Select all that are true of sensory pathways.
Check All That Apply
They are composed of primary, secondary, and sometimes tertiary neurons.
They send signals to muscles and glands.
They are also called ascending pathways.
They relay information from sensory receptors.
The correct answer and explanation is :
The correct answers are:
✅ They are composed of primary, secondary, and sometimes tertiary neurons.
✅ They are also called ascending pathways.
✅ They relay information from sensory receptors.
Explanation (300 words):
Sensory pathways, also known as ascending pathways, are responsible for transmitting sensory information from the peripheral nervous system to the brain. These pathways help us perceive sensations such as touch, pain, temperature, pressure, and proprioception (body position awareness).
Sensory pathways typically involve a three-neuron chain:
- Primary (First-order) Neurons – These neurons detect stimuli from sensory receptors (e.g., skin, muscles, joints) and transmit signals to the central nervous system, typically synapsing in the spinal cord or brainstem.
- Secondary (Second-order) Neurons – These neurons relay signals from the spinal cord or brainstem to the thalamus, where sensory information is processed. Many of these neurons cross over (decussate) to the opposite side of the brain.
- Tertiary (Third-order) Neurons – These neurons are found in the thalamus and project signals to the sensory cortex in the brain, where conscious perception of the stimulus occurs.
Since sensory pathways carry information from sensory receptors to the brain, they do not send signals to muscles and glands. That function belongs to motor pathways (descending pathways), which control voluntary and involuntary muscle movements.
Additionally, sensory pathways include major tracts such as:
- Dorsal column-medial lemniscus pathway (for fine touch and proprioception)
- Spinothalamic tract (for pain and temperature)
- Spinocerebellar tract (for coordination and balance)
These pathways ensure the brain receives vital sensory input, allowing humans to interact with their environment.