Nervous system

In this article we look at general information – what the nervous system actually is, what it is for, what are the basic units and the information spreads throughout the body.

The nervous system is very important for disseminating information throughout the body.Captures impulses from organs and cells, is transported into the brain, where it is evaluated and then sends the appropriate response.

The nervous system is divided into central and peripheral NS NS. CNS includes the brain and spinal cord, PNS all other parts of the nervous system.

Neuron

Basic structural and functional unit of the neuron NS. Their nutrition and provide support to NS glial cells. Neuron consists of body (soma) and projections – the dendrites and neurites (axons). Dendrite information leading to cell axon withdraws from the cell body and conveys information in the form of impulses from nerve cells. The axons are wrapped in myelin, the packaging is important for conduction and axon protection.

Synapse

Synapses indicates where to connect two cells, of which at least one nerve. Synapse enables transmission of nerve impulses from one cell to another. One part of the synapse is the final portion of the axon of one cell and the other cell membrane nerve cell body, dendrite, axon other nerve cells. Transmission may be conducted either chemically or electrically (human little expanded view rather fish and lower animals).Synapses can affect both the cells as much as axons and dendrites and axons or dendrites only.

Excitement

The functional expression of the neuronal excitation, which is generated by changing the membrane potential in the initial section of the axon.The excitement created on the ionic nature. Change of ions either opens or closes the ion channels and thus the information transmitted. It is necessary, potassium and sodium ions. The transfer rate is dependent on the thickness (site) nerve fiber. In the end, branching nerve cells axon extends and creates presynaptic department, where pouches with a mediator. Mediators can activate or suppress the nerve cells. In the CNS, mediates the major excitatory glutamic acid and aspartic acid. Inhibitory mediator acid is gamma-aminobutyric (GABA) and glycine in the spinal cord. The activity of nerve cells can be modified drugs.

Reflex + reflective track

Reflex is the basic functional unit of the nervous system. It is the body’s response to irritation. Reflective track is divided into five basic parts:

Receptor – centripetal (afferent, centripetal) track – Centre (brain, spinal cord) – centrifugal (efferent, centrifugal) track – the executive body, effector.

dividing reflexes

According receptors:

  • exteroreceptivní – react to changes in the external environment (skin, sight, hearing, smell and taste)
  • interoreceptivní – respond to chemical and physical changes in the external environment (chemoreceptors, thermoreceptors, baroreceptors)
  • propriosensory – disseminate information on skeletal muscles and joints (Golgi tendon organ, muscle spindles)

According to the center:

  • brain
  • spinal

According effectors:

  • somatic – effector is skeletal muscle
  • Vegetative – effector smooth muscle, myocardium and glands

Under the terms drawn reflex:

  • congenital
  • obtained

Receptors

Receptors (sensors, detectors) react to changes in the external environment and internal stimuli and converted to information. Receptors are sets of cells which are extremely sensitive (adequate) to certain types of stimuli to some already less (inadequate). Some of their activities are unaware, but others do, such as sight or taste.

Splitting recipes:

  • mechanoreceptors – record changes of pressure, tension and strain
  • chemoreceptors – register changes in the chemical decomposition of oxygen, pH and carbon dioxide in the body and react to changes in chemicals in the external environment
  • thermo – accept thermal stimuli
  • radioreceptory – respond to light stimuli and electromagnetic waves. They are located in the retina.
  • Nocireceptory – react to the pain

Effectors

Effectors are powerful central nervous system and respond to information sent from the brain or spinal cord, and this information then transported to the site where the body performs.

Division:

  • somatic functions – controls the activity of skeletal muscles, we can control them
  • autonomic functions – regulates the activity of smooth muscle and cardiac muscle can not control them.

Interest at the end – nerve impulses spread to the brain and from the brain speeds up to 270 km / h.

Sicknesses of this body part:

Neuritis

Neuritis

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Multiple sclerosis

Multiple sclerosis

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Prion infection

Prion infection

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Parkinson’s disease

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Concussion

Concussion

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Polio

Polio

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Acoustic neuroma nerve

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Description neurinoma of the acoustic nerve It is a benign, usually very slowly and gradually growing tumor packaging eighth cranial nerve. The eighth cranial nerve called vestibucochlear, and he also says statoakustický. Both names reflect that nerve signals from the…

Myopathy

Myopathy

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Myasthenia gravis

Myasthenia gravis

Description myasthenia gravis Myasthenia gravis is a neuromuscular autoimmune disease. Autoimmune means that the human body produces antibodies against its own structures which are harmful. In myasthenia gravis regard specifically to antibodies against receptors for acetylcholine. Acetylcholine is a neurotransmitter,…

Cerebral hemorrhage

Cerebral hemorrhage

Description cerebral hemorrhage The brain leads a rich vascular supply. The two main arteries – the carotid artery – resign from the aorta, the blood vessels going straight from the heart. Along the cervical spine also go two vessels that…