Term
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Definition
means by which brain receives info about environment from body
somatic: touch, pressure, temp, prop, pn
visceral: internal organs-pn and pressure |
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Term
| 7 Types of Sensory Receptors |
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Definition
Chemoreceptors: smell and taste
thermoreceptors: temp
photoreceptors: light/vision
nociceptors: pain
exteroreceptors: associated with skin
visceroreceptors: associated with organs
proprioceptors: associated with jts/tendons (GTO) |
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Term
Sensory Transduction
(ascending pathway) |
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Definition
adequate stimulus: changes membrane
receptor potential leads to AP
AP produced in receptor or in connected neuron. |
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Term
| Frequency Code of stimulus intensity |
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Definition
| number of AP's per unit of time |
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Term
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Definition
| more sensory receptors are activated as stimulus intensity increases |
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Term
| Labeled Line code of stimulus quality |
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Definition
info about quality or type of stimulus is maintained in each pathway without getting mixed with other info
Info sent to thalamus is contralateral |
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Term
adaptation
Slowly adapting
Rapidly Adapting |
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Definition
mechanoreceptors vary in persistence of response to long lasting stimulu
slow= merkel's disk and ruffini's endings
rapid= meissners and pacinian corpuscles |
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Term
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Definition
| region of the body surface that causes a sensory nerve cell to respond |
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Term
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Definition
Looks like onion
Fast adapting
large borders
good for rapid changing stimulus, vibration |
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Term
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Definition
Looks like tornado
good for tactile discrimination, 2 point
Fast adapting
Small sharp borders |
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Term
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Definition
Small Borders
Slow adapting
light touch, superficial pressure |
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Term
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Definition
Looks like cigar
senses tension
Large Borders
Slow adapting |
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Term
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Definition
| cold, warm and pain receptors |
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Term
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Definition
Large to small, myelinated to unmyelinated
Aalpha: touch
Abeta: touch
Adelta: pain and Temp
C: Pain and Temp |
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Term
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Definition
Large to small, myelinated to unmyelinated
Aalpha: touch
Abeta: touch
Adelta: pain and Temp
C: Pain and Temp |
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Term
| Second order sensory neurons |
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Definition
receive input from primary
Myelinated Abeta touch sensitive |
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Term
Dorsal Column System: Medial Lemniscal
Fasciculus Gracilis
Fasciculus Cuneatus |
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Definition
Fasciculus Gracilis= below T6
Fasciculus Cuneatus= lateral to gracilis above T6 |
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Term
| Dorsal Column- Medial Lemnsicus |
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Definition
| primary neuron enters SC at or below T6 . Ascends to lower medulla and synapses with 2nd neuron in dorsal column nuclei (gracilis/cuneatus). Ascend then Cross |
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Term
| Medial Lemniscus sensations |
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Definition
| 2 point discriminiation, proprioception, pressure, vibration |
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Term
| Trigeminal Touch - Trigeminal Nerve (5) |
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Definition
somatic sensation of face
breaks into 2 nerves to innervate face, mouth, tongue (opthalmic, maxillary, mandibular) |
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Term
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Definition
S1=Area 3b (touch)receives info from thalamus
postcentral gyrus
3a (proprioception)
1&2 receive info from 3b- texture, size and shape |
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Term
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Definition
legs and trunk fold over the midline; the arms and hands are along the middle
face is near the bottom
the lips and hands are enlarged since a larger number of neurons in the cerebral cortex are devoted to processing information from these areas. |
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Term
| Posterior Parietal Cortex Damage |
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Definition
needs info from visual system, the auditory system, and the somatosensory system
Agnosia: inability to recognize objects
Neglect Syndrome: part of the body or world is ignored |
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Term
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Definition
Pain= feeling of sore, aching, throbbing
nociceptoin= sensory process, provides signals that trigger pain |
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Term
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Definition
Mechanically gate channels opened by strong mech stimulation, temp extremes, oxygen deprivation, chemicals
Damaged cells release substance to open ion channels
-proteases (bradykinin), ATP, K
- Mast cells: histamine released causes depolarization (GPCR)
-Lactic Acid: H activates H gated channels |
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Term
Type of Nociceptors
Hyperalgesia |
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Definition
Polymodal: chemical, thermal, mechanical
Mechanical
Thermal
Chemical
Hyperalgesia: Primary- directly in damaged tissues
secondary: in surrounding undamaged tissues |
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Term
Fast vs Slow Pain
Aspirin? |
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Definition
first pain= Adelta, sharp
second pain= C, dull pain
Aspirin works on slow pain because it crosses into unmyelinated fibers |
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Term
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Definition
ex) Angina
Dorsal Nerve Nuclei run in same cells and body misinterprets origin |
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Term
| zone of lissauer (posterolateral tract) |
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Definition
1st order neurons carry discriminative pain and temperature information (location, intensity and quality
terminate in substantia gelatinosa |
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Term
| Differences between touch and pain pathways |
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Definition
1) Nerve endings: touch= specialized structures, pain= free nerve endings
2) diameter of axon- touch= fast Abeta, pain= slow Adelta and C
3) Spinal cord connections: touch= ipsilateral pain= contralateral
Abeta terminate in deep dorsal horn
Adelta &C terminate in substantia gelatinosa |
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Term
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Definition
Cross then ascend
Adelta, C= pain |
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Term
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Definition
Release serotonin into brain
inhibit pain sensation |
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Term
Spinocerebellar System
posterior vs anterior |
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Definition
carry proprioceptive info to cerebellum
posterior= ipsilateral (inferior cerebellar peduncle)
anterior= contralateral (crosses 2x)(superior cerebellar peduncle) |
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Term
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Definition
Cold= A delta and C
5-10x more abundant
temps less than 30 C
Hot= C
temps more than 30 C |
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