Lecture 3 Flashcards
Integration, decision making, and processing of signals occurs occurs in which NS?
CNS
Signals from CNS traveling to/from targets in the periphery occurs in which NS?
PNS
Where does synapsing occur?
gray matter:
- cerebral cortex
- cortical nuclei/diencephalon (ex., thalamus)
- grey horns of spinal cord
Where can we find white matter?
- cerebral tract (Corpus callosum)
- White columns of spinal cord
- Spinal pathways
- Peripheral Nerves
What are the 3 white matter columns in the spinal cord?
- posterior column
- lateral column
- anterior column
What is the anterolateral column of the spinal column comprised of?
the lateral & anterior column
What signals is posterior column of the spinal cord associated with?
ascending sensory signals
What signals is the anterolateral column associated with?
contains both ascending sensory & descending motor
What signal is the posterior gray matter horn associated with?
sensory signals
What signal is the lateral horn of the gray matter associated with?
autonomic (unconscious) signals
What signal is the anterior gray matter horns associated with?
motor signals
Signals travelling in spinal nerves can enter enter/exit the spinal cord via connections known as __ __
nerve roots
Provides pathway for afferent/ incoming information to flow from spinal nerve into the spinal cord
dorsal root
Where does sensory information synapse with reference to the dorsal roots?
may synapse in dorsal grey horn OR ascend in white columns
Provides pathway for efferent/outgoing signals to leave spinal cord and enter spinal nerve
ventral root
Where does motor information synapse with reference to the ventral root?
may synapse in ventral grey horn or descend in white columns
Neurons will pass the signal from one cell to the next by forming a synapse between?
adjacent axon terminal and the cell body
Where do ventral and dorsal roots come together to form a spinal nerve?
Intervertebral foramen
What are nervous signals classified based on?
- direction that they flow
- type of signal that is carried
- target/effector that carries out the response
“Code” of nervous system: Conscious/voluntary motor (body movement)
GSE: general somatic efferent
“Code” of nervous system: general sensation (sensation on skin)
GSA: general somatic afferent
“Code” of nervous system: Involuntary/subconscious motor to organs/viscera (beating of heart)
GVE: general visceral efferent
“Code” of nervous system: Visceral sensation (stretch of vessel)
GVA: general visceral afferent
T/F: Each spinal nerve can carry only one code of the nervous system
False, can carry many
__ = “of the body” what you are aware of (conscious)
SOMATIC
__ = what you are not aware of (unconscious)
AUTONOMIC
Define: Decussate
when signals cross over from one side to another (left to right; or right to left). Occurs within the CNS
What pathways are always going to be ipsilateral?
Where are receptors for sensory information be located?
end of peripheral nerves within the layers of the skin
Afferent/Sensory information comes into the CNS via the?
dorsal root of the spinal nerve
Efferent/Motor signals originate in the ?
pre-central gyrus of the frontal lobe (primary motor cortex)
Which root do efferent/motor signals exit the CNS by?
ventral root
Target for motor signals are known as ?
effectors
Where do the first-order neurons travel?
in peripheral nervous system
Where do first order neurons synapse?
typically in the brainstem
Where do second and third order neurons travel?
in central nervous system
The __-order neuron is located either in the dorsal horn of the spinal cord or within the medulla oblongata and relays impulses to the thalamus
second
The __-order neuron residing in the thalamus conveys impulses to the general sensory area (postcentral gyrus) of the parietal lobe of the cerebral cortex
third
The __-order neuron resides in the dorsal root ganglion of the spinal nerve and conducts impulses from sensory receptors to the spinal cord or medulla oblongata
first
What are the major ascending, sensory tracts?
- Spinothalamic: pain and temperature
- Spinocerebellar: proprioception
- Posterior/Dorsal column: discriminative touch
- Spinotreticular tract
- Spinotectal tract
- Spinomesecephalic tract
- Spino-olivary tract
What is the pathway of the dorsal Column (Medial Lemniscus) tract?
Neuron 1: 1st order neuron
- Originates in peripheral receptor
- Travels towards CNS via spinal nerve
- Enters CNS via dorsal root of spinal nerve and does NOT synapse
- Axon continues to ascend in dorsal columns of spinal cord
- Synapses in nuclei of medulla
Neuron 2: 2nd order neuron
- Cell body originates in nucleus of medulla
- Axon decussates in medulla oblongata
- Ascends to thalamic nuclei via medial leminiscus pathway
- Synapses in thalamus
Neuron 3: 3rd order neuron
- Cell body originates in thalamus
- Axon travels from thalamus to post-central gyrus of parietal lobe
- Synapses in primary somatosensory cortex
- Sensation is interpreted
FC (lateral columns) - fasciculus cunetaus carries touch information from?
upper limb
FG (medial columns) = Fasciculus gracilis carries touch information from?
lower limb
The dorsal column is divided into lateral and medial columns what are they?
- FG (medial columns) = Fasciculus gracilis
- FC (lateral columns) = Fasciculus cuneatus
Information travelling in the fasciculus cuneatus column will synpase where?
in the “nucleus cuneatus” (NC) of the medulla