2 - Brain anatomy and Cortical localisation Flashcards
Where is the brainstem located?
Beneath the cerebrum and in front of the cerebellum
What are the 3 parts of the brain stem?
- The midbrain
- The pons
- The medulla
What are the 2 paired structures coming out the midbrain called?
Cerebral peduncle
of midbrain
Describe the Cerebral peduncle
(of midbrain)?
White matter fibres travel here
These fibres attach our midbrain to the rest of the brain
What is found on the medulla?
Bulges
What is the innermost bulge in the medulla called?
The pyramids
What is the outermost bulge in the medulla called?
The olives
How many cranial nerves arise from the brain stem?
10
Which cranial nerves arise from the brain stem?
III- Occulomotor IV- Trochlear V- Trigeminal VI- Abducens VII- Facial VIII - Vestibulocochlear IX - Glossopharyngeal X - Vagus XII - Hypoglossal XI – Accessory
Where does the oculomotor nerve arise from?
The Cerebral peduncle in the midbrain
Ventral
Where does the trigeminal nerve arise from?
Emerges from the middle of the pons
Ventral
Where does the Abducens nerve emerge from?
The junction between the pons and the medulla
At the midline
(Ventral)
Where does the Facial nerve emerge from?
The junction between the pons and the medulla
Lateral to the midline
(Ventral)
Where does the Vestibulocochlear nerve emerge from?
The junction between the pons and the medulla
Lateral to the 7th
(Ventral)
Where does the Glossopharyngeal nerve emerge from?
At the medulla just inferior to 8th cranial nerve
Ventral
Where does the Vagus nerve emerge from?
At the medulla just inferior to 9th cranial nerve
Ventral
Where does the Hypoglossal nerve emerge from?
At the medulla between the junction of the pyramids and the olives
(Ventral)
Where does the accessory nerve emerge from?
At the medulla just inferior to 10th cranial nerve
Ventral
Which cranial nerves do not emerge from the brainstem
I- Olfactory nerve
II- optic
Where does the trochlear nerve emerge from?
Dorsal side of the brain stem below the inferior colliculi
What are the bumps visible on the dorsal side of the midbrain?
Colliculi
How many Colliculi are found on the dorsal side of the midbrain?
4 (2 pa
2 superior
2 inferior
Which of the 10 cranial nerves emerging from the brainstem is different to the rest and why?
The trochlear nerve as it emerges from the dorsal side of the brain
The space between the pons and the cerebellum is filled with what?
Fluid
What happens if we remove the cerebellum?
We are left is the floor of the fluid space
What is found at the top of the medulla?
The open medulla which is the space where fluid is
What is space lateral to the open medulla called?
The closed medulla
What are cranial nerves I and II
Extensions of the cerebrum
Where does the olfactory nerve emerge from
Synapses with the olfactory bulb which is an extension of the telencephalon
What is the olfactory nerve an extension of?
The telencephalon
How does information travel along the olfactory nerve?
- Electrical impulse travels through the olfactory nerve
- Synapses with the olfactory bulb
- Then passes through the olfactory tract
- Impulse is Brough to the cortex which processes the information
Where does the optic nerve emerge from?
Develops as an extension of the diencephalon
What is the diencephalon?
The inner brain
How many divisions are there of the diencephalon?
There are 4 division
What are the 4 divisions of the diencephalon
- Thalamus
- Hypothalamus
- Epithalamus
- Subthalamus
Where is the diencephalon found?
Sits on top of the brainstem connecting it to the central hemisphere
Describe the thalamus segment of the diencephalon
Made up of several nuclei
It is all grey matter
They relay stations between parts of the CNS
Kind of like the receptionist of the diencephalon
Where is the thalamus located in the diencephalon
In the centre
What does the thalamus do in the brain?
Receives info from the spinal cord and the brain and sends that information to the different corresponding parts of the brain
Describe the hypothalamus
Made up of several nuclei
Completely grey matter
Where is the hypothalamus found?
Below the thalamus
What is the function is the hypothalamus
Regulates neuroendocrine and autonomic functions
Where is the Subthalamus found?
Found below and lateral to the thalamus
What is the function of the sub thalamus?
It is involved in motor control
In which view is the sub thalamus not visible?
The midsagittal view
Where is the epithalamus found?
Upon (above) the thalamus
Describe the epithalamus
It includes the pineal gland
Describe the pineal gland
Secretes melatonin which regulates sleep an wake cycles
What are folds in the brain called?
Gyri (sing= gyrus)
What are grooves in the brain called?
Sulci (Sing= sulcus)
What are specific sulk in the brain used to do?
They are used to divide the cerebral hemisphere into lobes
What is the groove right in the centre called?
