Brain/Head anatomy and Inury Flashcards
how long does short term memory last?
30 seconds
What is declarative memory and which parts of the brain attribute to its function?
Form of long term memory, split into:
- Episodic is the memory of personal episode in time and space, involving the hippocampus, medial temporal lobe and neocortex
- Semantic is the retention of facts, knowledge and meaning, involving the lateral and anterior temporal cortex, and the prefrontal cortex
What is non-declarative memory and which parts of the brain attribute to its function?
Form of long term memory, split into:
- Procedural is skills and habits, involving th eprimary motor cortex and striatum cerebellum
- Priming and perceptual learnign involves neocortex
- Simple classical conditioning involves amygdala and cerebellum
- non-associative learning uses reflex pathways
Where is social cognition regulated?
Frontal cortex
What areas of the brain are involved in the regulation of emotion and mood?
- Hippocampus
- Amygdala
- Ventromedial prefrontal cortex
- Dorsolateral prefrontal Cortex
- Orbital prefrontal cortex
- Anterior cingulate cortex
Function, Entry point and test of CN 1
Olfactory - smell
Cribiform plate
Different smells for each nostril individually
Function, Entry point and test of CN 2
Optic - sight
Optic canal
Snellen chart and visual fields
Function, Entry point and test of CN 3
Oculomotor - eye movements - levator palebrae superioris - medial rectus - superior and inferior rectus - inferior oblique - sphincter papillae Superior orbital fissure H test and pupil dilation
Function, Entry point and test of CN 4
Trochlear - eye movement of superior oblique - move eye down
“LR6 SO4”
Superior orbital fissure
H test
Function, Entry point and test of CN 5
Trigeminal - muscles of mastication and sensation to face
Different branches leave in different positions:
- V1 Opthalmic - Superior orbital fissure
- V2 Maxillary - Foramen Rotundum
- V3- Mandibular - Foramen Ovale
Coton wool sensation, jaw reflex, mastication assessment
Function, Entry point and test of CN 6
Abducens - eye movement of lateral rectus - ABduct eye
“LR6 SO4”
Superior orbital fissure
H test
Function, Entry point and test of CN 7
Facial Nerve - Movement of facial expression and sensation to external ear, anterior 2/3 taste and secretion of saliva and tears
Internal acoustic meatus
Test taste and facial expressions
Function, Entry point and test of CN 8
Vestibulocochlear - hearing and balance
Internal acousic meatus
Rinnes (mastoid bone) and Webers (forehead) test
Function, Entry point and test of CN 9
Glossopharyngeal - posterior 1/3 taste, swallow and speech, sensory to carotid body and sinus
Jugular foramen
Gag reflex test
Function, Entry point and test of CN 10
Vagus - parasympathetic function, swallowing and speech
Jugular foramen
gag reflex and uvula deviation
Function, Entry point and test of CN 11
Spinal Accessory - movement of trapezius and sternocleidomastoid
Jugular foramen
test function of muscles (shoulder shrug and head turn)
Function, Entry point and test of CN 12
Hypoglossal - mottor innervation to muscles of the tongue
hypoglossal canal
fasciculations or weakness in tongue muscles (push against cheek)
What is the corpus collosum and what is its function
Connects cerebral hemispheres to allow communication between them
What is the function of the frontal lobe?
mood, reasoning, behaviour, movement
What is the function of the temporal lobes?
memory (hippocampus), hearing, semantics
What is the amygdala and what is its funtion?
Almond shaped neurons in temporal lobes responsible for processing and memory of emotional reactions
What is the function of the parietal lobes?
Sensory input of pain, pressure and temperature
What is the function of the occipital lobes?
Sight
What is the function of the basal ganglia?
Coordination of gross, automatic muscle movements and regulation of muscle tone
What makes up the basal ganglia?
Caudate nucleus
Putamen
Globus Pallidus externa
Globus Pallidus Interna
What makes up the epithalamus and what is its function?
Pineal Gland - secretes melatonin (bio clock and sleepiness)
Habenular nuclei - emotional response to smell
What is the function of the thalamus?
Relays all sensory information to cerebral cortex
has nuclei for vonultary motor actions and arousal
What is the function of the Superior and Inferior Colliculi?
Superior- movement of eyes in response to visual and other stimuli
Inferior - movement of head and trunk in response to auditory stimuli
What is the function of the cerebellum?
posture, Balance and coordination
What areas of the brain control breathing?
