Overview of NS Flashcards
Name the lobes of cerebrum
Frontal, parietal, temporal, occipital, insula
Function of frontal lobe
Motor commands and motor planning
thought and personality- coginition
Olfaction (smell)
(last lobe to develop, and make irrational decisions)
Function of Parietal Lobe
Somatosensation Sensory integration ( interprets sensory info)
Function of occipital Lobe
Visual processing
Function of temporal Lobe
Auditory information processing (located above ears)
memory in temporary
Function of Insula
Taste, Drive, Emotions, Memory
what dose broca’s area do and what hemisphere is it in
Production of speech
Located in frontal lobe and in the dominant hemisphere (generally left)
What does Wernicke’s area do and where is it located
Lauguage comprehension
located in temporal and parietal lobes–> auditiory association cortex
In the dominant hemisphere–> language is always in the dominant hemisphere (usually left)
Name the 5 nuclei of basal ganglia
Caudate Nucleus Putamen Globus Pallidus Subthalamic Nucleus Substantia Nigra
Role of Basal ganglia
Role in modulation of somatic activity (especially willed movement)
Involved in autonomic stereotyped motor activity of a postural and reflex nature
Exerts effects on motor systems via thalamus, motor cortex and motor pathways (descending)
Force, timing, amplitude and tone
What makes up the diencephalon
Thalamus Hypothalamus Epithalamus Subthalamus (all the 'thalamus')
Role/Importance of Thalamus
All information (except olfactory) must be processed via the thalamus before reaching the cerebral cortex
It is the gateway to cerebral corte
All thalamic nuclei project to the ipsilateral cerebral cortex (right thalamus communicates w/ right cortex)
Each nucleus of thalamus recieves highly organised info and relays this info to specific areas of the cortex
Cerebellum role
Modulates and corrdinated skilled voluntary movements of distal extremities and speech
Compares actual motor output to intended motor output and then adjusts movement as necessary (able to adjust to different surfaces of movement as a result)
maintains posture and balance
Maintains muscle tone
What does brainstem consist of
Midbrain–> Thalamus sits above midbrain
Pons
Medulla Oblongata–> merges into spinal cord
Where does spinal cord terminate and the structures it forms at the end
SC teriminates between levels L1 and L2 vertebral bodies
Forming conus medullaris
Conus medullaris ends to form the filum terminale–> this anchors the spinal cord to the sacrum
Cauda equina is a formed from the bunch of ventral and dorsal nerve roots that are exiting the spinal cord
How many cranial and spinal nerves are there
12 pairs cranial nerves
31 pairs spinal nerves
Roman numeral and name of each cranial nerve
I- Olfactory (smell)
II- Optic (vision)
III- Oculomotor (mediates vision)
IV- Trochlear (mediates vision)
V- Trigeminal (muscles of mastification, head and face sensation)
VI- Abducens (mediates vision)
VII- Facial (muscles of facial expression)
VIII- Vestibulocochlear (balance and equilibriu, hearing)
IX- Glossopharyngeal (taste, glands, swallowing)
X- Vagus (phonation, elevation of palate, swallowing/taste)
XI- Accessory (head and shoulder movt- SCM and trapz)
XII- Hypoglossal (tongue movement)
Cells of CNS (neurons)
Cells specialised for sending an receiving info
In CNS, neurons occur in laminae or nuclei (in PNS they occur in ganglia)
Principal Cells–> large neurons of a nucleus or comparable region
Interneurons–> Local Circuit neurons (great no of these in CNS)
Cells of CNS (Neuroglial/glia cells)
Astrocytes
Function–>insulation and metabolic support, mechanical support (maintenance of blood/brain barrier help in pH balance
surround all capillaries via end feet
Cells of CNS (Neuroglial/glia cells)
Microglia
Act as ‘sentinels’ (antigen presenting cells)
Mediation of health of brain
immune response
Phagocytosis
Cells of CNS (Neuroglial/glia cells)
Oligodendrocytes
Myelin production in CNS (Schwann cells produes myelin in PNS)
Cells of CNS (Neuroglial/glia cells)
Ependymal Cells
Line ventricles and choroid plexus–> produce and secrete CSF
White matter fibres
Association (Intracortical) fibres–> communication within the hemisphere (e.g. internal capsule/ optic radiation))
Commussural (intercortical) fibres–> communication between the 2 hemispheres (e.g. corpus callosum)
Projection Fibres–> communication between the cerebral cortex and lower parts of brain and spinal cord (e.g. cerebral pudencle–> coz it attaches to midbrain)
Significant Gyri and sulci and what it separates/importance
Longitudinal Fissure–> separates hemisphere
Central Sulcus–> seprates frontal and parietal (never gets to temporal)
Parieto-occipital sulcus–> seprates parietal and occipital (seen medially and laterally)
Calcarine Sulcus–> deep antero-posterior sulcus, starts in temporal and moves towards occipital (only seen on medial view)
Lateral Sulcus–> separates temporal and parietal
Precentral gyrus–> primary motor cortex
Postcenral Gyrus–> primary somatosensory cortex
Meninges–> name the 3
Dura–> outermost and hardest layer (under skull)
Arachnoid –> middle layer like a spider web due to arachnoid villi which attach to pia mater and through with CSF is reabsorbed
Pia Mater–> thinest and innermost layer covering the brain (sometimes arachnoid and pia are joined)
Cranial dura real and potential spaces
1 real space: Subarachnoid--> b/t arachnoid and pia 2 Potential spaces: extradural--> b/w dura and skull subdural--> b/w dura and arachnoid
Spinal dura real and potential spaces
2 real spaces: Subarachnoid--> b/w arachnoid and pia Epidural--> b/w tissues lining VC (vertebral periosteum) and spinal dura 1 Potential space: subdural--> b/w/ dura and arachnoid
What do the real spaces from meninges contain?