The central sulcus
Why is the central sulcus important?
It separates the frontal and parietal lobe
Why is the lateral sulcus important?
It separates the frontal lobe from the temporal lobe
Which grooves can be found in the temporal lobe?
The superior and inferior temporal sulci
What is the groove right at the back of the brain called?
The parieto-occipital sulcus
Which 6 sulci must we be aware of?
- Central sulcus
- Lateral sulcus
- Inferior temporal sulcus
- Superior temporal sulcus
- Parieto-occipital sulcus
- Calcarine sulcus
- The cingulate sulcus
Why is the parieto-occipital sulcus important?
It separates our parietal and occipital lobes
Which sulcus is found at the caudal end of the medial surface of the brain?
The calcarine sulcus
Why is the calcarine sulcus important?
It is involved in the visual pathway
What is the function os the corpus callosum?
Bind of white matter fibres that attaches the left hemisphere to the right hemisphere
What is the function of the frontal lobe?
It is the motor cortex
It regulates emotions, behaviour and personality
What is the function of the parietal lobe?
It is the sensory cortex
It is important fro spacial awareness
It is important for understanding language
What is the function of the temporal lobe?
It is the auditory cortex
It is responsible fro regulating emotions
What is the function of the occipital lobe?
It is the visual cortex
Why is Phineas Gage famous?
He survived after a steel rod went through his jaw and brain
He sustained massive damage to the left frontal lobe
What happened to Phineas Gage after he sustained his injury?
He survived but suffered massive damage to his left frontal lobe
This caused him to become impulsive He lost the ability to make sound judgements
How many types of projection areas do we have?
2: Primary and secondary projection areas
What are primary projection areas?
They are where sensory pathways finish or where motor pathways begin
What happens at sensory areas?
Specific sensory pathways terminate here
Where do general sensory impulses terminate?
In the post central gyrus
Where do visual impulses terminate?
Around the Calcarine sulcus and posterior aspect of occipital lobe (striate cortex)
Where do auditory impulses terminate?
Heschl’s gyrus
What originates in motor areas?
Major descending motor pathways originate here
Where does the primary motor cortex originate?
The Precentral gyrus
What do we call anything anterior to the central sulcus?
The precentral gyrus where the primary motor cortex originates
What do we call anything posterior to the central sulcus?
The postcentral gyrus where primary somatosensory impulses terminate
What is found at the top of the temporal lobe?
The Hechl gyrus
where the primary auditory cortex is found
What is found at the very back of our occipital lobe?
The primary visual cortex
Where does the primary cortex start and extend to?
Extends from around the calcimine suluc to the occipital pole
Where does sensory information from our legs get processes?
The mid line of the brain
Where does sensory information from our face get processes?
More lateral
Describe secondary sensory areas
They receive input from primary sensory areas
They are involved in interpretation and understanding
Where are general sensory impulses (somaesthetic) processed?
Superior parietal lobe
Where are visual impulses processed?
Pre-striate cortex
Where are audiory impulses processed?
Lateral fissure
Superior temporal gyrus
Describe secondary motor areas
They send outputs to primary motor areas
They organise patterns of movement
Where is the pre motor cortex located?
Anterior to precentral sulcus on lateral surface
Where is the supplementary motor area located ?
Anterior to precentral sulcus on medial surface
Where is the frontal eye field located
Anterior to pre-motor area
Where are motor association areas found?
Anterior to the pre central gyrus
What is the function of the frontal eye field?
It regulates voluntary movement of the eyes
Where are association areas found?
Surrounding our primary visual areas
Typically which of the 2 hemispheres is the more dominant one?
The left hemisphere for right handed people
What does the left hemisphere contain?
The 2o auditory area
What is Wernicke’s area important for?
It is essential for sensory understanding and understand language (sensory association cortex for auditory information)
What is Broca’s area important for?
It is found in the frontal lobe of the dominant hemisphere
It is important for speech production
What happens when there is a lesion in the Wernicke’s or Broca’s area?
You get Aphasia
What is aphasia?
Problem in speech
What is a lesion in the Broca’s area called and what can this lead to?
Broca’s aphasia (non-fluent aphasia)
Problems in finding words and articulating what they want to say
Trouble in forming sentences
What is a lesion in the Wernickes area called and what can this lead to?
Wernickes aphasia (fluent) Problems in understanding speech and speaking
Describe the levels in cortical organisation
Level 1: Some areas have precise sensory or motor function.
Level 2: Other areas progressively more associative or integrative.
Level 3+: As ascend “hierarchy” we find certain hemispheres are specialised in certain areas
What attaches the midbrain to the rest of the brain?
Cerebral peduncle
Which sulcus separates the frontal and temporal lobes?
