Neuro - Pt 3 Sensory and Receptors

Question 1

Cortical Motor Areas:

1. Primary Motor Cortex: causes muscle contraction with [] funtions
2. Supplemental motor area (anterior to the primary motor cortex): causes muscle contractions with [] [] functions
3. Premotor Cortex: capable of controlling [] movements involving [] muscles simultaneously

Answer 1

Cortical Motor Areas:

1. Primary Motor Cortex: causes muscle contraction with defined funtions
2. Supplemental motor area (anterior to the primary motor cortex): causes muscle contractions with less defined functions
3. Premotor Cortex: capable of controlling coordinated movements involving many muscles simultaneously

Question 2

Brainstem - a [] generator for posture

Answer 2

tone

Question 3

Receptors can be grouped accroding to…

1. The [] of the stimulus
2. The type of stimulus []
3. Type of [] they elicit
4. [] of adaptation

Answer 3

1. The source of the stimulus
2. The type of stimulus energy
3. Type of sensation they elicit
4. Rate of adaptation

Question 4

Receptors grouped according to the source of the stimulus:

1. []: respond to stimuli from outside of the body
2. []: respond to stimuli from within the body (ex: chemoreceptors)

Answer 4

1. Exteroreceptors: respond to stimuli from outside of the body
2. Enteroreceptors: respond to stimuli from within the body

Question 5

Nociceptors actually detect [] [] …not “pain.”

Answer 5

tissue damage

Question 6

Adequate Stimulus:

• a receptor may be stimulated by many kinds of stimuli, however, there is one form of [] to which it is [] sensitive

Answer 6

a receptor may be stimulated by many kinds of stimuli, however, there is one form of energy to which it is most sensitive

Question 7

Law of Specific Nerve Energies

• the [] characteristic of a sensory neuron is the one produced by its [] []

Answer 7

the sensation characteristic of a sensory neuron is the one produced by its adequate stimulus

Question 8

Receptors grouped according to the type of sensation they elicit:

• This is termed []
  
  • Include: vision, smell, taste, muscle tension, blood pressure, etc.

Answer 8

• This is termed modality
  
  • Include: vision, smell, taste, muscle tension, blood pressure, etc.

Question 9

Receptors grouped according to their rate of adaptation:

1. Slowly adapting - [], static receptors
   
   1. Respond [] during stimulation
   2. Inform the [] of the status of the body in relation to surroundings
2. Rapdily adapting - [], dynamic receptors
   
   1. Respond at a [] rate during []application
   2. Reacts [] when a change in th elevel of stimulation takes place

Answer 9

1. Slowly adapting - tonic, static receptors
   
   1. Respond continuously during stimulation
   2. Inform the CNS of the status of the body in relation to surroundings
2. Rapdily adapting - phasic, dynamic receptors
   
   1. Respond at a decreasing rate during stimulus application
   2. Reacts strongly when a change in th level of stimulation takes place

Question 10

Generator Potential of Receptors:

• Very similar to a [] potential…NOT an [] []
• It is [] change in the membrane potential of the receptor in proportion to the [] of the stimulus
• It is a [] potential at the receptor

Answer 10

• Very similar to a graded potential…NOT an action potential
• It is a graded change in the membrane potential of the receptor in proportion to the magnitude of the stimulus
• It is a local potential at the receptor

Question 11

Stimulus Intensity Discrimination:

• Firing frequency: stronger stimuli = [] firing rates. Stimulus intensity is derived from [] of impulses
• Recruitment: As the strength of the stimulus [], more receptors fire
• Threshold stimulus: it is the [] stimulus that can be detected.

Answer 11

• Firing frequency: stronger stimuli = faster firing rates. Stimulus intensity is derived from frequency of impulses
• Recruitment: As the strength of the stimulus increases, more receptors fire
• Threshold stimulus: it is the weakest stimulus that can be detected.

Question 12

Sensory Neuron Location:

1. Each sensory neuron receives information from a particular sensory area or its [] []
2. Each sensory neuron projects to a specific spot on the [] cortex
3. [] [] : While receptors are being stimulated are firing, their adjacent receptors are inhibits.

