Term
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Definition
metabolic function - vast S.A., controls glycogen breakdown
- agranular (synthesis of lipids) |
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Term
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Definition
- keeps cellular membrane intact
- processing center
- synthesis of CHO that can't be formed in ER |
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Term
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Definition
| help digest unwanted tissues |
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Term
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Definition
| - key to ETOH metabolism, men have more |
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Term
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Definition
means by which large particles enter a cell across membrane
- pinocytosis and phagocytosis |
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Term
|
Definition
- means by which most macromolecules (protein) enters cells
- vesicles formed by fibrillar proteins (clathrin, actin, myosin) |
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Term
|
Definition
- cell membrane reaches out and binds to bigger particles
- involves larger particles (bacteria, dead cells, tissue debris)
- cell membrane receptors bind to surface ligands of the particle, the membrane envaginates surrounding entire particle, forming a closed vesicle
- contractile fibrils push the vesicle to the interior, separating it from membrane |
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Term
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Definition
| the residual body is excreted through exocytosis |
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Term
|
Definition
- ameboid movement
- cilia and ciliary movements - found only in respiratory tract and fallopian tubes |
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Term
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Definition
| - composed of phosporic acid, deoxyribose, and nitrogenous bases (A, G, T, C) |
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Term
|
Definition
| building blocks - ribose and uracil, 4 nucleotides require activation |
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Term
|
Definition
| assembly of the RNA chain from activated numleotides using the DNA strand as a template |
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Term
|
Definition
1. mRNA - carry genetic code to the cytoplasm to dictate which protein will form.
2. tRNA - small nucleotide, specificity for a particular codon in mRNA to deliver the approp. AA.
3. rRNA - processed in the nucleolus and serves as immature subunits of ribosomes |
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Term
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Definition
| -each cell has internal feedback control mechanisms that are genetic and enzymatic (activation or inhibition) |
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Term
|
Definition
- growth factor from other parts of the body
- space limitations
- negative feedback from the cells own secretions |
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Term
|
Definition
apoptosis - programmed cell death through phagocytosis
necrosis - loss of cell membrane integrity due to injury |
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Term
|
Definition
- loss or inactivation of antioncogenes can lead to cancer
- very few mutated cells become cancer b/c they havve less survivability. many retain normal feedback mechanisms and don't overgrow. many are destroyed by the body's immune system (lymphocytes)
- need many activated oncogenes to support cancer growth |
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Term
|
Definition
1. channel proteins - allows free movement of water and selected ions and molecules
2. carrier proteins - highly selective, binds with molecules or ions that cause conformational change to the protein (uses ATP) |
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Term
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Definition
| random molecular movement with the energy gradient (uses kinetic energy) |
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Term
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Definition
| movement of substances against the energy gradient (requires energy) ex. glucose |
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Term
|
Definition
| net movement of water caused by a concentration difference of water |
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Term
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Definition
| the amount of pressure required to slow, stop, or reverse osmosis. This is determined by the number of particles (non-dissociated molecule) per unit of volume of fluid, not by the mass of the particles |
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Term
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Definition
uses the breakdown of ATP or some other high energy phosphate compound (NA+, K+, Ca2+, H+, Cl-)
ex. Na+/K+ pump |
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Term
|
Definition
-pumps Na+ ions outward and K+ ions inward
- establishes a negative electrical voltage inside the cells
- has binding sites for 3 Na+ inside and 2 K+ outside
- when Na+ binds, ATPase is activated cleaving ATP to ADP and Pi (energy released causes chemical and conformational changes necessary to move the ions
- controls volume of cells |
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Term
Primary Active Transport
calcium pump |
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Definition
| 1. Ca2+ pump - mantained in a very low concentration inside the cell. Achieved by 2 pumps, one moving Ca2+ out and one moving Ca2+ in. |
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Term
Primary Active Transport
H+ pump |
|
Definition
1. gastric gland parietal cells - releases hydrogen ions into the stomach along with chloride ions to form HCl
2. distal tubule intercalated cells - excretion of excess H+ from blood to urine |
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Term
| Secondary Active Transport |
|
Definition
1. co-transport - diffusion energy of an ion can pull other substances along through the cell membrane (glucose, A.A)
2. counter-transport - sodium - calcium and sodium-hydrogen: sodium binds to the protein on the outside of the cell, the ion binds inside and conformational change allows sodium to move inward and the other ion to moves outward. |
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Term
| Active transport through cellular sheets |
|
Definition
- occurs in epithelium (renal, intestinal, exocrine glands, gallbladder, and membrane of choroid plexus of the brain)
- mechanism by which almost all the nutrients, ions, and other substances are absorbed into the blood from the intestine and reabsorbed from the glomerular filtrate by the renal tubules.
