DB - neuroanatomy week 2 Flashcards
What is the embryological origin of the basal nuclei?
Telencephalon
What is the function of the basal nuclei?
Control of voluntary movement Procedural learning Eye movement Cognition Emotion
Which structures are associated with the basal nuclei?
Putamen
Globus pallidus
Caudate nucleus
Substantia nigra
What structures are collectively known as the lentiform nucleus?
Globus pallidus and putamen
What structure separates the caudate nucleus from the lentiform nucleus?
Internal capsule
What is the substantia nigra?
Dopaminergic neurones in the basal nuclei. Plays an important role in reward and movement.
What is the function of the thalamus?
Relays information to and from the cerebral cortex.
Processing of sensations.
Consciousness is controlled via the reticular formation
What does the thalamus receive input from?
Cerebellum, basal nuclei and limbic system
How are the 2 sides of the thalamus joined?
Interthalamic adhesion
Which ventricle runs down the midline of the thalamus?
3rd ventricle
What is the function of the hypothalamus?
Autonomic control via the reticular formation.
Controls appetite, thirst, temperature, electrolyte and water balance, sleep and behaviour.
Control pituitary gland.
What is the function of the limbic system?
Associated with emotion, memory, learning, personality and behaviour.
What structures are associated with the limbic system?
Hippocampus, amygdala and piriform lobe, septal nuclei, cingulate gyrus, hypothalamus and thalamus.
What is the function of the hippocampus?
Important in spatial memories.
Gives rise to axons forming the fornix and is also connected to the mammillary bodies.
What is the Papez circuit?
Basis for emotional experiences and memory storage.
Circuit of the hippocampus, fornix and mammillary bodies.
What is the function of the cingulate gyrus?
Connects areas of the cerebral cortex on the same side.
Processes emotions and cognitive processes.
Associated with the thalamus for repetitive behaviours.
What fibres are in the cingulate gyrus?
Association fibres.
What fibres are in the corpus callosum?
Commissural fibres.
What is the function of the corpus callosum?
Allows for communication between the cerebral hemispheres.
What is the function of the amygdala?
Processes and remembers emotions (fear and punishment)
Associated with the olfactory nerve.
What is the septum pellucidum?
Separates the lateral ventricles.
Runs as a sheet from the corpus callosum to the fornix.
What is the function of the colliculi?
Visual and auditory function
Where are the colliculi located and what is there collective name?
Located on the tectum of the midbrain. There are 2 rostral and 2 caudal colliculi.
Collectively, they are known as the corpora quadrigemina.
What are the main structures associated with the tegmentum of the midbrain?
Crus cerebri
Substantia nigra
Red nucleus
Parasympathetic and motor nucleus of CNIII (oculomotor)
Motor nucleus of CNIV (trochlear)
Reticular formation - fibres extend through the tegmentum
What is the location of the periaqueductal grey and what is its function?
Area that surrounds the cerebral aqueduct.
It is related to pain control by releasing opioid-like molecules from the neurones.
What is contained within the crus cerebri?
Efferent motor tracts which supply the muscles.
What is the function of the red nucleus?
Control of posture and movement.
It is the start of the rubrospinal tract.
What is the function of the reticular formation in the midbrain?
Alerts the cerebral cortex to wakefulness (ARAS)
What is the function of the reticular formation in the pons/medulla?
Regulates visceral functions and stimulates/inhibits motor activity of the body and limbs.
UMN control of CV and respiratory centres.
Swallowing and vomiting.
Part of the reticulospinal tracts.
What structures are associated with the pons?
Contains the nuclei of the trigeminal nerve. Sensory portion runs through the brainstem and the motor portion runs through the mid-region of the pons.
Corticospinal tracts cause the bulge.
What structures are associated with the medulla oblongata?
Nuclei of CNVI-XII
Reticular formation
Medullary pyramids, which contains corticospinal tracts.
Olivary nucleus
What is the function of the corticospinal tract?
Pre-processes input to the cerebellum.
Which cranial nerves arise from the pontine medullary junction?
CNVI-CNVIII
What is the function of the cerebellum?
important for balance/posture
Fine motor control
modifies intended movement
Is the function of the cerebellum ipsilateral or contralateral?
ipsilateral
What are the lobes of the cerebellum, and what is the function of each?
Rostral and caudal lobes - skilled movements.
Flocculonodular lobes - imbalance.
How is the cerebellum attached to the brainstem?
By peduncles (6 in total):
- Rostral - connected to the midbrain and found medially.
- Middle - connected to the pons and found laterally.
- Caudal - connected to the medulla and found between the rostral and middle lobe.
What is the consequence of a lesion of the basal nuclei?
Dyskinesia - rapid jerking or slow muscle spasms.
Increased muscle tone
Parkinson’s is associated with the degeneration of the substantia nigra.
What is the consequence of a lesion of the hypothalamus?
Behavioural changes and autonomic dysfunction, which is displayed as alimentary disorders.
What is the consequence of a lesion of the diencephalon?
Abnormal behaviour Total body hyperalgesia Slow postural reactions Depression -> Coma (ARAS) Blindness Alterations in thirst and thermoregulation
What is the consequence of a lesion of the ARAS?
Depression -> coma : therefore affecting mental status
What is the consequence of a lesion of the red nucleus and substantia nigra?
Ataxia
Stiffness with reduced voluntary control of muscles.
What is the consequence of a lesion of the crus cerebri?
Hyperalgesia - increased sensitivity to pain
What is the consequence of a lesion of the general somatic efferent of CNIII and CNIV?
Deviation of the eye
What is the consequence of a lesion of the general visceral efferent of CNIII?
Dilation of the pupil
What is the consequence of a lesion of the cerebellum?
Ataxia Wide based stance Tremor Loss of balance Overshooting of limbs - hypermetria
What is cerebellar abiotrophy?
genetic mutation causing the loss of purkinje fibres.
Which structures in the brain are required for the proper function of mental status?
Cerebral cortex
Relay to the thalamus
ARAS
Sensors for proprioception, exteroception and interoception.
What is the consequence of a lesion of the ARAS?
Lesions of the brain stem in this region could lead to a coma.
What is the definition of a reflex?
Unconscious reaction to a stimuli
What is the definition of a response?
Conscious reaction to a stimuli
