Exam 3 Pathways And Integrative Function Flashcards
Sensation comes into the
Spinal cord and send motor outflow to muscles
The sensory information coming into the spinal cord is
Relayed by several neurons in series
The motor outflow from the _ descends into motor neurons in the _
Cerebrum (UMN), ventral horn of the spinal cord (LMN)
The white matter of the spinal cord can be divided into functionally distinct regions called
Funiculi
Motor pathways _ into funiculi of the spinal cord
Descend
Sensory pathways _ into the funiculi of the spinal cord
Ascend
In sensory pathways, what are the series to transmit information to the brain
First neuron is primary, second is secondary, and third is tertiary
What does the posterior funiculus-medial lemnisal pathway carry?
Sensation regarding precise touch and pressure from the skin
The thalamus relays…
Somatosensory information
The primary neurons are multipolar or unipolar
Unipolar
The first step of the posterior funiculus pathway….
- The primary neurons enter the spinal cord and ascend into the posterior funiculus
In the posterior funiculus medial Lemniscal pathway the primary neurons relay the info to
Secondary neurons in the medulla
In step 2 of the posterior funiculus medial pathway….
The axons of secondary neurons cross to the opposite side and ascend into the thalamus
A bundle of secondary neuron axons that cross over in the posterior funiculus medial pathway are called?
Medial lemniscus
Step 3 of the posterior funiculus medial pathway….
The tertiary neurons in thalamus receive info and send it to the primary somatosensory cortex (post central gyrus)
The primary somatosensory cortex is also known as the
Postcentral gyrus
If there is damage to the posterior funiculus medial pathway..
You lose precise touch and pressure for a certain spinal cord level and below.
Central processes in the posterior funiculus medial pathway….
Ascend into the posterior funiculus
The anterolateral pathway carries
Sensation regarding pain, temperature, crude touch and crude pressure from skin
In the anterolateral pathway the first step is that the
primary neurons enter dorsal horn and relay info to secondary neurons
In the anterolateral pathway the second step is that the
Axons of the secondary neurons cross to the opposite side and ascend in the white matter of the spinal cord.
In the anterolateral pathway, axons carrying information regarding pain and temperature…
Ascend into the lateral funiculus
In the anterolateral pathway, axons carrying information regarding crude touch and pressure….
Ascend into the anterior funiculus
In step three of the anterolateral pathway, the tertiary neurons
In the thalamus receive the info and send to somatosensory cortex.
Lateral spinothalamic tract carries sensation for
Pain and temp
Anterior spinothalamic tract carries sensation for
Crude touch and pressure
The spinocerebellar pathway carries info regarding
Proprioception
Awareness of position of body parts based on the length and tension in individual muscles
Proprioception
There are no tertiary neurons in which pathway
spinocerebellar pathway
In the spinocerebellar pathway, the primary neurons
Enter the dorsal horn and relay info to secondary neurons
The axons of the secondary neurons in the spinocerebellar pathway…
Ascend in the lateral funiculi
The secondary neurons send what information and to where in the spinocerebellar pathway
Send proprioceptive info to BOTH sides of the cerebellum
If the lateral finiculus in the spinocerebellar pathway is damaged….
There is a loss of proprioception on both sides of the body.
Upper motor neurons can originate in the
Cerebral cortex or nuclei
Lower motor neurons are located in the
anterior horns of the spinal cord
Corticospinal tracts descend in the
White matter of spinal cord
What is the only motor pathway
The corticospinal tract
The corticospinal tract contains
corticospinal neurons that control skeletal muscles below the head
Upper motor neurons originate primarily in the _ in the corticospinal tract
Somatomotor cortex, pre central gyrus
In The corticospinal tract, as the descending axons of upper motor neurons reach the medulla, what happens?
85% cross to opposite side and descend into lateral funiculi
15% stay on same side, descend into anterior funiculi then cross over to opposite side
Lateral corticospinal tract contains how many
85%
Anterior corticospinal tract contains
15%
In summary, if there is damage on the right side of the posterior funiculi what happens
Loss of precise touch on the same side of the body
In summary, if there is damage on the right side of the lateral funiculi what happens
Loss of proprioception of both sides of the body; pain and temperature lost in the opposite side of the body; lose 85% strength of muscles of same side of the damage.
In summary, if there is damage on one side of the anterior funiculi what happens
Loss of crude touch on opposite side of the body; loss of 15% strength of muscles on opposite side of damage