Answer 12

Sensory Neuron Location:

1. Each sensory neuron receives information from a particular sensory area or its receptive field
2. Each sensory neuron projects to a specific spot on the cerebral cortex
3. Lateral Inhibition: While receptors are being stimulated are firing, their adjacent receptors are inhibits.

Question 13

Receptor Stimulus Quality:

1. [] [] regardless of how a receptor is stimulated, if it fires, the message received by the CNS is the same.

Answer 13

Receptor Stimulus Quality:

1. Labelled line: regardless of how a receptor is stimulated, if it fires, the message received by the CNS is the same.

Question 14

Receptor Stimulus Quality:

1. Law of Projection: no matter where along a [] pathway is stimulated, the cortex will perceive the same [].
   
   1. [] [] - feeling pain in a lost limb cuz you old nerves are still there.

Answer 14

1. Law of Projection: no matter where along a sensory pathway is stimulated, the cortex will perceive the same sensation.
   
   1. Phantom limb - feeling pain in a lost limb cuz you old nerves are still there.

Question 15

Receptor Stimulus Quality:

• Feature detectors: neurons in the brain that [] information from a variety of sensory fibers and fire to indicate the presence of a [] stimulus - higher level processing

Answer 15

• Feature detectors: neurons in the brain that integrate information from a variety of sensory fibers and fire to indicate the presence of a complex stimulus - higher level processing

Question 16

Vibration Reception:

• Receptor is [] Corpuscle
• Mediates fine [] and []
• Found underneath the []
• [] receptor
  
  • layered like an onion. So a mechanical stimuli deforms the [] layer, which in turn deforms the inner layer and the [] terminal = cell fires.
• Receptor is [] adapting
  
  • only rapid [] are perceived

Answer 16

Vibration Reception:

• Receptor is Pacinian Corpuscle
• Mediates fine touch and vibration
• Found underneath the skin
• Encapsulated receptor
  
  • layered like an onion. So a mechanical stimuli deforms the outer layer, which in turn deforms the inner layer and the nerve terminal = cell fires.
• Receptor is rapidly adapting
  
  • only rapid deformations are perceived

Question 17

Mechanoreceptors:

• Very Rapidly Adapting = (1 answer)
• Rapidly Adapting = ( 2 answers)
• Slowly Adapting = (3 answers)

Answer 17

• Very Rapidly Adapting = pacinian corpuscle
• Rapidly Adapting = Meissner’s Corpuscle and Hair-follicle receptor
• Slowly Adapting = Ruffini’s Corpuscle, Merkel’s receptors, and tacticle receptors

Question 18

Pressure Receptor(s):

• Receptor is the [] Corpuscle
• [] and [] receptor
  
  • filled with liquid, and deformation of [] fires the neuron
• Receptor is [] adapting (fires whenever stimulus is present and sustained touch)
• Found in [] capsules and the []ligament.

Answer 18

• Receptor is the Ruffini’s Corpuscle
• Encapsulated and multibranched receptor
  
  • filled with liquid, and deformation of skin fires the neuron
• Receptor is slowly adapting (fires whenever stimulus is present and sustained touch)
• Also found in joint capsules and the periodontal ligament.

Question 19

Touch and Pressure Receptors:

• Meissner’s Corpuscle: encapsulated, [] adapting receptors, located near the [] of skin
• Merkels Receptors: [] shape, [] adapting, located in the [] layer of the skin
• Both are important for localizing [] and for determinig [].

Answer 19

• Meissner’s Corpuscle: encapsulated, rapidly adapting receptors, located near the surface of skin
• Merkels Receptors: Disc shape, slowly adapting, located in the dermis layer of the skin
• Both are important for localizing touch and for determinig texture.

Question 20

Touch and Pressure Receptors:

• Hair Follicle receptors: [] adapting, detect [] of objects on the skin or []contact
• Free nerve endings: found [] in the skin and in many other tissues. Not as [] as other receptors.

