Voluntary actions — The actions or movements that are under the control of one's own will are called voluntary actions. For example, walking, jumping, lifting books, etc. Voluntary actions are controlled by Somatic nervous system.
Involuntary actions — The actions or movements that happen without consciousness or willingness of an individual are called the involuntary action. For example, beating of heart, breathing, digestion, etc. Involuntary actions are controlled by Autonomic nervous system.
Chapter 8: Human Body: Nervous System — ICSE Class VII Biology Notes
Comprehensive ICSE Class VII Biology notes on the Human Nervous System covering brain parts (cerebrum, cerebellum, medulla), spinal cord, neuron structure, reflex action, reflex arc, and voluntary vs involuntary actions.
Key Concepts and Topics
Topics covered: Brain, Spinal cord, Neurons, Reflex action, Reflex arc
Weightage: Approximately 8 marks in the exam
Important Points to Remember
- CNS = brain + spinal cord; PNS = nerves
- Brain parts: cerebrum (thinking), cerebellum (balance), medulla (involuntary)
- Neuron: cell body + dendrites (receive) + axon (transmit)
- Reflex action: automatic response controlled by spinal cord
- Reflex arc: receptor to sensory nerve to spinal cord to motor nerve to effector
- Brain protected by skull, meninges, and cerebrospinal fluid
- Voluntary actions involve brain; reflex actions bypass brain
Frequently Asked Questions
Q: What is a reflex action?
A: A quick, automatic, involuntary response to a stimulus, controlled by the spinal cord without involving the brain.
Q: What are the three main parts of the brain?
A: Cerebrum (thinking), Cerebellum (balance), and Medulla oblongata (involuntary actions).
Q: What is a reflex arc?
A: The pathway of a reflex: Receptor → Sensory nerve → Spinal cord → Motor nerve → Effector.
Exam Preparation Tips
- Focus on understanding concepts rather than rote memorization
- Practice drawing and labelling diagrams regularly
- Use comparison tables for topics that require differentiation
- Solve previous year questions and practice papers
- Review the chapter notes provided by Bright Tutorials for comprehensive coverage
For complete chapter notes, practice questions, and test papers, contact Bright Tutorials at 9403781999.