Term
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Definition
| at the peripheral ends of afferent neurons, change info into graded potentials that initiate action potentials, which travel into the central nervous system |
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Term
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Definition
| respond to mechanical stimuli, such as pressure or stretch and are responsible for many types of sensory info including touch, blood pressure and mucle tension. these stimuli alter the permeability of ion channels on the receptor membrane changing the membrane potential. |
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Term
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Definition
| detect sensations of cold or warmth |
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Term
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Definition
| respond to particular ranges of wavelength, only type of sensory cell that is depolarized at rest |
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Term
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Definition
| respond to the binding of particular chemicals to the receptor membrane. this type of receptor provides the senses of smell and taste and dectects blood pH and concentration |
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Term
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Definition
| specialized neuronal endings that respond to a number of different painful stimuli |
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Term
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Definition
| ion channels in a cell are present in a specialized region of the receptor membrane located at the distal tip of the cells single axon or on associated specialized sensory cells. the gating of these ion channels allows a change in the membrane potential which in turn produces a change in membrane potential this change is a graded potential called a receptor potential |
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Term
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Definition
| reduction in response( the number of action potentials) to the continuous presence of a stimulus; the mechanism helps prevent sensory overload |
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Term
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Definition
| another term for stimulus type, can be divided into submodalities i.e cold/warm are submodalities of temperature |
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Term
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Definition
| strong stimuli may also activate additional sensory units... when you touch a surface lightly the area of the skin in contact with the surface is small and only the receptors in that skin are stimulated. pressing down firmly increases the area stimulated. this in calling of receptors on additional afferent neurons is known as recruitment. |
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Term
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Definition
| a single afferent neuron with all its receptor endings makes up a sensory unit |
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Term
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Definition
| the area of the body that when stimulate leads to acitivty in an afferent neuron. receptive fields of neighboring afferent neurons usually overlap so that the stimulation of a single point activates several sensory units. |
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Term
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Definition
| sensation from the skin, muscles, bones, tendons and joints |
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Term
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Definition
| rapid adapting mechanoreceptors, touch and pressure light touch |
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Term
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Definition
| slowly adapting mechanoreceptors, touch and pressure, light touchmerkel discs are the lowermost portion of the epidermis sensitive to very fine touch |
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Term
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Definition
| slowly adapting, some are nocioceptors, some are thermo receptors and some are mechanoreceptors |
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Term
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Definition
| rapidly adapting mechanoreceptors, vibration and deep pressure respond to pressure when it is first applied- detect deep pressure and vibration |
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Term
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Definition
| slowly adapting mechanoreceptors, respond to continuous pressure |
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Term
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Definition
| when incoming nocioceptive afferents activate interneurons it may lead to the phenomenon of referred pain in which the sensation of pain is experienced at a site other than the injured or diseased tissue |
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Term
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Definition
| selective supression of pain without effects on consciousness or other sensation0 electrical stiumaltion of specific areas of the CNS can produce a profound reduction in pain- stimulation produced analgeseia- by inhibiting pain pathways |
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Term
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Definition
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Term
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Definition
| circular and radial smooth muscle fibers of the iris determine the diameter of the pupil which is the anterior opening that allows light onto the eye |
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Term
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Definition
| behind iris, shape and focusing power determined by activity of ciliary muscle and resulting tension on the zonular fibers |
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Term
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Definition
| anterior chamber of the eye, b/w the iris and cornea is filled with clear fluid called aqueous humor, high protein concentration |
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Term
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Definition
| jelly like substance located in the posterior chamber between the lens and the retina, thicker |
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Term
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Definition
