nervous system


Epineurium The structure indicated is the epineurium of a nerve. Nerves are surrounded by three layers of connective tissue: Endoneurium Perineurium Epineurium The endoneurium is a delicate layer of connective tissue which surrounds individual axons.  Collections of axons are known as nerve fascicles; the perineurium surrounds each nerve fascicle, and consists of several concentric layers. The epineurium is the outermost layer of connective tissue which encloses the whole nerve. It is composed of dense irregular connective tissue and encloses all the nerve fascicles together with any blood vessels which supply the nerve.


Thalamus The structure indicated is the thalamus. The thalamus is the largest of the structures which comprises the diencephalon. The diencephalon consists of: Epithalamus Thalamus Subthalamus Hypothalamus The thalamus essentially acts as a sort of “relay” for the brain, consisting of several nuclei with reciprocal connections to and from the cerebral cortex. It also forms important connections with the hippocampus via the mammillo-thalamic tract, and connections with the spinal cord via the spinothalamic tract which transmits peripheral information regarding pain, temperature and crude touch. The thalamus is therefore important in several functions including, sleep, wakefulness and arousal, consciousness, and sensory/motor …

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Globus Pallidus

Globus Pallidus The structure indicated is the globus pallidus. The globus pallidus is a subcortical structure located within the cerebral hemispheres, and is a major component of the basal ganglia. The basal ganglia are a group of subcortical nuclei (collection of neuronal cell bodies located within the CNS) located at the base of the forebrain. The term “basal ganglia” is a misnomer, and the name “basal nuclei” would be more appropriate, since ganglia are collections of neuronal cell bodies located within the peripheral nervous system. The basal ganglia form extensive connections with other areas of the brain and are involved …

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globus pallidus

Optic Tract

Optic Tract The structure indicated is the optic tract. The pathway of light from the retina to the occipital cortex is as follows: Retina Optic nerve Optic chiasm Optic tract Lateral geniculate body Optic radiation Occipital cortex There are two optic tracts, a right and a left optic tract. The optic tract is an extension of the optic nerve, conveying information from the optic chiasm to the lateral geniculate nucleus. The optic tracts convey information from the opposite visual field – the right optic tract will convey information from the left visual field, and vice versa. The right optic tract …

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Optic Tract