilding only 2 ATP from glycolysis |
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What is meant by the term uncoupling? |
the protons will flow back into the mitocondrial matrix and bypass the ATP synthase.. carbs/sugars/lipids are burned without any energy produced. This increases metabolism and heat production. |
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true or false? membrane transport is one of the primary ATP demanding processes in the cell |
true |
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what types of transport processes are there? |
1) passive transport (doesnt require ATP) a) simple diffusion (lipid bilayer) b) carrier mediated diffusion (protein chanel) 2) active transport ( requires ATP) a) primary b) secondary |
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what is the net flux? |
the overall rate and direction of diffusion (flux out - flux in) |
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What is it called when net flux is zero? |
diffusive equilibrium |
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what powers diffusion? |
chemical gradients |
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true or false? diffusion time is proportional to distance |
false! it is proportional to distance ^2 |
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true or false? net diffusion is proportional to the concentration difference between two locations |
true, except in the case of gasses |
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true or false? net diffusion rate across a membrane is proportional to the permeability |
true |
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what is the permeability constant affected by? |
1) temperature 2) solubility in lipid bilayers (generally O2, CO2, fatty acids and steroid hormones are nonpolar and diffuse more rapidly than charged/polar solutes 3) size and shape of the molecule |
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what does each variable in fick's law stand for? |
F - Net Flux rate Kp - permeability constant A - membrane area deltaC - concentration difference across membrane T - membrane thickness |
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differentiate between the chemical and the electric driving force? |
chemical is because of a concentration gradient, electrical is because of a difference of charge due to ions
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is the membrane potential in a resting cell positive or negative? |
negative |
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what is the electrochemical driving force? |
combined effect of the chemical and electrical forces, dictates direction of diffusion |
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what is the equilibrium potential (E)? |
the membrane potential (Vm) at which the electrical and chemical driving forces are equal |
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know the nernst eq, |
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K+ is much higher inside the cell, and Na+ is much higher outside the cell. Which has a positive E? |
Na because it is on the top of the raitio in the Nernst equation |
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explain the process of carrier mediated diffusion? |
occurs through protein channels, usually for substances with low membrane permeability |
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what does it mean for the rate of simple diffusion to be saturable? |
when a channel's maximum capaciyt is reached |
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how does primary active transport work? |
membrane proteins hydrolyze ATP and transport ions against their concentration gradient |
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describe the process of secondary active transport |
a substance is able to travel across its electrochemical gradient through the use of co-transporters. The co-transporters are traveling along their gradient, and taking the substrate in question with them. The co-transporter gradient is originally established by another ATPase. |
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what is osmosis? |
the passive diffusion of water across membranes |
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in which direction does water diffuse? towards higher or lower osmolarity? |
towards an area of higher osmolarity (lowest water concentration) |
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How many osmoles is 1M of NaCl? |
2 osmoles (will ionize to give you one osmole of Na and one of Cl) |
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describe hypotonic, hypertonic, and isotonic conditions. |
hypotonic: lower concentration of solute outside the cell, making water rush in and resulting in the cell swelling isotonic: equal concentration inside and outside the cell hypertonic: higher concentration of sulute outside the cell, causes the water to rush out and the cell deflates |
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What happens when a cellcontaining 300 mOsm ofnon-permeating solute isplaced into a solutioncontaining 300 mOsm ofpermeating solute (urea)? |
the permeating solute will difffuse into the cell, and the non-permeable solute will stay. This makes a osmatic driving force into the cell and hypotonic conditions |
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what is epithelial transport? |
transport of materials across entire cell layers |
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differentiate between the apical membrane and the basolateral membrane |
the apical membrane faces external environment (lumen) and the basolateral membrane faces the internal environment (interstitial fluid). They have different transport systems |
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what is the purpose of tight junctions in epithelial tissue? how do they facilitate epithelial transport? |
tight junctions fuse adjacent cells together toform a nearly impermeable barrier to the movement of substancesbetween cell.. because of this barrier, solutes generally must cross the epithelial cell layer to go from one side of anepithelium to the other, rather than goingaround the cells |
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describe the process of epithelial transport of Na+ ions and glucose |
Na+ and glucose enter the cellby a co-transporter across theapical membrane (secondaryactive transport), powered bythe outward transport of Na+across the basolateralmembrane by the Na+/K+ pump(primary active transport) Buildup of intracellular glucosecreates a driving force for itsdiffusion from the cell throughbasolateral channels |
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can water diffuse across an epithelial layer? |
