Term
| Exteroreceptors (based on location) |
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Definition
- found near body surface
- respond to stimuli from OUTSIDE the body
- sensitive to touch, pressure, pain, temperature
- includes special sense organs |
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Term
| Interoreceptors (based on location) |
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Definition
- found in internal viscera and blood vessels
- respond to stimuli from within the body
- sensitive to chemical changes, stretch, and temperature changes |
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Term
| Proprioceptors (based on location) |
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Definition
- located in skeletal muscle, joints, ligaments, and connective tissue coverings of bone and muscles
- respond to degree of stretch of organs they occupy
- constantly "advise" brain of movements |
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Term
| mechanoreceptors (based on stimulus type) |
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Definition
| - respond to touch, pressure, vibration, stretch, and itch |
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Term
| thermoreceptors (based on stimulus type) |
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Definition
| - respond to changes in temperature |
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Term
| photoreceptors (based on stimulus type) |
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Definition
| - respond to light energy (retina) |
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Term
| chemoreceptors (based on stimulus type) |
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Definition
| - respond to chemicals (taste, smell, changes in blood chemistry) |
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Term
| nociceptors (based on stimulus type) |
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Definition
| - sensitive to pain causing stimuli |
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Term
| Receptors are structurally classified as __ or ___. Most are ___. ___ receptors are special sense organs. |
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Definition
- simple or complex
- simple
- complex are special sense organs |
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Term
| Most receptors are ___ and are either ____ or ____. |
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Definition
- simple
- encapsulated
- unencapsulated |
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Term
| examples of unencapsulated simple receptors: |
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Definition
- free nerve endings of sensory neurons (most body tissues, connective tissue, tendons, dermis, joint capsules, epithelia, cornea, mucosae, glands)
- Merkel tactile discs= modified free nerve endings, basal layer of epidermis
- hair follicle receptors in and around hair follicles |
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Term
| examples of simple encapsulated receptors: |
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Definition
- Meissner's corpuscles- dermal papillae of hairless skin like nipples, external genitalia, fingetips, soles of feet, and eyelids)
- Pacinian corpuscles (lamellated corpuscles)- dermis, hypodermis, tendons, ligaments, joint capsules, deep pressure
- Ruffini endings: deep in dermis, hypodermis, and joint capsules
- muscle spindles
- golgi tendon organs- tendons
- joint kinesthetic receptors |
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Term
| VPM is innervated by the ___ nerve. |
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Definition
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Term
| VPL is innervated by what nerve? |
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Definition
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Term
| explain order of neurons in somatosensory tract : |
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Definition
| - receptors stimulated > CN V ganglion or dorsal root ganglion first order neuron carries information to spinal cord or medulla> in spinal cord or medulla axons cross to opposite side when first order synapses with the second order neuron> second order neuron carries information to VPL or VPM nucleus in the thalamus where the N2 synapses with the 3rd order neuron> 3rd order neuron carries information to the somatosensory cortex |
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Term
| look at slide 12 on this lecture and know where lateral and ventral spinothalamic tracts are and where dorsal and ventral spinocerebellar tracts are. |
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Definition
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Term
| What 2 ascending pathways are for conscious sensory information? What ascending pathway is for unconscious sensory information? |
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Definition
Conscious:
- Ventrolateral pathways: lateral and
ventral spinothalamic tracts
- Dorsal medial lemniscal pathways:
fasciculus gracilis and fasciculs
cuneatous
Unconscious:
- Spinocerebellar pathway: dorsal and
ventral spinocerebellar tracts |
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Term
| what are the two tracts in the ventrolateral pathway and what do they sense? |
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Definition
- lateral spinothalamic tract: pain and temperature
- ventral spinothalamic tract: light touch and pressure |
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Term
| what are the tracts in the dorsal column medial lemniscal pathway: |
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Definition
- fasciculus gracilis and fasciculus cutaneous (cutaneous only above t6)
- pressure
- discriminative touch
- stereognosis
- 2 point discrimation
- complex tactile discrimination
- vibratory sense
- proprioception |
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Term
| what 2 ascending pathways are for conscious sensory information: |
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Definition
- ventrolateral pathway: spinothalamic
- dorsal medial lemniscal pathway: gracilis and cuneatous |
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Term
| what ascending pathway is for unconscious snesory information? |
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Definition
| - Spinocerebellar: dorsal and ventral |
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Term
| what are the 2 tracts in the spinocerebellar pathway? |
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Definition
