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Flashcards by mathieteal, updated more than 1 year ago
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Created by mathieteal
almost 11 years ago
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| Question | Answer |
| Sensory receptors detect what? | Various stimuli and produce receptor potentials |
| Sensory receptors are based on? | Type of stimuli they are most sensitive to |
| Chemoreceptors sense? | smell, taste, PH, metabolite concentration (chemical) |
| Photoreceptors are for what? | Retina |
| Thermoreceptors sense what? | Temperature |
| Mechanoreceptors sense what? | physical deformation, touch, muscle tension, auditory vestibular receptors |
| Noriceptors sense what? | pain |
| Which of the receptors is most varied? | Mechanoreceptors |
| When multiple receptors combine, what kind of sensation is produced? | Richer and more complex |
| Is somatosensation varied? | Yes |
| What are some divisions of somatosensation? | Mechanical, chemical, thermal |
| Somatic sensory system mediates what? | The most diverse range of sensations |
| What are examples of somatic sensory sensations? | fine touch, crude touch, pressure, proprioception, heat, cold, pain |
| What are the most sensitive types of receptors? | Mechanoreceptors |
| All sensations are transducer by specialized PNS/CNS receptors? | PNS |
| How are sensations transducer? | From PNS to specific CNS targets |
| What are anatomically and functionally distinct for the variety of receptor systems? | Their neural pathways. |
| Where does somatic sensation arise? | from activity at endings of sensory nerve fibers - denritic process |
| Somatic sensation arises from nerve fibers in two places... __ and __. | Skin and muscle |
| Where do cell bodies of sensory neurons reside? (two places) | ganglia alongside spinal cord and brainstem |
| What are the two ganglia where sensory neurons reside? | Dorsal root ganglia and cranial nerve ganglia |
| Action potentials generated at the peripheral end along what fiber past a cell body and terminate where? | In the terminal CNS structure |
| What is transduction? | Conversion of one form of energy into another |
| Transduction converts ___ into ___. (electrical stimulus, physical stimulus, mechanical stimulus, chemical stimulus) | physical stimulus into electrical signal |
| Transduction requires a stimulus to be converted so what system can understand it's impulse? | Nervous system |
| What is sensory transduction? | Conversion or pressure, touch, heat, etc. into neural impulse |
| What is one form of energy? | Stimulus |
| What are examples of receptor potentials? | heat, pressure, pain, touch... |
| Nature and location of a stimulus indicate what? | What receptors will respond |
| What is needed to indicate the size and duration of the receptor potential produced? | Intensity and duration |
| Intensity can be? | low or high |
| Are all receptors the same in sensitivity? | No; some are more and some are less. |
| Do all receptors produce long or short responses? | Varied. |
| Can a receptor produce a short response even if the stimulus is maintained? | Yes. |
| Do receptors respond to a variety or stimuli? | No; they respond to only one kind. |
| How are receptor potentials produced? (ion channels) | Opening and closing of channels. |
| Sensory receptors are analogous to what? | postsynaptic membranes |
| Most post synaptic membranes and their adequate stimulus can be analogous to what? | Neurotransmitters |
| If a receptor contacts the next cell that is close to the site of transduction, what happens? | the receptor potential can modulate the rate of neurotransmitter released, causing a postynaptic potential and a change in action potential frequency. |
| If a receptor is far from the next cell, the receptor potential will do what? | Die out; but usually it can cause an action potential in the receptor. The frequency of the action potential is also modulated by the receptor potential. |
| What is the difference between a close and far receptor potential? | Whether a synapse will occur. |
| Can a receptor potential become an action potential? | Yes. |
| Define what a receptive field is? | particular areas in the periphery where application of an adequate stimulus causes them to respond. |
| Does a receptive field respond to everything? | No; stimulus must be big enough to trigger the field. |
| Are receptive fields the same size? | No; can be big or small. |
| When there is no obvious spatial domain in a receptive field, how does it sense stimuli? | the array of receptors have a systematic representation of parameters (i.e.: sound in the cochlea and auditory cortex). |
| What does a receptive field require to notice a stimulus? (2) | 1. have to be big enough to be detected 2. has to be within the receptive field to be detected. |
