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Encyclopedia > Filum terminale

The spinal cord is a part of the vertebrate nervous system that is enclosed in and protected by the vertebral column (it passes through the spinal canal). It consists of nerve cells. The cord conveys the 31 spinal nerve pairs of the peripheral nervous system, as well as central nervous system pathways that innervate skeletal muscles. A quick (and rough) diagram of a cross section through the spinal cord, roughly at lower cervical level. ... Typical classes Petromyzontidae (lampreys) Placodermi - extinct Chondrichthyes (cartilaginous fish) Acanthodii - extinct Actinopterygii (ray-finned fish) Actinistia (coelacanths) Dipnoi (lungfish) Amphibia (amphibians) Reptilia (reptiles) Aves (birds) Mammalia (mammals) Vertebrata is a subphylum of chordates, specifically, those with backbones or spinal columns. ... The nervous system of an animal coordinates the activity of the muscles, monitors the organs, constructs and processes input from the senses, and initiates actions. ... The vertebral column seen from the side The vertebral column (backbone or spine) is a column of vertebrae situated in the dorsal aspect of the abdomen. ... The spinal canal is the space in vertebrae through which the spinal cord passes. ... Neurons (also spelled neurones or called nerve cells) are the primary cells of the nervous system. ... The term spinal nerve generally refers to the mixed spinal nerve, which is formed from the dorsal and ventral roots that come out of the spinal cord. ... The peripheral nervous system or PNS, is part of the nervous system, and consists of the nerves and neurons that reside or extend outside the central nervous system--to serve the limbs and organs, for example. ... The vertebrate central nervous system consists of the brain and spinal cord. ... Structure of a skeletal muscle Skeletal muscle is a type of striated muscle, attached to the skeleton. ...


The vertebral column consists of vertebrae described as belonging to 5 groups (called segments). These segments are (in order from top to bottom): the cervical, thoracic, and lumbar vertebrae, and the sacrum and coccyx. A diagram of a thoracic vertebra. ... In anatomy, cervical is an adjective that has two meanings: of or pertaining to the neck. ... Sacrum, pelvic surface The sacrum (os sacrum) is a large, triangular bone at the base of the vertebral column and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. ... The coccyx is formed of four fused vertebrae. ...


Embryology

In the human fetus, the spinal cord extends all the way down to the sacral vertebrae. As a person matures, the spinal cord shortens relative to the rest of the body, so at adulthood, the spinal cord only reaches down to around the level of L1 (the first, i.e. highest, lumbar vertebra), where it terminates and the cauda equina begin - this is why lumbar punctures are usually carried out on an adult at the (lower) level of L3/L4. Fetus at eight weeks A fetus (alternatively foetus or fœtus) is an unborn human offspring from the end of the 8th week of pregnancy (when the major structures have formed) until birth. ... Sacrum, pelvic surface The sacrum (os sacrum) is a large, triangular bone at the base of the vertebral column and at the upper and back part of the pelvic cavity, where it is inserted like a wedge between the two hip bones. ... Categories: Anatomy stubs | Anatomy ... The cauda equina is a structure within the lower end of the spinal column, that consists of nerve roots and rootlets from above. ... In medicine, a lumbar puncture (colloquially known as a spinal tap) is a diagnostic procedure that is done to collect a sample of cerebrospinal fluid (CSF) for biochemical, microbiological and cytological analysis. ...


Anatomy

The spinal cord originates inside the brain at the inferior end of the medulla oblongata, exiting the skull via the foramen magnum. It is wrapped in three layers of membranes, called meninges. In the anatomy of animals, the brain, or encephalon, is the supervisory center of the nervous system. ... The medulla oblongata is the lower portion of the brainstem. ... For symbolic or mythic uses of the human skull, see Skull (symbolism) A Hippopotamuss skull A skull, or cranium, is a bony structure of vertebrates which serves as the general framework for a head. ... In anatomy, the foramen magnum is the large hole in the occipital bone in the base of the skull, through which the medulla oblongata (an extension of the spinal cord) exits the skull vault. ... The meninges (singular meninx) are the system of membranes that contain the brain. ...


The spinal cord carries sensory signals and motor innervation to most of the skeletal muscles in the body. Just about every voluntary muscle in the body below the head depends on the spinal cord for control. Similarly, most cutaneous sensation below the neck is transmitted via the spinal cord. Most of the sympathetic pathways and the lower (i.e. non-vagal) parasympathetic pathways also go through the spinal cord. Senses are the physiological methods of perception. ... A motor is a device that converts energy into mechanical power, and is often synonymous with engine. ... Structure of a skeletal muscle Skeletal muscle is a type of striated muscle, attached to the skeleton. ... Structure of a skeletal muscle Skeletal muscle is a type of striated muscle, attached to the skeleton. ... The sympathetic nervous system (SNS) is one half of the autonomic nervous system; the parasympathetic nervous system (PNS) is the other. ... The vagus nerve is tenth of twelve cranial nerves and the only nerve that starts in the brainstem (somewhere in the medulla oblongata) and extends way down past the head, all the way down to the abdomen. ... The parasympathetic nervous system is one of two divisions of the autonomic nervous system. ...


