Science Review: Endocrine System, Chemical Reactions, and Nervous System

Endocrine System

A network of glands that produce and release hormones into the bloodstream to regulate body functions and maintain homeostasis.

Hormones

Chemical substances produced in the body that control and regulate the activity of certain target cells or organs.

Pineal Gland

A gland located at the center of the brain that releases melatonin to help control the body's biological clock and sleep-wake cycle.

Thymus Gland

A gland located in front of the heart that releases thymosin, enabling the body to produce certain antibodies.

Adrenal Glands

Glands located on top of the kidneys that release adrenaline and cortisol to prepare the body for action during fight-or-flight responses.

Pancreas

A gland located between the kidneys that regulates blood sugar levels by releasing insulin and glucagon.

Pituitary Gland

The master gland located at the base of the brain that stimulates growth and controls the function of other endocrine glands.

Hypothalamus

A structure located at the base of the brain above the pituitary gland that maintains homeostasis and controls the pituitary gland.

Thyroid Gland

A gland located below the voice box that releases thyroxin and calcitonin to regulate body metabolism and cause calcium storage in bones.

Homeostasis

The body's ability to maintain a stable and balanced internal environment despite internal or external changes.

Negative Feedback Mechanism

A process where the body reverses a change to return its internal conditions to balance.

Positive Feedback Mechanism

A process where the body's response strengthens or increases the original stimulus until a specific event is completed.

Chemical Reaction

A process in which starting substances (reactants) are converted into new substances (products) that possess different properties.

Reactants

The starting materials present before a chemical reaction occurs.

Products

The new substances formed as a result of a chemical reaction.

Combination Reaction

A reaction where two or more substances combine to form a single product, following the general form $\text{A} + \text{B} \rightarrow \text{AB}$.

Decomposition Reaction

A reaction where a single compound breaks down into two or more