Unit 1–3 Key Terms & Topics (Anatomy, Physiology, Cells)

Vocabulary-style flashcards covering core concepts in anatomy, physiology, cells, bonds, biomolecules, and transport.

Anatomy

The study of the structure of body parts—what they are and where they are located.

Physiology

The study of the function of body parts—what they do and how they work.

Levels of Organization

Hierarchy from atom to organism: atom, molecule, macromolecule, organelle, cell, tissue, organ, organ system, organism.

Atom

The basic unit of matter, composed of protons, neutrons, and electrons.

Molecule

A chemical group of two or more atoms held together by bonds.

Macromolecule

A large, complex molecule such as proteins, nucleic acids, carbohydrates, or lipids.

Organelle

A specialized subunit within a cell with its own function, e.g., mitochondria, nucleus.

Cell

The basic unit of life; the smallest unit capable of independent function.

Tissue

A group of similar cells that perform a specific function.

Organ

A structure composed of two or more tissues that works together to perform a function.

Organ system

A group of organs that cooperate to perform major functions.

Organism

An individual living being that can carry out all basic life processes.

Homeostasis

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

Receptor

Sensor that detects changes in the environment.

Control center

Part of a feedback loop (often the brain) that processes information and makes a decision.

Effector

Organ or cell that carries out the response in a feedback loop.

Negative feedback

A loop that reverses a change to return to normal.

Positive feedback

A loop that amplifies a change until a completing event occurs.

Water

Essential nutrient; universal solvent involved in all body processes.

Food (nutrients)

Nutrients required for energy, growth, and maintenance.

Oxygen

Gas required for cellular energy production.

Heat

Body temperature regulation; byproduct of metabolic reactions.

Pressure

Force exerted by blood flow, breathing, etc.

Metabolism

All chemical reactions occurring in the body.

Responsiveness

Ability to detect and respond to stimuli.

Movement (internal/external)

Internal circulation and external locomotion.

Growth

Increase in size or number of cells.

Reproduction

Production of new cells or organisms.

Respiration

Obtaining oxygen, using it, and releasing energy.

Digestion

Breaking down food into usable molecules.

Absorption

Movement of substances across membranes into blood or cells.

Circulation

Transport of substances within the body.

Excretion

Elimination of wastes from the body.

Intracellular fluid (ICF)

Fluid inside cells.

Extracellular fluid (ECF)

Fluid outside cells (includes plasma and interstitial fluid).

Intracellular

Within a cell.

Extracellular

Outside a cell.

Axial

Head, neck, and trunk region of the body.

Appendicular

Limb bones and their supporting girdles.

Cranial cavity

Body cavity that houses the brain.

Vertebral (Spinal) cavity

Cavity that houses the spinal cord.

Thoracic cavity

Cavity that houses the heart and lungs.

Abdominopelvic cavity

Cavity that houses abdominal and pelvic organs.

Abdominal

Contains stomach, liver, intestines, etc.

Pelvic

Contains bladder and reproductive organs.

Visceral

The membrane covering an organ.

Parietal

The membrane lining a cavity wall.

Integumentary system

Skin and associated structures; protection and barrier.

Skeletal system

Bones and joints; support and movement.

Muscular system

Muscles; movement and heat production.

Nervous system

Brain, spinal cord, nerves; communication and control.

Endocrine system

Glands that secrete hormones for regulation.

Cardiovascular system

Heart and blood vessels; transport of substances.

Lymphatic system

Immunity and fluid return to the bloodstream.

Respiratory system

Lungs and airways; gas exchange.

Digestive system

Breaks down food and absorbs nutrients.

Urinary system

Filters blood and removes wastes; maintains balance.

Reproductive system

Organs involved in producing offspring.

Anatomical position

Body standing erect, facing forward, arms at sides, palms forward.

Superior

Situated above another part; toward the head.

Inferior

Situated below another part; toward the feet.

Anterior (Ventral)

Toward the front of the body.

Posterior (Dorsal)

Toward the back of the body.

Medial

Toward the midline of the body.

Lateral

Away from the midline; toward the side.

Proximal

Closer to the trunk or point of attachment.

Distal

Farther from the trunk or point of attachment.

Sagittal plane

Divides the body into left and right parts.

Frontal (Coronal) plane

Divides the body into anterior and posterior parts.

Transverse (Horizontal) plane

Divides the body into superior and inferior parts.

Quadrants

Four: right upper, left upper, right lower, left lower.

Nine abdominal regions

Right hypochondriac, epigastric, left hypochondriac, right lumbar, umbilical, left lumbar, right iliac (inguinal), hypogastric, left iliac (inguinal).

Right hypochondriac region

Upper right region of the abdomen.

Epigastric region

Upper middle region of the abdomen.

Left hypochondriac region

Upper left region of the abdomen.

Right lumbar region

Middle right region of the abdomen.

Umbilical region

Center region around the navel.

Left lumbar region

Middle left region of the abdomen.

Right iliac (inguinal) region

Lower right region near the groin.

Hypogastric (pubic) region

Lower middle region below the navel.

Left iliac (inguinal) region

Lower left region near the groin.

Proton

Positively charged particle in the nucleus.

Neutron

Neutral particle in the nucleus; adds mass.

Electron

Negatively charged particle orbiting the nucleus.

Atomic Number

Number of protons in an atom; defines the element.

Mass Number

Total number of protons and neutrons in the nucleus.

Cation

Positively charged ion (loses electrons).

Anion

Negatively charged ion (gains electrons).

Electrolytes

Ions in solution that conduct electricity (e.g., Na+, K+, Cl-).

Organic Compounds

compounds that contain carbon and hydrogen.

Inorganic Compounds

Compounds that do not contain both carbon and hydrogen.

Isotopes

Variants of elements with different neutron numbers.

Biomolecules

Large biological molecules: carbohydrates, lipids, proteins, nucleic acids.

Carbohydrates

Sugars and starches; quick energy; water-soluble.

Lipids

Fats, oils, phospholipids, and steroids; energy storage.

Proteins

Polymers of amino acids; structural and functional roles.

Nucleic acids

DNA and RNA; store and transmit genetic information.

Carbon dioxide (CO2)

A carbon and oxygen molecule; waste gas in respiration.

pH

A measure of hydrogen ion concentration in a solution.

Neutral (pH 7)

A pH value considered neither acidic nor basic.