Flashcards in 6. Spinal Reflexes Deck (23)
What is a reflex?
Response that occurs automatically without conscious effort
What are the functions of reflexes?
Rapid withdrawal from painful stimuli
Protection against over-stretching
Empty pelvic organs
Balance and movement
What are the 3 types of sensory receptors?
What stimuli are detected by interoceptors?
What stimulus is detected by proprioceptors?
Position in space
What stimuli are detected by exteroceptors?
What do somatic reflexes act on?
What are the two types of somatic reflexes?
Which reflex is monosynaptic?
What two types of receptors are used in the myotactic reflex?
Golgi tendon organs
What do muscle spindles detect?
Rate of change in length of muscle
What do golgi tendon organs detect?
Rate of change of tension in muscle
What are the primary regulators of muscle tone?
y-neurons continuously send info to brain and cerebellum
What neurons are efferent from golgi tendon organs?
What effect does an increase in tension have?
Reflex inhibition of motor neuron
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
What conditions can cause hyporeflexia?
Lower motor neuron lesions
What conditions can cause hyperreflexia?
Damage to motor area of cerebral cortex
Upper motor neuron lesion
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
What kind of reflexes are polysynaptic?
Which sensory fibres cause a withdrawal reflex?
How are spinal reflexes controlled?
Can be overrided by higher brain centres
IPSPs to flexor and EPSPs to extensor