Brain Anatomy Flashcards
What are the components of the brainstem from top to bottom?
Midbrain
Pons
Medulla Oblongata
What makes up the diencephalon?
Thalamus
Hypothalamus
Pineal Gland
Where is the diencephalon
Above the midbrain
Why is the thalamus often referred to as the ‘switchboard’ of the brain?
It receives and sends information to/from the cerebral hemisphere and has links to basal ganglia.
What is the neurocortex?
The cortex which has 6+ layers.
It is for higher functions including conscious thought
What are the connections between the cerebellum and the brainstem known as?
Peduncles
What are the three histological layers of the cerebellar cortex?
Molecular
Purkinje
Granular
What are the three meningeal layers?
Dura
Arachnoid
Pia
Where is CSF found?
In the subarachnoid space
What is white mater made up of?
Axons
White matter in internal in the brain and external in the spinal cord
What is grey matter made of?
Cell bodies, processes and synapses
Found mainly on the outside of the brain and inside of the spinal cord
What is the lentiform nucleus composed of?
Putamen
Globus Pallidus
Where is the cerebellum located?
Posterior and inferior to the cerebral hemispheres
posterior to brainstem
How many lobes does the cerebellum have? Name them:
3
Anterior
Posterior
Flocculonodular Lobe
What does the granular layer of the cerebellar cortex have a lot of?
Neurons
>50% of the neurons in the entire nervous system are found here
How do afferent fibers enter the cerebellum and which layer do they project onto?
Enter via the peduncles
Project onto the granular layer
State some of the afferent fibers which travel to the cerebellum and where they originate?
Somatic proprioceptors (spinal cord)
Pressure receptors (spinal cord)
Cerebral cortex via pons
Vestibular apparatus via vestibular nucleus
What are the efferent axons of the cerebellum mainly composed of?
Purkinje cells
Lesions on one side of the cerebellar hemisphere will lead to symptoms on the _________ side?
Ipsilateral
What are the functions of the basal ganglia?
Facilitates movement
Inhibits unwanted movement
Plays part in pressure and tone
What makes up the striatum?
Caudate nucleus
Putamen
What makes up the corpus striatum?
Caudate nucleus
Putamen
Globus Pallidus
Other than than the corpus striatum, what else forms the basal ganglia?
Subthalmic nucleus
Substantia Nigra
Where is the substantia nigra located?
In the midbrain
What is the substantia nigra composed of? Pathology here is seen in what disease?
Dark pigment involved in dopamine production
Loss of this pigment leads to Parkinsons
What is the role of the direct pathway of the basal ganglia and how does it do this?
Enhances desired movement
Stimulates the thalamus
How does the indirect pathway of the basal ganglia work?
Inhibits thalmic outflow, resulting in slowed or inhibited movement
What disease leads to problems with the indirect pathway of the basal ganglia?
Huntingtons
Lesions of the basal ganglia lead to symptoms on the ________ side of the body?
Contralateral
What region is the thinnest part of the skull?
Pterion
What vessel lies deep to the pterion?
Middle meningeal
A tough sheet of dura mater forming a roof over the pituitary fossa:
Diaphragm Sellae
A tough sheet of dura mater covering the cerebellum and attaching to the ridges of the petrous temple bone
Tentorium Cerebelli
Midline structure composed of dura mater, attaching to the deep aspect of the skull, which separates the right and left hemisphere:
Falx Cerebri
What are the attachments of the falx cerebri?
Ethmoid bone
Internal occipital protuberance
What cranial nerve supplies sensory supply to the dura?
CN V
What is the straight sinus?
This is where the falx cerebri and the tentorium cerebelli meet and attach to one another
Where do most afferent cerebellar fibers terminate?
Cerebellar cortex (granular layer)
What part of the cerebellum is responsible for the maintenance of balance/equilibrium?
Vestibulocerebellum
What part of the cerebellum is responsible for posture and muscle tone?
Spinocerebllum
What part of the cerebellum is responsible for muscle coordination, including trajectory and force of movements?
Pontocerebellum
What does the central sulcus show a divide between?
Frontal and Parietal lobes
What does the lateral sulcus show a divide between?
Parietal and Temporal lobes
Embryologically, where does the cerebral hemisphere derive from?
Telencephalon
What is the role of the gyri and sulci?
To maximize surface area
What separates the two hemispheres?
Great Longitudinal fissure
This accommodates the falx cerebri
What unites the two hemisphere’s, deep to the great longitudinal fissure?
Corpus Callosum
What is significant about the pre-central gyrus?
It is the primary motor region of the cerebral hemisphere
What is significant about the post central gyrus?
It is the primary somatosensory cortex
What on the occipital lobe indicates the location of the primary visual cortex?
The prominent calcarine sulcus
Where is the primary auditory cortex located?
The superior temporal gyrus
What makes up the “limbic lobe” of the cerebral hemisphere?
Cingulate Gyrus
Parahippocampal Gyrus
Hippocampus
(NOTE this is in the medial part of the cerebral hemisphere)
Which hemisphere in most individuals is thought to be dominant for language?
The left hemisphere
Where in respect to the pre-central gyrus is the head located?
The representation of the body is inverted, with the head area located in the most inferior part of the precentral gyrus, just above the lateral fissure.
Where is the lower limb represented on the pre central gyrus?
The lower limb is represented on the medial surface of the hemisphere, above the corpus callosum. .
What is Broca’s Aphasia and how does it occur?
This is characterized by choppy speech and the inability to form complete sentences. Speech is produced with great effort and poor articulation, repetition of words is impaired but powers of comprehension are relatively preserved.
There is also impairment of reading and writing
Caused by damage to the frontal lobe in a place known as Brocas Area
What is Wernicke’s Aphasia and how does it occur?
Speech that is fluent and rapid but contains word errors (paraphasia) and is incomprehensible. There is profound word-finding difficulty, impaired repetition of words and profound loss of comprehension.
Caused by damage to the Left Temporal Lobe
What are commissural fibers?
These form links between matching areas in the two cerebral hemispheres
What is the arcuate fasciculus
This is a connection of nerve fibers linking Wernicke’s and Broca’s Areas
Damage to this results in the inability to repeat something which is heard
