Functional anatomyBrain structure and function Flashcards
You are working as a PA in an emergency department. An 18 year old student comes to see you complaining of headache and feeling feverish. On examination he has photophobia, a non-blanching rash on his abdomen and a stiff neck. What is the most likely diagnosis?
Meningitis
What is this ?
Extradural Hematoma
What is this?
Subdural
What can happen within the subarachnoid space?
Subarachnoid Haemmeohage
This happens because there are blood vessels there !!
What is the presentation of a subarachnoid haemmoraghe?
Thunderclap headache
What are gyri and the sulcus of the brain?
What does the middle cerebral artery supply ?
The MCA supplies parts of the frontal lobe, parietal lobe and temporal lobe
What does the anterior cerebral artery supply ?
You will note that the ACA supplies parts of the frontal and parietal lobes
What does the posterior cerebral artery supply?
The PCA supplies the occipital lobe and part of the temporal lobe
What areas are perfused by the vertebrobasilar arteries ?
Areas perfused:
Medulla, pons, midbrain (brain stem)
Cerebellum
Thalamus
Occipital cortex
In 1848, Phineas Gage survived an iron bar passing through his brain in a railroad accident. After his recovery his personality was drastically different. Which part of the brain do you think was affected?
Frontal lobe
Frontal lobe- functions
1- Personality
2- Motor Function
3- Memory and language
4- Judgement
What is the blood supply for the frontal lobe ?
Blood supply is from the:
Anterior cerebral artery (ACA) and Middle cerebral artery (MCA)
A 78 year old man sustains a head injury in a road traffic accident. He is able to understand what is said to him but finds it very difficult to speak fluently in response. Which part of the brain is affected?
Brocas Area
What is brocas area important for ?
- The PRODUCTION of speech, the actual motor function. It is not used for comprehension.
- Processing thoughts into words
- Damage = able to understand but difficult to form words
What is the blood supply to Brocas area ?
Middle cerebral artery
Where is the Brocas area located ?
This new insight about Broca’s area, which is located in the frontal cortex.
An 87 year old lady presents to ED with a 1 hour history of left sided facial droop and arm weakness. Which part of the brain is affected?
Right Precentral Gyrus
Where is the motor cortex located ?
What is the blood supply ?
Precentral gyri
Supplied by Middle Cerebral Artery (MCA) and Anterior Cerebral Artery (ACA)
What does the motor cortex do ?
Controls movement of contralateral head, neck, trunk, arm and leg
Symptoms will be contralateral to the lesion
If a patient presented with leg weakness what part of the motor cortex would you expect there to be an issue with ?
ACA
If a patient presented with facial what part of the motor cortex would you expect there to be an issue with ?
MCA
A 19 year old patient comes to ED following a seizure. She describes hearing sounds that weren’t there, a strong feeling of fear, feeling like her heart was racing and profuse sweating. Her mother states that following this she had a wide eyed stare and was smacking her lips. She would not respond to her name.Which part of the brain was affected?
Temporal lobe
What is the role of the temporal lobe?
1) Organisation of sensory input
Auditory perception
Visual perception
Facial recognition
Smell
2) Memory
3) Speech and language
Especially language comprehension
4) Emotional Responses
What is the blood supply to the temporal lobe?
-Middle cerebral Artery
- Posterior cerebral Artery
What is the role of the limbic system ?
Self and species preservation behaviours
Autonomic and endocrine responses to emotional stimuli
Parts located within the temporal lobes:
Olfactory cortex
Hippocampus- memory formation and association
Amygdala- autonomic responses associated with fear
What is the role of Wernickes area ?
Responsible for:
Comprehension of language
Integration with other language areas
Damage= difficulty understanding spoken or written words. Speech may be fluent but make little sense
Receptive aphasia (or Wernicke’s aphasia)
What supplies the wernickes area ?
Middle Cerebral Artery (MCA)
How is wernickes area pronounced
VERNEKES
Where is wernickes area ?
Within the temporal lobe
A 76 year old man, who is taking warfarin for AF, presents to the ED. He tells you he had a sudden loss of vision in his left eye. However, on further examination, he actually has a left sided homonymous hemianopia. You suspect a haemorrhagic stroke.Which part of the brain is likely to be affected?
Occipital lobe
What is the role of the occipital lobe?
Damage to one side will cause homonomous hemianopia (loss of vision in same side in both eyes)
Visual loss is contralateral to the lesion
May cause visual hallucination or visual illusion (distorted perception)
What is the blood supply to the occipital lobe?
Supplied by Posterior Cerebral Artery (PCA)
Explain visual pathway
Numbers on left and right collaborate.
3 - issue with chaism.
What does hemineglect mean ?
Hemineglect involves the person neglecting and not having an awareness of one side of the body.
You are working as a PA on a neurology ward. You are asked to review a 68 year old patient with a brain tumour causing hemineglect on the right side. In which part of the brain is the tumour situated?
Parietal Lobe
What is the role of the parietal lobe ?
