Test 3 - 9/25 lecture Flashcards
Are motor pathways descending or ascending?
Descending
Is the motor pathway afferent or efferent?
efferent
What are the two main groups for the motor pathways?
Pyramidal and Extrapyramidal Tracts
How many subcategories are in the extrapyramidal tract?
Four
Where are the extrapyramidal tracts located?
Outside of the pyramidal tracts
What kind of pathway is the extrapyramidal tract? What function does it have?
accessory motor pathway. It helps us fine tune instructions for more complex tasks
Which pathway takes up more space in the cord (motor or sensory)? Why?
Sensory. It is bigger because we have so many sensors that send information (pain, temperature, vibration..etc.)
What happens in the grey matter of the spinal cord?
Decision making. We have lots of cell bodies sending synapses.
What is a tract?
A bundle of axons within the CNS
What are bundles of axons called outside of the CNS?
Nerves
what is the primary motor pathway?
Pyramidal tract
True/False. The pyramidal tract is voluntary movements
True
Where are the pyramidal tracts located?
Anterior and lateral parts of the cord
Is the sensory pathway ascending or descending?
Ascending
Is the sensory pathway afferent or efferent?
Afferent
What sensory pathway does pressure sensory (ex. touch perception) info transmit from?
Dorsal column
What sensory pathway system is for pain signal transmission?
Anterolateral System.
How many components make up the anterolateral system? and what are the names?
Two.
Lateral spinothalamic tract
Anterior spinothalamic tract
What does the spinothalamic terminology correspond to?
Spino- because its in the spine
thalamic- because the pain info gets relayed through the thalamus
from there it goes out to the parietal cortex to be sorted (like how bad is the pain and where is it located)
What is the name for the grey matter when it is divided up into the different lamina?
Rexed’s Laminae (or Rexed Laminae)
What is another name for Lamina I. Why do they call it that?
Lamina marginalis.
Because it is located on the margin on the dorsal horn.
How are the lamina numbered? Which Lamina is located in the most dorsal part of the dorsal horn?
They are numbered back to front. Most dorsal part is Lamina I
What is Lamina I responsible for?
What kind of fibers send the info from lamina I?
Fast pain. Sent via A delta fibers (myelinated nociceptors)
Fast pain signals enter the spinal cord via the ____ root and ____. There is a synapse in lamina ____. From there is crosses over to the ____ pathway via the ____.
- Dorsal root
- Rootlet
- Lamina I
- anterolateral pathway
- AWC
What is Lamina II and III responsible for? What kind of fibers are present?
Slow pain. Sent via C fibers (non myelinated nociceptors)
What is another name for Lamina II and III?
Substantia Gelatinosa
What other lamina might also have synaptic connection with slow pain (other than lamina II and III)
Lamina 5
Lamina 1-6 also have what role (other than fast/slow pain for lamina 1-3,5)? What pathway would they take?
They have mechanoreceptors that send sensory info via the dorsal column.
How many Lamina are there?
10
Which lamina contains a large amount of motor neurons?
Lamina 8
The anterior part of the grey matter in the cord is primarily used for relaying what kind of information?
motor
Where does cross over happen in the cord?
Lamina 10 or anterior white commissure.
Spinocerebellar tract(s) send what kind of info? Where is the info sent
Sensory. from spinal cord to cerebellum.
Dorsal-Column Medial Lemniscal System (DCML) send what kind of info? Why does it have that name?
Major pressure sensor (touch).
Dorsal-column: Sits in dorsal part of cord
Medial Lemniscal: the region of the brain stem that the signal passes through
Corticospinal Tracts: “Pyramidal tracts” are what kind of pathway?
Descending (Motor)
What kind of fibers are located in the DCML?
A fibers (alpha, beta, delta and gamma)
Where does the cross over happen for the DCML
Medulla
Where are the two places that sensory information can go when it enters the cord?
Some will go to grey matter and some will go straight to dorsal column and up to brain.
The sensory information that goes to the grey matter can be involved with what?
Lateral inhibition or modular activity
True/false. The inferior portion of the cord has a bigger dorsal column.
False. The superior portion is larger.
What is name for the part of the dorsal column that sends sensory signals from the lower parts of the body?
Fasciculus Gracilis
What is the name for the portion of the dorsal column that sends sensory signals from the upper parts of the body? Does this have a lateral or medial position in the dorsal column?
Fasciculus Cuneatus
Lateral
True/False: DCML send sensitive information (feather, fine vibrations, fine pressure)
True
List the steps for the DCML pathway for sensory information that starts at the foot.
- enter cord through dorsal root ganglion
- into Fasciculus Gracilis part of the dorsal column
- X-over at lower part of medulla oblongata
- Through Medial lemniscus
- Ventrobasal complex of thalamus
- internal capsule
- to parietal lobe
The top part of the parietal lobe takes care of what parts of the body?
Lower extremities
The lateral borders of the parietal lobe take care of what part of the body?
Face
True/False. The amount of area processing information is proportional to the amount of sensory receptors in that part of the body.
True
What parts of the body have lots of pressure sensors?
Face and hands
True/False. The trunk has more pressure sensors compared to the face
False
What is the name of the creepy looking drawing that shows the parts of the parietal lobe and the body parts that they relate to?
Homunculus
What is the main non pain sensory system?
Dorsal column medial lemniscus (DCML)
Describe the primary pathway of the pyramidal tract
- signal originates in frontal lobe
- internal capsule
- pyramids of medulla
- X-over at pyramidal decussation
- down lateral corticospinal tracts
- once it reaches the level it needs to exit..there is activation of motor neurons that are located in the anterior horn of the spinal cord
The primary pathway of the Pyramidal tracts account for what % of our motor function?
80%
The secondary pathway of the pyramidal tracts account for what % of our motor function?
~17%
What is the main difference between the primary and secondary pathway for the pyramidal tract?
Where the cross over happens. Primary - x-over at Pyramidal decussation
Secondary - x-over in the spinal cord at the level that the message needs to be communicated to.
Pyramidal tract: What tract is involved with the primary pathway?
Lateral corticospinal tract
Pyramidal tract: What tract is involved with the secondary pathway?
Anterior corticospinal tract
What % in the Pyramidal tract has no cross over at all?
2%