Introduction

Plasma membrane

A phospholipid bilayer that separates extracellular and intracellular fluid.

Endoplasmic Reticulum (ER)

Ribosomes that assemble proteins and produce cellular membranes.

Golgi apparatus

Sorts, processes, and packages proteins and membranes made by the rough ER.

Lysosomes

Contains digestive enzymes produced by the rough ER and breaks down lipids.

Mitochondria

Produces energy used by the cell and contains its own DNA.

Tight junctions

Belt-like seals between the apical regions of cells that prevent molecules from passing between cells.

Desmosomes

Anchoring junctions that bind adjacent cells at plaques and provide strength.

Gap junctions

Intercellular communication channels that allow molecules to move quickly between adjacent cells.

Microtubules

Hollow tubes of tubulin protein that serve as attachment sites for organelles.

Microfilaments

Actin filaments located just below the cell membrane that generate contractile forces for movement.

Intermediate filaments

Protein fibers that are wound like a rope and resist pulling forces.

Tissue

Group of similar cells and their binding extracellular matrix joined to perform a specific function.

Cell

The basic unit made up of molecules.

Organ

Formed by two or more tissues.

Organ system

Consists of different organs that work together closely.

Epithelial tissue

Covers and lines body surfaces.

Connective tissue

Provides support to other tissues.

Nervous tissue

Responsible for communication and control within the body.

Muscle tissue

Controls movement.