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Brain stem

The midbrain and hindbrain (composed of the pons and the medulla) are collectively referred to as the brain stem ( [link] ). The structure emerges from the ventral surface of the forebrain as a tapering cone that connects the brain to the spinal cord. Attached to the brain stem, but considered a separate region of the adult brain, is the cerebellum. The midbrain coordinates sensory representations of the visual, auditory, and somatosensory perceptual spaces. The pons is the main connection with the cerebellum. The pons and the medulla regulate several crucial functions, including the cardiovascular and respiratory systems and rates.

The cranial nerves connect through the brain stem and provide the brain with the sensory input and motor output associated with the head and neck, including most of the special senses. The major ascending and descending pathways between the spinal cord and brain, specifically the cerebrum, pass through the brain stem.

The brain stem

This figure shows the location of the midbrain, pons and the medulla in the brain.
The brain stem comprises three regions: the midbrain, the pons, and the medulla.

Midbrain

One of the original regions of the embryonic brain, the midbrain is a small region between the thalamus and pons. It is separated into the tectum    and tegmentum    , from the Latin words for roof and floor, respectively. The cerebral aqueduct passes through the center of the midbrain, such that these regions are the roof and floor of that canal.

The tectum is composed of four bumps known as the colliculi (singular = colliculus), which means “little hill” in Latin. The inferior colliculus    is the inferior pair of these enlargements and is part of the auditory brain stem pathway. Neurons of the inferior colliculus project to the thalamus, which then sends auditory information to the cerebrum for the conscious perception of sound. The superior colliculus    is the superior pair and combines sensory information about visual space, auditory space, and somatosensory space. Activity in the superior colliculus is related to orienting the eyes to a sound or touch stimulus. If you are walking along the sidewalk on campus and you hear chirping, the superior colliculus coordinates that information with your awareness of the visual location of the tree right above you. That is the correlation of auditory and visual maps. If you suddenly feel something wet fall on your head, your superior colliculus integrates that with the auditory and visual maps and you know that the chirping bird just relieved itself on you. You want to look up to see the culprit, but do not.

The tegmentum is continuous with the gray matter of the rest of the brain stem. Throughout the midbrain, pons, and medulla, the tegmentum contains the nuclei that receive and send information through the cranial nerves, as well as regions that regulate important functions such as those of the cardiovascular and respiratory systems.

Pons

The word pons comes from the Latin word for bridge. It is visible on the anterior surface of the brain stem as the thick bundle of white matter attached to the cerebellum. The pons is the main connection between the cerebellum and the brain stem. The bridge-like white matter is only the anterior surface of the pons; the gray matter beneath that is a continuation of the tegmentum from the midbrain. Gray matter in the tegmentum region of the pons contains neurons receiving descending input from the forebrain that is sent to the cerebellum.

Questions & Answers

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Monika Reply
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
airiz
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endocrine is a system through which the secretions of cell directly poured into blood.
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environment factor that cause a cell to respond
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deference between RNA and DNA
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.DNA stands for Deoxyribonucleic Acid. The sugar portion of DNA is 2-Deoxyribose.RNA stands for Ribonucleic Acid.  The sugar portion of RNA is Ribose.2.The helix geometry of DNA is of B-Form (A or Z also present).The helix geometry of RNA is of A-Form.3.DNA is a double-stranded molecule consisting o
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DNA consists of nucleotide but RNA consists of nucleoside DNA is double standard but RNA is single standard.In DNA at the nitrogen bases adinine,guanine,cytocin and thymine is present but in case of RNA instead of thymine uracil is present.
Tanveer
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Budumari
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walker Reply
A heart is an organ in the circulatory system that pumps blood throughout the systemic regions
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Anatomy is the study of internal and external structures and the relationship among body parts. (the study of structure).
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asthma is a lungs related disorder in which there is difficulty in breathing due to some allergic factors, their is inflamation of alveoli of respiratory part of lungs.also decreases the surface area.
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Types of wandering connective tissues
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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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