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Flashcards in Sensory receptors Deck (56)
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1

what are sensory receptors

are nerve endings, often with specialized non-neural structures

2

What do sensory receptors induce

convert different forms of energy into frequency of Action Potentials (APs)

3

what is a sensory modality

a type of stimulus activating a particular receptor

4

what is the type of energy a receptor normally responds to called

an adequate stimulus

5

What are Mechanoreceptors

stimulated by mechanical stimuli

6

what are the mechanoreceptors in joints and muscles that signal information related to body or limb position called

Proprioceptors

7

What are the receptors that respond to pain

Nociceptors

8

Damage to the nerve by stimuli activates a generator potential which in turn opens

ion channels causing ion flow across the membrane

9

an adequate stimulus causes a graded membrane potential change called

receptor potential

10

For action potential to be fired what needs to happen

receptor potential reaches threshold

11

frequency coding of stimulus intensity means

the larger the receptor potential the higher the frequency of APs in sensory neurone

12

Merkel receptors senses

pressure and texture

13

Pacinanan corpuscle sense

vibration

14

meissners corpuscle senses

flutter and stroking movement

15

ruffini corpuscle senses

skin stretching

16

Adaption of sensory nerves is

stimulus is enough to trigger an AP, but as stimulus continues generator potential decreases so mechanoreceptor only responds to onset of stimulus
ie stimulus there but you are no longer consciously aware

17

Rapidly/Moderately-adapting receptors are

Pacinian corpuscles and Meissner’s corpuscles

18

Slowly-adapting receptors are

Merkel’s discs and Ruffini endings

19

Why don't Nociceptors adapt

important not to ignore painful stimuli

20

Whats is the structure of Pacinian corpuscles

a myelinated nerve with a naked nerve ending,
naked nerve ending enclosed by a connective tissue capsule of layered lamella

21

Describe how Pacinian corpuscles respond to stimuli

mechanical stimulus deforms capsule
nerve ending is stretched
ion channels open
Na+ enters local depolarisation
generator potential reaches threshold
APs fire at myelinated nerve
detect stimulus ON

22

How does the Pacinian corpuscles show rapid adaptation

Due to fluid redistribution in the capsule, removes mechanical stretch of nerve ending, causing stimulus to disappear and AP stop firing

23

What can cause an AP to fire again in a Pacinian corpuscles after stimulus is applied

withdrawal of stimulus causes capsule to bring back and AP fired again

24

What is necessary for quick adaptation in Pacinian corpuscles and enhance sensory function

the lamella

25

what is the receptive field

a somatic sensory neuron is activated by stimuli in a specific area

26

What are the two things that tell parts of the skin apart

receptive field size
neuronal convergence

27

Neuronal convergence occurs when there is

sensory neutrons with neighbouring receptive fields

28

what can neuronal convergence stimulate

large secondary receptive field

29

relatively insensitive area indicated by
and example

So convergence and a large secondary receptive field
eg. fingers and lips

30

What is acuity

The ability to locate a stimulus on the skin and differentiate it from another close by

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