Animal Physiology Exam 1
Control System
Uses information from sensors to determine nervous or endocrine signals sent to effectors that can modify a controlled variable
Repolarization (re-establishing difference in charge across a membrane)
Voltage gated Na+ channel inactivates and K+ flows out loosing positive charge it results in the falling phase or______________.
continuous conduction
What type of conduction takes place in unmyelinated axons
Metabotropic receptors
Which type of receptor proteins are most commonly associated with the formation of second messenger molecules? These are slower G-protein coupled receptors *Slower because they must first activate a g-protein before going to the ion channels*.
Sensitization
____________: enhancement of response after a second novel or noxious stimulus from increased open calcium channels and more neurotransmitter release. (increasing calcium channels open having to strong of response)
Habituation (aplysia gill withdraw)
______________ : decreased response after repeated stimulation from fewer open calcium channels and less neurotransmitter release. (less calcium channel activated--less neurotransmitter release)
Ach Glutamate
______________ usually excitatory acting on sodium and potassium channels as well as _______________ the main neurotransmitter in CNS that creates EPSP)
Local Potential
a potential at a specific region
capacitance
ability to store voltage (creates lag time when measuring current)
Receptor
A molecule that binds with a specific signal molecule initiating a change in cell membrane permeability or cell metabolism.
vesicle exocytosis (From last picture)
(1) An action potential depolarizes the axon terminal of the motor neuron. (2) The depolarization opens voltage-gated Ca2+ channels. (3) Depolarization of the terminal triggers ____________________ at an active zone, *releasing acetylcholine* (ACh). (4) ACh diffuses rapidly across the synaptic cleft and binds to acetylcholine receptors at the postsynaptic membrane. (5) The receptor channel opens to allow Na+ and K+ ion flow, producing a depolarizing excitatory postsynaptic potential (EPSP). The EPSP spreads to depolarize nearby regions to threshold and triggers a muscle fiber action potential. (6) *The action potential propagates to all parts of the muscle fiber, eliciting contraction*. (7) Acetylcholinesterase hydrolyzes the acetylcholine into acetate and choline. (8) Choline is actively transported back into the motor axon terminal to be resynthesized into acetylcholine.
voltage gated Ca2+ (review the picture, know the steps!)
(A) A presynaptic action potential depolarizes the axon terminal and *opens* ______________ channels located near active zones. (B) Ca2+ ions enter the terminal and induce vesicles at the active zones (indicated by triangles on the membrane) to fuse with the presynaptic membrane and release neurotransmitter by exocytosis. Neurotransmitter molecules diffuse across the synaptic cleft and bind to postsynaptic receptor proteins. (C) Ionotropic neurotransmitter receptors open ion channels, creating an ionic current that changes the postsynaptic cell's membrane potential. In this example, Na+ influx would cause depolarization. (D) Metabotropic receptors activate a metabolic cascade in the postsynaptic cell. Metabotropic receptors are G protein-coupled receptors (GPCRs) that activate G proteins to produce a second messenger such as cyclic AMP (cAMP).
A) low B) Na+ out, K+ in C) Na+-K+ exchange pump
(A) All cells maintain _______ intracellular concentrations of Na+ and Cl- and high concentrations of K+ and nonpermeating anions (A-) within intracellular fluids, relative to extracellular fluid. (Symbol sizes represent relative concentrations.) (B) An active sodium-potassium exchange pump transports ______ out and ______ in, counteracting the tendency of Na+ to diffuse in and K+ to diffuse out. (C) Here the Na+ and K+ concentrations are maintained in a steady state across the membrane. The slow, passive leaks of Na+ and K+ (dashed arrows) are counteracted by active transport by the ________________ (solid arrows). Chloride, in contrast, can be at passive equilibrium in some cells.
