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Flashcards in Cerebral Hemispheres Deck (43):

Describe the general features of the cerebrum

Sulcus = dip
Gyrus = elevation
Fissure = larger dip

Gray matter on the surface.
White matter inside.

Basal Ganglia (collection of neuronal cell bodies buried in the white matter)

Lateral ventricle is the cavity in each hemisphere


Is the pattern of sulci and gyri variable?

Change pattern depending on what you use your brain for

Some sulci and gyri are constant features


What is the corpus callosum?

Bridges the two cerebral hemispheres


What sulci can you see on the cerebrum?

Just above temporal lobe is the lateral sulcus

Joint to this is the central sulcus which runs to the medial surface of the cerebrum

On the medial surface the cingulate sulcus can be seen above the corpus callosum.
The pirate-occipital sulcus can be seen at the back

This divides the brain into frontal, parietal and occipital and temporal lobes


What gyri can you see on the cerebrum?

Precentral gyrus:
-Just anterior to central sulcus

Postcentral gyrus:
-Just posterior to central sulcus

Cingulate gyrus:
-Superior to corpus callosum
-Inferior to cingulate sulcus


Where is the hippocampus located?

Medial end of temporal lobe which curls into itself


What structures are inside the lateral sulcus?

Transverse temporal gyri



What is the difference between different Brodmann Areas?

Each broaden area has a different function and therefore different cellular makeup


Describe the functional areas of the cortex

Posterior part of the cerebral hemisphere is sensory while the anterior part is motor.

Medial portions of the cerebral hemisphere (limbic system)
-Storage and retrieval of processed information

Dominant and non-dominant hemisphere for different tasks

There are primary sensory areas and adjacent association areas


What does the frontal lobe do?

Motor function


What does the parietal lobe do?



What does the occipital lobe do?



What does the temporal lobe so?

Hearing and smell


What does your Precentral gyrus do?

Area 4: Primary Motor Cortex
(Frontal lobe)

Somatotropic representation of contralateral half of body through motor homunculus


What does the inferior frontal gyrus do?

Area 44, 45

Broca's area of motor speech

Frontal lobe


What does the prefrontal cortex do?

Cognitive functions of higher order- intellect, judgement, prediction, planning

Frontal lobe


What does the post central gyrus do?

Areas 1, 2, 3
Primary sensory area
(Parietal lobe)

Receives general sensations from contralateral half of body.

Somatotopic representation through sensory homunculus


What does the superior parietal lobule do?

Interpretation of general sensory information (sensory association area) and conscious awareness of contralateral half of body

can recognise what you touch


What does the inferior parietal lobule do?

Interface between somatosensory cortex and visual and auditory association areas.



What can a parietal lobe lesion cause?

Hemisensory neglect

Inability to be aware of opposite side of body.

Will not even know that side is there


What does the superior temporal gyrus do?

Areas 41, 42
Primary auditory complex
Heschl's convolusions


What are the auditory association areas of the temporal lobe?

Posterior to 41, 42.

In dominant hemisphere -> Wernicke's area
Crucial for understanding of spoken word.
has connections with other language areas.


What does the inferior surface of the temporal lobe do?

Receives fibres from olfactory tract

Conscious appreciation of smell


Where is the primary visual cortex?

On the medial surface of the occipital lobe, on either side of the calcimine sulcus is the primary visual cortex
(Area 17)


Apart from the primary visual cortex what else does the occipital lobe do?

The rest of the occipital lobe is the visual association cortex concerns with interpretation of visual images.

(Areas 18, 19)


What is the limbic lobe?

The medial surface of the cerebral hemisphere has areas which together form a functional limbic lobe involved in memory and emotional aspects of behaviour.

It includes the cingulate gyrus, the hippocampus (medial aspects of temporal lobe), parahippocampal gyrus and the amygdala (subcortical grey matter close to temporal pole)


Describe the language areas of the brain

Broca's area is the motor speech area.

Wrenches' area is the auditory association area necessary for recognition of the spoken word.
Is in the dominant hemisphere.


What is aphasia?

Problem with speech due to damage to one or more speech areas in the brain


Describe Broca's aphasia

"Walk Dog"

Understands speech

Misses small words

Aware of difficulties in speech
(can't put thoughts into words)

Damage to frontal lobe

Weakness/paralysis of one side of body


Wernicke's aphasia

"You know that smoodle pinkered and that i want to get round him like you want before"

Fluent speeach, with new meaningless words, can't understand speech, doesn't know of mistakes

Damage to temporal lobe

No paralysis


There are 3 types of myelinated axon fibres bundles into tracts. What are they?

1. Commisural fibres
2. Association fibres
3. Projection fibres


What are commisural fibres?

-Connect corresponding areas of the two hemispheres
-Corpus Callosum


What are association fibres?

-Connect 1 part of the cortex with the other (same hemisphere).
-They may be short or long


What are projection fibres?

Run between the cerebral cortex and various subcortical centres.

They pass through the corona radiata and the internal capsule


What is the internal capsule?

Made up of projection fibres passing to and from the cerebral cortex

It is a narrow area between the thalamus and caudate nucleus medially and the lentiform nucleus laterally.

It derives blood supply from the middle cerebral artery and is frequently affected in a stroke


Why is an internal capsule stroke so dramatic?

All projection fibres coming from the cerebral cortex to the spinal cord must come through these two channels in the diencephalon.

If there is a stroke there will be massive effects to the contralateral side of the body


What are the basal ganglia?

Subcortical nuclei (collection of neuronal bodies - grey matter) deep within each cerebral hemisphere.

made up of the caudate nucleus, putamen and globes plallidus

Substantia nigra in midbrain is functionally part of them though not anatomically


What are the individual basal ganglia?

CAUDATE (one with a tail)

The PUTAMEN (means the hard shell)

GLOBUS PALLIDUS (the pale globe

The hard shell + the globe forms a lens like structure - the LENTIFORM NUCLEUS

SUBSTANTIAL NIGRA (the black substance, lies in the midbrain!)



What is the topographical anatomy of the basal ganglia?

The caudate nucleus starts as a large head medial to the internal capsule, a body and a slender curving tail which follows the curve of the lateral ventricle.

lateral to the internal capsule is the lentiform nucleus made up of the putamen laterally and globes plaids medially


How can you find the lateral ventricle, internal capsule, thalamus and lentiform nucleus on a brain section?

Identify the lateral ventricles and a third ventricle (if present)

Lying in the wall of the lateral ventricle is the caudate nucleus

Lying beside the third ventricle is the thalamus (diencephalon)

lateral to the caudate and thalamus lies the internal capsule

lateral to the internal capsule is the lentiform nucleus made up of the globes plaids medially and the putamen laterally


What are the connections of the basal ganglia?

1. the caudate nucleus and the putamen are the "input regions" receiving input from the motor cortex, premotor cortex and from thalamus

2. They are in turn connected to the output regions (the globes plaids and substantial nigra)

3. The globes plaids then projects primarily to the thalamus (which in turn sends fibres to motor area of cortex)


What does the basal ganglia do?

The major function is to help regulate initiation and termination of movements.

Because they play a role in controlling the motor system they are often referred to as the "extrapyramidal system"


What is the pathology of the basal ganglia?

Athetosis etc