nn
In what direction does local current flow with an IPSP in the post-synaptic cell?
Away from axon hillock, since the positive charges would be attracted away from the axon hillock and towards the incoming anions entering the ligand-gated channels.
What direction does local current flow in the postsynaptic cell in regards to the synaptic cleft with an EPSP?
Away from synaptic cleft in postsynaptic cell. This helps summate at axon hillock.
What molecules typically use simple diffusion?
Nonpolar molecules like O2, CO2, fatty acids.
Facilitated diffusion
NO ATP, pre-existing concentration gradient of solute to move large polar hydrophilic molecules into cell through the proteins. <br><br>Ex: glucose is immediately turned into glucose-6-phosphate in glycolysis in cells, so there is always a glucose concentration gradient that allows facilitated diffusion.
What regulates intracellular fluid and what regulates extracellular fluid?
Na+/K+ ATPase = intracellular, Kidneys = extracellular
(T/F) Unmyelinated excitable membranes allow fast action-potential propagation
False. Slower than myelinated.
(T/F) Action potentials has a threshold usually about 25 mV depolarized relative to resting potential
False<br><br>15mV depolarized to get -55mV
Channel-mediated diffusion
Ion channels, linear flux.
External environment separated by epithelial layer includes...
"1. Surroundings external to skin<br>2. Air in lungs<br>3. Food in <span style=""color: rgb(0, 0, 0); background-color: rgb(255, 255, 0);"">stomach and intestines</span><br>4. Urine in bladder<br><br>Note: Most cells have no direct exchange with external environment!"
PLA<sub>2</sub>-ARA Cascade
"<img src=""paste-0d17f088eb2bd01ab61410f1253c1ea64b55995f.jpg"">"
Synaptic transmission: Electrical Synapse<br><br>Draw a diagram<br><br>What type of junction helps conduct electrical signals directly from cell to cell in a FAST way?<br><br>Where are these electrical synapses found?
"<img src=""paste-1b8bf668c6461e97878724b05c868889bbf221e2.jpg"">"
Explain and draw neuronal divergence
"<img src=""paste-7057239e5b132a33ef75a5f5d652aa8c81c15a50.jpg"">"
What molecules typically use Channel-mediated diffusion?
Ions
What molecules typically use primary active transport?
Ions
"What is Ohm's Law as used in our physiology class? Describe each variable or set of variables."
"<img src=""paste-954594c86f6c23d083d50dcf30c33cf298377543.jpg""><br><br>I<sub>ion</sub> = current of the ion, amount of ion flux<br><br>g<sub>ion</sub> = conductance, whether or not ion can get across membrane, # of channels open for the ion.<br><br>V<sub>m </sub>= resting membrane potential<br><br>E<sub>ion</sub> = equilibrium potential of ion<br><br>(V<sub>m </sub>* E<sub>ion</sub>) = Enthusiasm to move thru a channel"
Voltage-gated K+ channels, reproduce negative feedback loop.
"<img src=""paste-9ebb04e58ce96c7a70fafdf4643e1f6893b0d5f6.jpg""><br><br>Repolarization of membrane potential is done by having K+ leave the cell. This reduces the opening of voltage-gated K+ channels, and in turn reduces the amount of K+ leaving/reduces repolarization eventually so we don't get too negative. "
Basic diagram of CNS and PNS neurons
"<img src=""paste-b0bf065137771b5916c3da9023e123d2bce58a3f.jpg"">"
Explain and draw neuronal convergence
"<img src=""paste-db2e1466fa1a35bd509860e9991a8ea1d4c93297.jpg"">"
Draw action potentials on a graph with related stimuli strength graph. Define the absolute and relative refractory periods. Describe an <br>experiment you could use to determine those periods.
"<img src=""paste-e2b87d2fc206474af1f7a6bdc449ff96529c9c63.jpg"">"
Voltage-gated Na+ channels, reproduce positive feedback loop.
"<img src=""paste-f240bb7afb4573dd6e005f2d3d6e9006f61716c4.jpg"">"
Synaptic Transmission: Chemical<br><br>Draw and label a diagram <br><br>Pre-synaptic axon terminals can go to... (3 possible locations)
"<img src=""paste-f9f09c068e5f70f20f15921c85b0ca2499bfe365.jpg"">"
Four properties of action potentials...