mobilization docking priming exocytotic fusion endocytosis classical kiss-and-run
(A) Synaptic vesicles cycle though several steps: (1) _________________ (also called targeting); (2) _____________; (3) ____________; (4) _______________; and (5) _________________. Endocytotic vesicles may have to fuse with an inner membrane compartment, the endosome, before budding off as synaptic vesicles again. (B) After synaptic vesicles fuse with the presynaptic membrane and undergo exocytosis, at least two different sorts of pathways can retrieve the vesicular membrane. In the(6) ______________ pathway, after complete fusion with the presynaptic membrane, the vesicular membrane is retrieved by endocytosis of clathrin-coated pits into endocytotic vesicles. This process selectively aggregates specific vesicle components and occurs away from the active zone. In the (7)______________ pathway, synaptic vesicles fuse transiently to the presynaptic membrane. They discharge their transmitter at a fusion pore and then are retrieved without having been fully integrated into the presynaptic membrane.
-acetylcholine (ACh). -Epinephrine (adrenaline) -Neurotransmitter, Neuromodulator -True
-Cholinerhic refers to ________ -Adrenergic refers to ___________ -Neurons may secrete more than one signal molecule. -_________________ and - ________________ -Most neurotransmitters affect more than one type of receptor eliciting different effects (true or false)
Generator potential (graded potential)
-Sensory receptor is also the primary afferent neuron. -Change in membrane potential spreads along membrane
G proteins
A GPCR has seven membrane-spanning segments (TM1-7) (shown pictorially on the left and lined up on the right). Several of the intracellular loops can interact with_______________. Neurotransmitter-binding sites are part of the membrane-spanning segments of the receptors for most small-molecule transmitters.
Oligodendrocyte (remember, in the CNS!) there are 4 types of glial cells (when these function insufficiently at myelinating these CNS axons, this may cause multiple sclerosis in humans)
A glial cell that holds nerve fibers together and produces the myelin sheath around axons in the central nervous system
the movement of positively charged atoms in and out of channels in the axon's membrane.
A neural impulse; a brief electrical charge that travels down an axon AKA, Action potential, is generated by what?
1. is present in the presynaptic terminal 2. is released upon presynaptic stimulation 3. mimics the effects of presynaptic stimulation when added to extracellular fluids and 4. has a mechanism for removal
A signal molecule is a neurotransmitter if it meets what 4 requirements.
Action potential
A succession of changing potentials that move across a membrane
IPSP EPSP
ACh on heart (muscarinic) muscle releases what? ACh on Skeletal muscle releases what?
Removes acytelcholine (breaks down into acetate and choline, choline is absorbed and recycled)
ACh-ase does what?
Modality
Ability to distinguish one type of sensation from another.
Self Propogating
Action potentials are all or none and are ____________ once initiated
Chemical synapse
Advantages of ___________ synapse include: -Amplification of current flow by increasing the -quanta of neurotransmitter released -Excitatory or inhibitory signal -One way Current -Modifiable Synapse (milisec) (the *currents escape between neurons and do not enter the postsynaptic neuron*. Instead, *released molecules of neurotransmitter carry the signal across the synaptic cleft*.)
Electrical synapse
Advantages of ___________ synapses include: -Fast escape responses, Synchronous firing of neurons as in electric organs. (nanosec) (these have low-resistance pathways that allow currents to flow *directly between neurons*. Current flow through the low-resistance pathways of gap junctions electrically couples the neurons. If current is injected into one neuron, the depolarization (or hyperpolarization) spreads to another electrically coupled neuron, and the depolarization of one cell produces a smaller depolarization of the adjacent cell.)
Small molecule neurotransmitters and neuropeptides
Amines (glutamate, GABA, glycine), biogenic amines (ACh, E/NE serotonin, dopamine), peptide (>90). are examples of what?
nicotinic and muscarinic receptors Alpha and Beta receptors ionotropic receptors (direct or without secondary messenger)
Any single neuron may respond to several different neurotransmitters and neuromodulators Cholinergic receptors include what? Adrenergic receptors include what? Ligand gated include what?
