Human Body System
LEVELS OF ORGANIZATION OF NERVOURS SYSTEM:
NEURONS: * STRUCTURE AND FUNCTION: Specialized cell transmitting nerve impulses; a nerve cell. Neurons have specialized projections called dendrites and axons. Dendrites bring information to the cell body and axons take information away from the cell body. Neurons communicate with each other through an electrochemical process. Information is transmitted to the receiving cell at junctions via chemical messengers called neurotransmitters. At this juncture, the neuron transmitting the information/signal is referred to as the presynaptic cell, while the cell receiving the signal is the postsynaptic cell. Glial cells, or glia, are support cells that nourish the neurons and insulate the axons, while regulating the extracellular fluid around the neurons. At the end, the axon is divided into many branches, from where the signal passing through the axon is transmitted to the next cell via a junction known as the synapse. Hence, the branch of the axon involved in this "specialized" conjugation is called a synaptic terminal.
TYPES OF NEURONS: * Neurons are the basic unit of the nervous system. All cells of the nervous system are comprised of neurons. While there are many different kinds of neurons, there are three broad categories based on function:
* Sensory neurons are sensitive to various non-neural stimuli. There are sensory neurons in the skin, muscles, joints, and organs that indicate pressure, temperature, and pain. There are more specialized neurons in the nose and tongue that are sensitive to the molecular shapes we perceive as tastes and smells. Neurons in the inner ear are sensitive to vibration, and provide us with information about sound. And the rods and cones of the retina are sensitive to light, and allow us to see. * Motor neurons are able to stimulate muscle cells throughout the body, including the muscles of the heart, diaphragm, intestines, bladder, and glands. * Interneurons are
NEURONS: * STRUCTURE AND FUNCTION: Specialized cell transmitting nerve impulses; a nerve cell. Neurons have specialized projections called dendrites and axons. Dendrites bring information to the cell body and axons take information away from the cell body. Neurons communicate with each other through an electrochemical process. Information is transmitted to the receiving cell at junctions via chemical messengers called neurotransmitters. At this juncture, the neuron transmitting the information/signal is referred to as the presynaptic cell, while the cell receiving the signal is the postsynaptic cell. Glial cells, or glia, are support cells that nourish the neurons and insulate the axons, while regulating the extracellular fluid around the neurons. At the end, the axon is divided into many branches, from where the signal passing through the axon is transmitted to the next cell via a junction known as the synapse. Hence, the branch of the axon involved in this "specialized" conjugation is called a synaptic terminal.
TYPES OF NEURONS: * Neurons are the basic unit of the nervous system. All cells of the nervous system are comprised of neurons. While there are many different kinds of neurons, there are three broad categories based on function:
* Sensory neurons are sensitive to various non-neural stimuli. There are sensory neurons in the skin, muscles, joints, and organs that indicate pressure, temperature, and pain. There are more specialized neurons in the nose and tongue that are sensitive to the molecular shapes we perceive as tastes and smells. Neurons in the inner ear are sensitive to vibration, and provide us with information about sound. And the rods and cones of the retina are sensitive to light, and allow us to see. * Motor neurons are able to stimulate muscle cells throughout the body, including the muscles of the heart, diaphragm, intestines, bladder, and glands. * Interneurons are