- combo of active transport on one side and either simple or facilitated diffusion. |
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Term
|
Definition
diffusion potential - caused by an ion concentration difference on the 2 sides of the membrane
Nernst potential - the diffusion potential level across a membrane that exactly opposes the net diffusion of a particular ion through the membrane (looks at 1 ion), not as accurate!!! determined by the ratio of the concentrations of that specific ion on the 2 sides of the membrane, relative to electrical charge. |
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|
Term
|
Definition
when a membrane is permeable to several ions, the diffusion potential depends on
1. the polarity of the electrical charge of each ion
2. the permeability of the membrane to each ion
3. concentrations of the respective ions on the inside and outside of the membrane |
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Term
|
Definition
| Na+, K+, Cl- are the most important ions in the development of membrane potentials in nerve and muscle fibers and in neuronal cells |
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Term
|
Definition
| Na+ and K+ channels undergo rapid changes during the transmission of a nerve impulse, whereas Cl- channels does not change much. (Na+ and K+ are primarily responsible for nerve signal transmission) |
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|
Term
| Resting membrane potential |
|
Definition
more Na+ outside than inside, therefore neg. charge is inside.
Na+: outside > inside
K+: outside < inside |
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Term
| Nerve Action Potential (3 stages) |
|
Definition
1. Resting - membrane potential before the action. It is said to be olarized at -90mV.(activation gate is closed)
2. Depolarization - membrane is suddenly very permeable to Na+ neutralizing the negative membrane potential, movement towards 0.
3. Repolarization - membrane Na+ channels close and K+ channels open causing K+ to rapidly move to the exterior, re-establishing the resting membrane potential (inactivation gate closes) |
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|
Term
Nerve Action Potential
(voltage-gated Na+ channel) |
|
Definition
| has 2 gates, one near the outside called the activation gate and one near the inside called the inactivation gate. |
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|
Term
Nerve Action Potential
(Activation of the Na+ channel) |
|
Definition
| when the membrane potential becomes less negative than the resting state, a sudden conformational change occurs, flipping the gate open and allowing Na+ to flow inward |
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|
Term
Nerve Action Potential
(inactivation of Na+ channel) |
|
Definition
| the same inc. in voltage that opens the gate causes the closing of the inactivation gate slightly after the gate opens. This starts the REPOLARIZATION process. The inactivation gate will not open again until the membrane potential returns to resting. |
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Term
|
Definition
voltage-gated K+ channel - closed when membrane is at rest
Activation of K+ channel - occurs when membrane potential rises toward 0 causing conformational opening of the channel and outflow of K+
* there is a slight delay in the opening which causes them to open the same time the Na+ channels are closing, allowing repolarization. |
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Term
|
Definition
| strength of contraction increases to a plateau |
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Term
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Definition
| results from a low rate of nerve impulses coming from the spinal cord |
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Term
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Definition
| increases almost in direct proportion to the rate of depletion of muscle glycogen |
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Term
| mechanics of skeletal muscle contraction |
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Definition
| co-activation of antagonist muscles - controlled by motor control centers in the brain and spinal cord. "For every action there is a reaction" |
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Term
|
Definition
*hypertrophy - fiber hypertrophy (new actin and myosin filaments)
*adjustment to muscle length - new sarcomeres
*hyperplasia - inc. in number of muscle fibers |
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Term
|
Definition
| dec. in muscle mass, under use, or denervation |
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Term
|
Definition
| caused by denervation atrophy (polio) |
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Term
|
Definition
| caused by denervation atrophy (polio) |
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Term
|
Definition
| caused by loss of all ATP, cross-bridges can't separate (myosin can't let go of actin filaments) |
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Term
|
Definition
| clostridium tetani bacteria (lockjaw) |
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Term
|
Definition
*specialized synapse - b/w a motorneuron and a muscle fiber. occurs at the motor end plate(usually one per fiber)
*synaptic trough - invagination in the motor endplate membrane
*synaptic cleft - space b/w the terminal and the fiber membrane, has large quantities of acetylcholinesterase which destroys acetylcholine after it has been released into the synaptic vesicles
*subneural clefts - inc. the SA at which the synaptic transmitter can act |
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Term
| Secretion of Acetylcholine |
|
Definition
| calcium exerts and attracts a force on the acetylcholine vesicles drawing them to the membrane surface near the dense bars where they empty into the synaptic space through exocytosis |
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Term
|
Definition
| negative ions do not enter due to the strong negative charge at the opening of the channel |
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Term
|
Definition
| - binds with acetylcholine receptors on the acetylcholine-gated ion channels allowing pos. ions to enter (Na, K, Ca) |
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Term
|
Definition
| Na+ is the primary ion that enters and creates a positive potential change inside the muscle fiber membrane called the end plate potential(this spreads along the membrane and causes contraction) |
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Term
| Destruction of acetylcholine |
|
Definition
| acetylcholine in the synaptic space continues to stimulate acetylcholine receptors until it is removed by ACETYLCHOLINESTERASE OR DIFFUSION OUT OF THE SYNAPTIC SPACE |
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Term
|
Definition
-generates action potential for the muscle fiber(acetylcholine-gated channels allow influx of Na+)
- impulses to the neuromuscular junction are usually MUCH GREATER than needed (safety factor) |
|
|
Term
| fatigue at neuromuscular junction (rare) |
|
Definition
| overstimulation causes a dec. in available acetylcholine and eventually the impulse fails to pass into the muscle fiber |
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Term
|
Definition
auto-immune, antibodies attack the acetylcholine-gated Na+ ion transport proteins
- causes paralysis |
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Term
|
Definition
-resting potential similar to the nerve
- last 5x longer than large myelinated nerves
- slower conduction than nerves (1/13 the velocity)
- T TUBULES conduct the action potential into the muscle fiber, stimulating the release of Ca ions, causing contraction |
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|
Term
| Excitation-Contraction Coupling |
|
Definition
- T tubules are extracellular
- T tubules interlace w/ individual myofibrils
- internal extensions of the cell membrane and articulate with and contain their lumens and ECF |
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|
Term
| Excitation-Contraction Coupling |
|
Definition
- the sarcoplasmic reticulum contains an excess of Ca2+ ions in its vestibular tubules that are released when an action potential occurs in the adjacent T tubules aiding in contraction
- a continuously active pump returns Ca2+ to the sarcoplasmic reticulum |
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Term
|
Definition
has thick and thin filaments, but not arranged in sarcomeres (no striations)
1. multi-unit: separate fibers that act independently and are often innervated by a single nerve ending.