yes, it will occur by osmosis and depends on the active transport of solutes to create an osmotic gradient |
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what three main methods of cell communication are there? differentiate the distinguishing factors |
1) Hormones: Long distance, secreted by endocrine cells, slow acting 2) Neurotransmitters: long distance, secreted by nerve cells at synapse, fast acting 3) Autocrine / paracrine agents: local homeostatic response, short distance |
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what are four features of signal transduction pathways? |
1) specificity: the signal molecule fits in its receptor while others dont 2) AmplificationL 1 receptor binding can lead to 1,000,000 intracellular signals 3) desensitization / adaptation: feedback can shut off receptor 4) integration: the intracellular signal can be the result of integration of multiple receptor units |
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How does the messengers concentration affect the number of receptors bound |
higher concentration makes the percentage of receptors bound move closer to saturation point |
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how does the number of receptors present affect the number of receptors bound? |
increases it in a linear relationship (increases the saturation point) |
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how does the receptors affinity for the messenger affect the number of receptors bound? |
the higher the affinity, the more receptors will be bound at giver concentration of messenger. There is still the same point of saturation, it just reaches it faster |
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what is the function of intracellular receptors? |
1. they bind to lipophillic messengers 2. Act as transcription factors to alter gene transcription and the translation of a specific protein 3. receptors are in the cytosol or nucleus |
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What is the function of membrane-bound receptors? what types are there |
they bind to lipophobic messengers and there are three main types: 1) channel linked receptor 2) enzyme lined receptor 3) G-protein linked receptor |
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How do channel linked receptors work? |
channels act as a receptor called ligand-gated channel, and respond very quickly to messenger binding. A change in electrical properties of the cell can initiate the cellular response to messenger binding (opening or closing channel). E.g. in response to a messenger, the ligand-gated calcium channel will open and calcium will flow down its concentration gradient into the cell |
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How do enzyme-linked channels work ? |
there is a ligand-binding domain on extracellular surface and an enzyme active site on intracellular surface. Messenger binding alters the activity of the intracellular enzyme domain, which creates a response in the cell |
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How do G-linked proteins work? |
the active membrane proteins (G-proteins) begin a signalling cascade, some regulate ion channels.. these channels respond more slowly to messenger binding because theres a time lag when the alpha subunit is activated to bind to the channel. The channel itself doesnt act as the receptor. some also regulate enzyme that produce second messengers (e.g. cAMP) |
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How are secondary messengers responsible for amplification? |
one messenger molecule will bind to a receptor, and from that receptor several G proteins are activated.. Each G protein activated an adenyl cyclase (for example), and each adenyl cyclase can generate hundreds of cAMP, which each activate a protein kinase A, and each protein kinase phosphorylates hundreds of proteins |
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which type of cell is most abundant in the nervous system? |
GLIA cells compose 90% of the nervous system, whereas neurons compose 10% |
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what are the properties of GLIA cells? |
they are not electrically excitable, they provide structural integrity, homeostatic regulation (glia produces metobolic fuels and gets rid of waste), electrical insulation (myelin), and local inter-cellular communication |
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what are the properties of neurons? |
electrically excitable, structurally and functionally classified |
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What is a synapse? |
an area where a presynaptic neuron makes specialized contact and communicated with postsynaptic neuron |
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What is an axon hillock? |
where an axon originates; trigger zone where action potentials are initiated |
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What are dendrites? |
numerous small branches, they receive most of incoming information from other neurons.. they are where graded potentials occur |
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what is in the cell body of a neuron? |
contains nucleus and organelles, its where metabolic functions and the synthesis of bio molecules occur |
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what are terminals? |
presynaptic compartment that sends information to other neurons |
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What are the three structural classes of neurons? |
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differentiate between afferent division and efferent division |
afferent: conducts information from external and internal sensors to the CNS efferent: conducts information from the CNS to effector organs |
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what are the 3 functional classes of neurons? |
1) afferent neurons: unipolar neurons, peripheral axond endings. Includes sensory receptors (somatosensory system, vision, hearing) 2) efferent neurons: multipolar neuron with cell body and dendrites in the CNS (enters PNS as it travels to effector neurons) 3) Interneurons: 99% of all neurons in the body, all are in the CNS (includes processing sensory information and sending commands to effector neurons) |
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what are the classes of glial cells in the CNS? PNS? |
CNS: Astrocytes, Microglia, Ependymal cells, ogliodendrocytes PNS: schwann cells, satelite cells |
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what are the ogliodendrocytes and schwann cells responsible for? |
they create an insulating wrap called myelin around axons which substantially reduces ion leak across membrane, helping neurons transmit action potentials rapidly |
