IB Biology Topic C3.1: Integration of Body Systems Key Definitions

Acetylcholine is a neurotransmitter found in many types of synapses, including neuromuscular junctions (where nerves connect to muscles).

Small glands located above the kidneys responsible for producing hormones, including epinephrine.

Auxin is a phytohormone that regulates growth by promoting cell elongation.

The central organ of the nervous system, responsible for processing sensory information, coordinating responses, and controlling various bodily functions.

The part of the brain responsible for coordinating voluntary muscle movements, balance, and motor control.

The cerebral hemispheres are the largest part of the brain, responsible for higher-order functions like decision-making, memory, and voluntary movement.

The 24-hour biological cycle that regulates physiological processes, including sleep.

Emergent properties arise when the interactions between subsystems create capabilities that individual parts cannot achieve alone.

The enteric nervous system, often called the “second brain,” responsible for controlling involuntary muscle contractions in the digestive tract.

A hormone and neurotransmitter, also known as adrenaline, produced by the adrenal glands that prepares the body for "fight or flight" responses during stress or excitement.

A region of the brain responsible for regulating many physiological processes, including the endocrine system. It sends signals to the pituitary gland to release hormones.

An IUPAC name is a name given to a chemical compound by the International Union of Pure and Applied Chemistry (IUPAC). IUPAC is an international organization that develops and maintains a standardized system for naming chemical compounds.

Part of the brainstem responsible for regulating involuntary functions, including heart rate, blood pressure, and respiration.

A hormone secreted by the pineal gland that regulates sleep-wake cycles.

Motor neurons are the messengers that carry instructions from the brain to the muscles.

A bundle of axons that transmits electrical signals between the CNS and the body.

Peristalsis is a wave-like contraction of smooth muscles that pushes food through the digestive tract.

pH is a measure of how acidic or basic a solution is, ranging from 0 (very acidic) to 14 (very basic).

Phototropism is the growth response of a plant towards or away from light.

Phytohormones are signalling chemicals that regulate growth, development, and responses to environmental stimuli in plants.

A small gland at the base of the brain divided into anterior and posterior parts; it secretes hormones that control other endocrine glands.

Positive feedback is a process where the end product of a reaction amplifies or enhances the initial stimulus, creating a self-reinforcing cycle.

A pathway followed by nerve impulses during a reflex action, including the sensory and motor neurons and sometimes an interneuron.

A neural pathway that allows a rapid, automatic response to a stimulus without brain involvement.