Class 8 Nervous System Question Answers
Fill in the blanks:
- A sense organ or receptor is an organ that receives external ……….
- Nervous tissue is composed of ……. cells or ………
- ………… is the basic unit of the nervous system.
- The main part of a neuron consists of ………… and ……………
- Neurons have protoplasmic outgrowths called …………….
- Sheathed …………. are called nerve fibers.
- …………… are the interconnections or junctions between neurons.
Answers
- Stimuli
- Nerve cells and neurons
- Neuron
- Cytoplasm and nucleus
- Dendrites
- Axons
- Synapses
Define the following terms.
- Effector –
- The term effector refers to an organ, tissue, or cell that responds to a stimulus by working or producing a substance.
- Conduction –
- The process by which information is transmitted or excited is called conduction.
- Impulse –
- An impulse is a wave of electric discharge conducted by nerves.
- Response –
- Response is a change in reaction brought about by a stimulus in an organism.
- Axon –
- A neuron’s axon is a fiber-like process that conducts impulses away from the cell body.
Answer the following questions: –
- [1] Define the nervous system.
- The Nervous System is a system of nerves and nervous organs which control, link and coordinate the activities of the different parts of the body.
- [2] Based on the type of impulse, how many types of neurons are there?
- Based on their type of impulse, neurons are classified as sensory, motor, and association neurons.
- [3] What is a nerve fiber?
- It consists of a bundle of axons enclosed within a sheath.
- [4] Which types of neurons are there?
- The sensory neurons, the motor neurons, and the interneurons.
- [5] What is the function of a neuron?
- A neuron transmits impulses throughout the body.
- [6] Neuron has how many parts?
- A neuron is composed of three parts: a cell body, an axon, and a dendrite.
