Lecture 9. Brain + CNS Flashcards
Where is the location of the 3rd order neuron in the medial lemniscus pathway
at the thalamus
Where will conscious tracts end
at the cortex
Where will the unconscious tracts end
at the cerebellar cortex
what is the difference between the unconscious and conscious pathways of proprioception
- unconscious: the 2nd order neuron is at the dorsal horn
conscious: the 2nd order neuron is that the medulla oblongata - unconscious: ipsilateral: ends at the same side of the cerebellar side
conscious: contralateral: ends at the other side - unconscious: has 2 neurons
conscious: has 3 neurons
* * similarity: Both are ascending pathways
What is ipsilateral?
Situated or affecting the same part of the body (not crossing the midline)
What is contralateral?
occurs or affects the opposite side of the body. (crossing the midline)
What is the purpose of the spinothalamic pathway
collects temperature and pain
Where is the 1st order neuron of the spinothalamic pathway
dorsal root ganglia
Where does the 2nd order neuron start in the spinothalamic pathway
posterior (dorsal) horn
Where does decussation of the 2nd order neuron of the spinothalamic pathway occue
contralateral: from the dorsal horn to the anterior horn and entering the anterior column
What are the 3 main ascending pathways
- spinothalamic
- spinocerebellar
- dorsal column pathway
Where is the 3rd order neuron of the spinothalamic pathway located
at the thalamus
Is the spinothalamic pathway one that is conscious or unconscious?
conscious since it ends at the brain
What are the classification of descending pathways
- extrapyrimidal
2. pyrimidal
What is the function of pyrimidal or extrapyrimidal pathways
- both control the skeletal muscles
1. pyrimidal pathways: start from cortex ( it is conscious)
2. extrapyrimidal pathway: starts at the lower cortex ( it is unconscious) - eg. muscles to maintain posture
What are the 2 neurons that are present in the descending athways
upper and lower neurons
Where is the 2nd neuron of the descending pathway located
ALWAYS sits in the anterior horn of the spinal cord
Where does the upper neuron descend past
passes through midbrain, pons and medulla oblongata
Where do all the upper neurons converge towards (ALWAYS)
pyramids of the medulla
what is the lateral corticospinal pathway
cortical spinal that crosses the midline and travels through the lateral column of the spinal cord
What is the anterior/ventral corticospinal pathway
upper neurons continue to travel through anterior column and because they did not decussate at the brain stem region (to descend at the anterior column )
What is the difference in the muscles controlled by the anterior or lateral corticospinal
anterior corticospinal controls your core muscles
lateral corticospinal controls muscles of your limbs
How many cranial nerves are there? How many arise from the brain stem?
12 cranial nerves, 10 arise from the brain stem.
Which 2 cranial nerves do not arise from the brain stem
CN 1 and CN2
What is the border which CN 6,7,8 arise from
pontomedullary sulcus
What is the function of the superior colliculus
regulates visual reflexes
What is the function of the inferior colliculus?
regulates auditory reflexes
What is the function of the olive
helps to maintain your balance.
Where is the location of the hypoglossal nerve
between the olive and nerve. It is CN12
What are nuclei
nerve cell bodies in the white matter
What is the function of the red nucleus
one of the center for the extrapyrimidal pathways
What is the function of the cerebral aqueduct
It connects the 3rd and 4th ventricles
What is the function of the reticular formation
mixture of nerve cell bodies and nerve tracts.
Function: helps keep you alert and awake
What is the function of the substantia nigra
It is almost black. fails during parkinson giving rise to resting tumors
What is seen at the cerebral peduncle
At the location of the pyramids, there are ONLY the tracts of the pyrimidal pathways
How far does the reticular formation extend to
midbrain, pons and medulla
Where is the pontine nuclei located
Pons
What is the function of the pontine nuclei?
received orders from the cortex and passes it to the cerebellum- makes voluntary motions smooth
What is the function of the inferior olivary nucleus
Helps maintain balance
