| 释义 |
brain stem
brain·stem or brain stem B5462000 (brān′stĕm′)n. The portion of the brain, consisting of the medulla oblongata, pons Varolii, and midbrain, that connects the spinal cord to the forebrain and cerebrum.brain stemA stalklike part of the brain, between the cerebrum and spinal cord. It contains the midbrain, pons, and medulla oblongata.Thesaurus| Noun | 1. |  brain stem - the part of the brain continuous with the spinal cord and comprising the medulla oblongata and pons and midbrain and parts of the hypothalamusbrainstem, brain-stemneural structure - a structure that is part of the nervous systembrain, encephalon - that part of the central nervous system that includes all the higher nervous centers; enclosed within the skull; continuous with the spinal cordmedulla oblongata, medulla, bulb - lower or hindmost part of the brain; continuous with spinal cord; (`bulb' is an old term for medulla oblongata); "the medulla oblongata is the most vital part of the brain because it contains centers controlling breathing and heart functioning"pons Varolii, pons - a band of nerve fibers linking the medulla oblongata and the cerebellum with the midbrainreticular formation, RF - a complex neural network in the central core of the brainstem; monitors the state of the body and functions in such processes as arousal and sleep and attention and muscle tone |
brain stem
brain stem, lower part of the brainbrain,
the supervisory center of the nervous system in all vertebrates. It also serves as the site of emotions, memory, self-awareness, and thought. Anatomy and Function
..... Click the link for more information. , adjoining and structurally continuous with the spinal cord. The upper segment of the human brain stem, the pons, contains nerve fibers that connect the two halves of the cerebellumcerebellum
, portion of the brain that coordinates movements of voluntary (skeletal) muscles. It contains about half of the brain's neurons, but these particular nerve cells are so small that the cerebellum accounts for only 10% of the brain's total weight.
..... Click the link for more information. . It is vital in coordinating movements involving right and left sides of the body. Below the pons and continuous with the spinal cord is the medulla, which transmits ascending and descending nerve fibers between the spinal cord and the brain. The medulla also directly controls many involuntary muscular and glandular activities, including breathing, heart contraction, artery dilation, salivation, vomiting, and probably laughing. The nuclei of some of the nerves that originate in the brain are also located in the brain stem. Nerve fibers in the brain stem do not readily regenerate, hence injury may result in permanent loss of function. See also nervous systemnervous system,
network of specialized tissue that controls actions and reactions of the body and its adjustment to the environment. Virtually all members of the animal kingdom have at least a rudimentary nervous system.
..... Click the link for more information. .brain stem
stem [stem] a stalklike supporting structure; see also peduncle.brain stem brainstem.brain·stem , brain stem (brān'stem), [TA] Originally, the entire unpaired subdivision of the brain, composed of (in anterior sequence) the rhombencephalon, mesencephalon, and diencephalon as distinguished from the brain's only paired subdivision, the telencephalon. More recently, the term's connotation has undergone several arbitrary modifications: some use it to denote no more than rhombencephalon plus mesencephalon, distinguishing that complex from the prosencephalon (diencephalon plus telencephalon); others restrict it even further to refer exclusively to the rhombencephalon. From both developmental and architectural viewpoints, the original interpretation seems preferable. Synonym(s): truncus encephali [TA]brainstem The central stalk-like axis of the lower CNS, which connects the brain with the spinal cord.
Components
• Medulla oblongata;
• Pons;
• Midbrain;
• Diencephalon.
Functions
• Transmission and “lower cortical” processing of sensory neural impulses from the periphery and motor impulses to muscles and other effectors;
• Anatomic site of egress of cranial nerves 3 to 12;
• Reticular functions, integrating cardiorespiratory control, arousal and alertness, consciousness.brain·stem , brain stem (brān'stem) [TA] Originally, the entire unpaired subdivision of the brain, composed of the rhombencephalon, mesencephalon, and diencephalon as distinguished from the brain's only paired subdivision, the telencephalon. More recently, the connotation of the term has undergone several arbitrary modifications: some use it to denote no more than rhombencephalon plus mesencephalon, distinguishing that complex from the prosencephalon (diencephalon plus telencephalon); others restrict it even further to refer exclusively to the rhombencephalon. From both developmental and architectural viewpoints, the original interpretation seems preferable. brain stem that part of the brain in vertebrates which excludes the CEREBELLUM and CEREBRAL HEMISPHERES.brain·stem , brain stem (brān'stem) [TA] Originally, the entire unpaired subdivision of the brain, composed of the rhombencephalon, mesencephalon, and diencephalon as distinguished from the brain's only paired subdivision, the telencephalon. More recently, the connotation of the term has undergone several arbitrary modifications: some use it to denote no more than rhombencephalon plus mesencephalon, distinguishing that complex from the prosencephalon (diencephalon plus telencephalon); others restrict it even further to refer exclusively to the rhombencephalon. From both developmental and architectural viewpoints, the original interpretation seems preferable. AcronymsSeeb-splinebrain stem
Related to brain stem: brain stem reflexesSynonyms for brain stemnoun the part of the brain continuous with the spinal cord and comprising the medulla oblongata and pons and midbrain and parts of the hypothalamusSynonymsRelated Words- neural structure
- brain
- encephalon
- medulla oblongata
- medulla
- bulb
- pons Varolii
- pons
- reticular formation
- RF
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