"<ol><li>All or none</li><li>Not graded by stimulus size</li><li>Cannot summate due to refractory period</li><li>Doesn't decrease with distance</li></ol>"
Four ways chemical synaptic strength can be modulated
"<ol><li>Pre-synaptic facilitation/inhibition (""the advisor to the monarchy"")</li><li>Neuromodulators (small peptides co-released with N.T that activate 2ndary messengers at non-synaptic receptors(usually metabotropic receptors on pre and post synaptic cells) to modify effectiveness of the synapse at transmitting a signal. Example: histamine co-released with N.T and binds to metabotropic receptors that triggers glutamate release(makes u awake). Thus anti-histamines prevents histamine release and thus no glutamate release and thus u become sleepy. </li><li> Persistence of N.Ts = densitization when N.T stays too long in cleft</li><li>Long Term-potentiation is mechanism of learning and memory. AMPA receptors are part of short-term memory. NMDA receptors are part of long-term memory. Mg2+ ion is stuck in NMDA receptors until a strong enough depolarization forces Mg2+ out of the pore. This allows long-term pathways to form. NOTE: Even one drink of alcohol can impair long-term learning </li></ol>"
Draw graph of subthreshold, threshold, and suprathreshold stimuli in relation to membrane potential graph with action potentials. <br><br>What assumptions are made?
"Assumptions are that the membrane is not refractory AND Na+ and K+ concentrations do not change.<br><br>Suprathreshold potentials increase frequency of action potentials, but they DO NOT increase size. <br><br><img src=""paste-9eeff222fe75ad4ef07227ed6af0635e563f5123.jpg"">"
Dysfunctional basal nuclei results in what kind of major known disease?
"Parkinson's syndrome"
Function of basal nuclei in brain?
"Participate in coordination of <b>skeletal muscle</b> activity, <b>limbic</b> system, help generate <b>emotions</b> and emotional behavior, some aspects of <span style=""background-color: rgb(255, 170, 0);""><b>learning</b></span>."
Draw covalent modulation
"Should have protein kinase phosphorylate the receptor using ATP, PO<sub>4</sub><sup>2- </sup>group is attached, reversible via phosphoprotein phosphatase (""take away"") that removes the phosphate group to return receptor to original conformation."
Nervous System Cells (2 types)
1. 1/2 are Neurons (Inter, Aff, Eff)<br><br>2. 1/2 are Glial cells <br><ul><li>Microglial = remove debris, scavengers</li><li>Oligodendrocytes (1:40) (CNS) = make myelin</li><li>Schwann cells (1:1) (PNS) = make myelin</li><li>Astrocyte = Regulate ECF, blood-brain barrier</li><li>Ependymal = Line fluid cavities, make cerebralspinal fluid</li></ul>
Five important generalizations about homeostatic control systems.
1. Control mechanisms try to balance input/output<br>2. Neg. feedback towards typical value<br>3. Range of typical values<br>4. Set points can be reset up or down<br>5. Conflicts arise
Extracellular fluid K+ and Na+ concentrations
145mM Na+<br>5mM K+
Intracellular fluid K+ and Na+ concentrations
150mM K+<br>15mM Na+
Sodium-Potassium ATPase; How many Na+ and how many K+ in?
3 Na+ out, 2 K+ in.
Order of Pre-synaptic events starting from axon hillock.
<ol><li>A.P propagates to terminal</li><li>Ca<sup>2+ </sup>voltage gated channels open</li><li>Ca<sup>2+ </sup>enters axon terminal</li><li>Ca<sup>2+ </sup>activates vesicle exocytosis by binding to synaptotagmin (a SNARE protein)</li><li>SNARE complex draws vesicle to plasma membrane for fusion and exocytosis</li><li>Vesicle membrane is recycled via endocytosis</li><li>Neurotransmitter released and diffuses across tiny gap (15nm) or a.k.a cleft</li></ol>
Postsynaptic events at inhibitory synapses order... starting with presynaptic A.P
<ol><li>A.P reaches axon terminal</li><li>Voltage-gated Ca2+ channels open and Ca2+ enters</li><li>N.T released via exocytosis(Ca2+ binds to synaptotagmin and triggers SNARE complex) and diffuses across cleft </li><li>N.T binds to receptor/ligand-gated channels/ionotropic receptors</li><li>K+ leaves post-synaptic cell and/or Cl- enters post-synaptic cell</li><li>If post-synaptic cell has Cl- pumps then even more Cl- enters post-synaptic cell and further polarizes its resting potential below -70mV(type 2 cell). If no pump then resting potential stays at resting 70mV (type 1 cell). Regardless type 1 or type 2, Cl- is always inhibitory for our class. If any cation channels open, like Na+, Cl- would negate any excitation.</li><li> N.T unbinds after a short binding period, removed from cleft shortly after.</li></ol>
Postsynaptic events at synaptic clefts
<ol><li>Neurotransmitter binds to postsynaptic receptors(ligand-gated ion channels a.k.a ionotropic receptors) and unbinds quickly</li><li>Before N.T unbinds, cations like calcium or sodium flow through</li><li>Neurotransmitter removed from synaptic cleft</li></ol>
Show/draw how the five components of a negative feedback system sense and <br>respond to a deviation from normal.
