Page 34 - 84 human physiolofy part-1

Chapter 2

phagocytosis is performed by specialized cells called phagocytes, which serve to remove foreign bodies
and thus fight infection. In vertebrates, these include larger macrophages and smaller granulocytes,
types of blood cells. Bacteria, dead tissue cells, and small mineral particles are all examples of objects
that may be phagocytosed.

Pinocytosis: also called cellular drinking, is a form of endocytosis, a process in which small
particles are taken in by a cell by splitting into smaller particles. The particles then form small vesicles
which subsequently fuse with lysosomes to hydrolyze, or to break down, the particles. This process
requires adenosine triphosphate (ATP).

Receptor-mediated Endocytosis: occurs when specific molecules in the fluid surrounding the cell
bind to specialized receptors in the plasma membrane

Red Blood Cells (erythrocytes): cells that collect oxygen in the lungs and deliver it through the
blood to the body tissues

Ribosomes: play an active role in the complex process of protein synthesis, where they serve as
the structures that facilitate the joining of amino acids

Simple Diffusion: the net movement of substances from an area of higher concentration to an area
of lower concentration

Vacuoles: spaces in the cytoplasm that sometimes serve to carry materials to the cell membrane
for discharge to the outside of the cell

White Blood Cells (leukocytes): produced in the bone marrow and help the body to fight
infectious disease and foreign objects in the immune system

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34 | Human Physiology