Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
388 views
in Biology by (44.7k points)
closed by

Explain transmission of nerve impulse along the axon. 

OR 

Describe the conduction of a nerve impulse in the neuron.

1 Answer

+1 vote
by (48.1k points)
selected by
 
Best answer

1. Before conduction of nerve impulse, the cell membrane is in the polarized state. 

2. When a stimulus is applied at a site on the polarised membrane, the membrane at that site becomes freely permeable to Na . 

3. This leads to a rapid influx of Na followed by the reversal of the polarity at that site, i.e., the outer surface of the membrane becomes negatively charged and the inner side becomes positively charged. 

4. The polarity of the membrane at that site [site A] is thus reversed and hence depolarised. The electrical potential difference across the plasma membrane at the site of stimulation is called the action potential, which is in fact termed as a nerve impulse. 

5. At sites immediately ahead [site B], the axon membrane has a positive charge on the outer surface and a negative charge on its inner surface. As a result, a current flows on the inner surface from site A to site B.

6. On the outer surface current flows from site B to site A to complete the circuit of current flow. Hence, the polarity at the site is reversed, and an action potential is generated at site B. Thus, the impulse (action potential) generated at site A arrives at site B.

7. The sequence is repeated along the length of the axon and consequently the impulse is conducted. 

8. The rise in the stimulus-induced permeability to Na+ is extremely short-lived. It is quickly followed by a rise in permeability to K+

9. Within a fraction of a second, K+ diffuses outside the membrane and restores the resting potential of the membrane at the site of excitation and the fibre becomes once more responsive to further stimulation.

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...