| formed from an extension of the developing brain in fetal life. it forms the inner posterior surface of the eye, containing numerous types of neurons including the sensory cells of the eye called photorecptors |
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Term
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Definition
| all adjustments for distance are made by changes in lens shape, changing the shape of the lens to accommodate incoming light |
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Term
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Definition
| progressive diminished inability to focus on near objects caused by elasticity of the lens |
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Term
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Definition
myopia- nearsightedness, unable to see distance, eye is too long
hyperopia- farsightedness, unable to see close, eye is too short |
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Term
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Definition
| rods are extremely sensitive and respond to very low levels of ilumination wheras cones are considerably less sensitive and respind only when light is bright |
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Term
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Definition
| photopigments contain membrane bound proteins called opsins which surround and bind a chromophore molecule which is retinal, the opsin is different in each of the potpigments and binds to the chromophore in a different way |
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Term
| Bipolar and Ganglion Cells |
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Definition
| light signals are converted into action potentials through interaction of photreceptors with bipolar and ganglion cells. photoreceptors and bipolar cells only undergo graded reponses b/c they lack voltage gated ion channels. ganglion cells have those channels and are therfore the first cells in the pathway where action potentials can be initiated |
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Term
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Definition
| 1st step in hearing is the entering of sound waves into this |
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Term
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Definition
| eardrum, stretched across end of the external auditory canal, as air molecules push agaisnt the membrane they cause it to vibrate at the same frequency as the sound wave. |
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Term
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Definition
| tympanic membrane separates the external auditory canal from the middle ear which is an air filled cavity in the temporal bone of the skull, pressure is equal to atmospheric pressure- exposed through eustachian tube to atmospheric pressure |
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Term
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Definition
| called the chochlea, is a spiral shaped, fluid filled space in the temporal bone which houses the semicircular canals, which contain the sensory organs for balance and movement |
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Term
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Definition
| these bones act as a piston and couple vibrations of the tympanic membrane to the oval window- a membrane covering opening seperating the middle ears and inner ears |
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Term
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Definition
| side of the cochlear duct nearest to the scala tympani is formed by the basilar membrane which sits on the organ of corti which contains the ears sensitive receptor cells. pressure differences across the cochlear duct cause the basilar membrane to vibrate. |
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Term
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Definition
| the receptor cells of the organ of corti are called hair cells. these cells are mechanoreceptos that have hair like stereocilia protruding from one end. a single row of inner hair cells and 3 rows of outer hair cells. inner ear cells extend into endolymph and transduce pressure waves into action potentials. outer hair cells are embedded in a techtorial membrane and sharpen frequency tuning |
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Term
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Definition
| structure in organ of corti in contact with receptor cell hairs |
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Term
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Definition
| a connected series of endolymph filled membraneous tubes that also connect with the chochlear duct. consists of 3 membraneous semicircular canals and 2 sac like swellings, the utricle and sacculae all of which lie in tunnels in temporal bone on each side of the head |
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Term
|
Definition
| stereocilia are encapsulated within a gelatinous mass, the cupula, which extends across the lumen of each semicircular canal at the ampulla, a slight bulge in the wall of each duct. |
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Term
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Definition
| the sterocilia preohecting from hair cells are covered by a gelatinous substances in which tiny stones or otoliths are embedded. otoliths are calcium carbonate crystals, make the gelatinous substance heavier than surrounding fluid, in response the gelatinous otolithic material moves according to the forces of gravity and pulls against hair cells so stereocilia bend and receptor cells are stimulated |
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Term
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Definition
| organs for taste also called gustation are 10,000 or so taste buds found in the mouth and throat. taste buds are small groups of cells arranged like orange slices around a hollow and are found in the walls of visible structures and are called lingual papillae |
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Term
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Definition
| sense of smell, 80% of flavor from food, odor is related to chemical structure |
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Term
|
Definition
| olfactory receptor neurons, the first cells in the pathway that give rise to the sense of smell, lie in a small patch of epithelium called the olfactory epithelium in upper part of nasal cavity |
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Term
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Definition
| the most important mechanism enabling the localization of a stimulus, sharpens contrast in the pattern of action potentials received by the CNS allowing a finer resolution of stimulus location |