<u><b>Stimulus</b></u> --> <u><b>Receptor</b></u> --(Afferent pathway)--> <u><b>Integrating center</b></u> --(Efferent pathway)--> <u><b>Effector</b></u> --> <b><u>Response</u></b> --(Negative feedback)--> Stimulus
Three bullet points that define and describe positive feedback loops.
<ul><li>Causes rapid change in a variable</li><li>Further increase/reinforce change in variable</li><li>Requires terminating event</li></ul>
The brain has 3 main parts and subparts (along with subpart details)
<ul><li>Forebrain = <u>Cerebrum</u>(Frontal Lobe, Parietal Lobe, Occipital Lobe, Temporal Lobe), <u>Diencephalon</u>(Thalamus, Hypothalamus) </li></ul><ul><li>Brainstem = Midbrain, Pons, Medulla oblongata</li></ul><ul><li>Cerebellum </li></ul>
What are possible routes for N.Ts to take after release into the synaptic cleft?
<ul><li>Reuptake into pre-synaptic cleft</li><li>Diffuse away from synaptic cleft</li><li>Destruction via enzyme and reuptake of products</li></ul>
The net effect of EPSP depolarization is about how many mV per Neurotransmitter-Receptor complex?
About 0.5 mV per NT-R complex
About how many EPSPs must summate to get an A.P?
About 30
What part of the brain controls posture and balance?
Brain>cerebellum
basal nuclei is organized under what larger brain part categories?
Brain>forebrain>cerebrum>basal nuclei
Cerebral cortex is organized under what other larger brain part categories?
Brain>forebrain>cerebrum>cerebral cortex
Nervous system general layout (CNS, PNS)
CNS = Spine and brain<br><br>PNS<br><ul><li>Afferent = <b>Somatic sensory</b> (touch), <b>Visceral sensory</b> (organs), <b>Special sensory</b> (vision, smell, taste). </li><li>Efferent = <b>Somatic motor</b>(Conscious movement), <b>Autonomic motor</b> (Sympathetic, Parasympathetic, Enteric)</li></ul>
Use figure 1.1 and list the four levels of organization in the human body, from smallest to largest.
Cells, tissues, organs, organ systems
Ion channels are specific and gated via 3 ways...
Chemical, electrical, mechanical events
What is an antagonist?
Competitively binds receptor and prevents subsequent events.
What is an agonist?
Competitively binds receptor and triggers subsequent events. Mimics regular ligand.
Use figure 1.1 and list the four basic tissue and cell types.
Connective tissue (connective-tissue cell)<br>Epithelial tissue (epithelial cells)<br>Muscle tissue (muscle cells)<br>Nervous tissue (neurons)
Which does NOT have chemical specificity?<br><br>A. Primary Active Transport<br>B. Facilitated Diffusion<br>C. Secondary Active Transport<br>D. Simple Diffusion<br>E. Channel-mediated diffusion
D. Simple Diffusion
Draw and label a diagram that illustrates the major fluid compartments of the <br>body. With labels for each compartment, indicate the volumes in an average-sized person.
Extracellular fluid (ECF)<br><ul><li>Plasma (3L) = surrounds blood, in blood vessels</li><li>Interstitial fluid (ISF, 11L) = surrounds all other cells</li></ul><div>Intracellular fluid (ICF, 28L) </div>
(T/F) Action potentials decrease with distance
FALSE.<br><br>Action potentials DO NOT decrease with distance. They propagate over long distances, large local currents.