K+
At -90 mV there is the same amount of _________ outside and inside.
Neurotransmitter is released
At the synapse what happens?
Stimulus--> Receptor --> Sensory (Afferent) Neuron --> interneuron (integration) --> Motor (Efferent) Neuron --> Effector
Describe the Neural Circuit when billie joe bob sammons decides that it would be a BRILLIANT idea to touch a stove top burner on high. (please note that the reasoning center of the brain is also the cerebral cortex responsible for sensation, assume that this seemingly brain damaged individual has a normal healthy brain, and list the path starting with stimulus)
Synapse
Cell to cell transmission at ___________, few cells stimulated, rapid response, short duration of signal, response intensity by frequency of signals.
Signal Molecules
Chemical messengers such as neurotransmitters and hormones that alter cellular activity after binding with a receptor.
Innervate
Competition between neurons to ______________ muscles during development
Neural plasticity.
Development, memory and learning depend on _________________. (repetition of a pathway strengthens the pathway for learning)
Open (K+ voltage gated channel is closed, K+ leak channel is open)
During Depolarizations the voltage gated Na+ channel is
Closed (however the LEAK channels are in fact open)
During resting membrane potential the voltage gated Na+ and K+ channels are
Excitatory Inhibitory
EPSP = IPSP=
Excitatory Postsynaptic Potential (toward threshold) Inhibitory Postsynaptic Potential (away from threshold)
EPSP means IPSP means?
Resting membrane potential (At rest the membrane is most permeable to K+, as represented by leakage channels that are always open) Depolarization (rising phase "sodium channel opens, influx of sodium")--> Repolarization (falling phase looses potassium, both K+ voltage gated and leak channels open Na+ channel inactivates)--> hyperpolarization (undershoot, due to V-gated K+ channels remaining open for a short time after an action potential -->upon which then Na+ channels recover from inactivation ready for opening by depolarization) leak channels remain open but are negligent due to more numerous voltage gated channels.
Explain the graph briefly (A) An action potential is a brief voltage change characterized by a rising phase that overshoots zero and a falling phase (repolarization) that may be followed by an after-hyperpolarization, or undershoot. (B) Recording action potentials in a squid giant axon, using a stimulating electrode (I) and a recording electrode (V1). (C) Responses of the axon to stimulating current pulses.
themselves activate ion channels, without a second messenger. ...can itself gate a potassium (K+) channel open. In this case the joined β and γ subunits activate the channel, rather than the more common activation by an α subunit.
G proteins can _________________ In this example of acetylcholine-mediated inhibition of vertebrate heart muscle fibers, a muscarinic acetylcholine receptor (a GPCR) activates a G protein, which... (on back)
cAMP
G-proteins can activate a transduction pathway using ____________
Inhibitory
Gaba or glycine utilizing Cl- ions results in __________ type CNS synapse
Schwann cell ( remember, in the Peripheral nervous system!) (no billie joe bob sammons, the myelin sheath is not made of foam board , its made of fats insulating the axon of a neuron increasing the speed of action potential transmissions in a saltatory or "jumping" fashion... skip to my loo my impulse)
Glial cells that are located in the peripheral nervous system and that form the myelin sheath around the axon of a neuron are called....
Astrocyte (certain drugs as well as alcohol and nicotine, in billie joe bob sammons case, can cross this barrier, upon which can be used for a positive effect medicinally, but also a negative effect when you abuse alcohol or certain drugs. if you are like billie joe bob sammons you want to take the flood gates down...seeing as his are old and rickety due to the Ronald Reagan like wall destruction methods he is using.)
Gliall cells that absorb signal molecules and have paravascular feet that cover blood vessles and the surface of the capillary creating a filter on the capillary wall protecting the brain (blood brain barrier) also known as metabolic support cells in the CNS.
