Somatic Nervous System lecture 17

This set of flashcards covers key concepts related to the somatic nervous system, including patterns of neural circuits, pathways, and functional areas.

What is decussation in the context of the somatic nervous system?

Decussation refers to the crossing of white matter tracts in the brainstem or spinal cord, indicating that the left side of the brain controls the right side of the body.

What do first order neurons do in the somatic sensory pathway?

First order neurons are located in the posterior root and transmit sensory information from the peripheral nervous system to the central nervous system.

Where is the cell body of the second order neuron located in the somatic sensory pathway?

The cell body of the second order neuron is located in the spinal cord and serves as an interneuron that transmits signals to the thalamus.

What functional area is associated with the postcentral gyrus?

The postcentral gyrus is involved in the processing and interpretation of somatic sensory information.

What type of circuit includes multiple neurons sending signals to one neuron?

This describes a converging circuit, commonly seen in sensory neurons.

How is a diverging circuit characterized in the nervous system?

A diverging circuit is characterized by an upper motor neuron sending signals to multiple lower motor neurons, allowing for increased innervation to effectors.

What is a serial circuit typically associated with?

A serial circuit is typically seen in sensory pathways, where one presynaptic neuron sends signals to one postsynaptic neuron.

What defines a parallel circuit in the context of neural pathways?

A parallel circuit involves multiple neural pools moving signals simultaneously, such as the alternating movements during walking.

What happens during synaptic fatigue in a reverberating circuit?

In a reverberating circuit, positive feedback loops may lead to synaptic fatigue or presynaptic inhibition after extended activation.

Which type of tracts carry motor information in the spinal column?

Descending tracts carry motor information from the CNS to muscles and glands.

In the withdrawal reflex, which circuit type best describes the interaction between interneurons and motor neurons?

The phenomena represents a diverging circuit, as it can activate specific motor neurons while inhibiting others.