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Nerve & Muscle Tissue
What are the core concepts of histology?
Histology Topics for Lincoln Scholars Program

Every beginning biology student learns three fundamental principles which together comprise Cell Theory: 

Although all tissues are assembled from cells, tissue biology (i.e., histology) contributes one additional organizing principle:

Our bodies are composed of four different types of tissue:

Each of these four basic tissue types has its own distinctive character, a set of properties which unites all examples of that tissue type and distinguishes it from examples of the other three tissue types. 

Practically every cell in the body belongs to one of the four basic tissue types. 

Most organs include tissues of all four types.  And wherever each tissue occurs, it shares that tissue's defining characteristics (but note caveat below).

These, then, are the core concepts of histology:  Four basic tissue types, together with the characteristic properties of each type, muscle, nervous, epithelial, and connective.  To "unpack" these concepts in much greater detail, see basic tissue types or follow any of the links in the text above. 

Understanding how certain organs work -- notably the kidney and the lung and the liver -- requires some detailed knowledge of microanatomy that is unique to each organ; for example, podocytes and juxtaglomerular apparatus in the kidney, or interalveolar septa in the lung and bile canaliculi in the liver.  But only a tissue-level perspective can organize that knowledge and make it far easier to comprehend, by revealing how all three of these organs share with pancreas the same basic glandular tissue architecture, of epithelial parenchyma supported by connective tissue stroma

For a brief essay on how the four basic tissues are arranged in relation to one another to form organs, see "What are the most common patterns of tissue organization?"

For a much longer and more formal introduction to the basic concepts of histology, see "Basic tissue types."

Histology Topics for Lincoln Scholars Program

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CAVEAT:  Several of the generalizations above have peculiar exceptions. 
A few of the more important exceptions are listed below; others are mainly curiosities. 

Comments and questions:

SIUC / School of Medicine / Anatomy / David King
Last updated:  7 February 2023 / dgk