Central Nervous System Flashcards
What 3 parts is the brain compromised of
Forebrain-cerebral hemispheres and diencephalon
Midbrain
Hindbrain-pons,medulla,cerebellum
Brain stem contains
Midbrain
Pons
Medulla
Frontal lobe
Language
Congnitive functions eg planning attention and memory
Regulating and initiating motor function
Parietal
Sensation
Sensory aspects of language
Spatial orientation
Self perception
Temporal and occipital
Auditory info
Visual info
Limbic lobe contains
Amygdala
Hippocampus
Mamillary body
Cingulate gyrus
Involved in learning memory emotion and motivation
Insular cortex location
Deep within lateral fissure
What is insular cortex involved in
Visceral sensation, autonomic control and interoception, auditory processing, visual vestibular integration
Where is cerebrospinal fluid produced and where does it circulate
Choroid plexus of lateral 3rd and 4th ventricles
Occupies ventricular system and sub arachnoid space
125ml needed and 500ml made everyday
Where is CSF reabsorbed
Arachnoid villi (granulations) into superior Sagittal sinus
CSF VS PLASMA
CSF has lower pH,less glucose,protein and potassium
Function of CSF
- Shock absorbing- protection of brain/CNS
- Removes waste products from cellular metabolism
- Supplies neurones with nutrients (secondary to blood) & transports nutrients
- Contains immune cells
What do spinal nerves emerge through
Intervertebral foramina
Which spinal nerves emerge above vertebrae
C1-C7
Which spinal nerves emerge below the vertebrae?
C8 - Co1
Spinal chord enlargements
- Cervical enlargement at upper part of cord because of the huge amount of innervation of upper limbs both going in an out
- Lumbar enlargement at lower part of cord because of increase in innervation of lower limbs
- Shape also changes
What are the 2 major ascending pathways for sensation/sensory?
Dorsal column pathway
Spinothalmic tract
Dorsal column pathway detects
fine touch, vibration and proprioception
Dorsal column pathway
1) First order neurons have cell bodies in dorsal root ganglion ,fibres enter via dorsal horn. Info from lower limbs (below T6) travel ipsilaterally along gracile tract. Info from upper limbs (above T6) travel ipsilateraly along the cuneate tract. synapse in medulla
2)second order neurons have cell bodies in the medulla which synapse into thalamus
3( third order neurones from thalamus project to somatosensory cortex
What tract do these second order neurons then form once they have crossed?
Contralateral medial lemniscus tract
Spinothalamic (anterolateral) tract- which sensations does it detect
Pain and temperature
Anterior spinothalmic tract detects crude touch
Spinothalmic tract pathway
1) first order neurons in dorsal root ganglion
2)second order neurons decussate immediately in the spinal cord
3)third order neurons from the thalamus project to the somatosensory cortex
Major descending pathway for voluntary movement
Corticospinal tract
What is the corticospinal tract composed of
Upper motor neurons in primary motor cortex and lower motor neurons in brainstem
How do the lateral and anterior/ventral corticospinal tracts differ in decussation, and what muscles do each of these tracts supply?
- The lateral corticospinal tract decussates in the medulla (this makes up 85% of fibres), supplies limb muscles
- The anterior (ventral) corticospinal tract doesn’t decussate- they stay on the same side as the side the upper motor neurones have come from, supplies trunk muscles
Corticobulbar tract
Pathway from primary motor cortex to muscles of face
Extrapyramidal tracts
Supply muscles that are more automated in their response
Vestibulospinal- provides info about head movement and position and mediated posture
Tectospinal-orientation of head and neck during eye movement
Reticulospinal-controls breathing and emotional motor function
Rubrospinal-innervate lower motor neurons of upper limb and becomes more active is corticospinal tract is injured
