Organizational Hierarchy: Cells, Tissues, Organs, and Body Compartments AG 25th

Vocabulary flashcards covering key terms related to the organization of the human body, cells, tissues, organs, and body fluids.

Atom

The basic unit of matter; the smallest unit of an element that retains its properties.

Molecule

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

Macromolecule

A very large molecule formed by polymerization of smaller units (e.g., proteins, nucleic acids).

Organelle

A specialized subcellular structure that performs a specific function inside a cell.

Cell

The basic unit of life; the smallest unit that can carry out life processes.

Tissue

A group of similar cells and their surrounding extracellular matrix that perform a common function.

Organ

A structure composed of two or more tissues that performs a specific function.

System

A group of organs that work together to perform a broad physiological function.

Organism

A living individual composed of organ systems functioning together.

Vacuoles

Membrane-bound sacs inside cells used for storage and transport.

Ribosome

Small particles that synthesize proteins by translating mRNA.

Mitochondria

Organelles that produce energy (ATP) for the cell through cellular respiration.

Microvilli

Tiny projections on cell surfaces that increase surface area for absorption.

Centrioles

Cell structures that organize spindle fibers during cell division in many animal cells.

Rough endoplasmic reticulum

Endoplasmic reticulum studded with ribosomes; site of protein synthesis.

Nucleus

The membrane-bound organelle that houses DNA and controls cellular activities.

Nucleolus

Region inside the nucleus where ribosome assembly begins.

Cytoplasm

The jelly-like interior of the cell excluding the nucleus; site of many metabolic processes.

Golgi apparatus

The cell’s shipping center; modifies, sorts, and packages proteins and lipids.

Smooth endoplasmic reticulum

Endoplasmic reticulum lacking ribosomes; synthesizes lipids and detoxifies.

Lysosome

Organelle containing digestive enzymes that break down waste and debris.

Plasma membrane

The phospholipid bilayer that encloses the cell and regulates movement of substances.

Sex cell

Gamete; a reproductive cell (sperm or egg) involved in sexual reproduction.

Muscle cell

Cell specialized for contraction; component of muscle tissue.

Fat cell

Adipocyte; stores fat within droplets.

Immune cell

White blood cell types that defend against pathogens.

Stem cell

Undifferentiated cell with the potential to differentiate into various cell types.

Bone cell

Osteoblasts/osteocytes; cells involved in bone formation and maintenance.

Epithelial cell

Cell that forms epithelial tissue, lining surfaces and cavities.

Nervous cell

Neuron; nerve cell that transmits electrical signals.

Blood cell

Cells in blood (red and white blood cells) that perform transport and immune functions.

Epithelial tissue

Tissue that lines surfaces and forms barriers; rests on the basement membrane.

Connective tissue

Tissue that supports, binds, or separates tissues; contains an extracellular matrix.

Muscle tissue

Tissue composed of muscle cells capable of contraction.

Nervous tissue

Tissue containing neurons and supporting cells that transmit electrical impulses.

Basement membrane

Extracellular protein layer on which epithelial cells rest; separates epithelium from underlying tissue.

Basal lamina

Thin layer of the basement membrane that underlies epithelial cells.

Apical surface

The top, exposed surface of epithelial cells facing the lumen or outside.

Simple squamous epithelium

A single layer of flat cells; lines air sacs of the lungs.

Simple cuboidal epithelium

A single layer of cube-shaped cells; lines kidney tubules.

Extracellular matrix (ECM)

Network of proteins, polysaccharides, and minerals outside cells that provides structural support.

Interstitial fluid

Fluid in the tissue spaces between cells; part of the extracellular fluid.

Plasma

The fluid portion of blood that carries cells and solutes.

Intracellular fluid (ICF)

Fluid inside cells; makes up the majority of body water.