Animal Tissues
Chapter Name : Structural Organization In Animals |
Sub Topic Code : 103_11_07_01_01 |
Topic Name : Animal Tissues |
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Sub Topic Name : Epithelial Tissue |
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Introduction
Epithelium tissue - This tissue has a free surface, which faces either a body fluid or the outside environment and thus provides a covering or a lining for some part of the body.
Pre-Requisites:
To understand what epithelium tissue is and what is it's function.
Activity:
Videos which show the structure and function of epithelium tissue.
Real Life Question:
Where is epithelium tissue present in the body?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Simple epithelium | composed of a single layer of cells and functions as a lining for body cavities, ducts, and tubes. |
| Compound epithelium | consists of two or more cell layers and has protective function as it does in our skin. They cover the dry surface of the skin, the moist surface of buccal cavity, pharynx, inner lining of ducts of salivary glands and of pancreatic ducts. |
| on basis of structural modification of cell, simple epithelium is further divided into - 1) Squamous epithelium | made of a single thin layer of flattened cells with irregular boundaries. They are found in the walls of blood vessels and air sacs of lungs and are involved in a functions like forming a diffusion boundary. |
| 2) Cuboidal epithelium | composed of a single layer of cube-like cells. This is commonly found in ducts of glands and tubular parts of nephrons in kidneys |
| 3) Columnar epithelium | composed of a single layer of tall and slender cells. Their nuclei are located at the base. Free surface may have microvilli. They are found in the lining of stomach and intestine. |
| Ciliated epithelium | columnar or cuboidal cells bear cilia on their free surface. present in the inner surface of hollow organs like bronchioles and fallopian tubes. |
| Glandular epithelium | Some of the columnar or cuboidal cells get specialised for secretion. |
| Exocrine glands | Exocrine glands secrete mucus, saliva, earwax, oil, milk, digestive enzymes and other cell products. These products are released through ducts or tubes. |
| Endocrine glands | do not have ducts. Their products called hormones are secreted directly into the fluid bathing the gland. |
Learning aids / Gadgets
| Gadgets | How it can be used |
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Practical examples around us
| Examples | Explainations |
|---|---|
| columnar epithelium | It is present in stomach and intestine in order to absorb and help in secretion. |
What you learn in Theory:
What is epithelium tissue.
What you learn in Practice:
Importance of epithelium tissue.