Topic 108 - Receptors, taste, olfaction   Flashcards

1
Q

Words to include in receptors

A
  • Stimuli
  • Membranes of the afferent nerve endings
  • Membranes
  • Stimuli
  • Local membrane potential
    • Hyperpolarization
    • Depolarization
    • Local response
  • Threshold
  • Action potential
    • Conducted along axon
  • Amplitude
  • Frequency
  • Neuron
    • Primary
      • Conformational change
      • Cation channel
      • Receptor potential
      • Action potential
    • Secondary
      • Second cell of sensation
      • Cation channels
      • Receptor potential
      • Primary sensory neuron
      • Electron potential
      • Action potential
      • Sound reception
        • Hair cell
        • Auditory nerve
    • Tertiary
      • Third cell
      • Transduction
      • Stimulus
      • Cell 1
        • Rodes
        • Cones
        • Sensing stimuli
        • Olfaction
          • Primary chemical reception
      • Cell 2
        • Bipolar cells
          • Transduction
          • Transformation
      • Cell 3
        • Ganglion cell
          • Afferent nerve
  • Interoceptors
  • Exteroceptors
    • Free nerve endings
  • Free nerve endings
    • Interoceptors
    • Exteroceptors
  • Pacinian corpscle
    • Exteroceptors
    • Golgi-mazzoni
  • Golgi tendon organ
    • Interoceptor
  • Surface receptor
    • Potential change
  • Transduces
  • Receptor potential
  • Myelin sheets
  • Generator potential
  • Decrement (possible info loss)
  • Mechanical reception
    • Vibration sensation
      • Pacini corpuscles
    • Encoding pressure
      • Ruffini coruscles
    • Touch realization
    • Hair follicle sensation
      • Hair follicle sensation
      • Orientation
  • Thermal reception
    • Dual receptor system
    • Warm receptor
      • AP between 30-45 degrees
      • A delta
      • C fibers
    • Cold receptor
      • 15-42 degrees
      • Paradox cold sensation
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2
Q

Words to include in olfaction

A
  • Chemical receptors
    • Chemical signals of the gaseous phase
    • Liquid phase
  • Adapts
  • High differenet threshold
  • Location of the source (difficult)
  • Dorsocaudal portion of the nasal cavity
  • Vomeronasal organ
    • Organ of Jacobsen
  • Olfactory musosa
    • Receptor cells
      • Bipolar neurons
      • Microvilli
      • Unmyelinated axons
      • Glomeruli of the olfactory organ (terminates here)
    • Supporting cells
      • Microvilli
    • Basal cells
  • Olfactory tract
    • Myelinated axons
      • Thinnest nerve fibers
    • Olfactory bulb
    • Criboform plate
    • Synapses
    • Dendrite
    • Mitral and tufted cells
    • Glomerulus
      • Periglomerular cells
      • Granule cells
  • Primary olfactory cortex
    • Amygdala
    • Prepyriform area
    • Olfactory tubercle
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3
Q

Words to include in taste

A
  • Gustation
  • Liquid phase
  • Mechano-receptor system
    • Texture
    • Odor
    • Taste
  • Gustation receptors
    • Gustatory papillae
      • Filiform papillae
        • Mechanoreceptors
      • Fungiform papillae
      • Circumvallate papillae
      • Foliate papillae
    • Serous glands of Ebner
  • Sweet
  • Salty
  • Sour
  • Bitter

Taste pathway

  • N. chorda tympani
  • N. glossopharyngeus
  • N. vagus
  • N. trigemini
  • N. facialis
    • Geniculate ggl
  • N. vagus / n. glossopharyngeus
    • Ggl. craniale
    • Ggl. caudale
  • Solitary nucleus of the myencephalon
  • Nerve impulses
    • Pons
    • Thalamus
  • Efferents of gustatory area of the pons
    • Thalamus
    • Amygdala
      • Hypothalamic area
  • Gustatory area in the thalamus
    • Ventral posteromedial nucleus
    • Thermal stimuli
  • Gustatory area in the cortex
    • Ipsilateral area (stimuli from)
    • Contralateral area (stimuli from)
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4
Q

Receptors

  1. Role of receptors
  2. How does receptors function in general?
A
  • Role: Sensing the stimuli from the outer or inner environment
  • Sensing stimuli is accomplished by the membranes of the afferent nerve endings
  • The membranes of these nerve terminals is able to generate local membrane potential change in response to a given stimuli
    • Either hyperpolarization or depolarization
    • Also called local response
  • At a given stimulus the evoked potential change will reach threshold and generate AP, which will be conducted along the axon
    • Increasing amplitude of the stimulus will increase the frequency of the APs of the afferent nerve
    • The extent of the stimulus is coded by the amplitude first, and then by the frequency
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5
Q