2. unitary(bladder, lumen of intestine) - a mass of many fibers that contract together as a single unit, arranged in sheets or bundles |
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|
Term
|
Definition
- contain myosin and actin fibrils that rely on Ca and ATP to contract
- has a large amount of actin filaments attached to dense bodies |
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Term
|
Definition
- myosin fibrils are interspersed among the more numerous actin fibrils
- myosin is sidepolar cross-bridges that allow for actin filaments to be pulled in an opposite direction. This allows smooth muscle to contract as much as 80% of its length (50% longer than skeletal) |
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|
Term
| smooth vs. skeletal contraction |
|
Definition
- smooth is prolonged and tonic (skeletal is brief due to dec. ATPase activity)
- smooth requires less energy to sustain tension (due to slow cross-bridge cycling) |
|
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Term
| smooth vs. skeletal contraction |
|
Definition
- onset of contraction is slow for smooth
- smooth muscle force of contraction is usually greater |
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Term
| Regulation of smooth muscle |
|
Definition
- no TROPONIN in smooth muscle
- the regulatory protein is CALMODULIN
- Ca2+ binds with calmodulin to activate myosin kinase (attachment to actin occurs)
- reversal of the phosphorylation of the myosin head occurs through myosin phosphatase |
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|
Term
| Membrane and Action potentials |
|
Definition
- resting potential of smooth is less negative than skeletal.
- action potentials usually don't occur in multi-unit smooth muscles |
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Term
|
Definition
| occur like those in skeletal muscle by electrical stimulation, hormonal/transmitter, stretch, spontaneous generation |
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Term
| action potentials with plateaus |
|
Definition
| in smooth muscles(unitary) delayed repolarization, prolonged contraction |
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Term
| membrane and action potentials |
|
Definition
| smooth has more voltage-gated Ca channels and fewer Na+ gated channels |
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Term
|
Definition
| - 1/2 of all smooth contractions are initiated by stimulatory factors acting directly on the muscle w/o action potentials |
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Term
| local tissue factors - vasodilation |
|
Definition
| RELAXATION of vascular muscle by feedback control due to lack of oxygen, excess CO2 or H+, adenosine, lactic acid, excess K+ ions, dec. Ca2+, or inc. body temp. |
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Term
| local tissue factors - hormones |
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Definition
| most circulating hormones have effect on contraction of smooth muscles. Norepinephrine, epinephrine, acetylcholine, angiotensin, vasopression, oxytocin (hormone-gated excitatory receptors and inhibitory receptors) |
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Term
|
Definition
SR is not prominent in smooth muscle. calcium comes from extracellular fluid
- force of contraction is highly dependent on extracellular fluid calcium ion concentration |
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Term
|
Definition
-walking movements
- reflexes causing withdraw from painful stimuli
- reflexes that stiffen the legs against gravity
- reflexes that control local blood vessels, gastrointestinal movements or urinary excretion |
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Term
| Subcortical (lower brain) - subconscious control |
|
Definition
- arterial pressure/respiration (medulla and pons)
- equilibrium (cerebellum and reticular substance of medulla, pons, and mesencephalon)
- feeding reflexes, salvation/licking lips (medulla, pons, mesencephalon, amygdala, hypothalamus |
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Term
|
Definition
| cortical level (higher brain)- memory storehouse, works with lower levels and enhances the precision of their functions. |
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Term
| CNS synapses - chemical synapses |
|
Definition
- secrete neurotransmitters that act on receptor proteins in the membrane of the next neuron.
