Question

Differentiate between sympathetic and parasympathetic nervous system with reference to the following:
a. Pre and post ganglionic nerve fibres.

Hint:

The sympathetic system prepares the body for 'fight or flight' by increasing heart rate, whereas the parasympathetic system promotes 'rest and digest' by decreasing heart rate.

Answer 1

Step 1: Understanding the Nervous Systems.
The sympathetic and parasympathetic nervous systems are part of the autonomic nervous system, which controls involuntary functions. Both systems have pre- and post-ganglionic fibres that transmit signals from the central nervous system to various organs.
- Sympathetic Nervous System: The pre-ganglionic fibres are short, and the post-ganglionic fibres are long. The ganglia are located near the spinal cord.
- Parasympathetic Nervous System: The pre-ganglionic fibres are long, and the post-ganglionic fibres are short. The ganglia are located near or within the target organs.
Step 2: Conclusion.
The main difference lies in the length of the pre- and post-ganglionic fibres and the location of the ganglia. The sympathetic system has short pre-ganglionic and long post-ganglionic fibres, whereas the parasympathetic system has long pre-ganglionic and short post-ganglionic fibres.
b. Effect on heart beat.
Solution:
Step 1: Effect on Heartbeat.
The sympathetic and parasympathetic nervous systems have opposite effects on the heart.
- Sympathetic Nervous System: It increases the heart rate by releasing norepinephrine, which stimulates the heart.
- Parasympathetic Nervous System: It decreases the heart rate by releasing acetylcholine, which slows down the heart.
Step 2: Conclusion.
The sympathetic nervous system increases heart rate, while the parasympathetic nervous system decreases heart rate.