First order sensory neurons begin in the receptor, travel to dorsal/posterior gray horn of the spinal cord where they synapse with the second order sensory neurons.
third order neuron
They can be found in the dorsal root ganglia, retina, peripheral vestibular organs, cochlea, and enteric nervous system. Then there are second order sensory neurons in the brain that form the basis of the 'sensory homonculus'.
The first order sensory neuron can sometimes be a sensory receptor because it is what sends the signal to the brain from the receptor. The second order goes from the brainstem to the thalamus.
A second order neuron is the 2nd neuron to carry an order. The order could be a sensory stimulus or a motor stimulus. For e.g. in order to move a muscle, the order for that muscle to contract starts at the cerebral cortex in the somatomotor area. That is the first order neuron. The axon of the 1st order neuron will synapse with the 2nd order neuron at the level of the brain stem, which commonly decussate (crosses over) to the opposite side. In turn, the axon of the 2nd order neuron will descend along the spinal cord tracts where it will synapse with the 3rd order neuron. The 3rd order neuron is located in the ventral horn of the spinal cord, which will exit with the spinal nerve to supply the muscle.
No! Only neurons of the specific (lemniscal) & non-specific (anterolateral) pathways decussate and sensation is therfore interpreted in the opposite cerebral hemisphere.Spinocerebellar ascending pathways transmit proprioceptive sensory stimuli to the same side of the cerebellum.
Second order neurons of both specific and nonspecific ascending pathways terminate in the thalamus. From there, the thalamus sends projections to the somatosensory cortex for further processing of sensory information.
In a ganglion.
Both use neurones which transmit in via action potential and synaptic transmission. Sensory neurones include pain neurones which enter directly into the brain, which perceives the stimulus as pain and gives emotional and motor responses accordingly. Sensory neurones also perceive homeostasis, in that they sense stimuli outside physiological norms and change homeostasis in order to rectify the problem. All motor and limbic (emotional) outputs from the brain are stimulated and therefore initiated by sensory neurone inputs. The spine relys information from peripheral sensory neurones to the brain, and is the literal connection between sensory neurones and the brain.
The order of a visceral reflex involves sensory receptors detecting a stimulus, which then sends signals via afferent neurons to the central nervous system. The central nervous system processes the information and sends signals through efferent neurons to the effector organs, resulting in a response to the stimulus.
ventral posterolateral nucleus of the thalamusthalamusin the thalamus
unce
Afferent neurons receive and transmit impulses to the CNS.