Central Nervous System Flashcards
What is the CNS comprised of?
Cerebrum Cerebellum Brainstem Spinal cord
What is the brain comprised of?
Forebrain Midbrain Hindbrain
What is the forebrain comprised of?
Cerebral hemispheres Diencephalon
What is the hindbrain comprised of?
Pons Medulla Cerebellum
What is the diencephalon comprised of?
Thalamus Hypothalamus
What is the function of the frontal lobe?
Regulating and initiating motor function, language, cognitive functions e.g. planning, attention and memory
What is the function of the parietal lobe?
Sensation (touch, pain) Sensory aspects of language Spatial orientation Self-perception
What is the function of the temporal lobe?
Processing auditory information
What is the function of the occipital lobe?
Processing visual information
What divides the frontal and parietal lobe?
Central Sulcus
What is the limbic lobe comprised of?
Amygdala Hippocampus Mamillary body Cingulate gyrus
What is the limbic lobe concerned with?
Learning, memory, emotion, motivation and reward
Where is the insular cortex found?
Deep within lateral fissure
What is the insular cortex concerned with?
Visceral sensations Autonomic control Interoception Auditory processing Visual vestibular integration
What are the three layers of the meninges?
Dura Arachnoid Pia mater
What is the dura comprised of?
2 layers Periosteal- layer of periosteum Meningeal- durable, dense fibrous membrane
What is the arachnoid comprised of?
Thin, transparent, fibrous membrane
What is the Pia comprised of?
Thin, transluscent and mesh like
Where is the Cerebrospinal fluid found?
Sub-arachnoid space Ventricular system
Where is the Cerebrospinal fluid made?
Choroid plexus of lateral 3rd and 4th ventricles
How much Cerebrospinal fluid is made a day?
125ml and 500ml
Where is the CSF absorbed into?
Into bloodstream via arachnoid villi and superior sagittal sinus
How is CSF different to plasma?
Lower pH (7.33) Less glucose Far less protein Less potassium
What is the. spinal cord comprised of?
Segments each gives rise to a pair of mixed spinal nerves
What are the different segments of the spinal cord?
Cervical (8) Thoracic (12) Lumbar (5) Sacral (5) Coccygeal (1)
What do nerves emerge through?
Intervertebral foramina
How does the relationship between nerves and foramina change between cervical and thoracic regions?
C1-C7 emerge above vertebrae C8-Co1 emerge below vertebrae
Label the diagram with the following:
Dorsal horn
Dorsal rootlets
Dorsal Root
Ventral root
Ventral rootlets
White matter
Grey matter
Mixed spinal nerve
Ventral horn
What is the major pathway for voluntary movement (descending)?
Corticospinal tract
What is the corticospinal tract comprised of?
Upper motor neurons in primary motor cortex
Lower motor neurons in brainstem and spinal cord
Descending (motor)
Crosses at medulla
What are the main ascending pathways for sensation?
Dorsal column pathway
Spinothalamic tract
What is the function of the dorsal column pathway?
Fine touch
Vibration
Proprioception
All from skin and joints
What is the function of the spinothalamic pathway?
Pain
Temperature
From the skin
(sensory)
Crosses at bottom of spinal cord
Where are the two spinal cord enlargements?
Cervical enlargement- innervation of upper limbs
Lumbar enlargement- innervation of lower limbs
In the simplest of cases how many neurons are there?
2
Upper motor neuron in brain
Lower motor neuron in spinal cord
What does decussate mean?
Go to the other side
Approx. 85% of fibres decussate in the medulla
What is the pathway of the corticobulbar tract?
From the cortex to brainstem to facial muscles
What is somatotopy?
Somatotopy is the point-for-point correspondence of an area of the body to a specific point on the central nervous system
Where do tracts synapse?
In the medulla
What is the doral column pathway?
Fibres enter via the dorsal horn
Enter the ascending dorsal column pathways
Information conveyed from lower limbs and body (below T6)
Travels ipsilaterally along the gracile tract
Information conveyed from upperlimbs and body (above T6)
Travel ipsilaterally along cuneate tract
Where is the first synapse of the gracile tract?
Gracile nucleus
Where is the first synapse of the cuneate tract?
Cuneate nucleus
Where fdo second order axons decussate?
In the caudal medulla
Form the contralateral medial lemniscus tract
Synpase in the thalamus
Where fo 3rd order neurons from the thalamus project?
Somatosensory cortex?
What is the size of the somatotopic area is proportional to?
Density of sensory receptors in that body region
Where do pain and temperarue sensations ascend within?
Lateral spinothalamic tract
Where does crude touch ascend within?
Anterior spinothalamic tract
Where do primary affernet axons terminate?
Upon entering the spinal cord
Second order neurons decussate immediately in the spinal cors and for the spinothalmic tract
Where do 2nd order neurons terminate?
The Thalmus
Where do 3rd order neurons from the thalamus project to?
Somatosensory cortex
In general, where in the brain is the motor cortex?
Front of brain
In general, where is the sensory cortex of the brain?
Towards the back of the brain
What is Brown-Sequard syndrome?
is a rare neurological condition characterized by a lesion in the spinal cord which results in weakness or paralysis on one side of the body and a loss of sensation on the opposite side