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Term
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Definition
| front portion of the parietal lobe which contains information about body position, temperature, and pain etc |
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Term
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Definition
| vision hearing equilibrium small and taste |
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Term
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Definition
| touch pressure vibration temp body position and pain |
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Term
|
Definition
| vision hearing equilibrium small and taste |
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Term
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Definition
| modified of a sensory neuron, sit just below the epidermis |
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Term
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Definition
| detect body limb and position |
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Term
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Definition
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Term
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Definition
| activates C fibers and causes itch |
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Term
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Definition
| represents the relative somatosensation of the body, somatosensory areas in the cortex of the brain are anatomically organized in relation to the source of information, with larger areas dedicated to parts of the body that process fine discriminations |
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Term
| visual transduction occurs on the retina, and is based on the images focused there by the cornea and the lens |
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Definition
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Term
|
Definition
| connective tissue that are connected to the lens itself, they are constantly stretching the lens, ciliary muscles relaxes and pulls down on the zonular fibers which relax the lens when the ciliary muscle relaxes the zonular fibers contract the lens |
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Term
|
Definition
| lens that has become cloudy due to aging |
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Term
|
Definition
| results when pressure of the aqueous humor damages retinal cells, leading cause of blindness |
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Term
|
Definition
| results in the absence of one or more types of cones |
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Term
|
Definition
| outersegment, stacks where photopigments are, consists of two components retinol and opsin |
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Term
|
Definition
| derived from vitamin A which is light sensitive |
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Term
|
Definition
| a protein that holds retinol in place within the membrane of that disc |
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Term
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Definition
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Term
|
Definition
| light strikes retinol then retinol changes its shape so opsin can no longer bind to it |
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Term
|
Definition
| breaks down cyclic GMP which causes sodium channels to close which takes the membrane from -40 to -70 which creates a hyperpolarization |
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Term
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Definition
| determined by wave amplitude |
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Term
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Definition
| determined by wave frequency |
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Term
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Definition
| sensory cells of the inner ear, similar to rods/ cones of the eye, basilar membrane hold the hair cells in place, techtorial membrane rubs hair cells |
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Term
|
Definition
| blockage of signal transduction from external canal to organ of corti |
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Term
| sensorineural hearing loss |
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Definition
| damage to hair cells or vestibulocochlear nerve |
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Term
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Definition
| detects changes in the motion and position of the head by the use of fluid filled tubes near each ear. this system is connected to the cochlear duct |
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Term
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Definition
| (macula) sense linear acceleration and head position, can become detached from the macula which causes vertigo which is fixed with the henely maneuver |
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Term
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Definition
| involves the interaction of tastant molecules in saliva with the receptor cells in the taste buds on the papillae of the tongue; these receptor cells undergo only graded potentials during gustatory transduction |
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Term
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Definition
| neurons with long cilia covered by mucus located in the roof of the nasal cavity, oderants dissolve in the mucus and bind to the receptors causing the opening of ion channels leading to stimulation that is relayed to the olfactory bulb in the brain. |
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Term
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Definition
| large straited cells, banding pattern, multineucleated voluntary motor control |
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Term
|
Definition
| small, branched, striated cells, intercalated disk, gap junctions, single neuron |
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Term
|
Definition
| small cells with no striations, single nucleus |
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Term
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Definition
| functional unit of skeletal muscle, composed of thick and thin filaments |
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Term
|
Definition
| myosin, anchored in place by titin (elastic fibers), actually a polymer of myosin molecules, each of which has a flexible cross bridge that binds ATP and actin |
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Term
|
Definition
| actin, anchored to z lines |
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Term
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Definition
