Key Terms
Anatomy
The study of the structure of living things, including their cells, tissues, and organs, and how these parts are organized.
Cell
The smallest, basic unit of a living organism that can function independently. All living things are composed of one or more cells.
Physiology
The scientific study of the functions and mechanisms of a living system (such as an organ, organism, or cell).
Pathophysiology
The study of the functional changes in the body that occur as a result of a disease or injury.
Homeostasis
The state of steady internal, physical, and chemical conditions maintained by a living organism's body (like body temperature and fluid balance) to ensure optimal functioning.
Protoplasm
The living contents of a cell that are surrounded by the cell membrane, including the cytoplasm and the nucleus.
Organelles
The specialized, membrane-bound structures within a cell that perform specific jobs (e.g., mitochondria, nucleus).
Cell Membrane
The semipermeable outer barrier of a cell that encloses its contents and controls which substances can enter or leave.
Centrosome
A small organelle near the nucleus that is involved in cell division (mitosis and meiosis) by organizing microtubules.
Cytoplasm
The jelly-like material that fills a cell, enclosed by the cell membrane, and surrounds the organelles (excluding the nucleus).
Endoplasmic Reticulum (ER)
A network of membranes inside a cell involved in processing and transporting proteins (rough ER) and producing lipids (smooth ER).
Golgi Apparatus (or Golgi complex)
An organelle that modifies, sorts, and packages proteins and lipids for storage or transport out of the cell.
Lysosomes
Small organelles containing digestive enzymes that break down waste materials, foreign invaders (like bacteria), and old cell parts.
Lysosomes: Mitochondria
Often called the "powerhouses" of the cell, these organelles generate Small organelles containing digestive enzymes that break down waste materials, foreign invaders (like bacteria), and old cell parts.
Nucleolus
A small, dense structure found inside the nucleus that is responsible for making ribosomes.
Nucleus
The large, central organelle that contains the cell's genetic material (chromosomes) and controls its growth and reproduction.
Pinocytic Vesicles
Small, fluid-filled sacs formed by the cell membrane folding inward to "drink" or take in fluids and dissolved substances from outside the cell.
Vacuoles
Membrane-bound sacs within a cell that are used for storage (of water, nutrients, or waste) and are much larger in plant cells.
Chromatin
The complex of DNA and proteins (mainly histones) that forms chromosomes within the nucleus. It condenses to become visible during cell division.
Genes
The basic units of heredity. They are segments of DNA that provide the instructions for making specific proteins, which determine an organism's traits.
Genome
The complete set of genetic material (all the DNA) present in an organism or cell.
Meiosis
Meiosis
Mitosis
A type of cell division that results in two identical daughter cells, each having the same number and kind of chromosomes as the parent nucleus. This is how the body grows and repairs itself.
Stem Cells
Unspecialized cells that have the unique ability to develop into many different specialized cell types in the body (e.g., muscle cells, brain cells) and to self-renew (make more stem cells).
Tissue
A group of similar cells and their extracellular matrix that work together to perform a specific function (e.g., muscle tissue, nerve tissue).