Exam 2- Chapter 4 Flashcards
Types of tissues
- Epithelial tissue
- Connective tissue
- Muscle tissue
- Nerve tissue
Two main types of epithelial tissue
- Covering and lining epithelia
2. Glandular epithelia
Characteristics of epithelial tissue cells
- Cells have polarity
- May bare microvilli or cilia (trachea)
- Noncellular basal lamina of glycoprotein and collagen lie adjacent to the basal surface - Are composed of closely packed cells
- continuous sheets held together by tight junctions and desmosomes. - Supported by connective tissue reticular lamina
- Avascular but innervated
- High rate of regeneration
Epithelium accomplished many functions, what are they?
- protection
- absorption
- filtration
- excretion
- secretion
- sensory reception
All epithelia have two kinds of surfaces. What are they?
Apical- exposed to exterior ( microvilli, cilia)
Basal- Exposed to internal organs (glycoproteins, collagen), acts as a filter, repairs wounds
The tight junctions and desmosomes of the specialized cell in the epithelium do what?
help keep proT in the apical region from diffusing into the basal region, thus maintaining polarity.
Deep into the basal lamina is the
reticular lamina
A layer of extracellular material containing a dine network of collagen protein fibers that belong to the underlying connective tissue
Reticular lamina
The reticular lamina and the basal lamina form the
basement membrane
helps stretching and tearing and defines the epithelial boundary
Basement membrane
consists of a single cell layer. They are typically found where absorption, secretion, and filtration occur and thin epithelial barrier is desirable
simple epithelia
composed of two or more cell later stacked on top of each other, are common in high-abrasion areas where protection is important, such as the skin surface and lining of the mouth
stratified epithelia
flattened and scalelike
squamous cells
boxlike and approximately as tall as they are wide
cuboidal cells
are tall and column shaped
columnar cells
this epithelia is mostly concerned with absorption and secretion, because they are single layered and very thin, protection is not one of their specialties
Simple squamous epithelia
Resemble a tiled floor because the cells are flattened laterally and disk shaped ( sometimes resemble fired eggs)
Simple squamous epithelia
because it is thin and permeable it is often found where filtration or the exchange of substances by rapid diffusion is a priority. ex/ kidneys and lungs
Simple squamous epithelia
provides slick, friction-reducing lining in lymphatic vessels and in all hollow organs of the cardiovascular system-blood vessels and heart
Endothelium ( inner covering)
is the epithelium found in serous membranes, the membranes lining the ventral body cavity and covering its organs
Mesothelium (middle covering)
consists of a single layer of cells as tall as they are wide
Simple cuboidal epithelium
important function is secretion and absorption
Simple cuboidal epithelium
forms the walls of the smallest ducts of glands and of many kidney tubules
Simple cuboidal epithelium
a single layer of tall closely packed cells aligned like soldiers in a row.
Simple columnar epithelium
lines the digestive tract from the stomach through the rectum
Simple columnar epithelium
The Simple columnar epithelium has to distinct modifications that make it ideal for secretion and absorption
1) Dense microvilli on the apical surface of absorptive cells
2) Tubular glands made primarily of cells that secrete mucus- containing intestinal juice
vary in height, all of its cells rest on the basement membrane, but only the tallest reach the free surface of epithelium
Pseudostratified Columnar Epithelium
Gives a false impression that many layers are present
Pseudostratified Columnar Epithelium
A ciliated version containing mucas-secreting cells line more of the respiratory tract
Pseudostratified Columnar Epithelium
contain two or more cell layers and regenerate from below
Stratified epithelia