Remain open
Inactivation of K+ channels allow calcium channels to __________
K+ negative
Loss of _____ creates a net ____________ charge *inside* the cell membrane. (selective permeability causes a net charge separation to develop at the membrane)
GPCRs (A) Three (B) GDP (C) Activated Receptor (D)
Metabotropic receptors: cAMP as a second messenger Some neurotransmitters act via (A)________ to alter cellular metabolism, rather than via ligand-gated channels. In this example, norepinephrine binds to (A) __________ (1) to activate a G protein (2). The G protein has (B)__________ subunits; when the protein is inactive, the α subunit binds (C)________. The G protein is activated when it encounters an ___________________ (D); it exchanges the GDP for a GTP, and the α subunit dissociates from the joined β and γ subunits. The α subunit in turn activates the enzyme adenylyl cyclase (3). Adenylyl cyclase catalyzes the conversion of ATP to the second messenger cAMP. Cyclic AMP activates a protein kinase (4), which phosphorylates proteins to activate or inactivate them. Cyclic AMP-dependent protein kinase can phosphorylate membrane proteins (5), which can indirectly gate them open or closed. The kinase can also phosphorylate cytoplasmic proteins (such as metabolic enzymes) (6) and nuclear proteins that regulate gene expression (7). Thus neurotransmitter binding can have widespread, long-lasting effects on postsynaptic cells.
current (the further from the current source the greater loss of voltage)
Net movement of charges
Dye-coupled
Neurons electrically connected by gap junctions are said to be ___________________, because low-molecular-weight dyes pass through the gap junctions to the coupled cells.
Acetylcholine
Neurotransmitter that produces an impulse in a muscle cell (binds to ion receptors causing more positive charge into the cell causing depolarization).
removed Enzymatic degradation Re-uptake of components (absorption by presynaptic neuron "takesies backsies") Recycling of whole molecules Diffusion Absorption by glial cells
Neurotrasmitters are _______ from the synapse to prevent long term stimulation. by what means? (5 means)
saltatory conduction
Rapid transmission of a nerve impulse along an axon, resulting from the action potential jumping from one node of Ranvier to another, skipping the myelin-sheathed regions of membrane.
1) Are specific to a stimulus (light, heat, mechanical, chemical) 2) Vary in sensitivity 3) act as transducers (ionotropic -stimulus triggers channels to open by direct action, Metabotropic - stimulant triggers channels to open via a secondary messenger)
Receptors have 3 important characteristics. name them.
Observe Nerons
Red dots are signaling molecules: neurotransmitter molecules in (A) and hormone molecules in (B). (A) Neurons have long axons that rapidly propagate action potentials, and also use short-distance chemical neurotransmitter signaling to communicate from cell to cell. (B) Endocrine cells release chemical hormones into circulatory fluids that carry the hormonal message over long distances to activate hormone receptors on other cells.
Resting Membrane Potential (RMP) (inside cell membrane is -90mV net charge)
Reflects a net Difference in charge across a cell membrane.
Increases receptors
Repeated stimulation ________ _______ and synaptic growth. (more branches on dendrites to increase surface area)
hippocampus
Repeated stimuli at glutamate receptors in the ____________________ can result in a more successful synapses.
observe read between the lines
Several proteins function in transmitter release from synaptic vesicles. SNARE proteins include synaptobrevin (a v-SNARE, vesicle-associated protein); and the t-SNAREs syntaxin and SNAP-25, which are attached to the terminal membrane. (A) A vesicle docks at the active zone, allowing its v-SNAREs to interact reversibly with t-SNAREs. Syntaxin is held in a folded, inactive conformation by Munc18. (B) The vesicle is primed by the formation of a SNARE complex. Syntaxin is open and *the complex of v-SNAREs and t-SNAREs holds the vesicle at the release site. The cytoplasmic protein complexin stabilizes the complex. (C) The vesicle fuses. Ca2+ entry through voltage-gated Ca2+ channels triggers fusion by the binding of Ca2+ to the vesicular protein* synaptotagmin. The *Ca2+*-synaptotagmin *complex binds to the SNARE complex, displacing complexin and inducing pore formation*.
