Science 10 - nervous, endocrine and reproductive system

• The nervous system connects all body parts and transmits signals from one part to another
• The nervous system is a system of cells, tissues, and organs that regulates the body’s responses to internal and external stimuli
• Each part of the nervous system has a specific role and functions as an important part of a system
• The basic unit of the nervous system is the nerve cell, also known as a neuron
• Neurons have a cell body containing the nucleus, dendrites that carry impulses towards the cell body, and axons that carry impulses away from the cell body
• Neurons can be joined together to form organs like the brain and spinal cord
• Nerve impulses in neurons are a combination of an electrical charge and a chemical reaction
• A nerve impulse is not a flow of electricity but an electrochemical signal moving along a neuron
• When a nerve impulse comes to the end of an axon, it produces a chemical called neurotransmitter to be released
• The chemical crosses the space between neurons called synapse and stimulates the nerve impulse to start in the next dendrite
• The nervous system is assisted by five sense organs: eyes, ears, nose, tongue, and skin
• Sense organs constantly receive information from the environment and send messages to the brain
• Stimuli are factors in the environment that may trigger a nerve impulse, and responses are reactions to stimuli
• An organism must be able to respond to a stimulus in order to survive
• Messages do not travel in both directions along the same neuron, only the axon releases neurotransmitters that cross the synapse
• Reaction time is the length of time between the application of a stimulus and the detection of a response
• Nerves are bundles of nerve fibers (axons) that transmit electrical impulses throughout the body.

  
• Nerves are bundles of nerve fibers (axons) that transmit electrical impulses throughout the body.