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Term
|
Definition
| weight that opposes contraction |
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Term
|
Definition
| creation of tension in the muscle |
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Term
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Definition
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Term
|
Definition
| myosin binds to actin and slides it pilling the z lines closer together and reducing the width of the I-bands |
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Term
|
Definition
| myosin cross bridges bind to actin, the cross bridges then flex (power stroke) to slide actin |
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Term
|
Definition
| release of Pi triggers release of the strained conformation pulling the actin filament towards the M line at the center of the sarcomere |
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Term
|
Definition
| when ADP is released, myosin is tightly bound to actin |
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Term
|
Definition
| tropomyosin on the thin filament blocks the myosin binding site |
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Term
|
Definition
| synapse between motor neuron and muscle fiber |
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Term
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Definition
| muscles stores, creatine phosphate, aerobic respiration, lactic acid fermentation |
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Term
|
Definition
| the inability to generate or maintain muscle contraction |
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Term
|
Definition
| tired feeling (psychological), lactic acid effects |
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Term
|
Definition
| glycogen depletion, Ca 2+ interference, high Pi levels, ECF high K+, Ach depletion |
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Term
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Definition
| single contraction-relaxtion cycle |
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Term
|
Definition
| between excitation and development of tension in a skeletal muscle includes the time needed to release Ca++ from sacroplasmic reticulum, move tropomyosin, and cycle the cross bridges |
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Term
|
Definition
| creates force without moving a load, tension increases rapidly and dissipates slowly |
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Term
|
Definition
| create a force and move a load, concetric contraction- shortening action ( load< tension), eccentric contraction is lengthening action ( load> tension), shortening occurs slowly only after taking up elastic tension, the relaxing muscle quickly returns to resting length |
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Term
| what determines the total tension developed by a muscle |
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Definition
| amount of tension developed by each fiber, the number of active fibers |
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Term
|
Definition
| the increase in muscle tension from successive action potentials |
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Term
|
Definition
| partial dissipation of elastic tension between subsequent stimuli |
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Term
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Definition
| no time for dissipation of elastic tension between rapidly recurring stimuli |
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Term
| why is the tension developed during tetanus greater than the twitch |
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Definition
| initial twitch overcomes elastic elements, persistent elevation of intra cellular ca ++ |
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Term
| skeletal muscles can be identified on the basis of |
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Definition
| their maximal velocities of shortening- fast or slow: myosin ATPase activity, the major pathways to form ATP-oxidative or glycotic |
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Term
|
Definition
| contract 2-3 times faster than slow twitch, faster uptake of Ca2+, faster ATP splitting( more myosin ATPase) |
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Term
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Definition
| aerobic, less fatigue, more mitochondria, more capillaries, myoglobin, endurance activities, postural muscles |
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Term
| fast oxidative glycolytic fibers |
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Definition
| intermediate speed, anaerobic and aerobic, most adaptable to training |
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Term
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Definition
| the activation of additional motor units |
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Term
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Definition
| genetic diseases that results in the progressive degeneration of skeletal and cardiac muscle fibers |
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Term
|
Definition
| caused by recessive gene of dystrophin protein involved in maintaining membrane integrity |
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Term
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Definition
| illness caused by the toxin botulinum (neurotoxin) produced by bacterium Clostridium botulinum, interferes with release of acetylcholine from motor neurons, causes muscle paralysis and even death |
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Term
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Definition
| illness caused by the neurotoxin tetanospasmin produced by bacterium Clostridium tetani, causes uncontrollable muscles spasms by amplifying signals at neuromuscular junction |
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Term
| single unit smooth muscle cells |
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Definition
| connected by gap junctions and the cells contract as a single unit |
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Term
| multi unit smooth muscle cells |
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Definition
| are not electrically linked and each cell must be stimulated independently |
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Term
|
Definition
| where adjacent cells are joined end to end, within them are gap junctions allowing rapid spread of electrical impulses |
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Term
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Definition
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Term