inactive protein kinase (activated by cAMP to phosphorylate protein to activate or inactivate)
Some neurotransmitters act via GPCRs to alter cellular metabolism, rather than via ligand-gated channels. In this example, norepinephrine binds to a GPCR (1) to activate a G protein (2). The G protein has three subunits; when the protein is ___________, the α subunit binds GDP. The G protein is activated when it encounters an activated receptor; it exchanges the GDP for a GTP, and *the α subunit dissociates from the joined β and γ subunits. The α subunit in turn activates the enzyme adenylyl cyclase (3). Adenylyl cyclase catalyzes the conversion of ATP to the second messenger cAMP*. *Cyclic AMP activates a* _______________ (4), which phosphorylates proteins to activate or inactivate them. Cyclic AMP-dependent protein kinase can phosphorylate membrane proteins (5), which can indirectly gate them open or closed. The kinase can also phosphorylate cytoplasmic proteins (such as metabolic enzymes) (6) and nuclear proteins that regulate gene expression (7). Thus neurotransmitter binding can have widespread, long-lasting effects on postsynaptic cells.
temporal summation (Both EPSPs and IPSPs can summate with other postsynaptic potentials of the same pathway (temporal summation) or a different pathway (spatial summation)).
Stimulating over time Summation by a postsynaptic cell of input (EPSPs or IPSPs in same pathway) from a single source over time.
Temporal summation
Stimulus at a local point over a period of time. (usually multiple stimulations across a point to the target, in contrast to spacial where there are multiple points stimulating )
spatial summation
Stimulus of many receptors at once
Cell body
Synaptic input often occurs at the _________________ as well as the dendrites, for example, and some dendrites can generate action potentials. In contrast, some local neurons generate no action potentials at all, and thus lack a separate function of active conduction.
Observe
Temporal Vs. Spacial Summation
Nernst equation Goldman
The _____________ equation Relates membrane potential to the concentration ratio of only one ion species. The ________________ equation takes multiple ion species into consideration.
potential
The measure of the difference in charge (measured in voltage) the further from the current source the greater loss of voltage (decremental)
Threshold stimulus
The minimal strength in mV required to cause contraction; Once this mV is reached, an action potential is executed and the muscle will contract.
Homeostasis
The range of internal constancy that is maintained as a result of regulatory processes.
The target cell
The signal molecule is released Directly at __________________
ionotropic
The signal molecule will bind with an ion channel and directly effect the channel causing it to open (FAST signal transmission) *Ligand-gated receptor* being a ____________ receptor
Integration
The summation and coordination of body functions to maintain homeostasis.
Hormone (for both)
Transmission in body fluids, most body cells exposed to signal, slow response, long duration, response intensity dependent on amount of ___________ The endocrine system releases ___________ carried in body fluids
Neuromuscular junctions (NMJ) (The postsynaptic muscle fiber membrane is deeply infolded, and these junctional folds contain ligand-gated acetylcholine (ACh) receptors at the upper parts of the fold. Voltage-gated channels are absent at the tops of the folds but are present deep in the folds and at the nonjunctional membrane. A basal lamina of extracellular, secreted proteins covers the muscle fiber.)