Answer 20

• Hair Follicle receptors: rapidly adapting, detect movement of objects on the skin or initial contact
• Free nerve endings: found everywhere in the skin and in many other tissues. Not as precise as other receptors.

Question 21

T/F -Sensations of pressure and touch are mediated by nerve endings that are encapsulated, unencapsulated, and also by Free nerve endings.

Answer 21

TRUE!

Question 22

Temperature Sensations: Warmth Fibers:

• Typically respond around [], reach max response at [] and stop firing at [] C
• Not as numerous as [] fibers
• [] ([]) free nerve endings are thought to serve as receptors.

Answer 22

• Typically respond around 30 C, reach max response at 45 C and stop firing at 47 C
• Not as numerous as cold fibers
• Unmyelinated (C-Fibers) free nerve endings are thought to serve as receptors.

Question 23

Temperature Sensations: Cold Fibers

• Typically beging to discharge at [] C and firing rate increases as temp drops to [] C…Max firing may be at [] C
• [] ([]) free nerve endings serve as receptors.
  
  • has a [] ending
• [] []
  
  • if temp is raised above 45 C, cold receptors will fire again and person perceives cold.

Answer 23

• Typically beging to discharge at 35 C and firing rate increases as temp drops to 20 C…Max firing may be at 25 C
• Myelinated (small type Adelta fiber) free nerve endings serve as receptors.
  
  • has a multibranched ending
• Paradoxical cold
  
  • if temp is raised above 45 C, cold receptors will fire again and person perceives cold.

Question 24

1. Where is the temperature “comfort zone”?
2. Does the skin perveive hot and cold changes in this range?

Answer 24

1. 31- 36 C
2. No, skin temperature in this range is not perceived as hot or cold.

Question 25

1. Temperatures below 15 C and above 45 C are perceived as [] 2. There are cold and warm pain receptors 1. These can even be found in the [] []!

Answer 25

1. Temperatures below 15 C and above 45 C are perceived as **pain** 2. There are cold and warm pain receptors 1. These can even be found in the **oral mucosa!**

Question 26

Pain Sensations: * Receptors found on the free nerve endings of [] and [] fibers * Adelta - [] * C - [] * Respond to [] stimuli including: mechanical, chemical, and thermal stimuli * Most pain receptors can be stimulated by [] types of stimuli * Pain not felt until [] tissue damage has been done.

Answer 26

* Receptors found on the free nerve endings of **Adelta** and **C** fibers * Adelta - **myelinated** * C - **unmyelinated** * Respond to **damaging** stimuli including: mechanical, chemical, and thermal stimuli * Most pain receptors can be stimulated by **multiple** types of stimuli * Pain not felt until **afte**r tissue damage has been done.

Question 27

2 Types of pain based on receptor Type 1. Fast Pain 1. Well-localized, called []/[] pain 2. [] receptors carry fast pain 3. travels in [] tract 4. elicits [] reflex 2. Slow pain 1. poorly [] 2. [] fibers carry slow pain 3. Travels in [] tract 4. elicits nausea, sweating, decreased blood pressure, decreased muscle tone.

Answer 27

1. Fast Pain 1. Well-localized, called **bright/electric** pain 2. **Adelta** receptors carry fast pain 3. travels in **spinothalamic** tract 4. elicits **withdrawal** reflex 2. Slow pain 1. poorly **localized** 2. **C** fibers carry slow pain 3. Travels in **spinoreticulo-thalamic** tract 4. elicits nausea, sweating, decreased blood pressure, decreased muscle tone.

