Raftery Neuroanatomy Flashcards
What separates the 2 cerebral hemispheres?
Longitudinal fissure
Filled by falx cerebri (
dura mater)
What is the cerebrum derived from embryologically?
Prosencephalon
Which parts of the cranial fossae does the cerebrum fill?
Anterior and middle cranial fossae
What structure is the cerebrum located above inferoposteriorly?
Tentorium cerebelli
Major subdivisions of the brain
Forebrain
Midbrain
Hindbrain
Parts of the forebrain
Cerebral hemisphere or telencephalon (lateral ventricle)
Diencephalon - contains thalamus and hypothalamus (third ventricle)
Parts of midbrain
Mesencephalon (cerebral aqueduct)
Parts of hindbrain
Pons
Medulla
Cerebellum (fourth ventricle)
Which fossa does the frontal lobe lie in?
Anterior cranial fossa
Which fossa does the temporal lobe lie in?
Middle cranial fossa
Temporal pole at anterior extremity
Uncus on medial surface
2 types of tissue making up the cerebrum
Grey matter
White matter
What is grey matter?
Forms the external surface of each cerebral hemisphere (aka cerebral cortex)
Associated with processing and cognition
What is white matter?
Forms bulk of deeper parts of brain
Consists of glial cells and myelinated axons connecting various grey matter areas
What causes the convoluted external appearance of cerebrum?
Sulci (grooves/depressions)
Gyri (ridges/elevations)
What connects the 2 cerebral hemispheres?
Corpus callosum (white matter)
What separates the frontal and parietal lobes?
or the precentral (motor) from postcentral (sensory) gyrus?
Central sulcus
What separates the temporal from frontal and parietal lobes?
Lateral sulcus
What separates the occipital from parietal lobe?
Parieto-occipital sulcus on medial surface of hemisphere
What is the lunate sulcus?
A groove located in the occipital cortex
What are the calcarine and postcalcarine sulci?
Concerned with visual centres
Lie on medial aspect of occipital lobe
What is the superior temporal gyrus?
Ridge located below the lateral sulcus
For receiving and processing sound
Important areas of frontal lobe
Motor cortex in precentral gyrus
Broca’s area
Frontal cortex
What are the association areas of the frontal lobe responsible for?
Higher intellect Personality Mood Social conduct Language (dominant hemisphere side only)
Fibres of motor cortex
Afferents from thalamus and cerebellum
Pass through internal capsule
To motor nuclei and cranial and spinal nerves
Location of Broca’s area
Posterior part of inferior frontal gyrus of dominant hemisphere
Functions of frontal cortex
Lateral - intellect
Medial and orbital - affective behaviour
Important areas of parietal lobe
Sensory cortex in postcentral gyrus
Parietal association cortex
What are the association areas of the parietal lobe responsible for?
Language and calculation (dominant)
Visuospatial functions (non-dominant)
Important areas of temporal lobe
Auditory cortex
Temporal association cortex
Uncus
Fibres of auditory cortex
Afferents from medial geniculate body
Location and function of temporal association cortex
Surrounds auditory cortex
Perceiving auditory stimuli and their integration with other sensory modalities
Function of uncus
Olfactory stimuli
Important areas of occipital lobe
Visual cortex
Occipital association cortex
Location and function of visual cortex
Surround calcarine and postcalcarine sulci
Vision of opposite half-field of sight
What happens if there is damage to frontal lobe?
Impairment of emotions and intellect
What happens if there is damage to motor cortex?
Weakness in contralateral side of body
What does the basal ganglia consist of?
Subcortical nuclei grouped functionally rather than anatomically
Why is anatomy of the basal ganglia complex?
It is spread throughout the forebrain
Parts of basal ganglia
Corpus striatum (caudate nucleus, putamen, globus pallidus)
Claustrum
Amygdaloid nucleus
Thalamus
How can the components of the basal ganglia be divided?
Input nuclei
Intrinsic nuclei
Output nuclei
What forms the input nuclei of basal ganglia?
Caudate nucleus
Putamen (neostriatum)
What forms the intrinsic nuclei of basal ganglia?
External globus pallidus
Subthalamic nucleus
Pars compacta of substantia nigra
What forms the output nuclei of basal ganglia?
Internal globus pallidus
Pars reticulata of substantia nigra
What is the most rostral aspect of the neostriatum called?
Nucleus accumbens (Acb) - part of functionally separate domain called ventral striatum
Where caudate nucleus and putamen join together
Where does the subthalamic nucleus lie?
In diencephalon
Where does the substantia nigra lie?
In mesencephalon
2 parts of substantia nigra
Pars reticulata (anterior) Pars compacta (posterior)
Location of caudate nucleus
Collection of gray matter forming lateral wall of lateral ventricle
Follows telencephalic expansion during development
What separates the caudate nucleus from putamen during development?
Descending white matter fibres
Aka internal capsule
What does the lentiform nucleus consist of?
Globus pallidus
Putamen
Anatomically related but no functional relationship
Location of putamen with respect to lentiform nucleus
Lateral aspect of lentiform nucleus
Location of globus pallidus with respect to lentiform nucleus
External globus pallidus lies on the concave inner surface of lentiform nucleus
What separates the putamen from GPe?
Lateral medullary lamina
What separates the GPe from GPi?
Medial medullary lamina
What is the collection of WM fibres lateral to the putamen called?
External capsule
What is the thin bundle of grey matter lateral to the external capsule called?
Claustrum
What lies lateral to the claustrum?
Extreme capsule (WM tracts separating claustrum from neocortical insula)
What causes the dark appearance of substantia nigra?
Neuromelanin produced by cells of SNc
Location of subthalamic nucleus
Below the thalamus, above substantia nigra
Function of basal ganglia
Feedback mechanism to cerebral cortex
Motor refinement - prevent unwanted/exaggeratedmovements to start, reduce excitatory input to cortex
Modulate cognitive and emotional responses
Inputs and projections of putamen
Inputs from motor and somatosensory cortices
Project back to motor areas
Hence related to motor loop
Inputs and projections of caudate nucleus
Input from cortical association areas
Project to prefrontal areas
Inputs and projections of ventrial striatum (including nucleus accumbens)
Limbic inputs
Hence related to emotions
Arterial supply to basal ganglia
Mainly MCA
Main artery - lenticulostriate artery (most circulation to striatum and lenticular nucleus)
Minor arterial supply to basal ganglia
ACA
Anterior choroidal artery
Both are branches of ICA
Supply more anterior aspect of ganglia (i.e. head of caudate nucleus and nucleus accumbens)
Esp large artery - medial striate artery (of Heubner)
Arterial supply of substantia nigra and subthalamic nucleus
PCA
Posterior communicating arteries
(as location more posterior)
Venous drainage of basal ganglia
Striate branches of internal cerebral vein
Drain into great cerebral vein
Types of cells in pineal gland
Pinealocytes = secrete hormones
Glial cells = support cells