Neuroanatomy Dorsal Root Ganglia and Sensory Neurons

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Questions and Answers

What is the primary function of a sensory system?

To activate the primary sensory cortex directly

To generate conscious decision-making processes

To transmit information to the central nervous system for processing (correct)

To translate electrical signals into stimuli

Which sensory receptors are activated by physical force like touch and vibration?

Mechanoreceptors (correct)

Photoreceptors

Thermoreceptors

Chemoreceptors

What type of receptors are activated by light?

Nociceptors

Photoreceptors (correct)

Thermoreceptors

Chemoreceptors

Which part of the brain is primarily associated with conscious perception of sensory stimuli?

Primary sensory cortex Signup and view all the answers

In sensory systems, what is modulated based on inputs from other sensory receptors?

Sensory perception Signup and view all the answers

Which sensory system involves detection of odors?

Olfactory Signup and view all the answers

Where are the cell bodies of the sensory neurons located?

Dorsal root ganglia Signup and view all the answers

What is the term for inflammation of the dorsal root ganglia?

Ganglioneuritis Signup and view all the answers

Where do the central processes of somatosensory neurons usually synapse in the spinal cord?

Dorsal horn of the grey matter Signup and view all the answers

How is the grey matter organized in the spinal cord based on function?

Layers called Rexed’s laminae Signup and view all the answers

Which half of the spinal cord contains sensory neurons and axons based on their function?

Dorsal half Signup and view all the answers

Which major somatosensory pathway transmits information about touch, pain, temperature, and body position to the cerebral cortex?

Dorsal somatosensory pathway Signup and view all the answers

Where do first order sensory neuron axons typically branch?

Both on second-order neurons and other interneurons that mediate local effects Signup and view all the answers

Which ascending pathway transmits information about posture and balance to the vestibular nuclei?

Spinovestibular tract Signup and view all the answers

What is the primary function of the thalamus in sensory processing?

Acting as a relay station for almost all sensory information going to the cerebral cortex Signup and view all the answers

Where are the nuclei that contain the cell bodies of third-order neurons of the somatosensory system located?

Ventral part of the thalamus Signup and view all the answers

Where is the primary somatosensory cortex located relative to the primary motor cortex?

Just caudal to it Signup and view all the answers

How are the neurons in the cortex organized regarding sensory information?

In a somatotopic map Signup and view all the answers

Where do the third-order neurons project in the sensory pathways?

Somatosensory cortex Signup and view all the answers

What distinguishes the sensory pathways for the facial and glossopharyngeal nerves from the trigeminal nerve pathway?

Axons of first-order neurons don’t travel in the trigeminal nerve Signup and view all the answers

How is visceral sensation different from somatic sensation?

Somatic sensation includes sensations from skin, muscles, tendons Signup and view all the answers

What type of receptors are found on visceral organs?

Enteroreceptors Signup and view all the answers

What are some signs of colic in horses according to the text?

Stretching, rolling, pawing, or kicking/biting at the flanks Signup and view all the answers

What type of receptors respond to tissue damage or stimuli associated with tissue damage?

Nociceptors Signup and view all the answers

Which type of receptors are activated by the binding of specific chemicals?

Chemoreceptors Signup and view all the answers

What is the role of transient receptor potential (TRP) channels in sensory reception?

Result in depolarization in response to stimuli Signup and view all the answers

Which receptors show a decreased rate of action potential production in response to a prolonged stimulus?

Slow adapting receptors Signup and view all the answers

Which receptors include rods and cones of the retina and hair cells in the inner ear?

Secondary receptors Signup and view all the answers

What is receptor adaptation in sensory systems defined as?

Decrease in sensitivity to a prolonged stimulus Signup and view all the answers

Study Notes

Sensory Systems

Sensory systems detect changes in the environment and relay information to the central nervous system to elicit an appropriate response
There are five sensory systems: somatosensory (touch, temperature, pain, itch, pressure, position), olfactory (odors), gustatory (taste), visual (light), and vestibular (movement)

Somatosensory System

Somatosensory system detects touch, temperature, pain, itch, pressure, and position
Mechanoreceptors detect physical force (touch, stretch, vibration)
Nociceptors detect tissue damage or stimuli associated with tissue damage
Thermoreceptors detect heat or cold temperature
Chemoreceptors detect specific chemicals

Sensory Receptors

Primary receptors: specialized terminals of sensory neurons that detect touch, pain, and temperature
Secondary receptors: specialized cells separate from sensory neurons, including rods and cones of the retina and hair cells in the inner ear
TRP channels are important in sensing pain, temperature, taste, pressure, and light

Adaptation in Sensory Systems

Adaptation: decrease in sensitivity to a prolonged stimulus
Slow adapting receptors show decreased rate of action potential production in response to a prolonged stimulus

Dorsal Root Ganglia and Spinal Cord

Dorsal root ganglia contain cell bodies of sensory neurons and support cells called satellite cells
Axons carrying signals to and from cell bodies
Central processes of somatosensory neurons enter the spinal cord and synapse in the dorsal horn of the grey matter

Somatosensory Pathways

Dorsal somatosensory pathway (dorsal column pathway) transmits information about touch, pain, temperature, and body position to the cerebral cortex
Other ascending pathways transmit information to parts of the brain other than the cerebral cortex

Thalamus and Primary Somatosensory Cortex

Thalamus acts as a relay station for almost all sensory information going to the cerebral cortex
Nuclei that contain cell bodies of third-order neurons of the somatosensory system are located in the ventral part of the thalamus
Primary somatosensory cortex is located just caudal to the primary motor cortex
Neurons in the cortex are organized in a somatotopic map, receiving information from a particular part of the body

Visceral Sensation

Sensation from internal organs (visceral sensation) is not as well understood as sensation from skin, muscles, tendons, and mucous membranes (somatic sensation)
Enteroreceptors detect stretch, pH, oxygen and carbon dioxide levels, and tissue damage
Visceral pain is described as dull or aching and is often poorly localized or referred to a part of the body distant from the site of the stimulus

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Description

Learn about the structure and function of dorsal root ganglia in the nervous system, which play a crucial role in processing sensory information. Explore the connection between sensory neurons, dermatomes, and support cells within the dorsal root ganglia.