| Receptive fields correspond to: efferent/afferent fibers? | Afferent. |
| Receptive fields correspond to single/multiple afferent fibers? | single |
| Which has smaller receptive fields: fine touch/crude touch | Fine |
| Where do fine touch have small receptive fields than crude touch? | because of fewer branches and denser innervation |
| What receptive fields are the finest? | lips, tongue, fingers |
| Give an example of a receptor field with spatial domain? | Fingers, lips, tongue. |
| give an example of an area with no spacial domain? | hair cells (the respond to frequency) |
| Do neuros in high orders (such as the thalamus or cortical neurons) have receptive fields? | Yes |
| Are higher order RF more or less complex? | More. |
| What does the visual cortex respond to? | edges with particular orientation |
| How can you test for a receptive field? | A two point discrimination test |
| What do you use to do a two-point discrimination test? | Calipers |
| If a caliper has a perception of two points, what does this indicate? | Activation of different fibers |
| If a caliper has only one point indicated, what does this mean? | The two points are within one receptive field |
| Sensory receptor adaptation: become more/less sensitive during maintained stimulus? | Less |
| What is the exception of becoming less sensitive to a stimulus with continued exposure? | Pain (nociceptors) |
| What are slowly adapting receptors suitable for? | static position, size, shape, duration |
| What are rapidly adapting receptors good for? | change and movement of stimuli |
| Adaptation takes place at CNS/PNS level? | PNS |
| Does the CNS regulate sensitivity of receptors? | Yes; moment-to-moment basis |
| What does the CNS do to regulate moment-to-moment sensitivity? | controls amount of light to retinas |
| CNS control over sensitivity or receptors is bottom up / top down / both? | Top down control |
| Slowly adapting sensitivity, is short/long; continual/fades? | Long, continual |
| Rapidly adapting sensory response is short/long, continual/brief? | short, brief |
| Afferent fibers of different receptors also differ in what? | diameter myelination |
| What does the largest afferent supply? | Receptors in muscles |
| What do intermediate diameter fibers mediate? | touch |
| What do the smallest afferent fibers mediate? | Temperature and pain |
| How many kinds of touch receptors do we have? | 4 |
| What are the four kinds of touch receptor sensory function? | proprioception, touch, pain/temperature, pain/temperature/itch |
| Receptor type: muscle spindle function? | proprioception |
| receptor type: free nerve ending and the smallest kind. function? | pain/temperature/itch |
| receptor type: merkel, meissner, pacinian, and ruff ini cells. function? | touch |
| Receptor type: free nerve ending, A theta function? | pain and temperature |
| What is the largest receptor type based on axon diameter? | muscle spindle |
| Second largest sensory fiber axon diameter belongs to what receptor type? | merkel, meissner, pacinian, ruffini |
| Do both free nerve endings have myelin? | No; smallest does not |
| Are all afferent fiber endings covered in myelin? | No. Some are and some aren't. |
| Encapsulated means? | have layers of myelin |
| What do capsules serve to do? | mechanical filter, modifying the mechanical stimuli before it reaches the end. |
| Afferents with specialized/encapsulated receptors are: slow/rapidly adapting and generally have lower/high thresholds for AP? | rapidly, lower |
| Where ar free nerve endings (non encapsulated) found? | formed by branching terminations of sensory fibers in the skin... no obvious specialization around them. Found throughout the body. |
| What are the four kinds of tactile receptors in the skin? | Meissner, merkel, ruffini, pacinan |
| If a receptor has a bigger field, density will be higher/lower? | Lower |
| If a receptor has a high density, the field will be bigger/smaller? | Smaller |
| What are the two big receptor field cells? | Pacinian and Ruffini |
| What are the two smaller receptor fields? | Merkel and Meissner |
| Merkel sensory function? | Form and texture perception |
| Meissner sensory function? | Motion detection; grip control |
| Pacinian sensory function? | Tool use; perception of distant events |
| Ruffini sensory function? | Hand shape, motion, direction |
| Which has a smaller receptive field, merkel or meissner? | Merkel (9mm) |
| Which cell has a receptor field of the entire finger/hand? | Pacinian |
| Merkel cells are rapidly/slowly adapting fibers? | Slowly |
| Merkel cells account for 15, 25, 35 % of mechanoreceptors in the hand? | 25% |
| Where are Merkel cells most densely located? | fingertips |
| Merkel cells have high spatial resolution for detecting what? (3) | edges points curvature (texture) |
| Meissner cells are slowly/rapdily adapting? | Rapidly |
