Reflexes 2 Flashcards
What are some facts about muscle reflexes
They are autonomic and fast
Do not require conscious intervention for movement control
Stereotyped response to given stimuli (used in diagnosis)
What’s a monosynaptic reflex
Reflex that involves sensory neurone input to appropriate motor neurone across SINGLE SYNAPSE in spinal cord
Knee jerk reflex is an example
What is a polysynaptic reflex
Electrical impulse transferred from sensory neurone to motor neurone via at least one connecting interneuron in spinal cord
Example is pain receptors stimulation of which initiates withdrawal reflex which involves severe synapses with several motor neurones to result in removal of hand from stimuli
What’s an ipsilateral reflex
Reflex in which response occurs on side of body which is stimulated
What is a contralateral reflex
Reflex response occurs on opposite side of body from stimulus - several branches of afferent nerve fibres cross from stimulated side to contralateral side of spinal cord
Found in legs and feet relating to balance after injury on one leg
What’s an intrasegmental reflex
Where the reflex arc is restricted to one or two spinal cord segments
What is an Intersegmental reflex
Where reflex arc involves number of spinal cord segments
How long does knee jerk take
20-25ms
As bypasses brain
Time components of a muscle reflex
1 activation of sensory receptors (start clock)
2 conduction to CNS along nerve
3 transmission across neuron and/or synapses in CNS (1-2ms)
4 conduction from CNS along nerve to muscle
5 activation of muscle contractile machinery (5ms)
What can muscle stretch reflex do
Enable muscle to oppose external forces that tend to eongate them
How is muscle stretch reflex mediated
Via sense organs within muscles known as
MUSCLE SPINDLES
