Neurology Flashcards
Name the 3 primary, and five secondary vesicles of the developing adult brain:
Forebrain (prosencephalon) becomes the telencephalon and diencephalon. Midbrain (mesencephalon) persists as the mesencephalon. Hindbrain (rhombencephalon) becomes the metencephalon and the myelencephalon.
Name the derivatives of the 5 secondary vesicles of the developing brain:
Telencephalon becomes cerebral hemispheres and lateral ventricles. Diencephalon becomes the thalamus and third ventricle. Mesencephalon becomes the midbrain and aqueduct. Metencephalon becomes the pons, cerebellum, and upper part of the 4th ventricle. Myelencephalon becomes the medulla and lower part of the 4th ventricle.
Neuropores are supposed to fuse when? Which two biochemical markers can help predict this?
4th week of gestation. Amniotic AFP and AChE and maternal AFP. Unless it is SPO (normal AFP).
Hemispheres separate when? Failure to separate is associated with what? Characteristic MRI findings of failure to fuse?
Usually between the 5th and 6th week. Seen in Trisomy 21 and FAS. MRI shows mono ventricle and fusion of basal ganglia.
How do you distinguish Chiari I from Chiari II malformations?
Chiari I involves one structure; the cerebellar tonsils. cf Chiari II which also involves the vermis. Chiari I is associated with spinal cavitations. Chiari II is associated with lumbosacral myelinmeningocoele and causes hydrocephalus.
What is Dandy Walker syndrome?
Agenesis of the cerebellar vermis with cystic enlargement of the 4th ventricle. Presents with enlarged posterior fossa and cerebellar signs. Associated with non-communicating hydrocephalus, and spina bifida.
Schwann cells versus Oligodendrocytes: Number of axons myelinated? Injured in which diseases?
Schwann cells are located in the PNS and only myelinated one axon. They may be injured in GBS. Oligodendrocytes myelinate many axons (~30) in the CNS and may be injured in MS, PML, and the leukodystrophies.
Merkel discs: Have what type of fibres? Are responsible for what senses? Are located where?
Large, myelinated fibres. Responsible for pressure, deep touch, position sense. Located in the finger tips and superficial skin.
Describe the implication and histological appearance of Chromatolysis.
Reaction of neuronal cell body to axonal injury. Changes reflect increased protein synthesis. Histological appearances of round cellular swelling, displacement of the nucleus to the periphery, and dispersion of Nissl substance throughout the cytoplasm.
What is Nissl substance?
Nissl substance or a Nissl body is a large granular body found in neurons. These granules are of rough endoplasmic reticulum (RER) with rosettes of free ribosomes, and are the site of protein synthesis.
What is the location of synthesis of:
Ach
Dopamine
GABA
Norepinephrine
Serotonin
Ach - Basal nucleus of Meynert
Dopamine - Ventral tegmenjtum and SNc
GABA - Nucleus accumbens
Norepinephrine - Locus ceruleus
Serotonin - Raphe nucleus
What are the roles of the Hypothalamus?
(TANHATS) Thirst. Regulates adenohypophysis and neurohypophysis. Controls Hunger, Autonomic nervous system, Temperature, and Sexual urges.
What are the anatomical divisions of the hypothalamus? What are their functions?
Lateral area - Hunger (+ghrelin, -leptin)
Ventromedial area - Satiety (+leptin)
Anterior - Cooling, parasympathetic
Posterior - Heating, sympathetic
Suprachiasmatic nucleus - Circadian rhythm
Supraoptic and paraventricular nuclei - ADH and Oxytocin
What are the stages of sleep, their make-up of total sleep, and the EEG wave forms associated with each?
Awake eyes open - Beta waves (highest freq, low amp)
Awake eyes closed - Alpha waves
N1 (5%) Light sleep; Theta waves
N2 (45%) Deeper sleep; Sleep spindles and K complexes
N3 (25%) Deepest non-REM; Delta (lowest freq, highest amp)
REM (25%) Loss of tone etc. Beta waves (at night, BATS Drink Blood)
What is the role of the Thalamus?
The Thalamus is the major relay for ascending sensory information except olfaction.
Which part of the thalamus relays and coordinates: Vibration, Pain, Pressure, Proprioception, Light touch, and Temperature? What is the relay destination?
The ventral posterolateral nucleus. The primary somatosensory cortex.
