Question

Label the parts of a neuron in Figure 13.2 Exercise 1: Neuron Structure AXON Node of Ranvier Dendites -2 Niss/ bodies RAxo dendritic -Blinapon sapete Gunction) - Axonic Angrening mydin hilock schwann.cell Yxonic timmar Figure 13.2: Neuron model. Neurons may be classified according to their differences in structure or in function. Functionally, there are three types of neurons. A change in the environment, such as a change in temperature or pressure against the skin, is detected by receptors associated with the dendrites of sensory (afferent) neurons. The sensory neuron carries the information of this change in the form of an action poten- tial to the CNS. Within the CNS, the impulse is passed to an interneuron (association neuron). which carries the impulse to other interneurons for integration. The response to the information begins when an interneuron passes the impulse to a motor (efferent) neuron, which carries it away from the CNS to terminate at an effector, such as a muscle cell or a gland. Structurally, neurons are distinguishable by the number of processes they may contain; there are three recognized types (see Figure 13.3). Multipolar neurons, such as motor neurons and interneu- rons, have numerous processes, including a single axon and many dendrites. A neuron with two processes – one axon and one dendrite on either side of the cell body – is called a bipolar neuron. Bipolar neurons are found in organs of special sense, such as the retina of the eye and olfactory cells of the nose. A neuron with just one process, the axon, is known as a unipolar neuron. Unipolar sensory neurons form part of peripheral nerves.

Answer 1

Ans Labeling of Neuson Structure Axon >7. Node of Ranvier Myelin sheath Schwann cell >9. Dendeutes Nissl bodies , Nissel granules 3. Axon terminal or terminal button 94. Synapse or Axodendritic synapse junction) Axon hilock S.

Dendrites: The first two neuronal functions, receiving and processing incoming information, generally take place in the dendrites and cell body.

Axon: it arises from the cell body at a specialized area called the axon hillock. Many axons are covered with a special insulating substance called myelin, which helps them convey the nerve impulse rapidly.

At its end end, the axon splits up into many branches and develops bulbous swellings known as axon terminals (or nerve terminals). These axon terminals make connections on target cells.

Neuron-to-neuron connections are made onto the dendrites and cell bodies of other neurons. These connections, known as synapses, are the sites at which information is carried from the first neuron, the presynaptic neuron, to the target neuron (the postsynaptic neuron). The synaptic connections between neurons and skeletal muscle cells are generally called neuromuscular junctions.