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what is a node of ranvier? |
the nodes between myelin sheaths where action potentials are fired |
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differentiate between the ogliodendrocyte's method of myelination and the Schwann cell's method |
the ogliodenrocyte forms several myelin sheaths across several axons, the nucleus isnt wrapped around any axon. The Schwann cell forms one myelin sheath on one section of an axon, the nucleus is wrapped around it too. |
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What is white matter? |
regions with clusters ("tracts") of axons, in which the lipid in the myelin makes it appear white |
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What is grey matter? |
makes up 40% of CNS, there is no myelin or axon tracts. There are clusters of cell bodies, dendrites, and axon terminals where the synaptic communication and integration occurs |
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what are visceral receptors? |
they sense internal environment e.g. blood pressure (they are on organs) |
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what determines the membrane potential (Vm)? |
it is the result of an extremely small difference in the # of charged particles across a membrane. Overall the cell could have electrical neutrality, but the micro layer of particles just inside the membrane makes a charge. |
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how does the sodium potassium pump contribute to creating a negative membrane potential? |
it moves two potassium in and three sodium out, making a net movement on one positive charge out. Also contributes indirectly to the potential by creating concentration gradients |
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on test might be simplified to this version of nernst equation |
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calculate the Ek and the ENa given the following |
Ek = -94mV ENa = +60mV |
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true or false? more permeable ions have a greater influence on the resting membrane potential |
true |
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What does an ions conductance refer to? |
the propensity to move across the membrane (increases with permeability) |
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which is more permeable in a neuron? potassium or sodium |
potassium is 25X more permeable |
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is PNa increases how will the Vm change? what is this process called? |
It will move towards +60mV (ENa), referred to as depolarization |
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If Pk increases, how will Vm respond? what is this called? |
it will move towards -94mV, referred to as repolarization or hyperpolarization (depending on if it has crossed resting potential) |
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what are two types of electrical signals? |
1) graded potentials 2) action potentials |
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differentiate between graded potentials and action potentials |
graded: short distance, decremental signals that initiate the firing of action potentials in the dendrites action potentials: all or none events that can transmit signals that travel long distances along axons, initiated by strong graded potential |
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what types of gated chanels are there? |
Ligand gated, voltage gated, and mechanically gated |
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How are gated channels different than leak channels? |
The leak channels are always on and dictate the resting Vm. The gated channels need a stimulus to open or close and they cause electrical signals |
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true or false? graded potentials can be depolarizing and hyperpolarizing |
true! it depends on the type of channels that open or close |
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when do graded potentials occur? |
then ion channels are opened or closed on the dendrites of the cell body, causing a current to flow |
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How to the leak channels effect the graded potential? |
as the GP spreads from the site of stimulation, some current leaks through the background leak channels, causing the signal to decrements / decrease |
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how strong must a graded potential be to induce an action potential? |
-55mV (the threshold) |
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what would happen if a depolarizing graded potential and a hyperpolarizing graded potential were to activate the axon hillock at the same time? |
there would a very weak stimulus and no action potential fired, they work against each other |
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slide 28-35 talks about action potentials... talk it through. |
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are ogliodendrocytes in the CNS or PNS? Schwann cells? |
Ogliodendrocytes are CNS, Schwann cells are in the PNS |
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what is the process of action potentials "leaping" from one node of ranvier to the next? |
its called saltatory conduction |
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over short distances, are action potentials fast or slow? how about long distances? |
they are slow over short distances as they involve the diffusion of ions, but over long distances they can travel fast because of myelination |
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what would happen is the myelin internodes were longer? |
the action potential might not be strong enough to reach threshold in the next node of ranvier and the signal would stop |
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What would happen if the myelin internodes were shorter? |
the action potential would still fire the same way but wouldnt travel as fast throughout the body |
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What are the advantages of myelinated axons? |
1. much higher conduction velocity 2. saves space, axons can be much thinner 3. metabolically cheaper, action potentials occur only at nodes |
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What type of axons to invetebrates have? |
larger, unmyelinated axons - slower response time |
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how does conduction velocity respond to a change in axon diameter? why? |
larger diameter faster velocity, because it decreases resistance to current flow along axon.. theres less surface area for ions to leak out |
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Where are voltage gated channels present in an axon?
