Porth's Essentials of Pathophysiology, 4e

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Cell and Tissue Function

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Functional Components of the Cell The Cell Membrane The Nucleus The Cytoplasm and Its Membrane-Bound Organelles

C h a p t e r

Ribosomes, Endoplasmic Reticulum, and Golgi Apparatus Lysosomes

Cell Structure and Function

Peroxisomes Proteasomes Mitochondria The Cytoskeleton Microtubules Actin Microfilaments and Intermediate Filaments Cell Metabolism and Energy Storage Anaerobic Metabolism Aerobic Metabolism Integration of Cell Function Cell Signaling and Communication Mechanisms

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he cell is the smallest functional unit of life. Cells are the smallest unit capable of self-reproduction and are vehicles for transmitting genetic information that defines the organism. Cells with similar specialized func- tions are often organized into larger functional aggre- gates called tissues . These tissues in turn combine to form the various body structures and organs. Although the cells of different tissues and organs vary in structure and function, they are remarkably similar in their abil- ity to exchange materials with their immediate environ- ment, obtain energy from organic nutrients, synthesize complex molecules, and replicate themselves. Because most diseases begin at the cellular level, an understand- ing of cell function is crucial to understanding the dis- ease process. Some diseases affect the cells of a single organ, others affect the cells of a particular tissue type, and still others affect the cells of the entire organism. This chapter discusses the structural and functional components of the cell, basic cellular mechanisms, and tissue types.

Cell Surface Receptors Intracellular Receptors Membrane Transport Mechanisms Diffusion Active Transport Vesicular Transport Generation of Membrane Potentials Tissues Embryonic Origin of Tissue Types Epithelial Tissue Simple Epithelium

Stratified and Pseudostratified Epithelium Glandular Epithelium Epithelial Cell Renewal Connective Tissue Loose Connective Tissue Adipose Tissue Reticular and Dense Connective Tissue Muscle Tissue

Functional Components of the Cell

Although diverse in their organization, all eukaryotic cells (cells with a true nucleus) have in common struc- tures that perform unique functions. Under a light micro- scope, three primary components of the eukaryotic cell become evident: the plasma membrane, the nucleus, and the cytoplasm, while numerous structures are visible by higher magnification electron microscopy (Fig. 1-1).

Skeletal Muscle Smooth Muscle

Nervous Tissue Extracellular Tissue Components Cell Junctions Extracellular Matrix Cell Adhesion Molecules

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