A cross-section through the spinal cord reveals that there is a central canal (carrying cerebrospinal fluid - CSF) surrounded by grey matter on the inside, and this is surrounded by white matter. (This is the opposite to the brain's cerebral cortex.) A section of the cord can be divided into neat symmeterical halves by the dorsal median sulcus and ventral median fissure. The story is about the gradual possetion of an alchoholic by a grey worm that was at the bottom of a beer bottle he was guzzling. ... White matter is one of the two main solid components of the central nervous system. ... In the anatomy of animals, the brain, or encephalon, is the supervisory center of the nervous system. ... Cerebral cortex - Wikipedia, the free encyclopedia /**/ @import /skins-1. ...


The dorsal (towards the back) side of the spinal cord carries sensory information. The neurons that bring somatosensory information to the spinal cord reside in the dorsal root ganglion. Sensation from the lower body travels up the gracile tract, sensation from the upper body and arms travels up the cuneate tract, which lies lateral to the gracile tract. There is no cuneate tract in the lumbar part of the spinal cord as sensory information from the arms would not travel through this area. In anatomy and neurology, the dorsal root ganglion is a nodule on a dorsal root that contains cell bodies of afferent spinal nerve neurons. ...


Motor information (signals coming from the brain to move the muscles) travels down the ventral (close to the belly) half of the spinal cord. Motor neurons are located in the anterior (this means close to the front, in humans it means the same as ventral) horn of the grey matter. There are two main columns of neurons in the anterior horn, the medial and lateral motor columns. In vertebrates, motoneurons (also called motor neurons) are efferent neurons that originate in the spinal cord and synapse with muscle fibers to facilitate muscle contraction and with muscle spindles to modify proprioceptive sensitivity. ...


The actual cord is approxiamately cylindrical in shape, but the diameter varies at different vetebral levels. There are two enlargements, cervical and lumbar. The cervical enlargement is due to the cord segments from C3 to T1 which innervates the upper limb via the brachial plexus. The lumbar enlargement arise from segments L1 to S3 and innervates the lower limbs via the lumbar and sacral plexuses. A right circular cylinder In mathematics a cylinder is a quadric, i. ... The brachial plexus is an arrangement of nerve fibres (a plexus) running from the spine (vertebrae C5-T1), through the neck, the axilla (armpit region), and into the arm. ... In anatomy, lumbar is an adjective that means of or pertaining to the abdominal segment of the torso, between the diaphragm and the sacrum (pelvis). ...


The spinal cord proper ends at the level of L1. It terminates at a conical point known as the conus medullaris, from which a strand of connective tissue, the filum terminale extends caudally and attaches to the dorsal surface of the first cocygeal vertebra.


There is a higher proportion of white matter in the cervical (neck) part of the spinal cord. This is because information to and from the whole body (such as the feet) must pass through here. In contrast, the lumbar and sacral areas do not carry information from anywhere above them, so have less white matter. In anatomy, cervical is an adjective that has two meanings: of or pertaining to the neck. ...


Pathology


Spinal cord injury, or myelopathy, is a disturbance of the spinal cord that results in loss of sensation and mobility. ... Paraplegia is a condition where the lower half of a patients body is paralyzed and cannot move. ... Quadriplegia is caused by damage to the spinal cord at a high level (e. ... Spinal tumors are located in the spinal cord and are mostly metastases from primary cancers elsewhere (commonly breast, prostate and lung cancer). ... An uncollapsed syrinx (before surgery). ...

Nervous system

Brain - Spinal cord - Central nervous system - Peripheral nervous system - Somatic nervous system - Autonomic nervous system - Sympathetic nervous system - Parasympathetic nervous system The nervous system of an animal coordinates the activity of the muscles, monitors the organs, constructs and processes input from the senses, and initiates actions. ... In the anatomy of animals, the brain, or encephalon, is the supervisory center of the nervous system. ... The vertebrate central nervous system consists of the brain and spinal cord. ... The peripheral nervous system or PNS, is part of the nervous system, and consists of the nerves and neurons that reside or extend outside the central nervous system--to serve the limbs and organs, for example. ... The somatic nervous system is that part of the peripheral nervous system associated with the voluntary control of body movements through the action of skeletal muscles. ... // Anatomy and Physiology of the A.N.S. In contrast to the voluntary nervous system, the involuntary or autonomic nervous system is responsible for homeostasis, maintaining a relatively constant internal environment by controlling such involuntary functions as digestion, respiration, perspiration, and metabolism, and by modulating blood pressure. ... The sympathetic nervous system (SNS) is one half of the autonomic nervous system; the parasympathetic nervous system (PNS) is the other. ... The parasympathetic nervous system is one of two divisions of the autonomic nervous system. ...


  Results from FactBites:
 
IX. Neurology. 3. The Spinal Cord or Medulla Spinalis. Gray, Henry. 1918. Anatomy of the Human Body. (6259 words)
Above, it is continuous with the brain; below, it ends in a conical extremity, the conus medullaris, from the apex of which a delicate filament, the filum terminale, descends as far as the first segment of the coccyx (Fig.
The filum terminale consists mainly of fibrous tissue, continuous above with that of the pia mater.
The posterior gray commissure reaches from the central canal to the posterior median septum, and is thinnest in the thoracic region, and thickest in the conus medullaris.
Deep Back & Spinal Cord - Dissector Answers (2336 words)
This is tough, pierced by spinal nerves, and anchored inferiorly to coccyx by the filum terminale (internum).
Filum terminale: continuation of the pia mater inferior to the conus medullaris.
The filum terminale extends inferiorly from the conus medularis, as part of the cauda equina in the lumbar cistern, to become enclosed within the coccygeal ligament.
  More results at FactBites »

 
 

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