1. Microvilli: Projections on the walls of the absorptive ducts in animals are called microvilli. Each cell in the intestine and nephron contains about 3000 microvilli. It increases the absorption surface.
2. Pinocytic vesicle: The cavity containing liquid food particles created from the cell membrane is called pinocytic vesicle. The process by which pinocytic vesicles are formed is called pinocytosis.
3. Phagocytic vesicle: The cavity containing solid food particles formed from cell membrane is called phagocytic vesicle. The process by which phagocytic vesicles are formed is called phagocytosis. White blood cells contain phagocytic vesicles.
4. Desmosome: When the cell membrane of two closely adjacent cells transforms and forms a leaf-like structure, it is called a desmosome. Desmosomes are accompanied by tonofibril fibers. It keeps the two cells firmly attached.
5. Tight junction: The cell membrane of two closely adjacent cells forming a tight junction is called a tight junction. No matter can move through this zone. Neurons in the brain have tight junctions.
6. Pseudopodia: The extension formed outside the cell membrane during phagocytosis is called pseudopodia. It participates in food intake and locomotion.
7. Invagination: Cell membrane folds to form numerous tubular structures. This is called intussusception.