#1 (receive messages from other cells) #4 (the cell body, which maintains the health of the neuron) # 11 muscles contract to pull the finger from the flame. #3 (passes messages away from the cell body to other neurons, muscles, or glands) #9 Skin receptors detect the heat of the flame and generate nerve impulses. #2 (electrical signal traveling down the axon) Word Bank: A. Axon B. Terminal Branches C. Neural Impulse D. Soma E. Dendrites A. Myelin Sheath #5 (form junctions with other cells) #8 (incoming information) Sensory nerves carry the information to the spinal cord. #6 (covers the axon of some neurons and helps speed neural impulses) Kaal Brain # 10 Interneurons in the brain and spinal cord process the information. #7 (outgoing information) Spinal cord Motor neurons carry the command to withdraw the finger. Word bank: A. Motor Neuron B. Interneuron C. Sensory Information D. Muscle E. Skin Receptor
1) The essential characteristics of the nervous system is its ability to process information. The nervous system consists millions of nerve cells. The basic unit of the nervous system is known as nerve cell or neuron.
Neurons produce and transmit nerve impulses that are basic to all neurological functions. Neurons vary in sizes and forms, but all neurons have the same basic structures.
The neurons comprises of 3 basic parts, 1) Cell body, 2) an axon and 3) one or more dendrites. The soma or cell body of the neuron consists the nucleus and other structures. The soma also contains most of the cytoplasm of the neuron. The genetic information of the neuron is stored inside the nucleus. The axon emerges from the soma, usually much longer than dendrites. The point in the axon, which is nearest to the soma or cell body is known axon hillock.
Axons carry information away from the cell body to other neurons, muscles or glands.
Dendrites also emerges from the soma in a branch. Dendrites carry information from other cells towards the cell body. Neurons are one way mode of communication, which means information transmits from dendrites or the cell body towards the axon and then outwards along the structure. Neuronal communication is not done through direct contact between 2 neuron, but it is done via very small gaps, known as the synaptic cleft. The synapse is composed of a particular end foot of an axon, the synaptic cleft and the receiving part of the next neuron.
In many neurons, about half of all neurons have axons which are covered by a fat and protein substance called the myelin sheath. This covering, of myelin sheath is arranged in segments and each is interrupted or are separated by small gaps along the length of the axon. Between each segment of myelin, at a gap of 1 to 2 mm, are spaces, called nodes of Ranvier, where the axon is not insulated.
Myelinated axons carry information faster over a given distance than unmyelinated ones, this is because, nerve impulse is transmitted at a slow rate in unmyelinated axons and it give rise to a sequence of axon potentials along the entire axon.
Near the end of axons, the axon splits into several small branches. These end in round structures known as axon terminals or terminal branches. These axon terminals to not come in contact with the next neuron. This region between axon terminals of one neuron and the dendrites of the next neuron is called synapse.
Neurons generates and conduct nerve impulses which is fundamental to all neurological functions.
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