16.3 Flashcards
Somatic sensory (somatosensory) pathways relay information from where to where
Relay information from SOMATIC SENSORY RECEPTORS TO PRIMARY SOMATOSENSORY AREA (post central gyrus) in the parietal lobe of the cerebral cortex to THE CEREBELLUM
First order (primary) neurons
Sensory neurons that conduct impulses from somatic sensory receptors into the brain stem or spinal cord
Second order (secondary) neurons? Conduct impulses from the ___ to the ____
From the brain stem or spinal cord to the thalamus
Axons of second order neurons do what as they course through the brain stem or spinal cord before ascending to the thalamus?
Decussate (cross over to opposite side)
Third order (tertiary) neurons conduct impulses from ____ to ____
From thalamus to the primary somatosensory area on the same side
Regions within the CNS where neurons synapse with other neurons that are a part of a particular sensory or motor pathway are known as ?
Relay stations
Because neural signals are being relayed from one region of the CNS to another
Nerve impulses for touch, pressure, vibration and proprioception from the limbs, trunk, neck and posterior head ascend to the cerebral cortex along which pathway?
Posterior column-medial Lemniscus pathway
first order neurons in the posterior column-medial lemniscus pathway extend from what into what and ascend into what
extend from sensory receptors in the limbs, trunk, neck and posterior head into the spinal cord and ascend to the medulla oblongata on the same side of the body
The cell bodies of the first order neutrons are in the what of spinal nerves
in the posterior (dorsal) root ganglia of spinal nerves
the axons of the first order neutrons synapse with the dendrites of the second order neutrons whose cell bodies are located in what?
in the gracile nucleus or cuneate nucleus of the medulla
nerve impulses for touch, pressure, vibration & conscious proprioception from the UPPER limbs, trunk, neck & posterior head propagate along axons in the _____ and arrive at the _____
cuneate fasciculus , cuneate nucleus
Nerve impulses for touch, pressure, vibration, and copious proprioception from the LOWER limbs, trunk propagate along axons in the ____ and arrive at the ____
gracile fasciculus, gracile nucleus
the axons of the second-order neurons cross to the opposite side of the medulla and enter the ?
medial lemniscus ( a thin ribbon like projection tract that extends from the medulla to the ventral posterior nucleus of the thalamus)
in the thalamus the axons terminals of the second-order neurons synapse with third-order neurons which project their axons to?
the primary somatosensory area of the cerebral cortex
nerve impulses for pain, temperature, itch and tickle from the limbs, trunk & posterior head ascend to the cerebral cortex along which pathway?
anterolateral (spinothalamic) pathway
the cell bodies of the first order neurons are in the ?
(for spinothalamic pathway)
posterior root ganglion
the axon terminals of the first order neurons synapse with the second order neurons whose cell bodies are in the?
posterior gray horn of the spinal cord
the axons of the secondd order neurons cross to the opposite side of the spinal cord and then pass upward to the ?
brainstem
nerve impulses for most somatic sensations (tactile, thermal and pain) from the face, nasal cavity, oral cavity and teeth ascend to the cerebral cortex along which pathway?
trigeminothalamic pathway
first order neurons of the trigeminothalamic pathway extend from somatic sensory receptors in the face, nasal cavity, oral cavity and teeth into ?
the pons through the trigeminal (V) nerves
the cell bodies of the first order neurons are in the
trigeminal ganglion
the axons some first order neurons synapse with second order neurons in the ___? axons of other first order neurons descend into the ____ to synapse with second order neurons
pons, medulla
the axons of the second order neurons cross to the opposite sides of the pons and medulla then ascend as the _____
trigeminothalamic tract to the ventral posterior nucleus of the thalamus
anterior & posterior spinocerebellar pathways?
convey nerve impulses from proprioceptors in the trunk & lower limbs of one side of the body to the same side of cerebellum. proprioceptive input informs cerebellum of actual movements, allowing it to coordinate, smooth and refine skilled movements & maintain posture & balance