Question 28

2 types of pain based on duration: 1. Acute: when injury heals, pain []..within 2-4 weeks 2. Chronic: pain continues 1 month [] usual course of recovery and may [] at intervals

Answer 28

1. Acute: when injury heals, pain **subsides**...within 2-4 weeks 2. Chronic: pain continues 1 month **beyond** usual course of recovery and may **recur** at intervals

Question 29

Perception of Pain has 2 aspects: 1. Discriminative ([] function) - one can [] judge intensity, location, and quantity 2. Affective ([]) - one can [] describe level of suffer due to pain

Answer 29

1. Discriminative (**cortical** function) - one can **objectively** judge intensity, location, and quantity 2. Affective (**thalamic**) - one can **subjectively** describe level of suffer due to pain

Question 30

Referred Pain * Explained by [] rule, convergence and facilitation

Answer 30

Dermatomal

Question 31

Dermatone: * Each [] nerve innervates a segmental area of [] called a dermatone * By testing and mapping for deficits in skin [], it is possibel to determine at which level oof the spinal cord injuries have occured.

Answer 31

* Each **spinal** nerve innervates a segmental area of **skin** called a dermatone * By testing and mapping for deficits in skin **sensations**, it is possible to determine at which level of the spinal cord injuries have occured.

Question 32

Referred Pain * Pain from a [] organ may be referred to a patch of skinthat is innervated by tehs ame [] segment as the organ (different from phantom limb) * In the sensory cortex the [] is mapped, but the [] are not mapped. Therefore, the pain is identified as originating in the []

Answer 32

* Pain from a **visceral** organ may be referred to a patch of skin that is innervated by the same **spinal** segment as the organ (different from phantom limb) * In the sensory cortex the **skin** is mapped, but the **viscera** are not mapped. Therefore, the pain is identified as originating in the **skin**

Question 33

Referred Pain: 2 Mechanisms 1. Convergence 1. There are more [] fibers in []nerves than there are axons in the lateral spinothalamic tract 2. Somatic and visceral afferents converge on the same [] neuron 3. Pain generated in viscera is referred to a [] area 2. Facilitation 1. Incoming impulses from visceral structures [] the threshold of spinothalamic neurons 2. [] activity, which would normally die out in the spinal cord, [] to the brain.

Answer 33

1. Convergence 1. There are more **sensory** fibers in **peripheral** nerves than there are axons in the lateral spinothalamic tract 2. Somatic and visceral afferents converge on the same **spinothalamic** neuron 3. Pain generated in viscera is referred to a **somatic** area 2. Facilitation 1. Incoming impulses from visceral structures **lower** the threshold of spinothalamic neurons 2. **Minor** activity, which would normally die out in the spinal cord, **passes** to the brain.

Question 34

What are the 2 mechanisms of referred pain?

Answer 34

Convergence Faciliatation

Question 35

CNS Analgesic System The brain is capable of controlling the degree of input from [] to the nervous system via areas inthe [], [], and [] connections in the [] cord.

Answer 35

CNS Analgesic System The brain is capable of controlling the degree of input from **nociceptors** to the nervous system via areas in the **pons**, **medulla**, and **inhibitory** connections in the **spinal** cord.

Question 36

CNS Analgesic System: 1. Pain activates a path beginning inthe [] grey matter of the []-brain and [] pons 1. This area synapses in the lower [] and upper [] 2. These fibers then descend in the spinal cord in the [] columns 3. They synapse with neurons in the [] tract, releasing [] that modulate transmissions from nociceptors

Answer 36

CNS Analgesic System: 1. Pain activates a path beginning in the **periaquaductal** grey matter of the **mid**-brain and **upper** pons 1. This area synapses in the lower **pons** and upper **medulla** 2. These fibers then descend in the spinal cord in the **dorsolateral** columns 3. They synapse with neurons in the **spinothalamic** tract, releasing **peptides** that modulate transmissions from nociceptors

Question 37

CNS Analgesic System: * Peptides ([] and []) activate opiate receptors that [] pain signals at the level of the [] [] * Pain signals are inhbited where they synapse at the [] [] * ([] is an example of a narcotic antagonist and would block pathways where opiates act)

Answer 37

CNS Analgesic System: * Peptides (**enkephalins, endorphins)** activate opiate receptors that **suppress** pain signals at the level of the **spinal cord** * Pain signals are inhbited where they synapse at the **dorsal horn** * (**Naloxone** is an example of a narcotic antagonist and would block pathways where opiates act)