Week 3 Flashcards
What is tinnitus?
This is a sensation of a sound when there is no auditory stimulus
What is vertigo?
Definitive illusion of movement of the subject , surroundings which indicates a disturbance of vestibular VIII CN brainstem or cortical function
What is Ménière’s disease ?
An excessive accumulation of endolymph in the membraneous labyrinth . The volume of endolymph increases with the distension of the Scala media untill the membrane ruptures
Clinical features of Ménière’s disease ?
Tinnitus
Fluctuating sensorineural hearing loss
Vertigo
Sensation of fullness in the ear
Treatment for Ménière’s disease ?
Symptomatic relief and surgical interventions
Symptomatic - during acute episodes with antiemetics and anticholinergics
Keeping a low sodium diet may help reduce vol of endolymph
Cessation of smoking
Surgical-
Shunts in place to drain excess endolymph
Removal of portions of the vestibulocochlear nerve and destruction of the membraneous labyrinth are option .
Explain tendon jerk reflexes
Stimulus - tendon tap stretches muscle and activates muscle spindle receptors then there is conduction along afferent sensory fibres .
Transmission at synapses between the afferent and motor neuron then there is conduction along the efferent motor fibres.
Neuromuscular transmission-> excitation contraction coupling -> twitch contraction of skeletal muscle
What are the three main divisions of the frontal lobe?
Prefrontal cortex - personality expression , complex cognitive behaviour
Premotor cortex - voluntary muscle movement
Primary motor cortex ( motor homunculus) - voluntary muscle movement
What cortex is in the parietal lobe?
Somatosensory cortex which is essential to the processing of the body’s senses . Pressure , touch , pain
The occipital lobe is the main centre for visual processing , what cortex is situated here?
Primary visual cortex.
This region of the brain receives visual input from the retina via the optic nerve and these visual signals are interpreted on the occipital lobes
What are the structures of the limbic system and what lobe are they in?
The olfactory cortex
Amygdala
Hippocampus
- all located in temporal lobe
What is wernicke’s area ?
Sensory language understanding , lexical processing .
Damage to here will result in aphasia and poor comprehension
What happens if there is damage to Broca’s area?
Results in aphasia , non fluent and slow speech because it is the motor aspect of speech
What is the primary auditory cortex?
Processing of auditory info
What parts is the basal ganglia divided into?
Corpus striatum
Subthalamic nuclei
Substantia Nigra
What is the corpus striatum made up of ?
Caudate nucleus
Putamen
Globus pallidus
What does the subthalamic nuclei produce?
The excitatory neurotransmitter glutamate
Substantia Nigra produces what?
The neurotransmitter dopamine which is involved in Nigro-striatal pathway. Damage to this causes Parkinson’s
What does the medulla oblongata do?
Deals with autonomic / involuntary functions . Carries out many life sustaining functions such as breathing , heart rate , blood pressure , swallowing
What does the pons connect?
Connects the cerebral cortex to the medulla
What is the thalamus ?
(Relay station)
It the location of the cell bodies of 3rd order neurons in ascending pathways
What is the hypothalamus
The control centre for many autonomic functions of the PNS
Influences the pituitary gland
What does the Amygdala do?
Almond shaped group of neurons located in medial temporal lobes that perform processing and memory of emotional reactions
The cranial cavity has 2 dural reflections what are they called and where are they?
Tentorium cerebelli ( between occipital lobes and cerebellum )
Falx cerebri ( between cerebral hemispheres in the longitudinal cerebral fissures )
What are the muscles of mastication
Temporalis
Masseter
Medial and lateral pterygoids
What nerves come of the trigeminal nerve CN V
Opthalamic
Maxillary
Mandibular
Function of the facial nerve ?
Motor- fascist muscles
Sensory - anterior 2/3 of tongue
Parasympathetic - submandibular , sublingual , lacrimal, pharyngeal glands.
What is the Rinne test?
Place a sounding tuning fork on the patients mastoid process and then to their ear and ask which is louder . Normal patient finds second position louder
What is webers test ?
Place the tuning fork base down in the centre of the patients forehead and ask if it’s louder in either ear - should be heard equally in both ears
Function of glossopharyngeal nerve CN IX
Sensory - posterior 1/3 of tongue , middle ear cavity , soft palate and tonsils
Motor- stylopharyngeus muscle
Parasympathetic - parotid gland
Function of the vagus nerve ?
Sensory - larynx , laryngopharynx, external acoustic meatus
Motor- most muscles of the larynx and pharynx
Parasympathetic - smooth muscles of the bronchioles , SA node of the heart , GI motility
Clinical test for vagus nerve ?
Patient says aghhhhhhh
The uvula should be observed to check that it lies centrally and doesn’t deviate
Asking the patient to speak
What nerve controls the sternocleidomastoid and the trapezium ?
Spinal accessory
What does the hypoglossal nerve do?
Muscles of the tongue except palatoglussus which is innervated by CN X
Picks out and destroys the temporal lobe ?
Herpes simplex
Impairment in person knowledge . Can’t put names to face or recognise peoples voice
Prosopagnosia
Implicit memory
No conscious access to implicit memory stores
Can function independently of explicit like typing
Profound amnesia can occur in context of normal implicit memory (korsakoffs)
Dependent on networks involving basal ganglia and cerebellum
Can’t be tested at the bedside
Where does the facial nerve exit the skull?
Internal acoustic meat is and the Stylomastoid foramen
What is excitotoxicity?
Excitotoxicity is the pathological process by which neurons are damaged and killed by the overactivations of receptors for the excitatory neurotransmitter glutamate, such as the NMDA receptor and AMPA receptor.
What is intracranial pressure
Intracranial pressure (ICP) is the pressure inside the skull and thus in the brain tissue and cerebrospinal fluid (CSF). ICP is measured in millimeters of mercury (mmHg) and, at rest, is normally 7–15 mmHg for a supine adult.
Cerebral perfusion pressure is what?
Cerebral Perfusion Pressure (CPP) is defined as the difference between the Mean Arterial Pressure (MAP) and the Intracranial Pressure (ICP). CPP = MAP - ICP. This represents the pressure gradient driving cerebral blood flow (CBF) and hence oxygen and metabolite delivery.
what epithelium is seen in the choroid plexus in lateral ventricle
simple cuboidal with microvilli
How can you assess the depth of consciousness by a method involving one of the trigeminal divisions
By applying pressure to the supraorbital nerve
what thin membrane seperates the two lateral ventricles
septum pellucidum
the third ventricle lies in the midline of the forebrain
diencephalon
where is the 4th ventricle located
located between the brainstem and the cerebellum
where does the cerebral aqueduct pass through
the mid brain
where does the CSF escape?
the fluid reaches the 4th ventricle and from here escapes through foramina to enter the subarachnoid space which surrounds the brain. the CSF is removed from the space through the arachnoid granulations which project into the superior sagittal sinus and thus reenters the blood stream.
Which nerve provides somatosensory
innervation to the nasal cavity?
Innervation of the nasal cavity responsible for the sense of smell is via the olfactory nerve, which sends microscopic fibers from the olfactory bulb through the cribriform plate to reach the top of the nasal cavity. General sensory innervation is by branches of the trigeminal nerve (V1 & V2)
what is the superior oblique muscle of the eye innervated by?
trochlear nerve
lateral rectus muscle of the eye is innervated by?
abducens nerve
what are ballistic movements
pre programmed. movement based largely on a set of pre-programmed instructions . rapid but at expense of accuracy
