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Flashcards in Sensory receptors Deck (18)
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1
Q

What are the 5 types of receptors?

A
Mechanoreceptors (most common) - skin
Nociceptors
Photoreceptors - eye (retina)
Thermoreceptors - heat
Chemoreceptors - olfactory (nose) and taste
2
Q

How can a receptor be stimulated appropriately?

A

By its own modality (type of sensation)

With sufficient quantity

3
Q

What is an adequate stimulus?

A

A stimulation that is sufficient to evoke a reaction (correct modality)

4
Q

What is a sensory unit?

A

A sensory unit is a single afferent neuron with all its receptor endings

5
Q

What is a receptive field?

A

The receptive field is a portion of sensory space that can elicit neuronal responses when stimulated - overlap

6
Q

What is lateral inhibition?

A

Repeated stimulation - the smaller signals are inhibited to the bigger ones can be targeted

7
Q

What type of receptor is a Pacinian corpuscle?

A

Mechanoreceptor

8
Q

Describe the structure of a pacinian corpuscle: (3)

A
Outer lamellae (detect pressure)
Inner fluid filled capsule of membranes
Nodes of ranvier along the axon out
9
Q

What happens when lamellae are deformed?

A

Na+ influx into the axon across the membrane, causing depolarisation, action potential propagated

10
Q

Why do we not constantly feel pressure?

A

Pacinian corpuscles sensitive to CHANGES in pressure not ABSOLUTE pressure therefore we cannot feel constant pressures

11
Q

How do we phase out constant sounds?

A

The hair receptors work with the muscle spindle. The muscle spindles constantly react but hair and PCs are blockers and phase out the noise

12
Q

What are the 3 categories of sensory input?

A

Cutaneous - external (heat, pain, touch) terminates S1
Visceral - internal (homeostasis) terminates S1
Special senses - vision hearing taste smell

13
Q

What is S1?

A

S1 is a primary somatic nervous sense in the somatosensory cortex

14
Q

Describe the specific pathway: (5)

A
Chain of 3-5 specific neurones receptors (type 1 or 2)
Spinal cord
Brainstem
Thalamus
Cortex area
15
Q

Describe the non-specific pathway:

A

APs travel through lots of different channels to alert brain to potential danger

16
Q

Whats the difference between a phasic and tonic receptor?

A

Tonic receptors adapt slowly to a stimulus and continues to produce action potentials over the duration of the stimulus.
Phasic receptors adapt rapidly to a stimulus. The response of the cell diminishes very quickly and then stops.

17
Q

What is a phasic receptor?

A

A phasic receptor is a sensory receptor that adapts rapidly to a stimulus.

18
Q

What is a tonic receptor?

A

A tonic receptor is a sensory receptor that adapts slowly to a stimulus