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Nutrition

Epithelial tissue Cilia (microvilli)
Task 5.10 Mucus in goblet cell
Search from the internet sources videos
or images showing the structures of Nucleus
Absorptive cell
epithelia tissue in relation to digestive Basement membrane
role. Note what you have observed. Connective tissue
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Epithelial tissue is a living tissue that consists
of a single cell layer which usually occurs on Figure 5.11: Simple columnar epithelium
the surface and covers the organs, cavities,
and tubes. For instance, it lines the heart, Glandular epithelium
blood vessels, lymphatic vessels, and the This epithelium tissue contains secretory
intestine. There are two major types of cells that are closely packed (Figure 5.12).
Secretory cells secrete materials, such as
epithelial tissues; one is the simple epithelial mucus into the cavity or a space lined by it.
tissue, which has a single layer of cells and For example, in the stomach and the small
is further subdivided into five sub types intestine the mucus protects and lubricates
namely; squamous, cuboidal, columnar the lumen of the intestine and stomach. In
pseudostratified, ciliated, and glandular some parts, glandular epithelium is folded
epithelial tissues. The second group of in various ways to form glands, such as
epithelial tissue comprises epithelia tissues, gastric glands whose major function is
which are more than one cell thick. This to secrete enzymes and fluids. Glandular
group includes transitional and stratified epithelium can be individual cells, such
epithelial tissues. as goblet cells or aggregates of glandular
cells, such as multicellular glands like
Columnar epithelium exocrine and endocrine glands. Examples
This tissue consists of thin columns of of glandular epithelial tissues found in the
elongated cells arranged at right angle to digestive system include simple tubular
the basement membrane. The cells possess glands, such as crypts of Lieberkuhn found
nuclei at their bases, and they are mostly in the intestines, simple branched tubular
associated with regions, such as the walls of glands such as gastric glands found in
the intestines and stomach, where secretion the stomach walls (gastric mucosa), and
and absorption are the major functions. compound saccular and compound tubular
Columnar epithelium tissues are adapted glands of the salivary glands.
to withstand wear and tear. Epithelial tissue
cells are interspaced by the goblet cells that Secreted materials
are responsible for secreting mucus that
helps to protect the stomach from digestive
enzymes and acidic content of the gastric
glands. Some epithelial tissues are ciliated, Duct
while others have microvilli that increase
the surface area for absorption. Part of the Secretory cells of gland
surface that is occupied by the microvilli is
called brush boarder (Figure 5.11).
Figure 5.12: Glandular epithelium

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