1a Central Nervous System Flashcards
What are the three sections of the brain called?
Forebrain, midbrain and hindbrain
What does the diencephelon consist of?
Thalamus and hypothalamus
What are the three compoents of the hind brain?
Cerebellum, pons and medulla
What are the four lobes called?
Frontal, parietal, temporal and occipital
What does the frontal lobe do?
regulates motor function, language and cognitive function
What does the temporal lobe do?
Processes auditory information
What does the parietal lobe do?
Sensation, sensory aspects of language and spacial orientation
What doe the occipital lobe do?
Processes visual information
What does the insular cortex do?
visceral sensations and autonomic control
What does the limbic lobe include?
The hippocamus, amygdala, mamillary body and cingulate cortex
What is the limbic lobe concerned with?
Learning, memory, emotion, motivation and reward
What are the two layers of the dura called?
Meningeal and periosteal
What are the three layers of the meninges called?
Dura, arachnoid and pia
Which layer of the dura is present in the vertebral column?
meningeal layer
Where is cerebrospinal fluid produced?
The choroid Plexus of lateral, 3rd and 4th ventricles
What reabsorbs the CSF and into where?
arachnoid villi into superior sagittal sinus
What is a ganglion?
A group of cell bodies of sensory neurones outside the CNS
At what levels does the spinal cord end?
L1/2
Where do spinal nerves C1-7 emerge?
Above the corresponding vertebrae
Where do spinal nerves C8 to S5 emerge>
Below the corresponding vertebrae
Where does cervical enlargement start and end?
Starts at C3 level and ends at T1
What is the point of cervical enlargement between C3 and T1?
The cervical enlargement of the spinal cord is the source of the spinal nerves that contribute to the brachial plexus and supply the upper limbs.
Where does the lumbar enlargement occur?
Extends between L1 and S2
what is the point of the lumbar enlargement?
Contains the spinal nerves which innervate the lower limbs
What do ascending tracts do?
Carry sensory information from the body to the CNS
How many cells thick is the pia mater layer of the meninges ?
2
Compare CSF to plasma?
CSF has a lower pH, less glucose, protein and potassium than plasma
What are the two main ascending pathways called?
Dorsal column and spinothalamic tract
What is the dorsal column for?
Fine touch, vibration and proprioception
Where does the dorsal column take information from?
The skin and joints
What is the spinothalamic tract for?
Pain, temperature and crude touch from the skin
What is the main descending pathway called?
Corticospinal tract
Which part of the spinothalamic tract is for crude touch?
Ventral spinothalamic
Where do most of the upper motor neurones originate in the corticospinal tract?
primary motor cortex or pre motor frontal areas
Where do lateral corticospinal neurones decussate?
Most in the medulla (85%)
What do lateral corticospinal tract neurones innervate?
limbs and digits
When do anterior corticospinal neurones decussate?
In the spinal cord at the level in which they exit
What do anterior ventral corticospinal tract neurones innervate?
The trunk, shoulder and neck muscles
What is the purpose of the corticobulbar tract?
Controls head, neck and spine
Which nuclei of cranial nerve are innervated by the corticobulbar tract?
5, 7, 9 and 12
What percentage of corticobulbar fibres decussate?
50%
What does the corticobulbar tract synpase with?
Motor cranial nerves in the brainstem
What are the lower motor neurones of the corticobulbar tract? and what do they do?
motor nuclei of the cranial nerves - carry efferent signals directly to the muscles of the face, head and neck.
Information from the lower limbs and body travels ipsilaterally along which tract?
Gracile
Information from the upper limbs and body travels ipsilaterally along which tract?
Cuneate
Where do the gracile and cuneate tracts decussate?
Medulla
Where do second order neurones of the spinothalamic tract decussate?
they decussate immediately in the spinal cord
Where do 2nd and third oder neurones synpase?
The thalamus
Where do third order neurones from the thalamus project to?
The somatosensory cortex
After the dorsal pathway has crossed to the other side, what does it form?
The contralateral medial lemniscus tract
What is the place where first order neurones and second order neurones that come from the lower limbs synpase?
Nucleus gracilis
What is the place where first order neurones and second order neurones that come from the upper limbs synpase?At
nucleus cuneate
Where do anterior corticospinal tract neurones decussate?
At the level of the spinal cord where they exit
Which cranial nerves have their nuclei synapsed with at the midbrain level?
3,4,6
Which cranial nerves have their nuclei synapsed with at the pons level?
5 and 7
Which cranial nerves have their nuclei synapsed with at the medulla level?
9, 10, 11, 12
What medication is given to reduce jerky movements
Diazepam
Where do fibres enter into the dorsal column pathway from?
The dorsal horm
How many pairs of spinal nerves are there?
31 pairs
What sulcus is found between the pre-central gyrus and post-central gyrus?
Central sulcus
Where are the upper and lower motor neurons for the corticospinal tract found?
Upper motor neurons - Primary Motor Cortex
Lower motor neurons - Brainstem (medulla) and Spinal Cord
What does the vestibulospinal tract do?
Provides information about head movement and position and mediates postural adjustments
What does the tectospinal tract do?
Orientation of the head and neck during eye movements
What does the reticulospinal tract do?
Control of breathing and emotional motor function
What does the rubrospinal tract do?
Innervate lower motor neurons of the upper limb
Only becomes functional after injury to corticospinal tract
Where would the first synapse be of the cuneate tract?
Cuneate nucleus
Which part of the spinothalamic tract takes information about crude touch?
Ventral spinothalmic tract
Outline the pathways of the anterior and lateral spinothalamic tracts
Primary afferent axons terminate upon entering the spinal cord
Second order neurons decussate immediately in the spinal cord and form the spinothalamic tract
2nd order neurons terminate in the thalamus
3rd order neurons from the thalamus project to the somatosensory cortex
How much CSF is produced at any one time, and in any one day?
125ml at any one time and 500ml a day
Where is CSF produced?
In the choroid plexus of the lateral, 3rd and 4th ventricle
How many cervical pairs of nerves are there?
8 pairs of nerves
How many thoracic pairs of nerves are there?
12
How many lumbar pairs of nerves are there?
5
How many saccral pairs of nerves are there?
5
How many coccygeal pairs of nerves are there?
1
Where do spinal nerves exit from?
Intervertebral foramina
Where does C8 spinal nerve emerge from?
Below the C7 Vertabrae
After Spinal nerve C8, Where do the more inferior spinal nerves leave from?
Below the corresponding vertabrae eg T4 nerve emerges from below T4
Where is the pre-central gyrus found?
In front of the central sulcus
Where are the lower motor neurones of the corticspinal tract that innervate the head and neck muscles found?
In the brain stem
Where are the lower motor neurones of the corticospinal tract that innervate the trunk and limb muscles found?
In the spinal cord
What percentage of upper motor neurones in the corticospinal tract decussate in the medulla?
85% as this makes up the lateral corticospinal tract
What percentage of upper motor neurones in the corticospinal tract decussate in the spinal cord?
15%