Which part of the thalamus relays and coordinates: Face sensation and taste? What is the relay destination?
The ventral posteromedial nucleus. The primary somatosensory cortex.
Which part of the thalamus relays and coordinates: Vison? What is the relay destination?
The lateral geniculate nucleus. The calcarine sulcus.
Which part of the thalamus relays and coordinates: Hearing? What is the relay destination?
The medial geniculate nucleus. The auditory cortex of the temporal lobe.
Which part of the thalamus relays and coordinates: Motor function? What is the relay destination?
The ventral lateral nucleus. The motor cortex.
What structures comprise the Limbic system? What is their role?
Hippocampus, Mamillary bodies, Anterior thalamic nuclei, cingulate gyrus, entorhinal cortex. Responsible for feeding, fighting, fleeing, feeling, sex.
What are the 4 Dopaminergic pathways in the brain? What does altering their activity cause symptomatically?
Mesocortical - Reduced activity = “Negative” symptoms Mesolimbic - Increased activity = “Positive” symptoms **Nigrostriatal - Reduced activity = Parkinsonism Tuberoinfundibular - Reduced activity = Increased PrL, reduced libido etc.
What are the 4 anatomical components of the Basal Ganglia?
Striatum
Pallidum
SN pars compacta
Subthalamic nuclei
Describe the input/output pathways of the basal ganglia and how they relate to Parkinson’s disease.
Describe the relationship of CPP to changes in oxygen versus carbon dioxide.
Hypoxaemia increases CPP only when PO2 <50mmHg
whereas
CPP is directly proportional to PCO2 until PCO2 >90
Which cranial nerves emerge from:
Above the pons?
In the pons?
In the medulla?
Which cranial nerves emerge medially?
4 CN from above the pons - I, II, III, IV
4 CN from in the pons - V, VI, VII, VIII
4 CN from in the medulla - IX, X, XI, XII
4 CN emerge medially - III, IV, VI, XII
Where do the cranial nerve nuclei arise?
2 from midbrain - III, IV
4 from pons - V, VI, VII, VIII
3 from medulla - IX, X, XII
1 from spinal cord - XI
What is the role of:
The pineal gland?
The superior colliculi?
The inferior colliculi?
Pineal gland - melatonin secretion, circadian rhythm
Superior colliculi - Conjugate vertical gaze
Inferior colliculi - Auditory signal relay
What is the role of the Nucleus Solitarius?
Which cranial nerves originate here?
Visceral sensory information - taste, baroreceptors, gut distension
CN VII, IX, X
What is the role of the Nucleus Ambiguus?
Which cranial nerve nuclei arise from here?
Motor innervation of the pharynx, larynx, upper oesophagus (eg. swallowing, palate elevation)
CN IX, X, XI
Where in the spinal cord do the following nerve fibres ascend/descend?
Pressure, Vibration, Fine Touch, Proprioception?
Pain and Temperature?
Crude touch and pressue?
Voluntary motor?
Pressure, Vibration, Fine Touch, Proprioception - Dorsal column
Pain and Temperature - Lateral Spinothalamic Tract
Crude touch and pressue - Anterior Spinothalamic Tract
Voluntary motor - Anterior and Lateral Corticospinal Tract
What is internuclear ophthalmoplegia?
Where is the lesion?
In what disease typically?
Impaired aDDuction of ipsilateral eye, nystagmus of contralateral eye with ABduction
(normal eye is rapidly trying to reset the gaze center for the abnormal eye)
Medial longitudinal fasciculus.
MS.
What is Wernicke-Korsakoff syndrome?
Where is the lesion?
What is the typical pathology?
Confusion, Ataxia, Nystagmus, Ophthalmoplegia
Mamillary bodies
Alcoholism
What is Kluver-Bucy syndrome?
Where is the lesion?
What typically causes it?
Disinhibited behaviour; hypersexuality, hyperphagia, hyperorality.
Amygdala
HSV-1 Encephalitis.
What is Parinaud syndrome?
Where is the lesion?
What is the typical cause?
Paralysis of conjugate vertical gaze
Superior colliculus
Pinealoma, hydrocephalus, stroke.
Stoke Pattern:
Contralateral paralysis and sensory loss - face and upper limb
Aphasia if in dominant, hemineglect if in non-dominant
Middle Cerebral Artery