Chemical senses Flashcards

1
Q

What are the two chemical senses?

A

Smell and taste

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2
Q

What two things are influenced by the presence of chemical signals?
____ and ____ behavioural ____

A

Motivated and emotional behavioural responses

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3
Q

What three things are odours key in detecting?

A
  1. Potential dangers
  2. Opportunities for food
    3… or social interactions
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4
Q

What two things does flavour help in identification of?

A
  1. Specific foods and food quality
  2. Support learning associations between tastes and emotional events
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5
Q

What are some diverse behaviours that olfactory cues support?

A
  1. Food or mate seeking
  2. Feeding
  3. Co-specific identification (group or non-group)
  4. Marking territories
  5. Reproduction
  6. Aggression and early warning
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6
Q

Compare how relevant smell is to humans and dogs

A

Dogs can detect odors 100x less concentrated than humans can
Receptors equally sensitive - respond to one single odor molecule
Dogs have 100x more receptors

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7
Q

What is the primary and secondary function of the human nose?

A

Primary = humidify and warm air going into lungs
Secondary = Olfaction

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8
Q

How does the nose capture odorants?

A

Air flows into nose cavity
Odorants interact with olfactory epithelium
Mucus in epithelium captures odorants

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9
Q

What are the three types of cell in the olfactory epithelium?
1. S____ cells - ____ and ____ support
2. B____ cells - olfactory cell ____
3. O____ s____ n____ - detect ____ and produce ____

A
  1. Supporting, metabolic, physical
  2. Basal, progenitors
  3. Olfactory sensory neurons, odors, mucus
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10
Q

Finish the sentences about olfactory receptors…
1. Odorants are recognised by _______ receptors in the ______ of OSNs
2. ________ receptors are G-coupled ________ whose activation opens ____/____ channels
3. OSN is _______ by Na+/Ca2+ influx, firing _____ _________

A
  1. specific, cilia
  2. Olfactory, proteins, Na+/Ca2+
  3. depolarised, action potentials
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11
Q

Fill in the gaps about olfactory pathways…
1. A_____ from OSNs pass through the tiny holes in the c________ plate (bone) to enter the brain.
2. Each type of OSN p______ its axon to a single g________ within the olfactory b______.
3. OSN axons make synapsis with m______ and t______ cells, that project to the p______ o______ c______ and other brain regions

A
  1. Axons, cribriform
  2. projects, glomerulus, bulb
  3. mitral, tufted, primary olfactory cortex
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12
Q

Humans have around 1000 different odor receptors, but how many different odorants can they receive?

A

Around a trillion

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13
Q

What is the shape pattern theory?
Each ____ activates a ____ array of olfactory ____ in the olfactory ____
These various arrays produce specific ____ patterns of neurons in the olfactory ____, which then determines the ____ we perceive.

A

scent
unique
receptors
epithelium.
firing
bulb
scent

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14
Q

Olfaction is a subjective experience. What are some factors detection threshold can be affected by?

A

Gender - women generally lower thresholds than men, especially during ovulatory period of menstrual cycles
Training - professional perfumers and wine tasters can distinguish up to 100,000 odorants
Age - by 85, 50% of population is effectively anosmic (sense of smell loss)

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15
Q

Smell means detector of changes. What does smell stop during? Why does this happen?

A

Continuous exposure to odorant
Due to receptor adaptation - continuous exposure to odourant makes the receptor stop responding and detection ceases
Mechanism - receptor internalisation or Na+/Ca2+ channel inactivation in the olfactory sensory neuron

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16
Q

What are some functions of taste recognition?
1. Guide a____
2. Trigger p____ processes for absorbing n____ and adjusting m____

A

Guide appetite, trigger physiological processes for absorbing nutrients and adjusting metabolism

17
Q

What are two tastes and meanings that are greatly influenced by culture?

A

Good taste = usually good
Bad or bitter taste = potentially harmful

18
Q

Define taste
Detection of c____ c____ in the mouth by d____ c____ with c____ on the t____ and the r____ of the m____

A

Detection of chemical compounds in the mouth by direct contact with chemoreceptors on the tongue and the roof mouth

19
Q

What is retronasal olfactory sensation?
Perception of o____while c____ and s____ food

A

Perception of odorants while chewing and swallowing food

20
Q

Odor sensations are perceived as originating from the mouth, even though the actual contact of odorant and receptor occurs where?

A

At the olfactory mucosa

21
Q

Fill in the gaps about the structure and function of taste sensation…
1. Taste receptors are arranged in____ _____, distributed along the t____, p_____, p______, e_____, and upper third of the o_______.
2. Taste buds arranged in three kind of _____, distributed in specific _____ of the tongue.
3. Receptors for different tastes _____ together in the same _____.
4. Receptor activation sends _____ _______ through taste nerves

A
  1. taste buds, tongue, palate, pharynx, epiglottis, oesophagus
  2. papillae, regions
  3. group, bud
  4. Neural signal
22
Q

Fill in the gaps about taste buds and taste receptors…
1. Each taste bud contains several types of taste r____ c___.
2. Receptor cells are s______ cells containing m_______, containing r______ p______.
3. T_____ main receptor types according to their function.
4. Type I: s______ function.
5. Type II: detect b_____, s_____ and u_____. Chemical signal to n________ cells (including Type III).
6. Type III: detect s____. Synaptic communication with a______ fibers

A
  1. receptor cells
  2. specialised, microvilli, receptor proteins
  3. three
  4. support
  5. bitter, sweet, umami, neighbouring
  6. Sour, afferent
23
Q

What are the G-coupled protein taste receptors? What do they detect?
TR____ and TR____
TR____ detects s____ and u____ taste
TR____ detects b____ taste

A

TR1 and TR2
TR1 detects sweet and umami taste
TR2 detects bitter taste
(Ion (Na+) channel ENaC detects salty)

24
Q

What are the three cranial nerves that detect taste information?
1. Ch____da ty____ni
2. Gl____so-ph____geal
3. Va____

A
  1. Chorda tympani
  2. Glosso-pharyngeal
  3. Vagus
25
Q

What responses do the following tastes evoke in humans?
1. Bitter
2. Sour
3. Sweet and salty

A
  1. May signal poisonous food
  2. May be related to acidic substances that may cause damage
  3. Induce seeking behaviour since such substances increase survival