Which part of the neuron carries information from the cell body to axon terminals?

Although the nervous system is very complex, there are only two main types of cells in nerve tissue. The actual nerve cell is the neuron. It is the "conducting" cell that transmits impulses and the structural unit of the nervous system. The other type of cell is neuroglia, or glial, cell. The word "neuroglia" means "nerve glue." These cells are nonconductive and provide a support system for the neurons. They are a special type of "connective tissue" for the nervous system.

Neurons

Neurons, or nerve cells, carry out the functions of the nervous system by conducting nerve impulses. They are highly specialized and amitotic. This means that if a neuron is destroyed, it cannot be replaced because neurons do not go through mitosis. The image below illustrates the structure of a typical neuron.

Each neuron has three basic parts: cell body (soma), one or more dendrites, and a single axon.

Cell Body

In many ways, the cell body is similar to other types of cells. It has a nucleus with at least one nucleolus and contains many of the typical cytoplasmic organelles. It lacks centrioles, however. Because centrioles function in cell division, the fact that neurons lack these organelles is consistent with the amitotic nature of the cell.

Dendrites

Dendrites and axons are cytoplasmic extensions, or processes, that project from the cell body. They are sometimes referred to as fibers. Dendrites are usually, but not always, short and branching, which increases their surface area to receive signals from other neurons. The number of dendrites on a neuron varies. They are called afferent processes because they transmit impulses to the neuron cell body. There is only one axon that projects from each cell body. It is usually elongated and because it carries impulses away from the cell body, it is called an efferent process.

Axon

An axon may have infrequent branches called axon collaterals. Axons and axon collaterals terminate in many short branches or telodendria. The distal ends of the telodendria are slightly enlarged to form synaptic bulbs. Many axons are surrounded by a segmented, white, fatty substance called myelin or the myelin sheath. Myelinated fibers make up the white matter in the CNS, while cell bodies and unmyelinated fibers make the gray matter. The unmyelinated regions between the myelin segments are called the nodes of Ranvier.

In the peripheral nervous system, the myelin is produced by Schwann cells. The cytoplasm, nucleus, and outer cell membrane of the Schwann cell form a tight covering around the myelin and around the axon itself at the nodes of Ranvier. This covering is the neurilemma, which plays an important role in the regeneration of nerve fibers. In the CNS, oligodendrocytes produce myelin, but there is no neurilemma, which is why fibers within the CNS do not regenerate.

Functionally, neurons are classified as afferent, efferent, or interneurons (association neurons) according to the direction in which they transmit impulses relative to the central nervous system. Afferent, or sensory, neurons carry impulses from peripheral sense receptors to the CNS. They usually have long dendrites and relatively short axons. Efferent, or motor, neurons transmit impulses from the CNS to effector organs such as muscles and glands. Efferent neurons usually have short dendrites and long axons. Interneurons, or association neurons, are located entirely within the CNS in which they form the connecting link between the afferent and efferent neurons. They have short dendrites and may have either a short or long axon.

Neuroglia

Neuroglia cells do not conduct nerve impulses, but instead, they support, nourish, and protect the neurons. They are far more numerous than neurons and, unlike neurons, are capable of mitosis.

Tumors

Schwannomas are benign tumors of the peripheral nervous system which commonly occur in their sporadic, solitary form in otherwise normal individuals. Rarely, individuals develop multiple schwannomas arising from one or many elements of the peripheral nervous system.

Commonly called a Morton's Neuroma, this problem is a fairly common benign nerve growth and begins when the outer coating of a nerve in your foot thickens. This thickening is caused by irritation of branches of the medial and lateral plantar nerves that results when two bones repeatedly rub together.

The nervous system is a huge ensemble consisting of two distinct classes of cells: nerve cells or neurons, and glial cells or glia.

The brain analyzes information coming from the peripheral receptors and creates perceptions some of which are stored in memory. On the basis of this information it coordinates complex patterns of muscle contractions and thus, behavior... Any cerebral process, ranging from the so called higher functions (learning, imaginery, language) to the simplest spinal reflex has the same cellular substrate: the neuron.

In its best estimate the human brain contains as many as 1011 neurons. Although there are many different types of nerve cells they share common features. The functional versatility of neurons rest mainly in a few principles that give rise to considerable complexity. Thus, it is possible to understand a great deal about the functioning of the brain by paying attention to the following general features.

GENERAL STRUCTURE

Dendrites which serve an input role. A typical neuron has several dendrites, normally arranged in an extremely branched fashion, in order to establish contacts with many other neurons.

The cell body also known as the soma which includes the nucleus and perikaryon. It is involved in the main metabolic functions of the cell.

The axon, representing the conduction component of the neuron. Every neuron has only a single axon, a thin cylindrical process that can ramify and extend up to 1m. The axon arises from a specialized region of the soma called the axon hillock where an all or none signal (the action potential) is initiated once a critical threshold is reached.

The presynaptic terminals. These are distinct structures located at the very end of an axon. Since an axon can ramify, it give rise to many presinaptic terminals. By means of its terminals one neuron transmits information about its own activity to the receiving structures (mainly dendrites) of other neurons.This transmission is achieved by releasing in the terminal a specific chemical signal: the neurotransmitter.

The point of contact between two neurons is called a synapse. The neurotransmitter is released into this synaptic space also known as the synaptic cleft. The neuron sending out information is called the presynaptic cell and, therefore, the cell receiving information is called the postsynaptic cell. Normally a presinaptic neuron terminates at the postsynaptic neuron�s dendrites but communication may take place at the cell body, or even , although less often, at the initial or terminal portions of the axon.

Morphologically, on the basis of the number of processes arising from the cell body neurons are classified into three groups: unipolar, bipolar and multipolar neurons.

See the general signaling mechanism.

Which part of the neuron carries information from the cell body to axon terminals quizlet?

What part of the neuron carries information to the cell body?

What part of the neuron carries the information from the cell body and transfers the information to the synapse?