Question

From rostral to caudal order, name the structures and junctions that make up the brainstem.

Answer 1

Brain stem includes all the structures arising from the rhombencephalon and mesencephalon, except for cerebellum. These structures are the medulla, pons and midbrain.
Brain stem emerges from the forebrain’s ventral surface which connects spinal cord and brain. Midbrain is responsible for the coordination of sensory representations of the auditory, visual and somatosensory perceptual spaces. Medulla is not the main input to the cerebellum.The midbrain has a stratified structure comprising various layers including the tectum, tegmentum and cerebral peduncle. These structures are found in a dorsoventral sequence. The tectum lies dorsally to the cerebral aqueduct and it has four major rounded surface swellings; colliculi.The tegmentum is the core of the midbrain and a large proportion of it is made up by the reticular formation.The major cranial nerve nuclei within the midbrain are the mesencephalic nuclei of the trigeminal nerves (V), the trochlear nuclei (IV), the principle and parasympathetic oculomotor nuclei (Cranial Nerve III), the 'red nuclei' (so named due to its pronounced vascularity) and the periaqueductal gray nuclei. Cerebral aqueduct,caudal colliculi,rostral colliculi,substania nigra,crura cerebri these are the parts of midbrain.This includes the corticospinal tract (motor), the dorsal column-medial lemniscus pathway (fine touch, vibration sensation, and proprioception), and the spinothalamic tract (pain, temperature, itch, and crude touch).The pons lies between the medulla oblongata and the midbrain. It contains tracts that carry signals from the cerebrum to the medulla and to the cerebellum and also tracts that carry sensory signals to the thalamus.The medulla oblongata often just referred to as the medulla, is the lower half of the brainstem continuous with the spinal cord.the rootlets for CN IX (glossopharyngeal), CN X (vagus) and CN XI (accessory nerve).CN VI (abducens nerve), CN VII (facial nerve) and CN VIII (vestibulocochlear nerve)Cranial nerve III (the oculomotor nerve),CN IV (the trochlear nerve) emerges out from the dorsal aspect of midbrain.