Human Biology: Endocrine System, Reflex Arc, and Brain Functions

A comprehensive vocabulary review of the endocrine system (melatonin and cortisol), reflex arc components and pathways, central vs. peripheral nervous systems, and major brain regions and their functions based on the lecture notes.

Melatonin

A chemical messenger produced by the pineal gland that regulates the sleep-awake cycle, lowers body temperature, and manages the circadian rhythm.

Pineal Gland

The endocrine gland that releases higher levels of melatonin when it gets dark outside.

Cortisol

A hormone with an opposing function to melatonin that spikes in the morning to wake you up and provide energy.

Too Little Melatonin

A hormonal imbalance condition that leads to sleep problems and schedule disruptions during the day.

Too Much Melatonin

A hormonal imbalance condition that leads to excessive sleeping, disrupted sleep cycles, headaches, and vivid dreams.

Reflex

A rapid, automatic, and involuntary response to a stimulus that helps protect the body before damage occurs.

Stimulus

Something in the environment that causes a change or triggers a response.

Receptor

A specialized organ or sensor (such as temperature, pain, light, or stretch sensors) that detects a stimulus.

Sensory Neuron

A nerve cell that carries impulses from sensory receptors toward the Central Nervous System.

Relay Neuron

A nerve cell found in the Central Nervous System (spinal cord) that transfers impulses between sensory neurons and motor neurons.

Motor Neuron

A nerve cell that carries impulses away from the Central Nervous System to an effector.

Effector

A muscle or gland that carries out the physical response to a stimulus.

Reflex Arc

The complete pathway followed by nerve impulses from stimulus detection to physical response, bypassing conscious brain processing to save time.

Central Nervous System (CNS)

The division of the nervous system made up of the brain and spinal cord that receives and processes information.

Peripheral Nervous System (PNS)

The sensory and motor neurons outside the central nervous system that carry information to and from the CNS.

Frontal Lobe

The region of the brain responsible for decision making, planning, weighing pros and cons, and speech production.

Occipital Lobe

The region of the brain dedicated to receiving, processing, and interpreting visual information.

Cerebellum

The brain structure responsible for balance, motor speed, and fine movement coordination.

Parietal Lobe

The region of the brain that processes touch sensations and integrates sensory information.

Temporal Lobe

The region of the brain responsible for processing sound and storing memory.

Cerebrum

The large part of the brain that integrates sensory input and handles higher functions like speech and language.