One way conduction only – presynaptic to postsynaptic neurons
Best known neurotransmitters – acetylcholine (muscles), norepinephrine, epinephrine, histamine, gamma-aminobutyric acid (GABA), glycine, serotonin and glutamate |
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Term
| CNS synapses - electrical |
|
Definition
- 2 way conduction system
- characterized by direct open fluid channels that conduct electricity between neurons in the form of gap junctions
Conduction through electrical synapses can move in either direction |
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Term
| Physiologic Anatomy of the Synapse |
|
Definition
- Presynaptic terminals lie in great numbers on the surfaces of the dendrites and to a much lesser extent the soma
- Action potential causes emptying of the vesicles into the synaptic cleft |
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Term
| Physiologic Anatomy of the Synapse – neurotransmitter into synaptic cleft |
|
Definition
- The presynaptic membrane contains large numbers of voltage-gated calcium channels that open with depolarization allowing large amounts of calcium ions into the terminal
- The amount of transmitter substance released into the synaptic cleft depends on the amount of calcium ions present that bind to release sites |
|
|
Term
Postsynaptic Membrane Ion Channels
(Cation channels,attract charges) |
|
Definition
| - Opened by excitatory transmitters – the increased positive charge from the sodium ions excites the neuron – depolarizing (becoming more positive) |
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|
Term
| Postsynaptic Membrane Ion Channels (anions) |
|
Definition
| – Opened by inhibitory transmitters – the increased negative charge from the chloride ions inhibits the neuron – hyperpolarizing (becoming more negative) |
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Term
| Postsynaptic Membrane “Second Messenger” System |
|
Definition
- Most common type uses G proteins that are comprised of an alpha component – the activator, beta and gamma components that are attached to the alpha component
- G-proteins are inside the cell adjacent to the receptor protein |
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Term
|
Definition
- allow channels to stay open for longer
- Opening specific ion channels through the postsynaptic cell membrane – allow channel to stay open a long time
- Activation of cyclic adenosine monophosphate (cAMP) or cyclic guanosine monophosphate (cGMP) – this in turn activates highly specific metabolic machinery and can result in long term changes of the cell itself (used instead of ATP) |
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Term
|
Definition
| - Small-molecule, rapidly acting transmitters – stored in vesicles of the presynaptic terminal, effect is to increase or decrease conductance through ion channels |
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|
Term
| Synaptic Transmitters (small, rapid, and recyclable) |
|
Definition
– Acetylcholine
– Norepinephrine
– Dopamine
– Glycine
– GABA
– Glutamine
– Serotonin
– Nitric oxide |
|
|
Term
|
Definition
- synthesized as integral parts of large-protein molecules by ribosomes in the neuronal cell body
- These protein molecules move through the ER of the cell body and into the Golgi apparatus where the protein is enzymatically split and packaged into transmitter vesicles that are released into the cytoplasm
- Axonal streaming carries the vesicles to the terminal for release by and action potential
- The neuropeptides are autolyzed and not reused
- Cause prolonged actions |
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Term
| Electrical Events During Neuronal Excitation |
|
Definition
Lower voltage allows for greater control of the degree of excitability
– Na+: 142mEq/L outside, 14mEq/L inside
– K+: 4.5mEq/L outside, 120mEq/L inside
– Cl-: 107mEq/L outside, 8mEq/L inside |
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|
Term
| Electrical Events During Neuronal Excitation |
|
Definition
| - It is known that sodium and potassium pumps exist and theorized that chloride pumps exist to aid in maintaining ion concentrations |
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Term
| Electrical events during neuronal excitation |
|
Definition
- Excitatory postsynaptic potential (EPSP) increases permeability of sodium ions taking the resting potential closer to zero – requires simultaneous discharge of many terminals, ie. Summation
Summation – you need a lot of things to happen at the same time
- Action potential does not originate at the excitatory synapse, but rather the initial segment of the axon – this is due to the much greater number of voltage-gated sodium channels in the axon |
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Term
| Electrical Events During Neuronal Inhibition |
|
Definition
- Inhibitory synapses open mainly chloride channels that influx chloride ions and potassium channels that efflux potassium ions
- Presynaptic inhibition – caused by the release of an inhibitory substance onto the outsides of the presynaptic nerve fibrils before their own endings terminate on the postsynaptic membrane – usually GABA which opens anion channels |
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Term
| Presynaptic inhibition occurs in many sensory pathways |
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Definition
| - minimizes spread and mixing of signals (lateral inhibition) an unencumbered signal needs inhibition to keep the action wanted on track (ex. Seizures – no inhibition) |
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Term
| Summation of electrical responses |
|
Definition
- Spatial summation – simulating wide areas of a neuron, many presynaptic terminals are usually stimulated at the same time and though they are spread out over wide areas of the neuron, their effects are additive
- Temporal summation – rapid successive discharges from a single presynaptic terminal can generate an action potential. Ion channels open and close rapidly, but the leaking of the ions takes a longer period of time allowing for cumulative change in the membrane potential to occur |
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Term
|
Definition
| Simultaneous summation of IPSP and EPSP can occur |
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Term
|
Definition
| when the membrane potential is increased, but has not yet reached the threshold for firing – easily excitable |
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Term
|
Definition
