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Flashcards in 6. Spinal Reflexes Deck (23)
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1

What is a reflex?

Response that occurs automatically without conscious effort

2

What are the functions of reflexes?

Rapid withdrawal from painful stimuli
Protection against over-stretching
Empty pelvic organs
Balance and movement
Learned

3

What are the 3 types of sensory receptors?

Interoceptors
Proprioceptors
Exteroceptors

4

What stimuli are detected by interoceptors?

Pain
Stretching

5

What stimulus is detected by proprioceptors?

Position in space

6

What stimuli are detected by exteroceptors?

Temperature
Pressure

7

What do somatic reflexes act on?

Skeletal muscle

8

What are the two types of somatic reflexes?

Monosynaptic
Polysynaptic

9

Which reflex is monosynaptic?

Myotactic reflex

10

What two types of receptors are used in the myotactic reflex?

Muscle spindles
Golgi tendon organs

11

What do muscle spindles detect?

Rate of change in length of muscle

12

What do golgi tendon organs detect?

Rate of change of tension in muscle

13

What are the primary regulators of muscle tone?

Muscle spindles
y-neurons continuously send info to brain and cerebellum

14

What neurons are efferent from golgi tendon organs?

1b

15

What effect does an increase in tension have?

Reflex inhibition of motor neuron

16

What are the steps in the knee jerk reflex?

1. Tapping on the patellar ligament stretches the quads
2. Stretch of muscle spindles
3. Increased firing 1A sensory nerves
5. Increased activity of motor neuron to quads
6. Quads contract

17

What conditions can cause hyporeflexia?

Polio
Muscular dystrophy
Lower motor neuron lesions

18

What conditions can cause hyperreflexia?

Stroke
Brain tumour
Damage to motor area of cerebral cortex
Upper motor neuron lesion

19

What is reciprocal innervation?

In stretch reflexes, the antagonist muscle must relax to allow the protagonist to contract
Stretch reflex in the antagonist is inhibited by an interneuron

20

What kind of reflexes are polysynaptic?

Withdrawal reflexes

21

Which sensory fibres cause a withdrawal reflex?

A-delta

22

How are spinal reflexes controlled?

Can be overrided by higher brain centres
IPSPs to flexor and EPSPs to extensor

23

What is the crossed extensor reflex?

Eg. Stepping on a sharp object
Simple reflex arc in leg that was hurt
Interneuron from hurt leg crosses into opposite
Activates motorneuron on opposing side to allow planting of foot