The Nervous System and The Endocrine System

Central Nervous System (CNS)

The part of the nervous system composed of the brain and spinal cord, responsible for processing information.

Peripheral Nervous System (PNS)

The system of nerves that carries messages to and from the CNS from other parts of the body.

Sensory Neurons

Neurons that carry impulses from sensory receptors to the CNS.

Interneurons

Neurons that relay impulses within the CNS.

Motor Neurons

Neurons that carry impulses from the CNS to effectors.

Afferent

Refers to pathways that carry information toward the CNS.

Efferent

Refers to pathways that carry information away from the CNS.

Endocrine System

A system that releases hormones into the bloodstream, overseeing processes like metabolism and homeostasis.

Hormone

A chemical produced by a gland that has a biological effect on target organs.

Target Organs

Organs that are acted upon by hormones.

Pituitary Gland

The 'Master Gland' located at the base of the brain that regulates metabolism and stress.

Pineal Gland

A gland that produces melatonin, regulating sleep-wake cycles and circadian rhythms.

Thyroid

A gland that produces hormones T3 and T4, including Thyroxine and Triiodothyronine.

Adrenal Glands

Glands atop each kidney that produce cortisol, aldosterone, and adrenaline.

Homeostasis

The maintenance of a constant internal balance within the body.

Thermoregulation

The process by which the body maintains its temperature within a normal range.

Vasodilation

The widening of blood vessels, which increases blood flow to the skin, often seen when the body is hot.

Vasoconstriction

The narrowing of blood vessels, which decreases blood flow to the skin, often seen when the body is cold.