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only needed at the nodes of ranvier, not under the myelin sheath |
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How do action potentials encode a stimulus in intensity? e.g. the magnitude of a pain stimulus |
if you take a stimulus above threshold and apply it for longer you can have multiple action potentials induced, the duration of stimulus is encoded by a greater frequency in AP. |
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You applied a stimulus of 'x' strength and induced one action potential. What would happen if you applied a stronger stimulus for the same amount of time? |
there would be multiple action potentials fired, because the larger stimulus is more likely to generate an AP during the relative refractory period |
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Is there a limit to the amount of action potentials that can be fired? if an infinite amount of energy were applied as a stimulus? |
yes because there is an absolute refractory period. The increased energy can only induce another AP in the relative refractory. |
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what are two types of synapses? |
electrical and chemical |
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what type of junctions are present in electrical synapses |
gap junctions, there is direct cytoplasmic connections between the pre and post synaptic cells that allow electrical signals to be transmitted from one neuron to another |
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describe the process of electrical synapses |
signal is directly transferredto the adjacent cell by means of ions flowing through the gap junc-tions |
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what are the advantages of electrical synapses? |
allows for rapid communication between cells, synchronizes activity of connected cells |
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what are the disadvantages of electrical synapses? |
often bidirectional communication, so its harder to target a signal. Also, there is no capacity for modulation or amplification of the signal (no gradient or decide on a barrier.. the signal in the presynaptic will be identical to post synaptic) |
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describe the process of a chemical synapse |
the arrival of an AP leads to neurotransmitter to release into the synaptic cleft the NT binds to receptors on the postsynaptic membrane and causes a response (this is how the information is sent) |
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where might you find chemical synapses? |
they can be neuron-neuron or neuron-effector. |
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what are the advantages of chemical synapse? |
they are unidirectional and they facilitate integration (it sums the information from many neurons) |
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what are the disadvantages of chemical synapses? |
they are relatively slower |
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- voltage-gated calcium channels open when the axon terminal is depolarized, which occursupon arrival of an action potential at the axon terminal - When the calcium channels open, they allow calcium to flow down its electrochemical gradient into the axon terminal, thereby increasing the concentration of cytosolic calcium inthe axon terminal - Calcium then causes the membranes of synapticvesicles to fuse with vesicle attachment sites on the inner surfaceof the axon terminal membrane and release the neurotransmitters into the synaptic cleft - the concentration of neurotransmitter in the synaptic cleft increases as thefrequency of action potentials increases - Once in the synaptic cleft, neurotransmitter molecules diffuseaway from the axon terminal and toward the postsynaptic neuron, where they bind to receptorsinducing a response in the postsynaptic neuron - a number of processes quickly clear the neurotransmitter from the cleft, thereby terminating the signa. Some neurotransmitter molecules are degraded by enzyme, other neurotransmitter molecules can be activelytransported bacl into the presynaptic neuron that released them,a process known as reuptake |
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what kind of receptors are there at in the signal transduction of chemical synapses? |
1) channel-linked (ionotropic) receptors: neurotransmitter binding causes fast change in Vm. The channel returns to its resting state as soon as neurotransmitter leaves 2) G-protein coupled (metabotropic) receptors: they are slow acting |
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what are postsynaptic potentials? |
a type of graded potential. Can either be excitatory PSP (EPSP) or inhibitory PSP (IPSP). |
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Fast responses at a channel-linked receptor, shows the opening of the ion channel by the binding of neurotransmitterto receptor.The neurotransmitter binding opens/closes the channel directly and ion flux makes a graded potential resulting depolarization is called fast PSP |
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is there a larger electrochemical driving force of Na or K in a typical EPSP? |
the membrane potential is close to Ek so there will be less push for it to go (it is closer to equilibrium) . Na therefore will have a greater driving force |