(T/F) Axon Hillock has least density of voltage-gated Na+ channels
FALSE<br><br>Axon Hillock has MOST density of v-gated Na+ channels. First site of action potentials.
4 Carrier-mediated transport types...
Facilitated diffusion - NO ATP and going DOWN concentration gradient powers conformation changes.<br><br>Primary active transport - YES ATP hydrolyzed to power conformation change and move solute against concentration gradient. When solute and ATP binds the ATP is NOT covalently bound. Releasing solute into or out of cell also releases phosphate group to reset everything. <br><br>Secondary active transport - NO ATP directly used, cotransport(symport) and countertransport(antiport) of solutes against solute concentration gradient, <b>ion concentration gradient</b> created by primary active transport protein powers this. <br><br><b>Channel-mediated diffusion</b> - NO ATP, linear ion flux into cell
(T/F) Graded potentials amplitudes increase with distance
False
(T/F) Graded potentials cannot be summed
False
(T/F) Graded potentials has a threshold
False
Define feed forward regulation. How is it different than negative feedback control? Describe some examples of when this occurs in the body.
Feed Forward Regulation (FFR) limits amount of change, but does not prevent change. Ensures change in variable is not too big.<br><br>Occurs BEFORE negative feedback.<br><br>Ex: <br>Skin temperature receptors anticipate core temp. change when entering new environment<br><br>Blood pressure and respiration changes prior to anticipated physical activity<br>
Brain forebrain cerebrum has 4 lobes. Define each of them and their functions
Frontal lobe = Reasoning logic, higher order thinking, executive decisions<br>-------------------<br>CENTRAL SULCUS = divides front and back of brain<br>-------------------<br>Parietal lobe = Sensory info from body arrives here and processed. Somatic sensations and processing.<br><br>Occipital lobe = Visual info arrives and processed<br><br>Temporal Lobe = Hearing, sounds arrive and processed
3 Levels of Affinity for Receptors and Ligands
High = Shape and Charge fit<br><br>Medium = Shape OR Charge fit<br><br>Low = NO Shape fit and NO Charge fit
Define and distinguish between four types of chemical messengers.
Hormones = from secreting gland cell into distant targets<br><br>Neurotransmitters = close targets like neuron or effector cell<br><br>Paracrine substance = released by a local cell and targets close neighbors<br><br>Autocrine substance = released by a cell and acts upon same cell.
Effects of IPSPs?
Hyperpolarizations or inhibition of further depolarization in cells without active Cl- pumps.
Draw a simplified body plan as we did in lecture. Differentiate between the external and internal environments. Include all the talking points presented during lecture.
Includes: Blood vessel loop with heart, digestive tract, basement membranes(structural support), lungs, kidneys, cells.<br><br>See notes.
"Fick's Law: <br><br>J = (P * A * ΔC * Temp) / (MW * ΔX)<br><br>Define each variable and their relationship (direct/inverse) to J"
J = (rate of diffusion of a solute across a membrane)<br><br>P = Permeability of solute<br>A = Area of membrane<br>ΔC = Concentration gradient across the membrane<br>MW = Molecular weight<br>ΔX = Distance the solute must diffuse, thickness or distance
Locate/describe basement membrane
Layered along epithelial cells on internal side. Structural support for inside of epithelial barrier. <br><br>Internal side is basolateral side. External side is apical side. <br><br>Made of collagen fibers, microfibrils, glycoproteins.
Secondary active transport
NO ATP directly, couples pre-existing concentration gradient of an ion for example to a solute for power, cotransport(symport) and countertransport(antiport) moves solute together with ion or in opposite directions. <br><br>Solute always moves against concentration gradient.
Hydrophilic solute entry into cell via ion channel order
Membrane receptor called ionatropic receptor, binding of ligand causes ion channel to open.
Hydrophilic solute entry into cell; PKA cascade order and effects
Metabotropic receptor, G(s) protein, adenylyl cylase stimulated, ATP turned into cAMP. cAMP tells cAMP dependent protein kinase to phosphorylate proteins/enzymes/pumps/ion channels/alter transcription factors, change organelle function, alter metabolism (lipid and/or glycogen breakdown).
Spatial summation means...
Multiple pre-synaptic inputs
What is it called when Na+ and K+ are maintained at a concentration, and ATP is used to keep Na+ and K+ fluxes equal
Steady State<br><br>NOT equilibrium.