Pneumotaxic and apneustic areas pons and Medulla
List functions of the medulla oblongata
Regulaton of breathing, heartbeat and diameter of blood vessels
Swallowing, vomiting, coughing, sneezing, hiccoughing
Describe the layers of the Skull
"SCALP": Skin Connective tissue - dense Apopneurosis Loose connective tissue Periosteum
What is the pterion and what structure associates closely with it?
Site where temporal, parietal and frontal bones meet
Anterior branch of middle meningeal artery
What is the danger of a depressed fracture?
Can come into contact with the brain
What consitutes the make up of normal intracranial pressure?
Brain
Arterial Volume
CSF
Venous volume
When ICP increases, what natural compensatory mechanisms take place?
Decrease of CSF and venous volume - these can adapt whilst the other two cant
What is Cerebral Perfusion Pressure and how is it calculated?
represents pressure gradient driving cerebral flow and hence oxygen and metabolite delivery
= MAP - ICP
Where is the emissary vein located and what is the clinical significance of this?
Within apopneurosis of scalp - increased risk of infection spread
Name the arteries which make up the Cricle of willis
Receive from Internal jugular and basilar (from vertebral), producing:
- anterior cerebral artery
- middle cerebral artery
- posterior cererbal artery (connected via posterior communicating artery)
List the Venous Sinuses of the head
Cavernous
sigmoid
Superior and Inferior Sagital
Straight
although not commonly used, what blood biomarker could be used to measure concussion?
SNTF - binds to protein and would normally travel down axon so builds up in damaged axons
A patient present with a history of head injuries and short periods of unconsciousness followed by a lucid period before deterioration… what is the liekely diagnosis
Epidural haematoma
List and describe the variations of cranial bleeds
Epidural haematoma - bleed betweendura mater and skull, commonly due to middle meningeal artery and pterion
Subdural haematoma - bleed between dura and arachnoid mater (subdural space), usually as a result of torn bridging veins (subdural sinuses).
Intracerebral haematoma - occurs within brain with blood spreading out from point of origin, possibly resulting in burst lobe
Which haematoma is more common in the elderly and alcoholics and why?
Subdural haematomas - brain shrinks, increasing the straight on the bridging veins, increasing the risk of them tearing and causing bleed
What is the danger of an untreated cranial haematoma?
- Increased ICP until the point that compensatory mechanisms don’t have effect.
- This results in midline shift, compressing nerves and then uncal herniation where the uncus of temporal lobe passes tentorium.
- This applies pressure on pons, with pressure on CN3 first, and also compression on corticospinal tract - causes motor problems on contrlateral side
- Tonsillar herniation then occurs where the cerebellum follows, applying pressure on medulle - CV and respiratory fatalities
- Results in death
What are the most common cranial nerve damages due to a a fractured skull?
olfactory optic oculomotor trochlear trigeminal (V1 and V2) facial vestibulocochlear
What is a diffuse axonial injury?
Rotation of the brain within the skull causes axonal damage upon shear force - the axons change from rubbery and elastic to brittle (“reverse spaghetti”)
How can cerebral ischaemia be caused and what are the consequences?
Raised ICP
Reduced CPP
Hypoxaemia
Initiation of ischaemic cascade resulting in further neuronal death
List types of secondary head injuries
DAI
Ischaemia
Brain swelling - through contusions
Diffuse vascular brain injuries - multiple small haemorrhages occuring in cerebral hemispheres and brainstem - death within minutes
Location and function of Broca’s area
Region of frotnal lobe in dominant hemisphere (normally)
Speech production - reduced blood flow etc causes aphasia
Location and function of Wernicke’s area
Located in cortex of dominant temporal lobe
Comprehension of language - damage presents with fluent and unaffected speech but inability to use or understand more than basic nouns and verbs
Symptoms of Cerebellar Damage
“VANISHED”:
- Vertigo
- Ataxia (loss of full control of bodily movement)
- Nystagmus
- Intention tremor
- Slurred speech
- Hypotonic reflexes
- Exagerrated broad based gait
- Dysdiadochokinesia
Signs of Cerebellar damage
“DASHING”:
- Dysdiadochokinesia
- Ataxia
- Speech
- Hypotonia
- Intension tremor
- Nystagmus
- Gait
Learn the boundaries of the GCS:
Eye opening: 4- opens spontaneously 3- Opens to voice 2- Opens to pain 1- None
Verbal Response: 5- Normal conversation 4- Disorientated conversation 3- Icoherent words 2- Incomprehensible sounds 1- None
Motor Response: 6- Normal 5- Localises pain 4- Withdraws from pain 3- Decorticate posturing 2- Decerebrate posturing 1- None
Regarding brain development, what changes occur to white and grey matter?
White increases
Grey decreases