Functional Anatomy
2
Abstract
The microscopic examination of stained sections and the ability to interpret the relationship
between fine structure and function is essential. The recognition and interpretation of
physiological and pathological processes requires a thorough understanding of normal
tissue structure and microanatomy, and importantly the variations within species are crucial
for correct interpretation. This chapter covers the physiological changes, sexual maturation
and aging processes that are ‘normal’, and inherently different from those resulting from
injury, infection or disease.
Keywords
Histology Anatomy Normal structure Salmon Trout
Microanatomy or histology, the science of tissues, is the
microscopic examination of thin, stained sections that allows
the interpretation of the relationship between fine structure
and function. Individual cells and tissues may undergo
changes during physiological responses, sexual maturation
and aging, that are ‘normal’ and largely different from those
resulting from injury, infection or disease processes. Therefore, knowledge of the normal structure and variations
within species is of crucial significance for correct interpretation and understanding of pathological changes.
Within the body, the coelomic cavities (pericardial and
abdominal), various organs and components, are surrounded
or held in position by layers of a serous membrane, the peritoneum, a mesothelium and connective tissue containing blood
and secondary (lymph) circulation which also lines the septum
transversum that separates both cavities. In this way the outermost layer covering the different regions of the alimentary
canal known as the ‘serosa’, is effectively the ‘visceral peritoneum’, and covers other viscera lying within the ‘peritoneal
cavity or space’, hence they are not in the body cavity but
enveloped within a double layer of peritoneum, and analogous
to pushing a finger within a balloon. This also determines that
some organs are ‘retroperitoneal’, for example, the kidney.
Throughout this chapter we will refer to the functional unit
of an organ as the parenchyma, while the space in between
these parts, cells or functional units, is referred as the
interstitium. The latter may contain various cellular and extracellular elements, supporting structures or secretions. For
example, in the kidney the nephrons and the blood vascular
system are embedded in the meshwork of the interstitium, with
non-renal elements such as haematopoietic, secretory and
supportive cells; whereas the liver consists of hepatocytes,
with a meshwork of connective tissue, namely the framework
of the organ.
In this chapter an overview of the anatomy of salmonids
is presented by ‘systems’ (e.g. respiratory system, excretory
system) and organised by a functional approach.
The staining of light micrographs are only identified
when haematoxylin and eosin (H&E) is not used, and the
magnification for the images are given either as a scale bar or
if without a scalebar are identified as low power Â4–10;
medium power Â20–40; high power Â60–100 (Fig. 2.1).
D.W. Bruno et al., A Colour Atlas of Salmonid Diseases,
DOI 10.1007/978-94-007-2010-7_2, # Springer Science+Business Media B.V. 2013
5
2
Abstract
The microscopic examination of stained sections and the ability to interpret the relationship
between fine structure and function is essential. The recognition and interpretation of
physiological and pathological processes requires a thorough understanding of normal
tissue structure and microanatomy, and importantly the variations within species are crucial
for correct interpretation. This chapter covers the physiological changes, sexual maturation
and aging processes that are ‘normal’, and inherently different from those resulting from
injury, infection or disease.
Keywords
Histology Anatomy Normal structure Salmon Trout
Microanatomy or histology, the science of tissues, is the
microscopic examination of thin, stained sections that allows
the interpretation of the relationship between fine structure
and function. Individual cells and tissues may undergo
changes during physiological responses, sexual maturation
and aging, that are ‘normal’ and largely different from those
resulting from injury, infection or disease processes. Therefore, knowledge of the normal structure and variations
within species is of crucial significance for correct interpretation and understanding of pathological changes.
Within the body, the coelomic cavities (pericardial and
abdominal), various organs and components, are surrounded
or held in position by layers of a serous membrane, the peritoneum, a mesothelium and connective tissue containing blood
and secondary (lymph) circulation which also lines the septum
transversum that separates both cavities. In this way the outermost layer covering the different regions of the alimentary
canal known as the ‘serosa’, is effectively the ‘visceral peritoneum’, and covers other viscera lying within the ‘peritoneal
cavity or space’, hence they are not in the body cavity but
enveloped within a double layer of peritoneum, and analogous
to pushing a finger within a balloon. This also determines that
some organs are ‘retroperitoneal’, for example, the kidney.
Throughout this chapter we will refer to the functional unit
of an organ as the parenchyma, while the space in between
these parts, cells or functional units, is referred as the
interstitium. The latter may contain various cellular and extracellular elements, supporting structures or secretions. For
example, in the kidney the nephrons and the blood vascular
system are embedded in the meshwork of the interstitium, with
non-renal elements such as haematopoietic, secretory and
supportive cells; whereas the liver consists of hepatocytes,
with a meshwork of connective tissue, namely the framework
of the organ.
In this chapter an overview of the anatomy of salmonids
is presented by ‘systems’ (e.g. respiratory system, excretory
system) and organised by a functional approach.
The staining of light micrographs are only identified
when haematoxylin and eosin (H&E) is not used, and the
magnification for the images are given either as a scale bar or
if without a scalebar are identified as low power Â4–10;
medium power Â20–40; high power Â60–100 (Fig. 2.1).
D.W. Bruno et al., A Colour Atlas of Salmonid Diseases,
DOI 10.1007/978-94-007-2010-7_2, # Springer Science+Business Media B.V. 2013
5