CSF flows through this area
Name the layers of dura
Endosteal Layer–> outer layer on skull
meningeal layer–> inner layer closer to arachnoid (this is also the only layer that is present in the VC - no endosteal layer)
Dural reflections name
Falx cerebri–> separates left and right hemispheres
Tentorium cerebelli–> separates cerebellum and brainstem from cerebrum; cerebellum located right under tentorium cerebri hence the flat superior surface of cerebellum
Blood supply to meninges
blood supply–> meningeal arteries and veins
Dural venous sinuses formation
Formed when the 2 layers of dura separate, resulting in channels called dural venous sinuses (“trapped epidural veins”)
Dural venous sinus names
Superior sagittal sinus–> lies at superior attached border of falx cerebri
Inferior Sagital sinus–> lies at the inferior free border of falx cerebri
Straight sinus–> lies at attachment of falx and tentorium cerebri
Occipital Sinus–> lies in the attached border of tentorium cerebri (on occipital lobe part of skull and forms a Y shape at the bottom)
Transverse Sinus–> runs transversely at the posterolateral margin of tentorium cerebelli
Sigmoid Sinus–> ‘S’ shaped and goes into jugular foramen and continues as internal jugular vein
Superior petrosal sinus–> anterolateral attachment of tentorium cerebelli (on temporal bone)
Inferior petrosal sinus–> under superior sagittal on temporal bone
How are dural reflections formed
Formed by meningeal (inner) layer of dura mater folding in on itself
Nerve supply of meninges
Nerve innervation–> trigeminal nerve (mostly) and vagus nerve (for posterior fossa)
Due to nerve innervation means that meninges are pain sensitive and have sensory innervation
Dural Venous sinus function
Where the cerebral veins empty and are valveless–> hence has bidirectional flow
From blood drained into DVS, CSF is reabsorbed through the arachnoid villi mostly in superior sagittal sinus
Drainage into DVS then goes into the internal jugular veins
Dural venous drainage path
Venous blood leaving cerebral cortex Through subarachnoid and subdural spaces Enter Superior sagittal sinus Empty into straight sinus Passes through Sigmoid sinus into internal jugular veins
What cells line ventricles
Ependymal cells–> forms the choroid plexuses
What produces CSF
choroid plexus that lines ventricles
Flow path of CSF
Lateral ventricles 3rd Ventricle (via interventricular formen) Cerebral Aqueduct 4th Ventricle Median and Lateral aperture of 4th ventricle Cerebellomedullary and pontine cistern Spinal subarachnoid space To lumbar cistern Forward through basal cisterns Upwards and over cerebral hemispheres
Role of CSF
Suspends brain–> cushioning and shock absorber
Regulates composition of fluid bathing glia and neurons of cns
Circulates nutrients and chemicals, which need to be distributed in the NS
CSF absorbtion
Reabsorbed through arachnoid villi in dural venous sinus (esp. superior sagittal sinus)
Reabsorbtion depends on the pressure of CSF being higher than that of blood in dural sinuses
What is hydrocephaly
Pathology marked by excessive accumulation of CSF within cranial cavity (hydro=water, cephalus=head)
Neural structures can be destroyed by the pressure that accumulates
Presentation of Hydrocephalus
Head a=often enlarged
acquired hydrocephalus may occur with head trauma/conditions such as meningitis
Communication hydrocephalus
non-obstructive
Problems with the production/absorption of CSF
free communicating between ventricles/subarachnoid space
Lesion usually distal to ventricular system
Enlargement of all ventricular cavities and subarachnoid spaces
Non-communicating hydrocephalus
obstructive
Obstruction within the ventricular system that prevents CSF from flowing/communicating within brain
CSF in ventricles cannot reach subarachnoid space due to obstruction
Possible lesion sites: cerebral aqueduct, foramen monro
Enlargement of ventricles–> dependent on site of lesion
