Nervous Tissue – Long Answer Questions
Medium Level (Application & Explanation)
Q1. Explain how the structure of a neuron helps it transmit impulses.
Answer:
- A neuron has a cell body, dendrites, and an axon.
- The cell body has the nucleus and organelles. It keeps the neuron alive.
- Dendrites are branch-like. They receive signals from other neurons.
- The axon is long. It carries impulses away from the cell body.
- The design gives a one-way flow of information. From dendrites to axon.
- This shape helps in fast and directed communication in the body.
- So, structure supports the function of signal transmission.
Q2. Differentiate between neurons and glial cells. Explain why glial cells are important.
Answer:
- Neurons are the functional units that transmit impulses.
- Glial cells (neuroglia) are the support cells. They protect and nourish neurons.
- Neurons handle information. Glial cells handle care and maintenance.
- Glial cells outnumber neurons in the brain. They are very essential.
- They keep the environment stable for neurons to work well.
- They help with nutrition, clean-up, and protection of neurons.
- Without glial cells, neural communication would fail.
Q3. Describe how impulses travel within a neuron and between neurons.
Answer:
- Within a neuron, signals are electrical. They are called action potentials.
- The impulse starts at dendrites, moves through the cell body, and goes down the axon.
- At the end of the axon, there is a synapse.
- Across the synapse, the signal becomes chemical.
- Neurotransmitters carry the message to the next cell.
- The next neuron then creates a new action potential.
- Thus, signals move by electrical and then chemical steps.
Q4. Explain the roles of the CNS and PNS. How do they work together?
Answer:
- The CNS includes the brain and spinal cord. It processes information.
- The PNS includes nerves that connect the CNS to organs and limbs.
- The PNS brings sensory signals to the CNS.
- The CNS makes a decision and sends motor signals back through the PNS.
- Together, they coordinate responses in the whole body.
- This teamwork allows smooth communication and control.
- It helps in both voluntary and involuntary actions.
Q5. Why is nervous tissue vital for voluntary and involuntary actions and for homeostasis?
Answer:
- Nervous tissue carries messages quickly across the body.
- It controls voluntary actions like walking and writing.
- It controls involuntary actions like heartbeat and breathing.
- It helps the body sense changes and respond at once.
- It keeps the internal environment balanced. This is homeostasis.
- Without it, the body cannot coordinate or adjust properly.
- So, it is essential for daily life and survival.
High Complexity (Analysis & Scenario-Based)
Q6. You touch a hot pan and pull your hand back quickly. Using CNS, PNS, neurons, and synapse, explain what happens.
Answer:
- Sensory neurons in the PNS detect the heat and pain.
- They send impulses to the spinal cord and brain in the CNS.
- In the CNS, neurons process the signal and decide to act.
- Signals go to motor neurons in the PNS.
- These motor neurons tell your muscles to pull back the hand.
- Messages pass across synapses using neurotransmitters.
- The quick flow shows the fast communication of nervous tissue.
Q7. A student suffers an injury that cuts some axons in a nerve. Predict the effects and explain why.
Answer:
- The axon carries impulses away from the cell body.
- If axons are cut, signals cannot reach the next cells.
- This leads to loss of function in the area served by that nerve.
- Movements may be weak or absent. Sensations may be reduced.
- Glial cells may try to support and protect, but limits remain.
- The main reason is the break in communication along the axon.
- So, the body part does not get the needed messages.
Q8. A chemical blocks the release of neurotransmitters at synapses. Analyze the impact on body functions.
Answer:
- Neurotransmitters are needed to cross the synapse.
- If they are blocked, the signal stops between neurons.
- Action potentials in the first neuron cannot trigger the next neuron.
- Muscle control may weaken, and sensations may drop.
- Both voluntary and involuntary actions can be affected.
- Thinking, reflexes, and coordination can become slow or fail.
- This shows how vital chemical signaling is for life.
Q9. A person has a spinal cord injury and cannot move their legs. Explain this using CNS-PNS communication.
Answer:
- The spinal cord is part of the CNS. It carries many signals.
- The PNS connects the CNS to the limbs, including the legs.
- Injury can block signals going from the brain to the leg muscles.
- It can also block sensory signals coming up from the legs.
- So, motor control is lost and sensation may reduce.
- This is due to damage breaking the communication pathway.
- The result is a loss of function below the injury level.
Q10. The brain can generate about 20 watts of power when awake. What does this tell you about nervous tissue activity?
Answer:
- It shows very high activity of neurons and synapses.
- Many action potentials are firing every second.
- Many synapses are using neurotransmitters at once.
- Glial cells must work hard to nourish and support neurons.
- Constant power use shows continuous communication and control.
- If energy is low, brain functions can slow or fail.
- So, nervous tissue needs steady support to keep working.