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
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
What are the segments of the spinal cord and how many pairs of spinal nerves are in each?
Cervical - 8
Thoracic - 12
Lumbar - 5
Sacral - 5
Coccygeal - 1
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 do spinal nerves exit from?
Intervertebral foramina
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
Which part of the spinothalamic tract takes information about crude touch?
Ventral spinothalmic tract
What is the main descending pathway called?
Corticospinal tract
Where do most of the upper motor neurones originate in the corticospinal tract?
primary motor cortex
Where do most of the lower motor neurones originate in the corticospinal tract?
Brainstem and spinal cord
Where do most lateral corticospinal neurones decussate?
medulla
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
What is the purpose of the corticobulbar tract?
Controls head, neck and spine
Information from the lower limbs and body travels ipsilaterally along which tract and synapses at which nucleus?
Gracile tract and gracile nucleus
Information from the upper limbs and body travels ipsilaterally along which tract?
Cuneate
Where do the gracile and cuneate tracts decussate?
Medulla
Name the extra pyramidal tracts
- Vestibulospinal
- Tectospinal
- Reticulospinal
- Rubrospinal
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?
Preparatory and movement related activities and
postural control
What does the rubrospinal tract do?
Innervate lower motor neurons of the upper limb
Only becomes functional after injury to corticospinal tract
Outline the dorsal column pathway
1) Primary neurone enters cord via dorsal horn and travels ipsilaterally up the cord along either the gracile or cuneate tracts
2) The neurone synapses onto second order neurones in either the gracile or cuneate nucleus
3) The second order neurones decussate in the medulla to form the contralateral medial lemniscus tract.
4) They then synapse onto third order neurones.
5) The third order neurones from the thalamus project to the somatosensory cortex
Outline the anterolateral pathway
1) Primary afferent axons synapses immediately upon entering the spinal cord
2) Second order neurones decussate immediately in the spinal cord at the level at which the neurone comes in to form spinothalamic tract
3) 2nd order neurones synapse in the thalamus
4) 3rd order neurones from the thalamus project to the somatosensory cortex
