Lobes and Features of the Brain Flashcards
Role of the frontal lobe
Primary motor and pre frontal cortex
Personality centre
- motor function
- problem solving
- spontaneity
- memory
- language
- judgement
- personality
- impulse control
- social and sexual behaviour
Anterior portion (pre-frontal lobe) - higher cognitive functions and determination of personality
Posterior portions - motor and pre-motor area
Contains Brocas area
Broca’s area
Left inferior frontal gyrus (in frontal lobe)
Important for language production and comprehension
Temporal lobes
Primary auditory cortex
Auditory association cortex
Contains Wernicke’s area, hippocampus and amygdala
Wernicke’s area
Located superior temporal gyrus of the left hemisphere
Understanding the spoken word
Where is the auditory cortex located
Lateral (Sylvian) fissure
Parietal Lobes
Primary somatosensory cortex and association cortex
Dominant lobe (normally left)
- perception
- interpretation of sensory information
- formation of idea of complex, meaningful motor response
Supramarginal and angular gyrus (of dominant lobe)
- Language and mathematical operations
Non-dominant lobe (usually right)
- visuospatial functions
Occipital Lobes
Primary visual and visual association cortex
Cerebellum
Motor control of equilibrium
Posture and muscle tone
Movement co-ordination
Two lobes - one either side of the medulla. Joined by = central vermis
Corpus Callosum
Large bundle of white matter connecting the two hemispheres
Where are the olfactory tracts
Run on the inferior surface of the frontal lobes
Mammillary bodies
Form part of the hypothalamus
Role in memory
Limbic system
Surrounds medial margin of the hemisphere
Emotion, memory, behaviour and olfaction
Includes
- hippocampus - long term memory formation
- fornix
- amygdala - reward and fear (motivationally significant stimuli)
Operates by influencing the endocrine system and autonomic nervous system
Highly interconnected with the brains pleasure centre - the nucleus accumbens
- role in sexual arousal and the high experience in recreational drugs
Cisterns
Subarachnoid cisterns are not anatomically separate
Only a porous wall that has numerous openings or various sizes separates cisterns
All arteries, veins and cranial nerves if the brain must pass through the subarachnoid space to leave the skull
They carrier there meningeal layer until the point at which they leave the skull
Blood brain barrier
Surface of brain arteries lie in subarachnoid space
As vessels pass into the substances of the brain they take with them prolongations of the pia mater and some of the subarachnoid space
Vessels penetrate the brain deeper
- tunica media thins
- prolongation of the subarachnoid space narrows
Level of capillary network
- Basement membranes of the endothelial cells and of the pia fuse
Pia acts as a barrier between the blood vessels and neurological tissue
What contributes to the blood brain barrier (3)
- Endothelial cells of the capillaries
- Basement membrane - lies between the endothelial cells and the astrocytic end-feet and is formed from the true basement membrane and the pia
- Astrocytic end-feet
Name the circle of Willis from the bottom (Vertebral arteries)
2 vertebral arteries
- branch posterior inferior cerebellar artery (PICA)
vertebral arteries join
Branches
- anterior inferior cerebellar artery
Become basilar artery
Branches
- superior cerebellar artery
- posterior cerebral artery
Circle
- Posterior communicating artery
Branch
- Internal carotid artery (coming in)
- middle cerebral artery (coming off the lateral side)
Further up
- anterior cerebellar artery
Circle
- anterior communicating artery
What is the order which CSF passes
Lateral ventricles
Interventricular foramen
3rd ventricle
Backwards through cerebral aqueduct
4th ventricle
Communicates with subarachnoid space via
- median foramen of Magendie
- lateral foramen of Luschka
Through these CSF passes out to occupy and subarachnoid space around the brain and the spinal cord
Production of CSF
Invagination vessels into the ventricles produces a vascular fold of pia mater covered by epithelium derived from the ependymal lining of the ventricle = choroid plexus
Tight junctions - prevent passage of fluid from extracellular space of the choroid plexus into the ventricles except via the choroid cells themselves
Enables close control over the volume and composition of CSF
Arachnoid Villi
Reabsorption of the CSF into venous drainage occurs via tufts of arachnoid mater
Advancing age = villi calcify = arachnoid granulations
Prescence tends to cause bone to be reabsorbed along the internal surface of the cranial vault near the midline = small-pit like structures
Levator palpebrae superioris
Is a thin muscle located in the bony orbit above the eyeball
Originates at the posterior of the orbit at the common tendinous ring and inserts into the upper eyelid
Facilitates movements of the eye by elevating and retracting the upper eyelid and allowing unhindered upward gaze
Array of facial expressions
Lacrimal Gland
Tear gland
Exocrine gland
Located above the eyeball - anterior part of the upper outer aspect of each orbit
Secretes lacrimal fluid (tear fluid) - a watery fluid isotonic to plasma, onto the surface of the eyeball
Fluid form aqueous portion of the multilayered tear film
- lubricates
- protects
- provides nutrients to the conjunctiva and cornea
Lacrimal fluid drains into a series of ducts into the nasal cavity
Just inside of the lateral margin of the orbit adjacent to the lateral margin of the levator palpebrea superiors
Cerebellum
Largest part of the hindbrain
Coordination of movement and balance
Red nucleus
A circular mass of grey matter ventro-lateral to the cerebral aqueduct - may be pink (due to iron) in a fresh specimen
Substantia Nigra
A black band of nerve cells overlying the crus cerebri (cerebral peduncles), ventro-lateral to the red nucleus on each side
Production of dopamine
