refabest.blogg.se - Cerebro medical term

Dendrites are short, thick processes which branch out of the soma in a tree like manor.

The soma (body) of the neuron contains the nucleus which acts as the cell's control centre, these contain many small neurofibrils which project from the nucleus into the.

Axons are long nerve processes which carry nerve impulses from the Soma to other neurons, they vary in length but can become almost as long as half of the human body.

Neurons are specialised cells of the nervous system, they vary greatly in appearance and length, but contain a similar structure: The nervous system can be further divided into sub-systems, all of which are composed of TheĬentral Nervous System (CNS) includes the brain and spinal cord, while Peripheral Nervous System (PNS) includes nerves connected to the spinal cord.

As opposed to the Endocrine system the Nervous system has a more or less instant effect on the body via a complex network of nerves and control centres. The complex activities of the body are controlled jointly by the Endocrine and the Nervous systems. Pressure of the cerebrospinal fluid is measured by a manometer attached to the end of the needle after it has been inserted.Contents Functions of the Nervous System About Neurons Nerves, Neuroglia, and Ganglia The Spinal Cord The Brian The Sensory Systems The Autonomic Nervous system (ANS) Roots, suffixes, and prefixes Cancer Focus Related Abbreviations and Acronyms Further Resources Functions of the Nervous System Samples of cerebrospinal fluid may be obtained by lumbar puncture, in which a hollow needle is inserted between two lumbar vertebrae (below the lower end of the spinal cord), or into the cisterna cerebellomedullaris just below the occipital bone of the skull (cisternal puncture). Information about changes in their concentrations is helpful in diagnosis of brain diseases. The major constituents of cerebrospinal fluid are water, glucose, sodium chloride, and protein. Since the cerebrospinal fluid contains nutrient substances such as glucose, proteins, and sodium chloride, and also some waste products such as urea, it is believed to play a role in metabolism. The pressure remains normal or decreases below the point of obstruction but increases above that point.Ĭell counts, bacterial smears, and cultures of samples of cerebrospinal fluid are done when an inflammatory process or infection of the meninges is suspected. Blockage of the flow of fluid in the spinal canal may result from a tumor, blood clot, or severance of the spinal cord. hydrocephalus, or excess fluid in the cranial cavity, can result from either excessive formation or poor absorption of cerebrospinal fluid. Fluid pressure may be increased by a brain tumor or by hemorrhage or infection in the cranium.

The normal cerebrospinal fluid pressure is 5 mm Hg (100 mm H 2O) when the individual is lying in a horizontal position on his side. There is a blood-cerebrospinal fluid barrier that prevents harmful substances, such as metal poisons, some pathogenic organisms, and certain drugs from passing from the capillaries into the cerebrospinal fluid. The cerebrospinal fluid aids in the protection of the brain, spinal cord, and meninges by acting as a watery cushion surrounding them to absorb the shocks to which they are exposed. The fluid is formed continuously by the choroid plexus in the ventricles, and, so that there will not be an abnormal increase in amount and pressure, it is reabsorbed into the blood by the arachnoid villi at approximately the same rate at which it is produced. Cerebrospinal fluid the fluid within the subarachnoid space, the central canal of the spinal cord, and the four ventricles of the brain.