are the shortest. Each branch at the distal end of the axon terminates into a bulb like structure called synaptic knob which possesses synaptic vesicles filled with neurotransmitters . The axon transmits nerve impulses away from the cell body to an inter neural space or to a neuro-muscular junction. The neurons are divided into three types based on number of axon and dendrites they possess (Figure.
. ). . Multipolar neurons have many processes with one axon and two or more dendrites.
They are mostly interneurons. . Bipolar neurons have two processes with one axon and one dendrite. These are found in the retina of the eye, inner ear and the olfactory area of the brain.
. Unipolar neurons have a single short process and one axon. Unipolar neurons are located in the ganglia of cranial and spinal nerves. XI Std Biology-Zoology Chapter- across their axolemma for transmission of impulses.
This unequal distribution of ions establishes the membrane potential across the axolemma. The axolemma contains a variety of membrane proteins that act as ionic channels and regulates the movement of ions across the axolemma. (Shown in Table . ).
. . Transmission of Impulses The transmission of impulse involves two main phases; Resting membrane potential and Action membrane potential. Resting membrane Potential: The electrical potential difference across the plasma membrane of a resting neuron is called the resting potential during which the interior of the cell is negative due to greater efflux of K + outside the cell than .
. Generation and Conduction of Nerve Impulses This section deals with how the nerve impulses are produced and conducted in our body. Sensation felt in the sensory organs are carried by the nerve fibres in the form of electrical impulses. A nerve impulse is a series of electrical impulses, which travel along the nerve fibre.
Inner to the axolemma, the cytoplasm contains the intracellular fluid ( ICF ) with large amounts of potassium and magnesium phosphate along with negatively charged proteins and other organic molecules. The extra cellular fluid (ECF) found outside the axolemma contains large amounts of sodium chloride,