Reflexes Flashcards
What is a reflex?
A stereotyped, involuntary and rapid response to a stimulus.
What is integration?
The computational process by which an individual neuron processes its synaptic inputs and converts them into an output signal
Which neurones are responsible for integration?
Interneurones
What are the neural components of a reflex?
Sensory receptors Afferents Integration (by interneurones) Efferents Effectors
What is the function of the stretch / myotatic reflex?
To maintain posture and adjust the degree of muscle contraction.
To prevent tearing of muscle.
Are interneurones found in the CNS, PNS or both?
Exclusively in the CNS. E.g., in the spine, the somata are found in the grey matter. Reflexes can be cranial or spinal.
*Also in the enteric nervous system.
What is a monosynaptic reflex?
A simple reflex that involves transmission of information from a sensory neurone to the appropriate motor neurone across a single synapse in the spinal cord.
E.g. the knee-jerk reflex (patellar).
What is a polysynaptic reflex?
A reflex that involves transmission of information from a sensory neurone to interneurones in the CNS, which relay the integrated impulse to appropriate motor neurones.
Most reflexes are polysynaptic.
E.g. pupillary reflex.
What morphology do interneurones have?
Multipolar morphology.
Is the patellar reflex ipsilateral or contralateral?
Ipsilateral
Is the crossed extensor reflex ipsilateral or contralateral?
Contralateral
What is a contralateral reflex? What about ipsilateral?
A reflex which occurs on the opposite side of the body from the stimulus.
Branches of the afferent nerve fibers cross from the stimulated side of the body to the contralateral side of the spinal cord.
Ipsilateral - same side
Is the pupillary reflex polysynaptic or monosynaptic?
Polysynaptic
Is the pupillary reflex a spinal reflex or a cranial reflex?
Cranial
Is the pupillary reflex an autonomic reflex or a somatic reflex?
Autonomic