- 80-95% of presynaptic terminals of the anterior motor neuron terminate on dendrites, thus the major share of excitation occurs here
- A large amount of the electrical current is lost due to the length of the dendrite and the “leaky” nature of the membrane that is at least partially permeable to potassium and chloride – decremental conduction (impulse is strong, but then weakens quickly) |
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Term
|
Definition
- Excitatory state – summated degrees of excitatory drive
- When the excitatory state of a neuron rises above threshold, it will fire repeatedly as long as the excitatory state remains at that level (not much fatigue) |
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Term
|
Definition
| - increases excitability and acidosis, depresses neuronal activity |
|
|
Term
| Neuronal excitability is: |
|
Definition
|
|
Term
| Drugs that effect synaptic transmission |
|
Definition
- Caffeine, theophylline and theobromine (for asthma) - increase neuronal excitability by reducing threshold
– Strychnine – inhibits inhibitory transmitters
– Anesthetics – increase the neuronal membrane threshold for excitation |
|
|
Term
|
Definition
| - time of the transmission of a neuronal signal from a presynaptic neuron to a postsynaptic neuron |
|
|
Term
| 5 basic sensory receptor types |
|
Definition
– Mechanoreceptors – detects mechanical compression or stretching
– Thermoreceptors – detects changes in temperature
– Nociceptors – pain receptors – detect chemical or mechanical damage
– Electromagnetic receptors – detect light on the retina
– Chemoreceptors – detect chemistry factors in the body – taste, smell, oxygen, carbon dioxide osmolality |
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|
Term
|
Definition
| - the change of the membrane electrical potential immediately after stimulus excites the receptor |
|
|
Term
|
Definition
| change in membrane permeability of the receptor that allows ions to diffuse redily through the membrane (depolarization/hyperpolarization) |
|
|
Term
| Action Potential Frequency |
|
Definition
| becomes greater the more the receptor potential rises above the threshold level |
|
|
Term
| Receptor Potentials - Mechanoreceptor (pressure) |
|
Definition
|
|
Term
|
Definition
| -almost all sensory receptors adapt either partially or completely to any constant stimulus after a period of time |
|
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Term
|
Definition
| slow adapting, transmit impulses to the brain as long as stimulus is present, can transmit for hours (muscle spindles, golgi tendon apparatus, macula, pain receptors, baroreceptors, chemreceptors) |
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|
Term
|
Definition
| cannot transmit a continuous signal, stimulated only when the stimulus |
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|
Term
|
Definition
| increasing the frequency of the nerve impulses in each fiber |
|
|
Term
|
Definition
| increasing signal strength by using progressively greater numbers of nerve fibers, one part of body has more nerve endings than another. |
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|
Term
|
Definition
each neuronal pool has its own special organization that causes it to process signals in its own unique way.
- divergence is an amplifying type
* input spreads to more neurons (corticospinal tract) |
|
|
Term
|
Definition
- a method used to test tactile discrimination, determined by number of specialized tactile receptors in the 2 areas.
- the 2 points signal to the cerebral cortex and the zone of excitation has 2 peaks.
- influenced by lateral inhibition |
|
|
Term
|
Definition
| inhibitory signals block lateral spread of the excitatory signal and increase the degree of contrast in the sensory pattern, in the dorsal column this occurs at the synaptic level |
|
|
Term
|
Definition
| the greater the background sensory intensity, the greater an additional change must be for the psyche to detect the change, applies well only to higher intensities of visual, auditory, and cutaneous sensations |
|
|
Term
|
Definition
| a linear relation can be attained b/w interpreted stimulus strength and actual stimulus |
|
|
Term
|
Definition
| - multiple receptor types help perception of joint angulation (skin tactile receptors, deep receptors, muscle spindles (stretch), and at the extreme (pacinian corpuscles and ruffini's endings) |
|
|
Term
|
Definition
|
|
Term
| Neuronal Circuits (inhibitory and fatigue) |
|
Definition
Inhibitory circuits - return from the termini of pathways back to the initial excitatory neurons
Fatigue of synapses - short term adjustment of pathway sensitivity, long term changes in synaptic sensitivity caused by autonomic down-regulation or up-regulation of synaptic receptors |
|
|
Term
| Somatic Senses (3 physiologic types) |
|
Definition
1. mechanoreceptive (tactile and position) - stimulated by mechanical displacement of tissue
2. thermoreceptive - heat and cold
3. pain sense - activated by any factor that damages tissue. |
|
|
Term
| sensations - Exteroreceptive |
|
Definition
|
|
Term
| sensations - proprioceptive |
|
Definition
| physical state of the body |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| 1. touch - tactile receptors in the skin (free nerve, meissners, merkel, ruffini's, pacinian corpuscle) |
|
|
Term
| Sensory Pathways - 2 pathways that carry somatic sensory info to the brain from the dorsal roots of the spinal nerves |
|
Definition
1. Dorsal Column-medial lemniscal system
- carries signal upward to medulla in the dorsal columns of the cord and to the medial lemniscus, faster velocity, mechanoreceptive sensations, inc spatial orientation.
2. Anterolateral system - ascend through the anterior and lateral white portions of the cord and terminate at lower brain stem and thalamus, slower, less spatial orientation |
|
|
Term
| Sensory Pathways - 2 pathways that carry somatic sensory info to the brain from the dorsal roots of the spinal nerves |
|
Definition
1. Dorsal Column-medial lemniscal system
- carries signal upward to medulla in the dorsal columns of the cord and to the medial lemniscus, faster velocity, mechanoreceptive sensations, inc spatial orientation.
2. Anterolateral system - ascend through the anterior and lateral white portions of the cord and terminate at lower brain stem and thalamus, slower, less spatial orientation |
|
|
Term
| Dorsal Column-medial Lemniscal System |
|
Definition
- nerve fibers enter dorsal columns pass up to dorsal medulla (synapse with dorsal column nuclei)
- 2nd order neurons cross to opposite side of brain stem and go up to thalamus.