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Slow responses, in which the neurotransmitter receptor iscoupled to a G protein. In the nervoussystem, G proteins can trigger either the opening or the closing ofion channels, depending on the specific synapse. |
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there is also 2nd messengers |
in this case the metabotropic receptor activated G protein, activates or inhibits enzyme, which produces a secondary messenger which then goes on to open/close ion channels (and other cell responses) |
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Closing K+ channels results in K+ having less influence on Vm, so other leakconductances (e.g. Na ) have a greater relative influence of Vm and the membrane depolarizes |
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explain the inhibitory role of GABA in the CNS (fast inhibitory response) |
GABA is released at inhibitory synapses in the CNS. The receptors are channel linked and permeable to Cl-. GABA binding to the receptors causes the hyper-polarization of the post-synaptic membrane as Cl enters. It reduces the probability that an action potential will fire in the post-synaptic cell. |
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what are three mechanisms that affect neurotransmitter release? |
1) action potential frequency in the presynaptic neuron (superthreshold stimuli increase AP frequency, and so does [ca] in axon terminal, so there is more neurtransmitter release 2) autoreceptors: on presynaptic membrane may promote or inhibit neurotransmitter release from the presynaptic terminal 3) presynaptic facilitation or inhibition: neurotransmitter release by anoaxonic synapses (modulary synapses) |
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what does a sensory unit comprise of? |
a single afferent neuron and all the receptors with which it is associated |
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what is the receptor potential? |
the graded potential produced by the stimulus in a sensory receptor |
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sensors adapt over time |
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what are second order interneurons? |
they are in the CNS and integrate signals from many afferent neurons (convergence) |
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where do all sensory signals typically end up? |
the thalamus, them major relay for sensory input |
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differentiate between dorsal and ventral roots? |
efferent neurons have cell bodies in the grey matter and their axons leave the spinal cord via ventral roots. the afferent axons enter the grey matter of the spinal cord via dorsal roots with cell bodies in the dorsal root ganglia |
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what five components make a reflex arc? |
1) sensory receptor 2)afferent neuron 3) integration centre 4) efferent neuron 5) effector organ |
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what is unique about the patellar tendon stretch reflex? |
it is the only monosynaptic reflex in the human body |
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what parts of the patellar tendon stretch reflex is considered excitatory and inhibitory? |
excitatory: connection with efferent neurons to the quads inhibitory: connection with afferent neurons to the hamstring ** contraction of the quads and relaxation of the hamstring shortens the quad muscle |
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which receptor detect temperature change in the skin? tissue damaging temperature change? |
the thermoreceptors sense skin temperature in the normal physiological range for skin, and the noniceptors detect tissue damaging temperatures |
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what is the autonomic nervous system? |
part of the PNS, it controls areas are located in the brainstem and hypothalamus |
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differentiate between the sympathetic and the parasympathetic nervous system |
the SNS is active during periods of excitation or physical activity, it has a big influence on the cardiovascular system. Is in all areas of spinal chord. the PSNS is active during periods of rest, stimulates the digestive systems and inhibits cardiovascular. mostly generates from the cranial nerves |
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the preganglionic fibers have acell body int he spinal chord. There are thinly myelinated axon projects to the autonomic ganglia. In PSNS it is at the target organ and in SNS it is next to the vertebral column the post ganglionic fibres: the cell body is in the autonomic ganglia. There is unmyelinated axon projects to the visceral effector organ |
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differentiate between pre and post ganglionic neirons in the PSNS |
the pre ganglionic neurons pass uninterupted to the target organ the post ganglionic neurons are short and innervate the target tissue |
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describe the PSNS Acetal Choline (ACh) receptors |
there is the nicotinic receptors which are ionotropic expressed by all post ganglionic neurons there is also the muscarinic which are metabolic receptors expressed at the effector organ |
