Nervous System Basics Quiz

Living Things and Their Environment - Unit III: Body Regulation

• This unit focuses on body regulation, specifically homeostasis.
• The lesson competencies include understanding homeostasis, the roles of the nervous and endocrine systems in maintaining it, and common disorders associated with these systems.

Nervous System - Lesson 8.1

• The nervous system acts as the body's control, regulatory, and communication center, responsible for thought, learning, and memory.
• It works alongside the endocrine system to maintain homeostasis.

Stimulus-Response Coordination

• A stimulus is anything that prompts a response from the body.
• Every stimulus requires a body response.
• Homeostasis is the body's ability to maintain a stable internal environment through adjustments.

Homeostasis

• Homeostasis uses internal control systems to maintain a stable internal environment.
• It involves a receptor, control center, and effector.

Nervous System Components

• Neurons: Specialized cells that transmit electrical and chemical signals throughout the body. They form the fundamental units of the nervous system.
• Dendrites: Branch-like extensions of a neuron that receive signals.
• Cell body (soma): The central part of the neuron.
• Axon: A long, slender fiber that transmits signals away from the cell body.
• Myelin sheath: Fatty insulation around the axon that speeds signal transmission.
• Axon terminals: The end of the axon that transmits signals to other neurons, muscles, or glands.

Classes of Neurons

• Sensory neurons: Receive information from the body's internal and external environment and transmit it to the central nervous system (CNS).
• Motor neurons: Convey commands from the CNS to muscles, organs, and glands.
• Interneurons: Connect sensory and motor neurons within the CNS; they process information.

Synapses

• Synapses are junctions between neurons.
• Electrical Synapses: Direct electrical connection between neurons.
• Chemical Synapses: Information transfer via chemical messengers (neurotransmitters).

Neurotransmitters

• Neurotransmitters are chemical messengers that carry signals across synapses.
• Key neurotransmitters and their functions include serotonin (mood, memory), acetylcholine (muscle action), dopamine (message transmission), norepinephrine (arousal), endorphins (pain reduction).

Reflex Actions

• Reflex actions are automatic, involuntary, rapid responses to stimuli, protecting the body from harm.
• They involve neural pathways called reflex arcs.

Divisions of the Nervous System

• CNS (Central Nervous System): The brain and spinal cord; the control center for the body.
• PNS (Peripheral Nervous System): The network of nerves that extend throughout the body; relays messages to/from the CNS.
• Somatic Nervous System: Controls voluntary muscle movement.
• Autonomic Nervous System: Regulates involuntary bodily functions (e.g., heart rate, digestion).
• Sympathetic Nervous System: Prepares the body for action ("fight-or-flight" response).
• Parasympathetic Nervous System: Calms the body and promotes rest and digestion.

Brain and Spinal Cord

• Brain: Complex organ controlling thought, behavior, and body functions.
• Spinal Cord: Tube-like structure connecting the brain to the rest of the body, relaying messages.

Major Parts of the Brain

• The forebrain, midbrain, and hindbrain are the three primary parts of the brain. Each of these has numerous anatomical subdivisions with specialized functions.

Peripheral Nervous System (PNS)

• The PNS is the network of nerves that connect the CNS to the rest of the body.
• It relays information to and from the CNS.