- 3rd order neurons go to cortex |
|
|
Term
|
Definition
sensation term. in cerebral cortex
visual term. in occipital lobe
auditory term. in temporal lobe
ant. portion of cortex is motor |
|
|
Term
| Somatosensory area I and II |
|
Definition
I - more extensive, localization of diff. parts of the body, sends signals to II, can function when II is damaged
II - receives signals from I and other areas of the brain, requires I to function |
|
|
Term
|
Definition
| transmitted in the backward direction from the cerebral cortex to the lower sensory relay stations of the thalamus, medulla, and spinal cord. Controls intensity of the sensitivity of the sensory output. (inhibitory) |
|
|
Term
|
Definition
| each spinal nerve innervates a segmental field of the skin, used to determine what level of the cord is injured, based on lack of sensation. |
|
|
Term
|
Definition
1. directly after stimulus is applied, not felt in deeper tissues (sharp, acute)
2. 1 sec or more after stimulus is applied, usually assoc. w/ tissue destruction (burning, aching, throbbing) |
|
|
Term
| chemicals that excite pain |
|
Definition
| bradykinin, serotonin, histamine, K+, acids, prostaglandins, and substane P |
|
|
Term
|
Definition
- intensity of pain is correlated with the rate of tissue damage
- chemical pain(bradykinin) more painful, inc. K+ or proteolytic enzymes
- ischemic pain: accum. of lactic acid not proper blood flow
- muscle spasm: mechanosensitive pain receptors due to ischemia and chemical agents |
|
|
Term
|
Definition
| neurotransmitter for fast pain |
|
|
Term
|
Definition
- pain in a part of the body that is remote from the tissue causing pain
- branches of visceral pain fibers synapse in the spinal cord on the same 2nd order neuron that receive pain signals from the skin |
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Term
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Definition
- viscera have no other modalities of sensation besides pain
- highly localized tissue damage to the viscera rarely causes pain |
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Term
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Definition
- ischemia
- chemical stimuli
- spasm
- overdistention |
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Term
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Definition
| partially transected spinal cord, spinothalamic pathway sensations are lost on the opposite side of the body 2 to 6 segments below the injury |
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Term
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Definition
| trigeminal/glossopharyngeal neuralgia, pain over one sid eof the face distribution area of the 5th or 9th nerves |
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Term
| Types of intercranial headache |
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Definition
- meningitis
- low CSF
- migraine
- alcoholic
- constipation |
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Term
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Definition
- muscle spasm
- irritation of nasal and accessory nasal structures
- eye disorders |
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Term
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Definition
| the direction in which light travels is always perpendicular to the plane of the wave front |
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Term
| The degree of refraction increases as a function of |
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Definition
- the ratio of the 2 refractive indices of the 2 transparent media
- the degree of angulation b/w the interface and the entering wave front |
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Term
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Definition
| cause convergence of light rays that then meet at a focal point |
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Term
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Definition
| causes divergence in one plane |
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Term
| Focal length and image formation |
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Definition
the distance beyond a convex lens at which parallel rays converge, varies based on the distance of the light source, divergence of the light entering the convex lens and the convexity of the lens.
- any object in front of the lens is upside down and on the opposite side of the lens |
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Term
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Definition
- the more a lens bends light, the greater its refractive power
- concave lens are measured in neg. diopter (how much the refract light beyond the lens)
- convex lens are pos. diopters |
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Term
| The lens system of the eye (4 transparent layers) |
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Definition
- air and anterior cornea
- post. cornea and aqueous humor
- aqueous humor and ant. lens
- post. lens and vitreous humor |
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Term
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Definition
-when the lens of the eye is relaxed, it is spherical
- ciliary muscles (meridional and circular fibers) at the lateral attachment of the ligaments cuases the suspensory ligaments to move medially when they contract (sphincter-like) which lessens pull of the ligaments
- controlled by PNS nerve signals from CNIII |
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Term
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Definition
| the lens becomes less elastic with age and accommodation |
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Term
| Depth of focus is controlled by pupillary aperture |
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Definition
| the greatest depth of focus occurs when the pupil is the SMALLEST b/c the rays pass through the center of the lens (focuses light into center of lens) |
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Term
| Errors of Retraction (hyperopia) |
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Definition
| farsightedness, can only see far objects clearly. Convex lens, parallel light rays are not bent sufficiently by the relaxed lens system to focus by the time they reach the retina. |
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Term
| Errors of Refraction (myopia) |
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Definition
| nearsightedness, can only see near objects clearly, concave lens, parallel light rays are bent more sharply and the focal point occurs before the rays reach the retina when the lens system is relaxed, can't accommodate! |
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Term
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Definition
| normal vision, parallel light rays from distant objects are in sharp focus on the retinal when the ciliary muscle is relaxed. |
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Term
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Definition
- no common focal point
- results from too much curvature of the cornea in one plane of the eye
- the lens system is made up of 2 different strength lenses and is placed at right angles of each other
- correction: spherical lens where axis and strength were addressed |
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Term
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Definition
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Term
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Definition
| opaque areas caused by denatured proteins coagulating on the lens, corrected by replacing the lens with a plastic one |
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Term
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Definition
- helps maintain pressure inside the eyeball to keep it distended
1. Aqueous Humor - lies in front of the lens, free flowing, continually being formed and reabsorbed regulating the total volume and pressure of the intraocular fluid (ant. chamber)
2. vitreous humor - lies b/w the post. lens and the retina, gelatinous mass with little flow |
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Term
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Definition
secreted by ciliary processes projecting from the ciliary body, secreted by active transport
- goes from pupil, to ant. chamber, to angle b/w cornea and iris, into trabeculae and then the canal of schlemm and then the aqueous veins |
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Term
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Definition
| measured by a tonomoter, pressure is determined by the resistance to outflow of aqueous humor |
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Term
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Definition
| eye inflammation can cause build up of debris in the trabecular spaces (emergency) |
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Term
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Definition
| inc. pressure compresses the axons of the optic nerve and causes nutritive death. |
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Term
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Definition
outer segment - contains light sensitive photochemicals (rods, rhodopsin, cones)
inner segment - mitochondria
- pigment layer prevents light reflection throughout the globe of the eyeball |
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Term
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Definition
| 1. central retinal artery - supply for the internal layer of the retina, enters through optic disc and branches, inner layers of the retina have their OWN blood supply |
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Term
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Definition
| outermost layer of retina, adheres to choroid and receives nutrition from diffusion from the choroid blood vessels, especially oxygen. |
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Term
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Definition
- when light energy is absorbed, rhodopsin decomposes, active rhodopsin excites electrical changes in the rods.