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Definition
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Term
|
Definition
| both sets of chambers are relaxed and ventricles fill passively |
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Term
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Definition
| atrial contraction forces a small amount of additional blood into the ventricles |
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Term
| isovolumic ventricular contraction |
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Definition
| first phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves |
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Term
|
Definition
| as ventricular pressure rises and exceeds pressure in the artieries, the semilunar valves open and blood is ejected |
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Term
| isovolumic ventricular relaxation |
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Definition
| as ventricles relax, pressure in the ventricles falls, blood flows back into cups of semilunar valves and snaps them closed |
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Term
|
Definition
| volume of blood pumped by one ventricle in a given period of time, CO=HR X SV |
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Term
|
Definition
| amount of blood pumped by one ventricle during contraction, at rest 70ml EDV- ESV= stroke volume |
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Term
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Definition
| deliver the sympathetic hormone, epinephrine and/or reduce release of parasympathetic neurotransmitter (acetylcholine) |
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Term
| to increase the heart stroke volume |
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Definition
| fill it more fully with blood. the increased stretch of the ventricle will align its actin and myosin in a more optimal pattern of overlap. |
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Term
|
Definition
| thick, muscular vessels that carry blood away from the heart must withstand high blood pressure |
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Term
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Definition
| alternating expansion and recoiling of arteries, measure of heart rate |
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Term
|
Definition
| function of cardiac output and resistance in the arterioles |
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Term
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Definition
| connect arteries to capillaries, the prime controllers of blood pressure, regulate blood flow to capillary networks |
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Term
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Definition
| increase resistance, decreased flow |
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Term
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Definition
| decreased resistance increased flow |
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Term
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Definition
| mass movement as a result of hydrostatic or osmotic pressure gradients |
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Term
|
Definition
| fluid movement into capillaries, net absorption at venous end |
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Term
|
Definition
| fluid movement out of capillaries, net filtration at arterial end |
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Term
|
Definition
| carry blood back to the heart and also serve as a reservoir for blood volume |
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Term
|
Definition
| alternations in venos return alter end diastolic volume; increased EDV directly increases stroke volume and cardiac output |
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Term
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Definition
| interstitial fluid that bluids up around the cells, enters lymph capillaries, then passes through a series of vessels and is returned to the circulatory system. |
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Term
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Definition
| filter lymph and contain macrophages and lymphocytes (WBCs) that activaley defend against disease causing organsisms |
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Term
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Definition
| parastitc worms blocks lymphatic vessels, causes build up of extracellular fluid- edema |
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Term
|
Definition
| function as sensors in the homeostatic maintenance of MAP by constantly monitoring pressure in the aortic arch and carotid sinuses |
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Term
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Definition
|
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Term
|
Definition
| erythrocyctes, transport oxygen to the cells, hemoglobin molecules in the RBCs bind to oxygen making oxyhemoglobin |
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Term
|
Definition
| leukocytes, help defend the body against disease and remove wastes, toxins, and damaged and abnormal cells, immunity; destroy pathogens, destroy cancerous or other abnormal cells, remove dead or injured cells |
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Term
|
Definition
| thrombocyctes, fragments of larger precursor cells called megakaryocytes which are essential to blood clotting |
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Term
|
Definition
| transportation, regulation of temperature, water volume, pH and defense |
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Term
|
Definition
|
|
Term
|
Definition
| EPO, a hormone controls RBC production, may stimulate production at 20 million cells a second, RBCs ultimately degraded by liver and spleen and excreted as bilirubin |
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Term
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Definition
| function of the pressure differences between the alveoli and the atomsphere divided by airflow resistance |
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Term
|
Definition
| the pressure of a fixed number of gas molecules is inversely proportional to the volume of the container |
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Term
|
Definition
| active process, expansion reduces aveolar pressure below atmospheric so air moves into the lungs |
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Term
|
Definition
| passive, the volume reduction increases alveolar pressure above atmospheric pressure so air moves out of the lungs |
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Term
|
Definition
| produced by red blood blood cells , cholesterol, the more 2,3 DPG facilitates unloading |