Temporal summation means...
One pre-synaptic input only
The propagation of the action<br>potential from the axon hillock<br>region to the axon-terminal end<br>is typically _______ because the<br>absolute refractory period<br>follows along in the "wake"<br>of the moving action potential.
One way<br><br>Burned black powder = Ash=no ignition<br>All Voltage-gated Na Chs Inactivated
Brain forebrain cerebrum cerebral cortex has what function?
Perception and generation of skilled movements, reasoning, learning, memory
Hydrophobic signal molecules order of entry into cell
Plasma of capillary, interstitial fluid, plasma membrane of cell, nucleus, intracellular receptor in nucleus, alteration of DNA.
What molecules typically use secondary active transport?
Polar ones, amino acids, glucose, some ions
Hydrophilic solute entry into cell; PKC cascade order
Receptor, G(q) protein, Phospholipase C breaks down PIP<sub>2 </sub>(inner leaflet phospholipid) into IP<sub>3 </sub>(Head of PIP<sub>2</sub>), IP<sub>3 </sub>binds to IP<sub>3 </sub>receptors on endoplasmic reticulum, ER releases Ca<sup>2+</sup> and this triggers Protein Kinase C to phosphorylate proteins. <br><br>IP<sub>3 </sub>can also DIRECTLY cause Protein Kinase C to phosphorylate proteins.
What is it called when action potentials "jump" from one node of clustered Na+ channels to the next as they propagate along a myelinated axon.
Saltatorial Conduction
Draw allosteric modulation
Should have modulator molecule, reversible non-covalent change. Receptor reverts to original shape when modulator leaves.
Define functional unit as used in human physiology.
Smallest piece of organ retaining full function of organ
Brain forebrain diencephalon has ? parts. Define each of them and their functions
Thalamus = Relay station, switching/distributing station, like a router. Distribute signals that can go between brain regions (pass thru Thalamus) or info from spinal cord that need be sent to right part of brain. Info from brain also need pass thru Thalamus to reach periphery. Allows us to change our attention. <br><br>Hypothalamus = Master control center for homeostasis. Lots of set points in here.
(T/F) Action potentials are all or nothing
True
(T/F) Action potentials are conducted without decrement; the depolarization is amplified to a constant value at each point along the membrane
True
(T/F) Action potentials durations are constant for a given cell type under constant conditions
True
(T/F) Action potentials is only a depolarization
True
(T/F) Action potentials mechanisms depends on voltage-gated ion channels
True
(T/F) An EPSP is a graded potential that makes an A.P more likely.
True
(T/F) Graded potentials amplitudes vary with size of initiating event
True
(T/F) Graded potentials can be inititiated by environmental stimulus (receptor), neurotransmitter (synapse), or spontaneously.
True
(T/F) Graded potentials duration varies with initiating conditions
True
(T/F) Graded potentials mechanisms depends on ligand-gated ion channels or other chemical and physical changes
True
(T/F) N.T rapidly binds and unbinds receptors
True
(T/F) There are no Na+ channels under myelin nodes.
True
Brain brainstem function and parts
Unconscious life support like respiratory and cardiovascular control. <br><ul><li>Midbrain</li><li>Pons </li><li>Medulla oblongata </li></ul>
A few examples of positive feedback in the human body?
Upstroke of Action Potential<br><br>Blood clotting cascade<br><br>Childbirth
Potential Difference
Voltage difference between two points due to separated electrical charges of opposite time.
Primary active transport
YES ATP needed, move solute against concentration gradient. <br><br>Ex: sodium-potassium ATPase is part of primary active transport<br>NOTE: primary active transport does NOT have covalently bound ATP. This makes <b>primary active transport allosteric modulation</b> and NOT covalent modulation. <br><br>H+ pumps can form proton motive force.
Action potential velocity along axon increases with...
axon diameter. There is less resistance in cytoplasm at larger diameters.
Brain cerebellum function
motor control; skeletal muscles
"Pre-synaptic facilitation/inhibition (""the advisor to the monarchy"") does what?"
pre-synaptic Facilitation increases neurotransmitter release from Pre-synaptic terminal to post-synaptic cell. Both excitatory and inhibitory synapses are promoted.<br><br>pre-synaptic inhibition decreases N.T release from pre-synaptic terminal to post-synaptic cell. Both excitatory and inhibitory synapses are inhibited.
