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Brain
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Cerebrum
Diencephalon
o Thalamus
o Hypothalamus
Brainstem (mid brain, pons, medulla oblongata)
Cerebellum
Development of nervous system
Week 3
Prosencephalon
(forebrain)
Week 5
Telencephalon (Far brain)
Adult
cerebral hemisphere, basal nuclei
Diencephalon (through
brain)
Thalamus, hypothalamus, epithalamus
Mesencephalon
(midbrain)
Mesencephalon (midbrain)
Brain stem (midbrain)
Rhombencephalon
(hindbrain)
Metencephalon (after brain)
Myelencephalon
Brain stem (pons), cerebellum
Brain stem (Medulla oblongata)
Functional areas of the cerebral hemispheres
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Primary areas receive/put out information
Association areas interpret info or initiate motor patterns
Function:
o Frontal lobe  Motor
o Parietal lobe  sensation
o Occipital lobe  vision
o Temporal lobe  auditory
o Insula cortex  taste, memory
o Primary motor cortex  Sends motor commands to skeletal muscles
 In precentral gyrus
o Primary somatosensory cortex Receives somatic sensory input (pain, pressure,
temperature, touch)
 In postcentral gyrus
o Right hemisphere vs left hemisphere:
 Left hemisphere  logical
 Right hemisphere  perception
Features
o Gyri
o Sulci
o Central sulcus
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Longitudinal fissure
Precentral gyrus
Postcentral gyrus
Lateral sulcus
Lobes
Nucleui (including basal nuclei)
Diencephalon
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Thalamus
o Function
 Gatekeeper for sensory and motor information
 All sensory information (except olfactory) passes through the thalamus
before reaching the cortex
 Relays information from basal nuclei and cerebellum to cortex
Hypothalamus
o Function
 Maintains homeostasis via control of autonomic and endocrine systems
 Vital role in emotional behaviour
 Food intake
 Temperature regulation
 Reproduction
 Sleep/wake cycle
Brainstem
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Midbrain, pons, medulla oblongata
Function
o Conduit for sensory and motor pathways
o Consciousness
o Reflex centres for respiratory and cardiovascular systems
o Contains nuclei of cranial nerves (3-12)
Cerebellum
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Function:
o Coordinator and predictor of movement
 Receives somatosensory information
 Compare this info with movement orders from the cerebral cortex
 Predicts consequences and adjusts the movement
o Maintenance of equilibrium
o Regulation of muscle tone
Cerebellar peduncles: connect cerebellum to cerebrum
Identify:
o Hemispheres
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Lobes
Outer cortex
Inner white matter
Folia (gyri)
Sulci
Cerebellar peduncles (anterior, middle, posterior)
Connecting tracts
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Projection tracts
o Up and down
o e.g internal capsule
Association tracts
o within hemisphere
Commissural tracts
o Joins left and right hemispheres
o Eg. Corpus callosum
Meninges
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Function
o Protective covering
o Limits displacement of brain
o Provide a space for cerebrospinal fluid and blood vessels
Dura mater
o tough 2 layered connective tissue
o Sensory nerve supply (pain)
o Not connected to spinal cord to facilitate movement.
Arachnoid mater
o Translucent spider web membrane
Pia mater
o Thin delicate membrane
o Adheres to brain surface
Ventricular System
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Ventricles are cavities within the brain that contain cerebrospinal fluid
Originate from embryonic neural tube
Filled with cerebrospinal fluid
Identify :
o Lateral ventricles
o Third ventricle
o Fourth ventricle
Cerebrospinal fluid
o Function:
 Support
 homeostatic environment for brain
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 Distribute hormones/neurotransmitters
How it works
 Clear liquid produced by choroid plexis in ventricles
 CFS travels from the 4th ventricle, passes through medial and 2 lateral
apertures into subarachnoid space
 CFS travels through arachnoid villi into venous sinuses (usually superior
sagittal venous sinus) which then enter the circulatory system
Arterial supply to brain
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15% of all blood pumped by heart goes to the brain as neurons have high protein synthesis
and metabolic rates and are very active
Arteries:
- Internal carotid artery (left and right)
- Vertebral artery (left and right)
Venous sinuses:
- Internal jugular vein
Spinal cord
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Reached lower L1 in adults
o Conus Medullaris
 Caudal tip of the spinal cord
o Cauda Equine
 Sensory and motor nerve roots
o Filium Terminale
 Pia mater extension between Conus Medullaris and coccyx
Organisation of grey and white matter
o Grey matter  3 horns
 Dorsal horn (sensory)
 Lateral horn (autonomic motor)
 Ventral horn (somatic motor)
o White matter  3 columns
 Dorsal column
 Lateral column
 Ventral column
o Central canal, ventral median fissure, dorsal median sulcus
o Many projection tracts (up and down)
Blood supply
o 1 anterior (supplies blood to 2/3 spinal)  ventral and lateral horns
o 2 posterior spinal arteries