ANIMAL TISSUE STRUCTURE

Animal Tissue Structure
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookAnimalTS.html#Table%20of%20Contents

ANIMAL TISSUE STRUCTURE

                   All vertebrates share the same basic body plan, with similar tissue and organ that operate in much the same way. The micrograph show a portion of the duodenum, part of digestive system, which is made up of multiple types of tissue. Group of cells that are similar in structure and function are organized into tissue. Early in development, the cells of the growing embryo differentiate into three fundamental embryonic tissue, called  germ layers. From the innermost to the outermost layers, these are the endoderm, mesoderm and ectoderm. Each germ layer, in turn, differentiates into the scores of different cell types and tissues that are characteristic of the vertebrate body.

            In adult vertebrates, there are four principal kinds of tissues, or primary tissues: They are epithelial, connective, muscle and nerve tissue, and each type. 

Four fundamental characteristics of epithelial tissue.

          (1)  densely packed cells joined by a variety of specialized intercellular junctions
          (2)  form linings (sheets and layers) which exhibit polarity, i.e., epithelia have apical and basal surfaces
          (3)  the basal surface is attached to, and supported by, underlying connective tissue
          (4)  avascular (no direct blood supply)

  Eight types of epithelium, distinguished by cell shape and pattern of layering.

          (1)  simple squamous
          (2)  simple cuboidal 
          (3)  simple columnar 
          (4)  pseudostratified 
          (5)  stratified squamous 
          (6)  stratified cuboidal 
          (7)  stratified columnar 
          (8)  transitional 

 The three arrangements of epithelial tissue by number of cell layers using correct scientific terminology.

          (1)  simple - one cell layer thick
          (2)  pseudostratified - more than one cell layer thick
          (3)  stratified - appears in the microscope as if multiple layers were present, but actually only one cell layer present, cells of different height

  The four shapes of epithelial cells using correct scientific terminology.

          (1)  squamous - flat
          (2)  cuboidal - about as wide as tall 
          (3)  columnar - tall narrow cells 
          (4)  transitional - cells that change shape depending on whether the tissue is relaxed or stretched

Explain or describe: 

Classify the various epithelial tissues by shape and layers. Describe at least one function and location in the body for each type of epithelium

Epithelial Tissue Type	Example of a Location and Function
simple squamous	alveolar lining - gas exchange; parietal wall of nephron capsule - lining; visceral wall of glomerulus - plasma filtration to make urine
simple cuboidal	ducts of salivary glands, pancreatic acinar glands - delivery of exocrine secretion; proximal and distal convoluted tubules in kidneys - urine formation
simple columnar	stomach and intestinal linings - digestion and absorption of nutrients
pseudostratified	trachea & bronchi - mucous traps dust and microbes
stratified squamous	skin, oral and nasal cavities, vagina, distal urethra - protective linings
stratified cuboidal	ureters and proximal urethra - protective linings
stratified columnar	pharynx, male urethra, some glandular ducts (minor component in each case) - transitional zone within protective linings
transitional	urinary bladder - extensible protective lining

3. the location and structure of endothelium and mesothelium.

	Location	Structure
Endothelium	interior lining of heart chambers and blood vessels	simple squamous epithelium
Mesothelium	interior lining of sterile body cavities; serous membranes of pericardial, pleural and abdominal cavities; lining of chambers housing and circulating cerebrospinal fluid (CSF)	simple squamous epithelium

4. the difference between endocrine versus exocrine glands.

Endocrine Glands	Exocrine Glands
Their secretions are carried away from the glands by the blood stream.	Their secretions are carried away from the glands in ducts.
Their secretions are delivered to internal target tissues and organs.	Their secretions are delivered to body surfaces, either mucous membranes or the skin.
Their secretions are internal regulatory substances.	Their secretions have a variety of functions, but they are not internal regulatory substances.