| Meissner account for 10, 30, 40, 60% of receptors in hand? | 40% |
| Meissner receptor field is bigger/smaller than Merkel? | Bigger |
| Meissner is most sensitive to skin ___? | Deformation |
| Meissner is highly sensitive to ___? | Vibration (motion detection when things move across the skin) |
| Detecting slippage between skin and object is a role for: Merkel, Meissner? | Meissner |
| Pacinian receptor field is slowly/rapidly adapting? | Rapidly |
| Pacinian accounts for , 5, 10, 15% of receptors in the hand? | 15% |
| Pacinian is an onion like structure found where in the hand? | Deep |
| Pacinian is most sensitive to what? | Tiny skin displacements, such as detecting tiny vibrations from tool use |
| Ruffini is a slowly/rapidly adapting receptor? | Slowly |
| Ruffini accounts for 10, 15, 20, 25% of receptors? | 20% |
| Ruffini provides information about what? | hand shape and finger position; sensitive to movements |
| Do non-nociceptive thermal receptors discharge at greater rates if pain is induced? | no |
| When do nociceptors respond? | When stimulus reaches intensive levels and continues to increase |
| How many types of pain conduction fibers are there? | 2 |
| What are the two types of nociceptors? | A delta and C fiber |
| Which pain fiber is this: rapidly conducting; respond to dangerously intense mechanical and/or thermal stimuli; thinly myeliniated; more selective to the type of stimuli? | A delta; "first pain" or "delta pain" |
| Which pain fiber is this? is unmyelinated, polymodal and respond to thermal, mechanical, and chemical stimuli | C fiber - "slow pain" or "aching pain" |
| Which responds to more kinds of stimulus: a delta or c fiber? why? | C fiber. Unmyelinated and slower. |
| Which respond to sharp first pain? | A delta |
| Which pain is diffused and lasts longer? | C fiber pain |
| Pain pathways are located where? | Dorsal root ganglia and cranial nerve ganglia |
| Pain enters the spinal cord, processes run up and down several levels to provide contact with what? | 1st neuron |
| What do second order neurons do in pain pathways? | Decussate and ascent in ventrolateral quadrant of spinal cord |
| Spinal cord carries pain to where? | Medulla |
| Pain ends in the ___ (location) call ___ (tract) | anterolateral system and spinothalamic tract |
| Does the pain pathway always/sometimes/never decussate? | Always |
| Does pain decussate in dorsal? | No... in spinal cord 2nd neuon |
| Proprioception is about information received from? | limbs, muscle force, muscle tension, joint stress |
| What is another meaning for proprioception? | receptors for self |
| Vestibuloreceptors convey information about what? | head position |
| We understand proprioception from studying what? | Muscle spindles |
| Muscle spindles are found in most skeletal muscles EXCEPT? (2) | Face and larynx |
| Muscle spindle is a capsule of what? | specialized muscle fibers |
| Muscle spindles are activated how? | stretching of fibers |
| Jaw/tongue have sparse/dense muscle spindles? | Dense |
| Golgi tendon organs are activated how? | Changes in muscle tension |
| Are golgi tendon organs activated with high or low threshold mechanoreceptors? | low |
| Golgi tensors are between what? | muscle fibers and tendons |
| Muscle contraction ___ golgi tendon organs | stretches |
| there are few/many golgi tendon organs in the face/pharynx | few |
| Somatosensory information is _ neuron pathway? | 3 |
| Neuon pathway for somatosensory information is? | 1. muscle spindle 2. spinal cord 3. thalamus |
| The spinal cord has how many types of sensation? What are they? | 3. 1. propreoception 2. touch/pressure 3. pain |
| Which decussate? proprioception/pain/touch and pressure? | pain |
| Primary afferents carrying tactile and proprioceptive information synapse where? | posterior column nuclei of ipsilateral medulla |
| second-order neurons then cross the midline and form the? | meial lemniscus, and ascent to the VPL nucleus of thalamus |
| Third order neurons project the somatosensory information ? | cortex of the post central gyrus |
| Spinothalamic tract: has what | pain, temperature, and some touch/pressure afferents |
| spinothalamic tract: 2nd order fibers cross the midline forming? and ascent to? | spinothalamic tract VPL nucleus of the thalamus |
| Spinothalamic tract: thalamic cells project somatosensory cortex of the | postcentral gyrus, insula, and other cortical areas |
| Damage to the spinal cord at level of the ventral horn will cause diminution of ___ on the ___ side to the lesion and diminution of ___ to the ___ side of the lesion | touch on the ipsilateral pain to the contralateral |
| Damage rostral to the medulla would cause diminution of ___ and ___ on the ___ side of the lesion | pain and touch on the contralateral |
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