Control and Coordination: Human Nervous System Flashcards

Vocabulary practice flashcards covering key terms, receptors, structural components of neurons, nerve divisions, and reflex pathways from Class 10 Biology lecture notes on Control and Coordination.

Receptors

Groups of cells present in sense organs that are sensitive to energy provided by a stimulus and convert it into an electrical impulse.

Photoreceptors

Receptors present in the eyes that detect light.

Phonoreceptors

Receptors present in the inner ears that detect sound.

Olfactory receptors

Receptors present in the nose that detect smell.

Gustatory receptors

Receptors present in the tongue that detect taste.

Thermoreceptors

Receptors present in the skin that detect heat or cold.

Stimulus

A form of energy such as light, sound, smell, taste, heat, or mechanical pressure that sets off a response in receptors.

Electrical impulse

An electrical signal (also called a nerve impulse) generated at a receptor when stimulus energy triggers a chemical reaction.

Effector

A part of the body, mainly muscles and glands, that responds to a stimulus according to instructions sent from the nervous system.

Endocrine system

A system of coordination in humans (also called the hormonal system) that works alongside the nervous system to control and coordinate body activities.

Neuron

The structural and functional unit of the nervous system and the largest cell in the body, adapted to carry electrical impulses quickly over long distances.

Cell body

The main portion of a neuron resembling a typical animal cell, containing cytoplasm and a nucleus, from which nerve fibres stretch out.

Dendrites

The shorter fibres stretching out from the cell body of a neuron that pick up nerve impulses from receptors and pass them to the cell body.

Axon

The longest fibre stretching out from the cell body of a neuron that carries nerve impulses away from the cell body toward another neuron.

Myelin

An insulating and protective sheath made of fat and protein that covers the axon of a neuron.

Sensory neurons

Neurons that transmit impulses from sensory cells or receptors toward the central nervous system (spinal cord and brain).

Motor neurons

Neurons that transmit impulses from the central nervous system (spinal cord and brain) toward muscle cells or effectors.

Relay neurons

Neurons located within the central nervous system (brain and spinal cord) that serve as links between other neurons.

Synapse

A microscopic gap between a pair of adjacent neurons over which nerve impulses pass, functioning like a one-way valve because neurotransmitters exist on only one side.

Neurotransmitter substance

A chemical substance released at the axon end of a neuron that crosses the synapse to initiate a similar electrical impulse in the dendrite of the next neuron.

Brain

The primary organ of the nervous system located inside the skull that receives, processes, and interprets messages to direct body actions.

Spinal cord

A thick nerve running inside the cavity of the backbone with its upper end attached to the brain, responsible for linking nerves and mediating simple responses.

Cranial nerves

Nerves arising directly from the brain that connect to all parts in the head.

Spinal nerves

Nerves arising from the spinal cord along most of its length that connect all remaining body parts to the spinal cord.

Visceral nerves

Special nerves that mostly arise from the spinal cord and connect internal organs to the central nervous system.

Mixed nerves

Nerves containing both sensory and motor neurons, such as spinal, cranial, and visceral nerves in the peripheral nervous system.

Central Nervous System

The primary division of the nervous system consisting of the brain and the spinal cord.

Peripheral Nervous System

The part of the nervous system made up of all nerves outside the CNS (cranial, spinal, and visceral nerves) that enter or leave the brain and spinal cord.

Voluntary nervous system

A division of the peripheral nervous system that is under conscious or voluntary control from the brain.

Autonomic nervous system

A division of the peripheral nervous system that operates automatically and involuntarily.

Reflex action

A rapid, automatic, and involuntary response to a stimulus performed without conscious thought or voluntary control by the brain.

Reflex arc

The route or pathway taken by nerve impulses during a reflex action, leading from receptor to sensory neuron, spinal cord, motor neuron, and effector.