The synapse between a motor neuron and a muscle cell. At the _________, the muscle cell membrane is invaginated and the axon terminus is elongated so that a greater area of membrane can be depolarized at one time. (consists of a single presynaptic motor neuron contacting a single postsynaptic skeletal-muscle fiber)
Synaptic cleft (again, this is a very large distance for billie joe bob sammons because well, you know, he makes zero connections there is a nobel prize in it for anyone who can figure out how he is even alive)
The tiny gap between the terminal of one neuron and the dendrites of another neuron (almost never touch); is the location of the transfer of an impulse from one neuron to the next. (The cellular structure of a vertebrate neuron)
relative refractory period or RRP absolute refractory period or ARP
The undershoot phase is where the mV drops below the RMP into the _________________________ period (further from threshold making it harder to stimulate, however activation gate is closed and ready and i believe the leak channels remaining open helps to stabilize this). Below this period is the __________________ period (impossible to start a new impulse is not reset due to being to far away from threshold being a very high difference in charge across the membrane ). (recovery periods)
K+ Na+ (more potassium inside neuron, more sodium outside)
There are more ________ leak channels than ______ leak channels
Metabotropic (Think G-protein coupled receptors) (Metabotropic receptors activate a metabolic cascade in the postsynaptic cell. Metabotropic receptors are G protein-coupled receptors (GPCRs) that activate G proteins to produce a second messenger such as cyclic AMP (cAMP))
This is a slow type of synapse. when neurotransmitters act via GPCRs to alter cellular metabolism resulting in (for example) the activation of a G-protein that can activate a transduction pathway using cAMP. Can open an ion channel or activate enzymes inside cell changing activity or protein syntheses.
Mechanoreceptor
This receptor type is sensitive to touch, pressure, proprioception whose *mechanism of transduction is ionotropic*. Transform mechanical stimuli into electrical signals. All organisms (and most cells sense and respond to mechanical stimuli. There are two main type of proteins associated.
Vestibular receptors
This type of receptor is sensitive to balance, body position and movement whose mechanism of transduction is *ionotrophic*
proprioceptor
This type of receptor is used for detection of body position and movement. (localization)
SSRI selective serotonin re-uptake inhibitor
class of drugs used to relieve anxiety by limiting re-uptake of a neurotransmitter
depolarize
decreasing difference in charge across membrane
hyperpolarize
greater than normal difference in charge
ganglia (these are like mini-brains, upon which i believe may be the full extent of billie joe bob sammons capacity for thought processing)
groups of nerve cell bodies that coordinate incoming and outgoing nerve signals are _________ (Observe)
Synapse
junction between a pre-synaptic cell and post synaptic cell (between neurons or cells) effects muscles or glands.
resistance (yes billie joe bob sammons, you can have too much resistance, this may be a grain of sand in respect to the vast beach containing the rest of your issues)
limits current
Nervous or Endocrine
most organisms can be controlled by the ______________ or ___________ system
Chemical signal
neurotransmitters release results in releasing a type of __________________ in pre-synaptic cell for the post-synaptic cell to respond given correct receptors.
spatial summation *
opening up several channels at the same time
Microglial cell (these are phagocytes related to the cells in the immune system)
phagocytic glial cell that removes waste products from the central nervous system
RMP, action potential, equilibrium (basically charged nature by means of concentration of ions into and out of the cell to make the processes work. proteins being negatively charged is what brings about the higher concentration of K+ in the cell at RMP as well as there being more K+ leak channels that K+ flows into and out of, this negative net charge inside the axon greatly influences the electrostatic force necessary for its function and regulatory maintenance ).
pumps maintain what?
repolarize
re-establishing a difference in charge
depolarization (decreasing difference in charge in membrane)
rising phase where sodium goes into the cell
electrotonic current (or electrotonic conduction)
spreading of the current, -for example, Nonspiking neurons do not encode graded potentials into action potentials; instead the graded potentials spread to the axon terminal. If the axon is short relative to its membrane length constant, the amplitude of the graded potential will be sufficient to evoke graded neurotransmitter release. -This decremental spread of graded potentials is an example of this.
Motor Endplate
the sarcolemmal surface which contains membrane receptors that bind ACH (acetylcholine)
Ionotropic receptor
type of neurotransmitter receptor where binding site [+] ion channel = in same protein. A ligand-gated channel. In absence of neurotransmitter (the ligand), the ion channel component of "this" is closed. When correct neurotransmitter binds to the ___________________, the ion channel opens+ an EPSP or IPSP occurs in postsynaptic cell. This occurs fastest
Action potential starts
what happens at the axon hillock
polarized
when something exhibits a difference in charge between 2 regions it is what?
