In: Anatomy and Physiology
What is the brain stem? What structures comprise this region of the CNS? Describe each region anatomically, as well as how each of the structures within the brains stem communicate with the rest of the body. Describe 3 pathways and their components that communicate through the brain stem.
Brain stem is seen in the posterior side of the brain. It looks like a stem that is attached to the brain and is closely associated with the spinal cord. The parts are mid brain, pons and medulla oblongata.
Midbrain is also known as mesencephalon. It's located in the top portion of the brain stem. It is situated between the forebrain and hindbrain. Midbrain is small comparing hind brain and forebrain. Midbrain is linked with motor movements, controls movement of eye, auditory and visual processing. It is formed by cerebral penduncle, corpora quadrigemina, cerebral aqueduct
Pons is located in the brain stem superior to medulla oblongata and inferior to the midbrain. It can be considered as the part of hind brain. It controls the vital functions. It has the nuclei of some cranial nerves and also act a control centre.
Medulla oblongata is the inferior most part of the brain stem. Spinal cord starts after this region as a continuation. It's a cone shaped region and it controls the autonomic functions in the body.
The descending pathway from the brain starts from the mid brain which progress through the spinal cord to the pain fibres.
The motor pathways pass through the pins region connecting cerebrum and cerebellum.
Sympathetic and parasympathetic pathway. This pathways starts from the medulla of the brain stem. The nuclei of medulla propagated the signal through different spinal nerves and reach the effector organs. Sympathetic system dilatea pupil, decrease salivary secretion, increase heart rate etc. The parasympathetic system works opposite to the sympathetic system.