Integrates sensory information to develop a single perception
Sensation from the skin (pain, temperature, touch)
Proprioception
Visual information
Body/spatial awareness
Language processing
Defects may cause hemineglect, left/right confusion, agraphia, acalculia, aphasia, agnosia
what is agraphia
inability to writing
what is acalculia
inbaility to complete maths and simple calculations
Where is the sensory cortex
Within the parietal lobe
Located in the post-central gyri
role of sensory cortex
Located in the post-central gyri
Receives sensory data from the whole body
Symptoms will be contralateral to the lesion
Blood supply to sensory cortex
Blood supply from Anterior and Middle cerebral arteries
Explain homunculus for the sensory cortex
You are working as a PA in the Emergency Department. An intoxicated 21 year old male comes into the department following a fall in the street. He is ataxic and has slurred speech. Which part of the brain is affected?
Cerebellum
What is the role of the cerebellum
Regulates motor function
Coordination
Balance
Muscle tone and posture
Speech
What are the symptoms of cerebellar dysfunction- DANISH
Symptoms of cerebellar dysfunction- DANISH
Dysdiadokokinesia
Ataxia
Nystagmus
Intention tremor
Slurred speech
Hypotonia
What blood vessels supplies the cerebellum ?
Supplied by vertebral and basilar arteries
You go on a home visit to a nursing home to see a 76 year old man, because the carers are concerned he is becoming depressed. You note that he has a stooped posture, with difficulty initiating movement and slow, shuffling steps. He has a pill rolling tremor in his right hand. You see in his notes he was diagnosed with Parkinson’s Disease 3 years ago. Which part of the brain is affected by Parkinson’s Disease?
Basal ganglia
What is the role of the basal banglia ?
Essential in the control of movement
Particularly important in starting, stopping and monitoring movements executed by the cortex
Inhibit unnecessary movements
Also play a role in cognitive and perceptual functions
What artery supplies the basal ganglia ?
Supplied by middle cerebral artery (MCA)
You are a PA working on an acute stroke unit. An 89-year-old lady with hypertension and an extensive smoking history is admitted. She has right leg weakness and paraesthesia. She finds it difficult to make decisions or act spontaneously.What is the most likely vascular origin of her stroke?
Anterior cerebral artery
What is the ACA responsable for ?
Explain Anterior cerebral artery (ACA) stroke?
RARE ! But do happen
Rare due to collateral circulation by anterior communicating artery
Weakness or paralysis of contralateral lower limb, impaired gait
Sensory loss or paraesthesia of contralateral lower limb
Aphasia
Problems making decisions or performing acts voluntarily
Lack of spontaneity
Easily distracted
Slowness of thought
You are working as a PA in an emergency department. A 77 year old man is brought in with left sided facial droop and arm weakness. He seems to understand what you are saying but has difficulty speaking. You suspect a stroke and order an urgent CT scan.What is the most likely vascular origin of his stroke?
Middle Cerebral Artery (MCA)
This is because of the Broca’s area.
Where is the most common site for a stroke?
Middle Cerebral Artery (MCA) Stroke
Most common site of stroke
Contralateral face and arm weakness/paralysis
Contralateral face and arm sensory loss/paraesthesia
Broca’s (expressive) or Wernike’s (receptive) aphasia
May have contralateral hemiparesis due to basal ganglia and internal capsule involvement
What is paraesthesia
Tingling/ numbness
You are working as a PA in a GP surgery. A 69 year old lady, with a past medical history of diabetes, hypertension and MI, comes to see you due to sudden visual loss on the right side and visual hallucinations. You feel you need to rule out stroke. What is the most likely vascular origin of her stroke?
Posterior cerebral artery
Because its effected the occipital lobe which is responsible for vision.
What would you see if a patient has a posterior cerebral artery (PCA) stroke ?
Homonymous hemianopia
Other visual defects- colour blindness, loss of central vision, visual hallucinations
Memory deficits
Perseveration
Contralateral hemisensory loss (all modalities)
Contralateral hemiparesis
Spontaneous pain
Intention tremor
Aphasia
You are working as a PA in a GP surgery. You are told at a practice meeting that one of your patients has died suddenly and unexpectedly. The post-mortem showed a diagnosis of stroke.What is the most likely vascular origin of their stroke?
eg which is most likley to keep you alive
Vertebrobasilar arteries
Because it supplies the brain stem !!
What would you see with a vertebrobasilar stroke ?
85% mortality rate
Cranial nerves involvement- symptoms/signs ipsilateral. Corticospinal
symptoms/signs are contralateral
Signs/symptoms:
Death/coma
Cranial neuropathies
Quadriplegia or hemiplegia
Ataxia and other cerebellar signs such as nystagmus, vertigo, N+V, past pointing
Dysphagia
Dysarthria
Sensory loss (may have different modalities lost on each side)
Visual field loss or visuospatial deficits
What stroke has the highest mortality rate?
85% mortality rate in vertebrobasilar stroke
You are working as a PA in an emergency department. A 77 year old man is brought in with left sided facial droop and arm weakness. He seems to understand what you are saying but has difficulty speaking. You suspect a stroke and order an urgent CT scan.What is the most likely vascular origin of his stroke?
Middle cerebral artery
You are PA working on an acute stroke unit. A 89 year old lady with hypertension and an extensive smoking history is admitted. She has right leg weakness and paraesthesia. She finds it difficult to make decisions or act spontaneously.What is the most likely vascular origin of her stroke?
Anterior cerebral artery
An 87 year old lady presents to A+E with a 1 hour history of left sided facial droop and arm weakness. Which part of the brain is affected?
Right precentral gyrus
What is this ?
Haemorrhagic stroke
