Central Nervous system Flashcards
What is the brain composed of?
Forebrain (Cerebral hemisphere, diencephalon), Midbrain and
Hindbrain (Pons, Medulla, Cerebellum)
What lobe is concerned with learning, motivation, reward, memory and emotion?
Limbic Lobe
Includes:
Amyglada, hippocampus, mamillary body, cingulate gyrus
What lobe is concerned with visceral sensations, autonomic control, interoception, auditory processing, visual vestibular integration?
Insular cortex
Lies deep in lateral fissure
Where is CSF formed?
Where is it found?
How is it reabsorbed?
Choroid plexus of lateral 3rd and 4th ventricles
Occupies ventricular system and sub-arachnoid space
By structures in the superior sagittal sinus - Arachnoid granulations arachnoid Vili
What are the differences between plasma and CSF?
CSF has lower pH, Less glucose, protein and potassium.
What are the dorsal structures of the spine?
What name is used for opposing structures?
Dorsal horn as a part of grey matter
Dorsal roots, rootlets
Dorsal root ganglion
Ventral (ventral rootlets, root etc)
How is the spinal cord composed?
In segments with each segment giving rise to a pair of mixed spinal nerves
The nerves emerge through intervertebral foramina
How many pairs of nerves in each spinal cord segment
- Cervical?
- Thoracic?
- Lumbar?
- Sacral?
- Coccygeal?
8 pairs 12 pairs 5 pairs 5 pairs 1 pair
Where do Nerves C1-C7 emerge?
Where do Nerves C8-Co1 emerge?
Emerge above corresponding vertebrae
Below the corresponding vertebrae
Where would Cranial Nerve C5 emerge?
Above the Cervical vertebrae C5
Where would thoracic spinal nerve T3 emerge?
Below the thoracic Vertebrae T3
Why are there enlargements in the cervical and lumbar regions of the spinal cord?
Due to large innervation of upper and lower limbs from those regions
What is the corticospinal tract?
Major descending pathways
Major pathway for voluntary movement.
Made of upper motor neurones in primary motor cortex and lower motor neurones in brainstem (if going to head and neck) and spinal cord (if going to muscles of trunk or limbs).
What pathways bring information about fine touch, vibration and proprioception from skin and joints?
(major ascending pathways)
Dorsal column pathway
What type of pathway brings information for pain, temperature from skin?
Major ascending pathway
Lateral Spinothalamic tract
What pathway brings information about crude touch to brain?
Ventral / Anteror Spinothalamic tract
What does the lateral corticospinal tract supply and where did it originate?
Limb muscles
Came from contralateral hemisphere
What does the anterior corticospinal tract supply?
Trunk muscles
What is the decussation of the cotricospinal tract?
85% of fibres cross in the medulla from the lateral tract to the contralateral side and supply limb muscles .The rest remain on the anterior corticospinal tract and supply the trunk muscles
What is the corticobulbar tract, where are their lower motor neurones?
pathways that go from primary motor cortex to the muscles of the face.
Lower MN are in cranial cavity in brain stem where there are nuclei for extraocular muscles, mastication, facial expression etc
What is the internal capsule?
Many parts of motor cortex has been congregating together to make their way from cortex downards cord or brain stem. * Check horizontal plane represenation
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 neurones of the upper limb
What are the pyramidal tracts and extra pyramidal tract?
The corticobulbar tract and the corticospinal tract
(also known as brainstem motor tracts) Extra pyramidal tracts supply muscles which are more automated (vestibulospinal, Tectospinal, reticulospinal, Rubrospinal)
(Dorsal Column pathway)
Info conveyed from lower limbs and the body - Below T6- travel ipsilaterally along?
gracile tract, synapse in the gracile nucleus in medulla
(Dorsal Column pathway)
Info conveyed from upper limbs and the body - Above T6- travel ipsilaterally along?
Cuneate tract, synpases in cuneate nucleus in medulla
Sensory neurons crossing to contralateral side?
Second order axons Decussate in caudal medulla.
From contralateral medial lemniscus tract
Synapse in the thalamus onto tertiary neurone
What differs between the posterior column pathway and the spinothalamic?
Position of the secondary neurone differs and where the cell bodies of second order neurones are located.
Both pathways have 3 neurones and both pathways have crossings in 2nd neurone.
What do the 3rd order neurones do (posterior pathway)?
Projecting to somatosensory cortex.
Size of somatotopic areas is proportional to density of sensory receptors in that body region.
Spinothalamic pathway, where does primary neurone synpase?
In dorsal horn as they enter spinal cord. Second order neurones then decussate immediately to form spinothalamic tract (anterior or lateral depending on information)
- 2nd order neurone synapses in thalamus for both ascending pathways and then synapse at sensory cortex
What two layers is the dura composed of?
Periosteal and meningeal - dense fibrous membrane
