Question

Which of the following correctly summarizes how a sensory signal is transmitted from a touch receptor in the skin to the brain for processing?

Group of answer choices

1. sensory receptor --> afferent neuron --> dorsal root of spinal nerve --> dorsal horn of spinal cord --> descending tract --> brainstem --> cerebrum

2. sensory receptor --> efferent neuron --> ventral root of spinal nerve --> ventral horn of spinal cord --> descending tract --> brainstem --> cerebrum

3. sensory receptor --> efferent neuron --> ventral root of spinal nerve --> dorsal horn of spinal cord --> ascending tract --> brainstem --> cerebrum

4. sensory receptor --> afferent neuron --> dorsal root of spinal nerve --> dorsal horn of spinal cord --> ascending tract --> brainstem --> cerebrum

sensory receptor --> afferent neuron --> dorsal root of spinal nerve --> lateral horn of spinal cord --> ascending tract --> brainstem --> cerebrum

Answer 1

Answer) The correct sequence is (4)

sensory receptor --> afferent neuron --> dorsal root of spinal nerve --> dorsal horn of spinal cord --> ascending tract --> brainstem --> cerebrum.

• The dorsal root of nerve transmits sensory information through sensory receptors, forming the afferent sensory root of a spinal nerve.
• The ascending tracts refer to the neural pathways by which sensory information from the peripheral nerves is transmitted to the cerebral cortex.

STRUCTURE OF SOMATOSENSORY PATHWAY :-

The somatosensory system is distributed throughout all major parts of our body. It is responsible for sensing touch, temperature, posture, limb position, and more.

# A somatosensory pathway will typically consist of three neurons: primary, secondary, and tertiary.

• The primary neuron is the sensory receptor that detects sensory stimuli like touch or temperature. The cell body of the primary neuron is housed in the dorsal root ganglion of a spinal nerve.
• The secondary neuron acts as a relay and is located in either the spinal cord or the brainstem and travel up the spinal cord to the brain, where most will terminate in either the thalamus or the cerebellum.
• Tertiary neurons have cell bodies in the thalamus and project to the postcentral gyrus of the parietal lobe, forming a sensory homunculus in the case of touch.