- Dorsal Spinocerebellar tract: carries sensation from trunk and upper and lower limb proprioceptors for maintenance of posture and coordination of limb movements
- Ventral Spinocerebellar tract: carries sensation from trunk and lower limb proprioceptors for maintenance of posture and coordination of lower limb movements. |
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Term
| what is the main difference b/w the dorsal and ventral spinocerebellar tracts? |
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Definition
| - both have same function of maintaining posture and coordinating limb movements but the dorsal goes to trunk, lower, and upper limbs, while the ventral only goes to lower limb and trunk, no upper limb with ventral |
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Term
| the most white area is in the ___ region, as you descend this decreases |
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Definition
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Term
| For the dorsal medial lemniscal pathway, first order neurons are stimulated in the skin and this sensation passes in the first order neuron through the cell body in the dorsal root ganglion and up the spinal cord in the dorsal column. Then at the medulla oblongata, the first order neuron synapses with the second order neuron in the fasciculus gracilis or fasciculus cuneatus. The second order neuron crosses over to the other side of the medulla as the internal arcuate fibers which form the medial lemnsisucs. This crossing over is often referred to as sensory decussation. The second order neurons travel up the rest of the brainstem and then synapse in the thalamus with a third order neuron at the ventral posteriolateral nucleus or the ventral posteriomedial nucleus. The third order neurons travel up the internal capsule and the axons synapse in the primary sensory cortex with lower body senses more medial and upper body senses more lateral. |
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Definition
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Term
| all senses except for smell and cerebellum stuff have to go to the ___ before going to the cerebral cortex. |
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Definition
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Term
| look at slide 30 of this lecture for Broadmann's areas. |
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Definition
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Term
| look at homonculus drawn out from last week |
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Definition
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Term
| The spinothalamic tract crosses over at the ___ ___ instead of at the ___ like the dorsal medial lemniscal pathway. |
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Definition
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Term
| the dorsal medial lemniscal pathway crosses over at the ___ specifically the ___ ___. |
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Definition
- brainstem
- medulla oblongata |
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Term
| the spinothalamic tract crosses over at the __ ___. |
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Definition
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Term
| first order neurons of the lateral spinothalamic tract originate in the ___ horn but immediately decussate (cross over) in the ____ ___ ___ with second order neurons to the contralateral side of the spine. They then ascend up the spinal cord, past the medulla, and up to the ____ ____ ____ of the thalamus where they synapse with third order neurons which take the information to the sensory cortex |
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Definition
- dorsal horn
- anterior white commissure
- ventral posterolateral nucleus |
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Term
| crude/light touch and pressure on the right side of the body will travel up what tract and will end in what hemisphere of cerebrum. Where does the cross over happen? |
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Definition
- ventral spinothalamic tract
- left side
- cross over happens in spinal cord when first order neuron in dorsal root ganglion synapses with second order neuron that cross the anterior commissure |
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Term
| pain and temperature in the right side of the body will be carried by what tract and will be sent to what side of cerebrum? |
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Definition
- lateral spinothalamic tract
- left side of cerebrum |
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Term
| spinocerebellar axons terminate in the ___ side of the ____. |
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Definition
- ipsilateral
- cerebellum |
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Term
| with the dorsal spinocerebellar tract, first order neurons from the dorsal root ganglion synapse in Clark's nucleus with second order neurons. These second order neurons ascend uncrossed as the dorsal spinocerebellar tract and carry the information into the cerebellum via the inferior cerebellar peduncle. |
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Definition
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Term
| if the dorsal spinocerebellar tract is damaged what happens? |
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Definition
Fredericks ataxia= genetic
- loss of coordination
- muscle weakness in arms and legs |
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Term
| The ventral spinocerebellar tract has its first order neuron in the dorsal root ganglion. The first order neuron synapses with 2 second order neurons in the nucleus of Clark. The second order neurons send their axons bilaterally up the spinal cord. Most of the second order neuron axons cross and ascend as the contralateral ventral spinocerebellar tract.The ones that cross, recross within the cerebellum. Other second order neuron axons do not cross and ascend the spinal cord as the ipsilateral ventral spinocerebellar tract. The second order neurons enter the cerebellum via the superior cerebellar peduncle. |
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Definition
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Term
| So even though many of the ventral spinocerebellar second order neurons cross, they recross in the cerebellum, thus both dorsal and ventral spinocerebellar tracts synpase in the cerebellar cortex on the SAME side as the original stimulus. |
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Definition
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