Telencephalon | Diencephalon | Mesencephalon |Cerebellum and Pons | Medulla Oblongata | Spinal Cord

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Telencephalon
Telencephalon Animation
Telencephalon Label Animation

Cerebral hemispheres connected by corpus callosum

• Longitudinal fissure separates the cerebrum into right and left halves.
  Link to Major coverings
  
  
• The lateral or Sylvian fissure separates the temporal lobe of the cerebrum from the frontal and parietal lobes.
  
  
• The Frontal lobe is the largest part of the brain. Its caudal boundary is the central sulcus. It includes the olfactory bulbs and tract Link to olfactory and the orbital cortex. Link to visual.
  
  
• The Parietal lobe is bounded rostrally by the central sulcus and caudally by an imaginary line extended from the lateral fissure to the superior surface of the brain.
  
  
• The Temporal lobe plays an important role in memory and learning. On the inferior surface it includes the uncus and the parahippocampal gyrus
  
  
• The Occipital lobe is the most caudal part of the cerebrum. It plays an important role in the processing of visual stimuli.

Cerebral Cortex Brodmann areas

• The primary sensory cortex is located in the postcentral gyrus of the parietal lobe (Brodmann areas 1,2,3)
  
  
• Link to general sensation
  
  
• The primary motor cortex is located in the precentral gyrus of the frontal lobe (Brodmann areas 4,6,8)
  
  
• Link to pyramidal and Link to Neurohistology
  
  
• The auditory cortex is located in the superior temporal lobe (Brodmann area 41)

  Link to Auditory. Damage to this area results in Wernicke's or sensory aphasia.
  
  
• That part of the primary motor cortex that controls speech is located in the inferior part of the primary motor cortex of the frontal lobe (Brodmann area 41) Link to pyramidal. Injury to this area on the dominant hemisphere results in Broca's or motor aphasia.
  
  
• The visual cortex is located in the occipital lobe (Brodmann area 17). Link to Visual
  
  

Basal Ganglia Link to Extrapyramidal

• The caudate nucleus is a "C" structure that surrounds the lateral ventricles. It has a large "head" that compresses the ventricle, a smaller, rather long body and a tiny tail.
  
  
• The putamen is separated from the caudate by the internal capsule. It is the most lateral of the basal ganglia.
  
  
• The Globus Pallidus is immediately adjacent, inferior and medial to the putamen. It has two parts, the pars externa and the pars interna

• The thalamus or massa intermedia is the major sensory and motor relay nucleus. It includes medial and lateral geniculate bodies
  
  
• The hypothalamus is literally below the thalamus and controls basal functions.
  
  
• The Epithalamus consists of two structures, the Pineal and the Habenula

• The tectum is that part of the midbrain which is superior to the aqueduct. It contains the Superior and Inferior colliculi which are also called the corpora quadrigemina or quadrigeminal plate.
  
  
• The tegmentum is inferior to the aqueduct and includes the nuclei of Cranial nerves III, IV, the Red nucleus, the Substantia nigra and the Cerebral peduncle

• Cerebellum consists of the cortex, the Cerebellar Nuclei which are called Dentate,Embolliform, Globose and Fastigial. The dentate is the most lateral and fastgial is the most medial.
  
  
• The Cerebellar peduncles, Superior, Middle and Inferior connect the cerebellum to the pons.
  
  
• The pons like the midbrain has a tectum and tegmentum. The Pontine Tectum includes Cranial Nerve nuclei V,VI,VII. The Tegmentum includes the Pontine Nuclei, the Corticospinal tract and the Cerebellopontine crossing fibers

• The medulla contains the most important stuctures required to maintain cardiorespiratory function. When we say that a person is brain dead, that means that all parts of the brain except the medulla have stopped functioning. It contains Cranial Nerve nuclei VIII through XII, including the Vagus (CN X).
  
  
• The medulla also houses the descending corticospinal or pyramidal tract within the pyramids and the inferior olivary nuclei that modulate cerebellar function.

• The spinal cord connects the brain and medulla to the rest of the body. It contains 31 pairs of spinal nerves - Cervical (C1-C8); Thoracic (T1-T12); Lumbar (L1-L5); Sacral (S1-S5); Coccygeal (Cx1). Each of these spinal nerves innervates a very specific part of the body known as a Dermatome.
  
  
• The Dorsal part of the spinal cord contains the posterior columns that modulate proprioception, position and vibration sense.
  
  
• The Lateral part of the spinal cord contains the corticospinal tract which is the descending motor tract for voluntary movement. Spastic paralysis after a spinal fracture is due to injury to the corticospinal tract.
  
  
• The Ventral part of the spinal cord contains the anterior horn and the lower motor neurons.

last update September 18, 2002