The lateral sulcus
Which lobe is described as the auditory cortex?
The temporal lobe
What is the 3rd cranial nerve called?
Occulomotor
What is the 5th cranial nerve called?
Trigeminal nerve
What is found below and lateral to the thalamus in the diencephalon?
The subthalamus
Which nerve emerges lateral to the 7th cranial nerve at the junction between the pons and the medulla?
The Vestibulocochlear (8th)
Which nerve emerges at the medulla just inferior to 10th cranial nerve?
The accessory nerve (12th)
Which nerve emerges at the medulla just inferior to 9th cranial nerve?
The vagus nerve (10th)
Which 2 lobes are responsible for regulating emotions?
The temporal and frontal lobes
Which nerve(s) emerge from the junction between the pons and the medulla?
The Abducens (6th), Facial (7th) and Vestibulocochlear (8th)
What is the 6th cranial nerve called?
Abducens
Which lobe is important for special awareness?
The parietal lobe
What is the 7th cranial nerve called?
Facial
Why is the trochlear nerve different to the other cranial nerves found on the brain stem?
The trochlear nerve is different as it emerges from the dorsal side of the brain
Which cranial nerve emerges from the middle of the pons?
The trigeminal nerve (V)
What is the 8th cranial nerve called?
Vestibulocochlear
Which lobe is important for understanding languages?
The parietal lobe
Which sulcus separates the frontal and parietal lobes?
The central sulcus
Which nerve emerges st the medulla between the junction of the pyramids and the olives?
The hypoglossal nerve (11th)
Which nerve emerges from the MIDLINE of the junction between the pons and the medulla?
The Abducens (6th),
Which nerve is an extension of the telencephalon?
The olfactory nerve (1st)
What is the 9th cranial nerve called?
Glossopharyngeal
Which lobe is described as the visual cortex?
The occipital lobe
Which section of the diencephalon regulates neuroendocrine and autonomic function?
The hypothalamus
What is the 10th cranial nerve called?
Vagus
What is located Anterior to precentral sulcus on medial surface?
The supplementary motor area
What is the 12th cranial nerve called?
Hypoglossal
Where is the pre central gyrus found?
Anterior to the central sulcus
Which section of the diencephalon is in involved in motor control?
The subthalamus
Which lobe is described as the sensory cortex?
The parietal lobe
Where is the pineal gland found?
The epithalamus division of the diencephalon
What are sulci?
Grooves in the brain
Which cranial nerve arises from the Cerebral peduncle?
The 3rd cranial nerve
What is found below the thalamus in the diaencephalon?
The hypothalamus
What is located Anterior to precentral sulcus on lateral surface?
The pre motor cortex
Which nerve emerges lateral to the midline of the junction between the pons and the medulla?
Facial (7th)
Which lobe is in-charge of regulating emotions, behaviour and personality?
The frontal lobe
What is the 11th cranial nerve called?
Accessory
Which nerve is an extension of the diencephalon?
The optic nerve (2nd)
What is processed at the Lateral fissure and Superior temporal gyrus?
Auditory impulses
Which nerve emerges at the medulla just inferior to 8th cranial nerve?
The glossopharynegeal nerve (9th)
Where is the post central gyrus found?
Posterior to the central sulcus
Which nerve emerges just below the inferior colliculi?
The trochlear nerve (4th)
Which hormone regulates the sleep wake cycle and by which gland is it secreted?
Melatonin it is secreted by the pineal gland which is found in the epithalamus
Which section of the diencephalon is the relay system of the brain?
The thalamus
What does it mean when we say the thalamus is the relay system of the brain?
It Receives info from the spinal cord and the brain and processes and sends that information to the corresponding part of the brain
What are gyri?
Folds in the brain
What is processed at the Pre-striate cortex?
visual impulses
Where is the central sulcus?
The groove right in the middle of the brain
Where are the superior and inferior temporal sulci found?
In the temporal lobe
The calcarine sulcus is found where?
In the middle of our occipital lobe?
Which lobe is described as the “motor cortex”?
The frontal lobe
If someone is having trouble understanding speech and speaking what might they have?
Wernickes aphasia
What terminates in the post central gyrus?
General sensory impulses
What terminates Around the Calcarine sulcus and posterior aspect of occipital lobe (striate cortex)?
Visual impulses
What terminates at Heschl’s gyrus?
Auditory impulses
What originates at the Precentral gyrus?
The primary motor cortex
Where is the Hechl gyrus found?
At the top of the temporal lobe
What is processed at the Superior parietal lobe?
General sensory impulses (somaesthetic)
What is located Anterior to pre-motor area?
The frontal eye field
If someone is having trouble forming sentences what might they have?
Broca’s aphasia
