NERVOUS TISSUE

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Nervous Tissue Definition

Nervous tissue is the term for groups of organized cells in the nervous system, which is the organ system that controls the body’s movements, sends and carries signals to and from the different parts of the body, and has a role in controlling bodily functions such as digestion. Nervous tissue is grouped into two main categories: neurons and neuroglia. Neurons, or nerves, transmit electrical impulses, while neuroglia do not; neuroglia have many other functions including supporting and protecting neurons.
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Function of Nervous Tissue

Nervous tissue makes up the nervous system.If you want to know more about the nervous system click here.

Types of Nervous Tissue

Neurons

Neurons are cells that can transmit signals called nerve impulses, or action potentials. An action potential is a quick rise and fall in the electrical membrane potential of the neuron, which transmits signals from one neuron to the next. These are the different types of neurons:
    • Sensory, or afferent neurons, relay information from the PNS to the CNS; different types of sensory neurons can detect temperature, pressure, and light.

    • Motor, or efferent neurons, send signals from the CNS to the PNS; these signals provide information to sensory neurons to “tell” them what to do (e.g., initiate muscle movement).

    • Interneurons connect sensory and motor neurons to the brain and spinal cord; they act as connectors to form neural circuits and are involved with reflex actions and higher brain functions like decision-making.
While neurons can be specialized and look very different from one another, they each have components in common. Each neuron has a soma, or cell body, that contains the nucleus. Dendrites, finger-like projections that receive nerve impulses, branch off from the soma. The axon is a larger projection that branches off from the soma. Nerve impulses travel along the axon in the form of an action potential. The axon splits into axon terminals, which branch off to other neurons. Neurotransmitters are released from the ends of the axon terminals, and these travel across the synaptic cleft to reach receptors on the dendrites of other neurons. In this way, neurons communicate with each other and can send signals that reach many other neurons.
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Neuroglia

Imagen relacionadaNeuroglia, or glial cells, are cells that support neurons, supply them with nutrients, and get rid of dead cells and pathogens such as bacteria. They also form insulation between neurons so that electrical signals do not get crossed, and can also aid the formation of synaptic connections between neurons. There are several types of neuroglia such the Schwann cells or the astroglial cells.

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