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Term
|
Definition
| infection causes fibrous tissue to form in the lings, causes rod shpaed bacterium, mycobacterium tunerculosis, more causes of TB are present now than ever before due to anitbiotic resistance DOTS |
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Term
|
Definition
| destruction of alveoli usually smoking, less surface area for gas exchange |
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Term
|
Definition
| persistent headache and weakness, nausea, fatigue, dizziness, does not respond to pain killers, people should climb down to lower altitudes |
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Term
|
Definition
| too much fluid accumulating in the tissues |
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Term
|
Definition
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Term
|
Definition
| gait ataxia, changes in mental status, may be caused by vasodilation of cerebral blood vessels, the increased blood flow causes increased filtration from capillaries |
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Term
| high altitude pulmonary edema |
|
Definition
| symptoms of HARE include difficulty breathing at rest, cough or congestion, weakness or reduced performance, attributed to patchy hypotoxic vasoconstriction in the pulmonary vascular bed, blood flow shunted through fewer vessels, resulting in ECF fluid build up in lungs |
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Term
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Definition
| elongated shape, multiple nuclei, created from myoblasts |
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Term
|
Definition
| undifferentiated, monucleated cell |
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Term
|
Definition
| cylindrical bundles, linked to tendons at the ends of the fiber |
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Term
|
Definition
| wide dark band on the thick filaments |
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Term
|
Definition
| interconnecting proteins on one end of each thin filament |
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Term
|
Definition
| light band that lies between the ends of the A bands of the two adjacent sacromeres and contains those portions of the thin filaments that do not overlap the thick filaments, bisected by the Z line |
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Term
|
Definition
| a narrow light band in the center of the A band. it corresponds to the space between the opposing ends of the two sets of thin filaments in each sarcomere |
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Term
|
Definition
| narrow dark band in the center of the H zone, corresponds to proteins that link tofether the central region of adjacent thick filaments. |
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Term
|
Definition
|
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Term
|
Definition
| the space between overlapping thick and thin filaments known as cross bridges. these are portions of myosin molecules that extend from the surface of the thick filaments toward the thin filaments. during muscle contraction the cross bridges make contact with the thin filaments and exert force on them. |
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|
Term
| sliding filament mechanism |
|
Definition
| when force generation produces shortening of a skeletal muscle fiber, the overlapping thick and thin filaments in each sarcomere move past each other propelled by movements of cross bridges. during this shortening of the sarcomeres there is no change in the lengths of either thick or thin filaments. |
|
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Term
|
Definition
| 1) attach of the cross bridge to the thin filament 2)movement of the cross bridge, producing tension in the thin filament 3) detachment of the cross bridge from the thin filament and 4) energizing the cross bridge so it can again attach to a thin filament and repeat the cycle. each cross bridges undergoes its own cycle of movement independy |
|
|
Term
| excitation contraction coupling |
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Definition
| refers to the sequence of events by which an action potential in the plasma membrane of a muscle fiber leads to the cross bridge activity |
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Term
|
Definition
| homologus to endoplasmic reticulum |
|
|
Term
| transverse tubule or T tubule |
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Definition
| tubular structure, lies directly between and is intimately associated with the lateral sacs of adjacent segments of the sarcoplasmic reticulum |
|
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Term
|
Definition
| T tubule protein is a modified voltage sensitive Ca 2+ channel, the main role is to act as a voltage sensor |
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Term
|
Definition
| a motor neuron and all the fibers that it innervates. located in one muscle but scattered throughout the muscle, when an action potential occurs in a motor neuron all the fibers in the motor unit are stimulated to contract |
|
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Term
|
Definition
| because of the difference in electrochemical gradients across the plasma membrane, more Na+ moves that K+ out producing local depolarization of the motor end plate, Thus an EPP is analogous to and EPSP |
|
|
Term
|
Definition
| the increase in muscle tension from successive action potentials occuring during the phase of mechanical activation is known as summation |
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|
Term
| Length Tension relationship |
|
Definition
| the length at which the fiber develops the greatest isometric contraction is termed optimal length, when a muscle fiber length is 60 percent of the optimal length the fiber develops no tension when stimulated. as the length is increased from this point, the isometric tension at each length is increased up to a maximum at optimal length. further lengthening leads to a drop in tension. at lengths of 175 percent of optimal length or beyond, the fiber develops no active tension when stimulated. |
|
|
Term
|
Definition
| elevated oxygen consumption following exercise repays the oxygen debt which is the increased production of ATP by oxidative phosphorylation following exercise is used to restore the energy reserves in the form of creatine phosphate |
|
|
Term
|
Definition
| fibers containing myosin with high ATPase activity are classified as fast fibers and are sometimes referred to as type II fibers |
|
|
Term
|
Definition
| fibers containing myosin with lower ATPase activity are called slow fibers or type 1 fibers, force produced is about the same as fast fibers and slow fibers but slow are 4 times slower |
