Very Short Question and Answers - Nervous System in Animals

The main function of the nervous system in animals is to coordinate and control all body activities by transmitting signals to and from different parts of the body.

The two main parts of the nervous system are the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).

The Central Nervous System is made up of the brain and the spinal cord.

The brain is the main processing centre for the body, while the spinal cord transmits messages between the brain and the rest of the body.

The Peripheral Nervous System carries signals between the Central Nervous System and the rest of the body and consists of the somatic (voluntary actions) and autonomic (involuntary actions) systems.

A neuron is the basic structural and functional unit of the nervous system; it is a nerve cell that transmits nerve impulses.

The three main parts are: 1) Cell body (soma) – contains the nucleus and processes signals, 2) Dendrites – receive signals from other cells, and 3) Axon – carries signals away from the cell body.

Dendrites receive electrical messages from other cells and transmit them towards the cell body.

The myelin sheath is a fatty layer that covers some axons, insulating them and allowing nerve impulses to travel faster.

Sensory neurons carry signals from sense organs to the CNS, while motor neurons carry commands from the CNS to muscles or glands.

Interneurons connect sensory and motor neurons and are found within the Central Nervous System.

A synapse is a small gap between two neurons where neurotransmitters are released to transmit nerve impulses chemically from one neuron to another.

A nerve impulse travels from the dendrites, through the cell body, along the axon, to the axon terminals.

When a nerve impulse reaches the axon terminal, neurotransmitters are released into the synapse, where they bind to receptors on the next neuron, triggering a new impulse.

An action potential is a rapid change in the electrical charge across the neuron's membrane that travels along the axon as a nerve impulse.

Resting potential is the difference in electric charge across the neuronal membrane when the neuron is not transmitting a signal; the inside is negatively charged compared to the outside.

Example: A frog uses its nervous system to quickly extend its tongue and catch insects; a dog turns its head when it hears a whistle.

A reflex action is an automatic and rapid response to a stimulus, like pulling your hand away from something hot.

The somatic nervous system controls voluntary movements (e.g., moving your hand), while the autonomic system controls involuntary actions (e.g., heartbeat, digestion).

Within a neuron, nerve impulses are electrical (action potential), but between neurons at synapses, impulses are transmitted chemically using neurotransmitters.