- rhodopsin is reformed by retinal isomerase
- interconversion b/w retinal and vit. A that aids in long-term adaption of the retina to light intensities
- rod potential is hyperpolarizing |
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Term
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Definition
| - when rhodopsin decomposes, the outer segment of the rod is leaky to Na+ ions, Na+ is pumped out, but doesn't leak back in (inc. electronegativity of the rod) |
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Term
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Definition
- cones adapt more rapidly, but only for a short time.
- rods can cause neuronal signal summation which inc. their sensitivity |
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Term
| methods of light/dark adaptation |
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Definition
- change in pupil size
- neural adaptation
*** happen instantly |
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Term
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Definition
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Term
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Definition
| perceived by equal ratios of all 3, white is combo of all wavelengths |
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Term
| Color Blindness (red/green) |
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Definition
| - when a single group of color receptive cones are missing a person is unable to distinguish some colors from others – if red or green cones are missing then there is difficulty distinguishing between the two colors, genetic trait, carried on X chromosome, male predominance, mother (genetic carrier) to son |
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Term
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Definition
| loss of red cones, overall visual spectrum is shortened at the long end |
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Term
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Definition
| loss of green, normal spectrum |
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Term
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Definition
| rarely missing all together, may be underrepresented |
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Term
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Definition
| rods and cones, transmit signals to the outer plexiform layer, synapse with bipolar and horizontal cells |
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Term
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Definition
| transmit signals horizontally in the outer plexiform layer |
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Term
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Definition
| transmit signals vertically from the rods, cones, and horizontal cells to the inner plexiform layer where they synapse with ganglion and amacrine cells |
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Term
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Definition
| transmit signals in 2 directions, bipolar to ganglion or bipolar axons to ganglion dendrites of other amacrine cells |
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Term
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Definition
| transmit output signals from the retina through the optic nerve into the brain |
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Term
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Definition
neurons and nerve fibers are larger and faster
- cones to biplar cells to ganglion cells
- horizontal cells transmit inhibitory signals laterally in the outer plexiform
- amacrine cells transmit signals laterally in the inner plexiform
- only cones in fovea |
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Term
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Definition
- rod and cones are present
- rod to bipolar cells to amacrine to ganglion
- horizontal and amacrine cells provide lateral connectivity |
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Term
| Dorsal Lateral Geniculate Nucleus |
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Definition
- where optic fibers terminate
- relays visual info from optic tract to the visual cortex in occipital lobe
- gates the transmission of signals to the visual cortex by means of inhibition |
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Term
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Definition
- in medial occipital lobe
1. primary - terminates direct visual signals, fovea (acuity) is most of this cortex.
2. Secondary - surrounds primary, ANALYSIS of visual meaning |
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Term
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Definition
interspersed among the primary and secondary visual areas, are activated by specific color signals
- PRIMARY area to decipher color |
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Term
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Definition
| when the viewing object is not clear |
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Term
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Definition
intensity of stimulation of most neurons is proportional to the gradient of contrast.
- greater stimulation = greater contrast |
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Term
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Definition
- nasal and temporal field (deficiencies are assessed by perimetry)
- blind spot is 15' lateral b/c of lack of rods and cones over optic disc |
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Term
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Definition
| blind spots outside the optic disc area - caused by damage to the optic nerve or retina (diabetes) |
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Term
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Definition
| deposits of melanin in areas of degenerated retina (peripheral blindness eventually encroaches on central vision) |
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Term
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Definition
| s a collection of axons from relay neurons in the LGN of the thalamus carrying visual information to the visual cortex |
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Term
| Voluntary Fixation Mechanism |
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Definition
| movements are controlled by the cortical field in the frontal lobe |
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Term
| Involuntary Fixation Mechanism |
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Definition
| holds eyes on an object once its been found, controlled by secondary visual area of occipital cortex |
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Term
| Eye Movements - Superior Colliculi(old) |
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Definition
| - optic fibers travel here to control rapid directional movements of the 2 eyes. Orients body, eyes, and head with respect to external disturbances (visual, somatic, auditory) |
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Term
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Definition
| - when a visual field is moving, the eyes fix on an object and then jump (saccades) |
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Term
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Definition
| eyes remain fixed on a moving object, saccade movement, high degree of subconscious computational ability |
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Term
| Eye Movements (strabismus) |
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Definition
- lack of fusion of the eye in one or more visual coordinates.
