Glossary
Afferent nerve fibers
Sensory nerve fibers that transmit signals from sensory receptors in the body towards the central nervous system for processing.
Example:
When you feel the warmth of the sun on your skin, Afferent nerve fibers are carrying that sensation to your brain.
Autonomic Nervous System (ANS)
A division of the PNS that regulates involuntary bodily functions such as heart rate, digestion, respiration, and pupil dilation.
Example:
Your Autonomic Nervous System is responsible for making your stomach growl when you're hungry, without you consciously telling it to.
Brain
The primary organ of the CNS, responsible for processing sensory information, controlling movement, thought, emotion, and memory.
Example:
Your Brain allows you to remember your best friend's birthday and feel excited about it.
Central Nervous System (CNS)
Composed of the brain and spinal cord, it acts as the command center, processing information and sending out commands.
Example:
Your Central Nervous System is actively working when you solve a complex math problem or decide what to eat for lunch.
Efferent nerve fibers
Motor nerve fibers that transmit signals from the central nervous system to muscles and glands, initiating responses and behaviors.
Example:
When your brain decides to kick a soccer ball, Efferent nerve fibers carry the command to your leg muscles.
Fight or Flight response
A physiological reaction triggered by the sympathetic nervous system in response to perceived threats, preparing the body for immediate action.
Example:
When a deer sees a predator, its Fight or Flight response causes its heart rate to increase and muscles to tense, preparing it to run.
Ganglia
Clusters of nerve cell bodies located outside the central nervous system, serving as relay stations for nerve signals.
Example:
Sensory Ganglia near the spinal cord help process touch information before it reaches the brain.
Homeostasis
The body's tendency to maintain a stable internal environment, regulated by the autonomic nervous system's opposing divisions.
Example:
Your body's ability to maintain a consistent internal temperature, even when the outside temperature changes, is an example of Homeostasis.
Nerves
Bundles of nerve fibers (axons) that transmit electrical impulses throughout the body, forming pathways for communication.
Example:
When you stub your toe, Nerves in your foot send pain signals all the way up to your brain.
Nervous System
The body's complex communication network that transmits signals between different parts of the body, enabling coordination and response.
Example:
When you touch a hot stove, your Nervous System quickly sends a signal to your brain, telling you to pull your hand away.
Parasympathetic Division
A subdivision of the ANS responsible for 'rest and digest' functions, conserving energy and promoting calm by slowing heart rate and increasing digestion.
Example:
After a big meal, your Parasympathetic Division kicks in, making you feel relaxed and sleepy as your body focuses on digestion.
Peripheral Nervous System (PNS)
Consists of all the nerves and ganglia outside the brain and spinal cord, relaying signals between the CNS and the rest of the body.
Example:
The Peripheral Nervous System allows you to feel the texture of your shirt or move your fingers to type.
Rest and Digest functions
Physiological processes promoted by the parasympathetic nervous system that conserve energy, slow heart rate, and aid in digestion during relaxed states.
Example:
After a relaxing yoga session, your body engages in Rest and Digest functions, promoting calm and efficient digestion.
Somatic Nervous System (SNS)
A division of the PNS that controls voluntary movements of skeletal muscles and transmits sensory information from the body to the CNS.
Example:
When you decide to pick up a pen and write, your Somatic Nervous System sends the signals to your hand muscles.
Spinal Cord
A long, thin, tubular bundle of nerves that extends from the brainstem, serving as a major pathway for information between the brain and the body.
Example:
A reflex action, like quickly pulling your hand away from a sharp object, is often processed directly by your Spinal Cord before the signal even reaches your brain.
Sympathetic Division
A subdivision of the ANS that triggers the 'fight or flight' response, preparing the body for action in stressful or emergency situations.
Example:
When you hear a sudden, loud noise, your Sympathetic Division causes your heart to pound and your breathing to quicken.