|
|
Term
|
Definition
| some fibers contain numerous mitochondria and thus have a high capacity for oxidative phosphorylation. these fibers are classified as oxidative fibers |
|
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Term
|
Definition
| oxygen binding protein, which increases the rate of oxygen diffusion within the fiber and provides a small store of oxygen |
|
|
Term
|
Definition
| have few mitochondria but posses a high concentration of glycotic enzymes and a large store of glycogen . corresponding to their limited use of oxygen these fibers are surrounded by relatively few blood vessels and contain little myoglobin. |
|
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Term
|
Definition
| occurs when a phosphorylated cross bridge cecomes dephosphorylated while still attached to actin. in this circumstance, it can maintain tension in an almost rigor state without movement. disassociation of these dephosphorylated cross bridges from actin by the binding of ATP does occur, but at a much slower rate than dissociation of phosphorylated bridges. |
|
|
Term
|
Definition
| in some smooth muscle the cytosolic Ca 2+ concentration is sufficient to maintain a low level of basal cross bridge activity in the absence of external stimuli. this activity is known as smooth muscle tone |
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Term
|
Definition
| membrane potential change occuring during the spontaneous depolarization to threshold |
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Term
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Definition
| adjacent cells in cardiac muscles are joined at the end at this structure within which are desmosomes that hold cells together and to which the myofibrils are attached. |
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| depolarization during cardiac muscle cells action potentials is in part due to an influx of Ca 2+ through voltage gated channels. these Ca 2+ channels are known as L-type Ca 2+ channnels and are modified versions of the DHP receptors that act as the voltage sensor in skeletal muscle cell excitation-contaction coupling. these channels open much slower than do Na+ channels and because of that they remain open for a long period of time |
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| is defined as the percentage of blood volume that is erythrocytes |
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| includes blood pumped from the right ventricle through the lungs and then to the left atrium |
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| from left ventricle through all organs and tissue except the lungs and then to right atrium |
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| fibrous sac the heart is enclosed in |
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| inner layer of the pericardium closely affixed to the heart |
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| wall of the heart, composed of primarily cardiac muscles |
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| also known as the endothelium, thin layer of cells, also lines blood vessels |
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| permit blood flow from the atrium to ventricle but not backwards from ventricle to atrium |
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| cells that do not function in contraction of the heart but have specialized features that are essential for normal heart excitation. are in electrical contract with the cardiac muscle cells via gap junctions. the conducting system initiates the heartbeat and helps spread the impulse rapidly throughout the heart. |
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| the initial excitation of one cardiac cell therefore eventually results in the excitation of all cardiac cells. this initial depolarization normally arises in a small group of conducting cells called the SA node located near the right atrium near the entrance of the superior vena cava. the action potential then spreads from the SA node throughout the atria and then into and throughout the ventricles. |
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| potassium ion channels, which opened during repolarization phase of the previous action potential, gradually close due to the membranes return to negative potentials. second, pacemaker cells have a unique set of channels that, unlike most voltage gated channels, open when the membrane potential is at negative values. these nonspecific cation channels conduct mainly an inward depolarizing Na+ current and because of their unusual gating behavior, have been turned termed funny |
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| third pacemaker channel is a type of Ca 2+ channel that opens only briefly but contributes inward Ca 2+ current and an important final depolarizing boost to the pacemaker potential |
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| primary tool for evaluating electrical events in the heart |
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| ventricular depolarization |
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| ventricular repolarization, aterial presence is not evident on EKG because it occurs at the same time as the QRS complex |
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| absolute refactory period |
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| the inability of the heart to generate tetanic contractions is the result of the long absolute refactory period of cardiac muscle, defined as the period during and following an action potential when an excitable membrane cannot be re-excited. |
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| ventricular contraction and blood ejection |
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| ventricular relaxation and blood filling |
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| volume of blood each ventricle pumps, usually expressed in liters per minute. also the volume of blood flowing through either the systemic or the pulmonary circuit per minute |
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| the volume of blood each ventricle ejects during each contraction. |
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| the flow of blood from veins into the heart |
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| strength of contraction at any given end diastolic volume |
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| the high velocity blood flow is turbulent and therfore produces vibrations called korotkoffs sounds that can be hear through the stethoscope, not the same as heart sounds |
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| relax and causes radius to increase |
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| contract and decrease vessel radius |