- one eye fixates, the other does |
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Term
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Definition
in some patients with strabismus
- the eyes alternate in fixing OR
- one eye is repressed (dec. visual acuity, loss of neuronal connections) and the other one fixates |
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Term
| Parasympathetic Preganglion Fibers |
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Definition
- excites ciliary muscles that control focusing of the lens
- excites the sphincter of the iris that constricts the pupil |
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Term
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Definition
- see more clearly, controlled by negative feedback
- results from contraction or relaxation of the ciliary muscle and is regulated by negative feedback |
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Term
| Autonomic control of Pupillary Diameter |
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Definition
Midriasis - stimulation of sympathetic fibers causing pupillary dilation (drops)
Miosis - stimulation of the parasympathetic nerves causes dec. pupillary aperture |
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Term
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Definition
- TM to ossicles to cochlea
- the ossicles are attached in a way that pressure is exerted or relieved on the oval window by the movements in and out of the TM, which causes movement of cochlear fluid |
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Term
| Increased force is required to cause vibration in fluid |
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Definition
| impedance matching between the sound waves in air and the sound vibration in the cochlea is achieved by the TM and ossicular system |
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Term
| Conduction of Sound (loud sounds cause attenuation reflex) |
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Definition
| the tensor tympani muscle pulls the handle of the malleus inward at the stapedius muscle pulls the stapes outward causing rigidity of the ossicular system and reducing conduction (protects cochlea and reduces background noise) |
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Term
| Cochlea (scala vestibuli, scala media, scala tympani) |
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Definition
Reissner's membrane - b/w scala vestibuli and scalamedia, creates compartment for fluid
basilar membrane - b/w scala tympani and scala media |
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Term
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Definition
| bending hairs towards kinocillium creates pressure and opens cation gates (depolarization) causes inc. Ca2+ in cell |
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Term
| hyperpolarization of hair cells |
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Definition
| bending cilia away from tallest kinocilium relaxes hair membrane surface |
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Term
scala media
scala tympani, scala vestibuli (in labyrinth) |
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Definition
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Term
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Definition
| nervous system detects frequency of sound based on where along the basilar membrane stimulation is occurring |
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Term
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Definition
increases the amplitude of vibration of the basilar membrane and hair cells, exciting the nerve endings at more rapid rates
inc. amp = transmission through more nerve fibers
- outer hair cells only activate with high intensity vibrations |
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Term
| lateral directionality of sound |
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Definition
determined by:
- time lag b/w the 2 ears receiving the sound
- diff. in sound intensity b/w the ears |
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Term
| what determines ant. and post. directionality? |
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Definition
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Term
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Definition
| impairment of physical structures of the ear, sound waves can still be conducted to cochlea by bone conduction |
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Term
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Definition
sour - intensity is proportional to the H+ concentration
salty - Na+ concentration
sweet - caused by organic chemicals
bitter - caused by organic chemicals, long chain that inc. Nitrogen and alkaloids |
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Term
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Definition
| circumvallate, fungiform, and foliate |
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Term
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Definition
- cell becomes depolarized when the substance stimulates the hair
- sweet and bitter use 2nd messenger transmitter substances |
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Term
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Definition
Ant 2/3 - transmitted via lingual nerve to facial nerve
post. 1/3 - transmitted via glossopharyngeal nerve |
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Term
| anterior 2/3 of tongue taste signals |
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Definition
| transmitted via lingual nerve to the facial nerve and then to the tractus solitarius |
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Term
| posterior 1/3 of tongue taste receptors |
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Definition
| transmitted via the glossopharyngeal nerve to tractus solitarius at a more posterior level |
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Term
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Definition
- olfactory cells are bipolar nerve cells interspersed with sustentacular cells
- bowman's glands secrete mucus onto the surface of the olfactory membrane |
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Term
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Definition
| - 50% occurs rapidly at the olfactory receptors, then the remainder of the adaptation occurs in the CNS |
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Term
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Definition
medial - basic olfactory reflexes
lateral - automatic, but partially learned |
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Term
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Definition
large, branched, innervates large skeletal muscle
*motor unit is one alpha nerve and the muscle it innervates |
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Term
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Definition
| fewer, smaller, innervates specialized skeletal muscle fibers called intrafusal fibers in the middle of the muscle spindle to help control tone |
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Term
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Definition
| in all areas of gray matter, numerous, small, highly excitatory, synapes w/ each other and ant. motor neurons, responsible for most integrative functions of the cord |
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Term
| Renshaw cell inhibitory system |
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Definition
provide lateral inhibition of adjacent motor neurons.
- makes movements precise |
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Term
| Multisegmental connection |
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Definition
propriospinal fibers
- more than 1/2 of ascending and descending nerve fibers of the spinal cord, coord. with multisegmental reflexes.
- multiple movements of muscle fibers |
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Term
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Definition
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