Unit 1.8 - The Nervous & Endocrine Systems

Nervous System

The body's electrochemical communication network consisting of the nerve cells of the central and peripheral nervous systems.

Sensory Neurons

Neurons that carry incoming information from the body's tissues and sensory receptors to the brain and spinal cord; also known as afferent neurons.

Motor Neurons

Neurons that carry outgoing information from the brain and spinal cord to the body's muscles and glands; also known as efferent neurons.

Interneurons

Neurons located within the brain and spinal cord that process information between sensory input and motor output.

Central Nervous System (CNS)

The part of the nervous system comprised of the neurons of the brain and spinal cord.

Cerebrospinal Fluid

A fluid that bathes the brain and spinal cord, cushioning them, flushing waste products, and carrying some chemicals.

Neural Networks

Clusters of neurons in the brain that work together to process information.

Reflex

A simple, automatic response to a sensory stimulus.

Reflex Arc

The neural pathway that involves sensory neurons, interneurons in the spinal cord, and motor neurons to produce a reflex action.

Peripheral Nervous System

The part of the nervous system that includes all the other nerves of the body outside the CNS.

Somatic Nervous System

The part of the peripheral nervous system that transmits sensory messages to the CNS and allows voluntary movement.

Autonomic Nervous System

The part of the peripheral nervous system that regulates vital, automatic functions of internal organs.

Sympathetic Nervous System

The division of the autonomic nervous system that arouses and expends energy; associated with the "fight or flight" response.

Parasympathetic Nervous System

The division of the autonomic nervous system that conserves energy and returns the body's functions to normal levels.

Homeostasis

A state of equilibrium or normalcy for the body.

Endocrine System

A communication system that secretes hormones, influencing various bodily functions such as food interest and aggression.

Melatonin

A hormone produced by the brain that helps regulate sleep and maintain circadian rhythms.

Adrenaline

A hormone released during stress that aids in the fight or flight response by enhancing breathing and blood circulation.

Pituitary Gland

The most influential gland of the endocrine system, regulating growth hormones, cortisol, and oxytocin.