Receptors

Classification of receptors

A
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6
Q

Reseptor

Classification of receptor: According to the receptor

A
  • Primary
    • Stimulus elicit a conformational change on the cation channel or protein coupled to the channel of the sensory neuron
    • Receptor potential and action potential are generated directly on that cell
    • E.g. Olfaction (primary chemical reception)
  • Secondary
    • stimuli is sensed by the second cell of sensation
    • Cation channels open → generation of receptor potential
    • E.g. Sound reception:
      1. ​​Hair cells
      2. Auditory nerve
  • Tertiary
    • Afferent nerve fibersbelongs only to thethird cell involved in the transduction of stimulus
    • Cell 1: Rods and cones (sensing the stimuli)
    • Cell 2: Bipolar cells (transduction and tranformation)
    • Cell 3: Ganglion cells (afferent nerve)
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7
Q

Reseptor

Classification of receptor: Localization of stimulus

A
  1. ​Interoceptors
    • ​​Receptor sensing stimuli from inner environment
  2. Exteroceptors
    • ​Free nerve endings sensing stimuli from the external environment
  • Free nerve ending
    • Exteroceptor and interoceptor
  • Pacinian corpuscle
    • Exteroceptor
  • Golgi tendon organ
    • Interoceptor
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8
Q

Reseptor

Classification of receptor: Forms of energy of the stimulus

A
  1. Mechanical reception
    • Vibration sensation
    • Encoding pressure
    • Touch realization
    • Hair follicle sensation
      • Animals: orientation through mechanical sensation
  2. Thermal reception
    • ​​​Receptors feel changes in temperature
    • If the change is dangerous, pain will be felt
    • Dual receptor system
    • Warm receptors
      • Generate AP between 30-45 ºC
    • Cold receptors
      • Activated between 15-42 ºC
    • Paradox cold sensation
      • Cold can be felt with pain
    • Twice as many cold receptors as warm receptors
  3. Photo
  4. Chemical
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9
Q

Olfaction

General

A
  • Two chemical receptors (taste & smell) co-operate:
    • Smell receives chemical signals of the gaseous phase
    • Taste receives those of the liquid phase
  • Their co-operation is important for the sense of flavor
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10
Q

Olfaction

In contrast with other sensory organs

A
  • It adapts to stimuli quickly
  • High differential threshold
  • Location of source is difficult due to the diffusion
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11
Q

Olfaction

Location of the receptors of the olfaction organs

A
  • In the dorsocaudal portion of the nasal cavity
  • In the vomeronasal organ (organ of Jacobsen)
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12
Q

Olfaction

Which cell are the olfactory mucosa composed of?

A
  • The olfactory mucosa consists of 3 types of cells:
    1. Receptor cells
    2. Supporting cells
    3. Basal cells
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13
Q

Olfaction

Olfactory tract

A
  • Myelinated axons that leave the olfactory mucosa terminates in the glomeruli of the olfactory bulb after passing through the fenestration of the cribiform plate
  • Here they form synapses with the dendrites of the mitral and tufted cells
  • There are two types of cells inside the glomerulus, whose fibers do not leave the bulb:
    • ​Periglomerular cells
    • Granule cells
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14
Q

Taste

General

A
  • Gustation indentifies substances dissolved in a liquid phase
  • Taste is accompanied by a mechano-receptor system: odor, texture and taste of the subustance taken up by the animal provide information to the animal
    • E.g. animals prefer “real” forage to powder forage, even if they have the same nutritive value
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15
Q

Taste

Gustation receptors

A
  • Four types of gustation papillae:
    1. ​​Filiform papillae
      • ​​Mechanoreceptors
    2. Fungiform papillae
      • ​​All over the tongue
    3. Circumvallate papillae
    4. ​Foliate papillae
  • On the bottom of foliate and circumvallate papillae there are serous glands of Ebner
    • Role: washes out chemical substances
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16
Q

Taste

Elements of taste

A
  1. Sweet
    • ​​Apex of tongue
  2. Salty
    • ​​Sides of tongue
  3. Sour
    • ​Posterior edges of tongue
  4. Bitter
    • ​​Radix of tongue
17
Q

Taste

Taste pathway

A
  • N. chordae tympani (belonging to n. facialis)
    • Anterior 2/3 of tongue
    • Afferent
  • N. glossopharyngeus
    • Posterior 3rd of the tongue
    • Pharyngeal arch
  • N. vagus
    • Radix of tongue
    • Epiglottis
  • N. trigemini
    • Tactic and temperature receptors in oral cavity
  • Soma of these nerves are located in:
    • Ggl. geniculate of n. facialis
    • Ggl. craniale and ggl. caudale of n. glossopharyngeus and n. vagus
  • Terminates in the solitary nucleus of myencephalon
  • Nerve impulses are forwarded towards the pons and thalamus
  • Efferents of the gustatory area of the pons terminates partly in the thalamus and hypothalamic area of the amygdala
  • Gustatory area in the thalamus is in the ventral posteromedial nucleus
  • Gustatory areas in the cortex receives info from both ipsilateral and contralateral areas