Test: Nervous System - Class 8 MCQ

The nervous system is essential for controlling both voluntary actions, such as walking and talking, and involuntary actions, like breathing and heartbeat. It acts as a communication system, sending messages between different parts of the body to coordinate activities effectively.

Dendrites are the branched structures of a neuron that receive signals from other neurons. They play a crucial role in transmitting information to the cyton for processing.

Reflex actions can occur without conscious thought, allowing for rapid responses to stimuli. This is particularly important for protective responses, such as pulling away from a hot object.

The peripheral nervous system connects the central nervous system (CNS) to limbs and organs. It plays a critical role in transmitting sensory information to the CNS and carrying motor commands from the CNS to the body.

Blinking is a natural reflex that occurs without prior learning or experience. It serves a protective function for the eyes, demonstrating the body's innate ability to respond to stimuli.

In a reflex action, the withdrawal of the hand from a hot object occurs immediately through the spinal cord without the brain's involvement, providing a quick protective response to prevent further injury.

Sensory nerves specifically carry impulses from sensory organs (like the eyes and ears) to the brain or spinal cord, allowing us to perceive our environment. This is crucial for processing information and reacting to stimuli.

Nervous coordination is managed by the nervous system, which uses electrical impulses to send signals throughout the body, facilitating rapid responses to various stimuli.

Chemical coordination is managed by hormones, which serve as chemical messengers in the body. They play vital roles in regulating various physiological processes, such as stress response and metabolism.

Neurons are the fundamental units of the nervous system responsible for processing and transmitting information through electrical impulses. They connect various parts of the body and are crucial for all nervous system functions.

A stimulus is any change in the environment that triggers a response from the body, such as a loud noise prompting a reaction. Understanding stimuli is fundamental to the study of how organisms interact with their surroundings.

Neurons consist of a cyton (cell body) and an axon. The cyton contains the nucleus and organelles, while the axon transmits impulses away from the cell body to other neurons or muscles.

The autonomic nervous system regulates involuntary functions such as heart rate, digestion, and respiratory rate, operating without conscious control and maintaining homeostasis in the body.

The sympathetic nervous system prepares the body for 'fight or flight' responses during stress. It increases heart rate and constricts blood vessels, which helps redirect blood flow to essential muscles.

The cerebrum contains the cell bodies of neurons in its outer layer, known as grey matter. This area is responsible for higher brain functions, including thought, memory, and sensory processing.

The cerebellum is specifically responsible for coordinating voluntary movements and maintaining balance. It receives information from the sensory systems and other parts of the brain to fine-tune motor activity.

The spinal cord plays a crucial role in managing reflex actions below the neck and transmitting sensory information to the brain while carrying motor commands from the brain to the body.

Mixed nerves contain both sensory and motor fibers, allowing them to transmit signals in both directions—bringing sensory input to the brain and sending motor commands to muscles.

Receptors are specialized structures that detect stimuli from the environment, such as light, sound, or temperature. They play a vital role in the sensory input to the nervous system.

The medulla oblongata controls autonomic functions such as reflex actions below the neck, including coughing and sneezing. It acts as a critical pathway for transmitting signals between the brain and the body.