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differentiate between pre and post ganglionic nerves in the SNS |
the pre ganglions exit the spinal chord and synapse with the post ganglion neuron in a ganglia within the sympathetic chain. The post ganglionic fibres leaves the chain to innervate the target tissue. Transmitter is usually norepinephrine |
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explain how the SNS can also regulate the adrenal gland |
the neurons can travel to the adrenal gland and apinephrine will be released into the blood stream - it doesnt initiate and action potential |
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what are two classes of adrenergic receptors |
1) alpha adrenergic receptors (a1 and a2 subclasses) 2) beta adrenergic receptors (b1, b2, b3) subclasses |
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in the ANS how do synapses between post ganglionic neurons and effector organs differ from neuron-neuron synapses? |
the axons terminate as branches with spellings called variscocities. When an action potential is spreading the varcosities are like a synapse and it leads to an influx of calcium continues on and releases neuro transmitters at a different site -- has a broader range |
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differentiate between skeletal muscle, smooth muscle, cardiac muscle |
skeletal muscle: connected to at least 2 bones smooth muscle: no striations. found in blood vessels, GI tract, and uterus cardiac muscle: show characteristic of both skeletal and smooth muscle |
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what is the structure of the skeletal muscles? |
they are usually wrapped in connected tissue (epimysium). Made up of muscle fibers. They are further put into bundles by additional connective tissue perimysium and endomysium |
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what contains the contractile machinery in muscle |
the myofibrils |
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where are the mitochondria situated in muscle cells? |
the subsarcolemmal which is next to the sarcolemma the intermyofibrillar is interspersed with myofibrils |
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why are skeletal muscle striated? |
because of the arrangement of thick and thin filaments in myofibrils |
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what anchors the thin fillaments in sarcomeres? |
the Z-lines |
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where are thick filaments joined? |
the M-line (myosin) |
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what is an H zone? |
region between opposing ends of thin filament |
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differentiate between G-actin and F-actin |
G-actin (globular) has myosin binding site, where thick filamin are.. it binds together to form F-actin (fibrous protein) |
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What is tropomyosin? |
small strands, spans over multiple G actin molecules when the muscle is relaxed |
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what is troponin? |
it regulates the location of tropomyosin (in response to ca during muscle contraction) |
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what composes the thick filaments? |
myosin protein (which has ATPase and actin binding site) |
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describe the myosin protein |
it is a dimer of 2 inter-wined subunits |
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know a thing |
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what is the synapse in the muscle fibre called? |
the neuromuscular juction |
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what are nicotinic receptors? |
ionotropic cationchannels that open and allow Na+inux when ACh binds, which causes a VERY large end-plate potential |
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true or false? an action potential in the motor neuron always generates an action potential in the muscle |
true |
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how do hummingbirds muscles function at such high speeds? |
there is an increase in motor units.. you get the same number of spikes per burst until you reach maximum capacity, the stroke amplitude continues to increase (angle changes to conpensate for output), the fast oxidative fibers are aerobic, important to be able to fly for extended periods of time. They need to be oxydative. |
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how do mice survive in might altitudes? |
high altitude hypoxia acclimation in ancestors increases aerobic capacity in hypoxia, there are a lot more capillaries. There is also more high and low oxidative fibres.. high altitude would have more mitochondria that are around cell membrane advantage of subsarcho mitochondira: they are closer to capilarries reduces the space oxygen has to travel but they are further away from the contractile proteins so the ATP would have to travel furtur distance |
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how do fish survive in cold? |
the fish that were acclimated to winter temperatures, the number of capilaries per fibres goes up. The amount of oxygen that goes to these fibers increases. there is also an increase in mitochondria for the winter fish. This increases aerobic capacity so they can bring in oxygen even if temperatures are dropping. |