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| most organs and tissues manifest an increased blood flow when their metabolic activity is increased. |
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| during skeletal muscle contraction, the veins running through the muscle are partially compressed, which reduces their diameter and forces more blood back to the heart, the valves permit blood flow only toward the heart and prevent back flow towrds the tissues |
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| at the base of the thorax, the diaphragm a large muscle descends during inspiration pushing on the abdominal contents and increasing abdominal pressure. this pressure increase is transmitted passively to the intraabdominal veins. similtaneously the pressure in the intrathoracic veins and right atrium. the net effect of the pressure chanes in the abdomen and thorax is to increase the pressure difference between the peripheral veins and the heart. thus venous return is enhanced during inspiration. the larger the inspiration, the greater the effect. therefore, breathing deeply and frequently, as in exercise helps blood flow towards the heart. |
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| total peripheral resistance |
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| sum of the resistances to flow offered by all the systemic blood vessels |
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| medullary cardiovascular center |
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Definition
| primary integrating center for the barorecptor reflexes is a diffuse network of highly interconnected neurons located in the medulla oblongata. The neurons in this center receive input from the various barorecptors, this input determines the action potential frequency from the cardiovasular center along neurons of the vagus neurons to the heart |
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| stimulates erythropoiesis |
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| platelets are produced when cytoplasmic portions of large bone marrow called megakaryocytes pinch off and enter the circulation. platelet functions in blood clotting are described later in this section |
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| transformation of blood into a solid gel called a clot or thrombus which consists mainly of a protein polymer known as fibrin. clotting occurs locally around the original platelet plug and is the dominant hemostatic defense. |
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| larynx opens up into long tube called the trachea |
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| branches from the trachea, 2 of them which enters each lung |
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| the walls of the trachea and bronchi contain rings of cartilage, which give them their cylindrical shape and support them. the first airway branches that no longer contain cartilage are the bronchioles. have alveoli |
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| continuous layer, one cell thick, of flat epithelial cells |
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| produce a detergent like substance called surfactant |
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| large domed shaped muscle sheet of skeletal muscle that seperates the thorax from abdomen |
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| muscles that run in between the ribs |
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| gas pressure in the alveoli |
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| magnitude of the change in lung volume produced by a given change in the transpulmonary pressure, the greater the lung compliance the easier it is to expand the lungs at any given change in transpulmonary pressure. compliance can be considered the inverse of stiffness |
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| reduces the cohesive forces between water molecules on the alveolar surface. therfore, surfactant lowers the surface tension, which increases the lung compliance and makes it easier to expand the lungs |
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| disease charaterized by intermittent episodes un which airway smooth muscle contracts strongly markedly increasing airway resistance. chronic inflammation of the airways |
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| volume of air enter the lungs during a single inspiration |
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| inspiratory reserve volume |
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| the maximal amount of air that can be increased above the resting tidal volume during deepest inspiration |
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| functional residual capacity |
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Definition
| lung volume after relaxed expiration |
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| expiratory reserve volume |
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Definition
| additional volume expired after the resting tidal volume has been expired |
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| the volume in the lungs even after active expiration, approximately 1200 mL of air |
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| the maximal volume of air a person can expire after a maximal inspiration. under these conditions the person is expiring both the resting |
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| space within airways that do not permit gas exchange |
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| ratio of CO2 produced to O2 consumed |
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| oxygen-hemoglobin disassociation curve |
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Definition
| it is evident that increasing the blood Po2 should increase the combination of the oxygen with hemoglobin. the experimentally determined quantitative relationship between these variables |
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| increased arterial H+ concentration due to carbon dioxide retention |
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| hyperventalation would lower arterial values of both Pco2 and H+ concentration |
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| peripheral chemoreceptors |
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| located in the neck at the bifurcation of the common carotid arteries and in the thorax on the arch of the aorta, responds to changes in arterial blood Po2 and H+ concentration |
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| located in the medulla, provide an excitatory synaptic input to the meduallary inspiratory neurons. they are stimulated by an increase in the H+ concentration of the brains extracellular fluid. |
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