Tissue
• Tissue—a group of similar cells and cell products that arise from the same region of the embryo and work together to perform a specific structural or physiological role in an organ
• Organ—structure with discrete boundaries that is composed of two or more tissue types
• Histology- the study of tissues is called
Tissue
• Types of tissues
• Epithelial- covers the body's external and internal surfaces and most glands
• Connective- binds and support parts
•
Muscle- makes movement possible
• Nervous-conducts impulses from one part of the body to another and help to control and coordinate body activities
Interpreting Tissue Sections
• Preparation of histological specimens
– Fixative prevents decay (formalin)
– Histological sections: tissue is sliced into thin sections one or two cells thick
– Stains: tissue is mounted on slides and artificially colored with histological stain
• Stains bind to different cellular components
• Sectioning reduces three-dimensional structure to two-dimensional slice
5-4
Longitudinal section (l.s.)
– Tissue cut along long direction of organ
•
Cross section (c.s. or x.s.) or transverse section (t.s.)
Cross sections
– Tissue cut perpendicular to length of organ •
Oblique sections
Oblique section
– Tissue cut at angle between cross and longitudinal sections
Figure 5.2
5-5
Interpreting Tissue Sections
• Smear—tissue is rubbed or spread across the slide – Spinal cord or blood
• Spread—cobwebby tissue is laid out on a slide
– Areolar tissue
5-6
Epithelial Tissue
• Consists of a flat sheet of closely adhering cells
• One or more cells thick
• Upper surface usually exposed to the environment or an internal space in the body
• Covers body surface and lines body cavities
• Forms the external and internal linings of many organs • Constitutes most glands
5-7
Epithelial Tissue
• Extracellular material is thin
• Epithelia allow no room for blood vessels-
avascular
• Lie on a layer of loose connective tissue and depend on its blood vessels for nourishment and waste removal
5-8
Epithelial Tissue
• Basement membrane—layer between an epithelium and the underlying connective tissue
– Collagen
• Anchors the epithelium to the connective tissue below it
• Basal surface—surface of an epithelial cell that faces the basement membrane
• Apical surface—surface of an epithelial cell that faces away from the basement membrane
5-9
Epithelial Tissue
•
• Stratified epithelium
Simple epithelium
– Contains one layer of cells
– Named by shape of cells
• Four types of simple epithelia
• Three named for their cell shapes
– Simple squamous (thin, scaly cells)
– Simple cuboidal (square or round cells)
– Simple columnar (tall, narrow cells)
5-11
Simple Epithelia
• Fourth type
– Pseudostratified columnar
• Not all cells reach the free surface
• Shorter cells are covered over by taller ones
• Looks stratified
• Every cell reaches the basement membrane
• Goblet cells—wineglass-shaped mucus-secreting cells in simple columnar and pseudostratified epithelia 5-12
Stratified Epithelia
• Range from 2 to 20 or more layers of cells
• Some cells resting directly on others
– Only the deepest layer attaches to the basement membrane
• Three stratified epithelia are named for the shapes of their surface cells
– Stratified squamous
– Stratified cuboidal
– Stratified columnar
Related Documents: Epithelium and Mcgraw-hill Companies Essay
INTRODUCTION PHYSIOLOGY Physiology is the science of life. It is a broad science which aims to understand the mechanisms of living, from the molecular basis of cell function to the integrated behaviour of the whole body. Reference http://www.understanding-life.org Physiology is the branch of biology that deals with the normal functions of living organisms and their parts. Organ system Organ system is a group of organs that work together to perform a certain task or complex function. We…
Research Writing Research Process Organization Citing References Writing Process View All Research Writing Articles The Anatomy of a Research Paper A research paper encompasses many things. It may be a paper due at the end of a term or class. It may be the result of weeks, months or years of research. During the course of completing this type of academic writing assignment, you examine an issue to write an analytical or argumentative paper that is a summary of research and your conclusions…