Sensory Receptors

Question 1

What are the 3 types of sensory receptors

Answer 1

Mechanoreceptors = mechanical stimuli 
Propriocetors = mechanorceptors in joint and muscle
Nocireceptors = respond to painful stimuli

Question 2

What is the definition of sensory modality

Answer 2

The stimulus type which activates a particular receptor. Example is vibration, pressure, pain

Question 3

Define adequate stimulus

Answer 3

Form of energy to which a receptor normally responds

Question 4

What is the adequate stimulus for mechanoreceptors

Answer 4

Membrane deformation which leads to activation of stretch sensitive ion channels

Question 5

What is the point called which it depolarisation reaches will lead to AP firing in mechanoreceptor

Answer 5

First node of ranvier

Question 6

Increasing stimulus intensity creates a larger receptor potential which leads to what

Answer 6

High frequency of AP

Question 7

What nerve receptors don’t adapt

Answer 7

Nocireceptors

Question 8

Name a receptor which is slowly adapting

Answer 8

Merkels discs

Question 9

Name a receptor which is fast adapting

Answer 9

Pacinian and meissnes corpuscles

Question 10

The capsule of pacinian corpuscle is full of connective tissue, what is the name of the layer called

Answer 10

Lamellae

Question 11

How does pacinian corpuscles adapt so quickly

Answer 11

Fluid is rapidly redistributed within capsule lamellae minimising downward deformation stopping AP

Question 12

What is the area where a somatic sensory neutron is activated

Answer 12

Respective area

Question 13

Name the test which tests our ability to tell 2 points of pressure on the skin

Answer 13

Two point dscrimination test

Question 14

What factors determines the two point discrimination tedt

Answer 14

Respective field size and neuronal convergence

Question 15

The larger a receptive field and the more convergence will lead to sensitive skin

Answer 15

No you dumb bitch, less sensitive

Question 16

What method is used to increase specificity of location

Answer 16

Lateral inhibition

Question 17

Describe the track sensory info goes to

Answer 17

Sensory nerve, spinal chord, thalamus then somatosensory cortex

Question 18

What do the proprioreceptors do

Answer 18

They are mechanorecetors which signal the body or limb position

Question 19

Muscle spindles, Golgi tendon organs and joint r captors ar examples of what

Answer 19

Propioreceotors

Question 20

Are most contractile skeletal muscle extra fusal muscle or intrafusal muscle fibres

Answer 20

Extrafusal, inteafusal is muscle fibres which have th rthe own sensory and motor information which is only. A few

Question 21

Of the alpha and gamma axons, which go into extrafusla, and intrafusal

Answer 21

Extrafusal is alpha

Intrafusal is gamma

Question 22

Does the centre of intrafusal fibres contain sarcomeres

Answer 22

No only the ends

Question 23

Gamma motor neurone causes what to contact

Answer 23

Ends of the sarcomere to contract result in in stretching of the centre

Question 24

In intrafusal fibres, what causes AP firing

Answer 24

Gamma neurones cause contraction of sarcomeres, the stretching of the centre and which results in opening of ion channels causing AP in 1a afferent

Question 25

What is the Golgi tendon fibre afferent called

Answer 25

1b

Question 26

Golgi tendon lie in paralell while muscle spindles lies in series

Answer 26

False of course

Question 27

What will fire in isometric muscle contraction, 1b or 1a

Answer 27

Activation of GTO therefore 1b, as length doesn’t change 1a in muscle spindles is not fired

Question 28

The gamma axon is responsible for keeping the muscle spindles active, true or false

Answer 28

True, shortening of the spindle to match that of the muscle.

Question 29

What does information does the 1a send to the Brian

Answer 29

Sends reports of the muscle shortening

Question 30

In stretch reflex, the efferent goes to the antagonist muscle causing relaxation. What is this called

Answer 30

Reciprocal inhibition

Question 31

When reacting to pain receptor, what is the reflex which is responible for this

Answer 31

Flexor reflex

Question 32

Pain causes the flexor reflex to be engaged. Therefore describe the activation and inhibition of the extensor and flexor muscle on stimulated and opposite leg

Answer 32

Extensor inhibited STIM
Flexor activated STIM

opposite for unhurt leg

Question 33

What happenes when the GTO reflex is activated, what is the function

Answer 33

Load is dropped, to protect the muscle

Question 34

The alpha neurones integrate 10000 of signals which are excitery and inhibitory. Net effect is measure,what is this called

Answer 34

Summated

Question 35

If your carrying carrying a baby, how is the GTO overridden

Answer 35

Descending voluntary excitation of alpha motor neurone overrides the inhibition from the GTO

Question 36

What is the neurologist test to determine if an anxouis patient is causing descending inhibition hyperpolsrising alpha neurone

Answer 36

Jendrassik maneovre

Question 37

What is the clinical relevance of reflexes

Answer 37

Important to assess the integrity of the whole SC circuit

Can help with spinal level localisation of a problem

Question 38

Describe facilitation

Answer 38

Enhances effectiveness of sensory input. When activation occurs near by leading to activation of other neurones, see book