Textbook Question
Identify the six types of epithelial tissue shown in the drawing below.
e. ___
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4. Tissues & Histology
Characteristics of Epithelial Tissue
1:04 minutesProblem 22
Textbook Question
In adults, over 90% of all cancers arise in epithelium. Such cancers are called carcinomas, or adenomas (adenocarcinomas) if they arise in glandular epithelia. In fact, cancers of the skin, lung, colon, breast, and prostate are all in these categories. Why do you think this is so?
Verified step by step guidance1
Step 1: Understand the nature of epithelial tissue. Epithelial tissues line the surfaces and cavities of organs and structures throughout the body, forming protective barriers and involved in absorption, secretion, and sensation.
Step 2: Recognize that epithelial cells have a high rate of turnover. Because they are constantly exposed to environmental damage and wear, epithelial cells frequently divide to replace lost or damaged cells, increasing the chance of DNA replication errors.
Step 3: Consider that frequent cell division increases the likelihood of mutations. Each time a cell divides, there is a risk of mutations occurring in the DNA, which can accumulate and potentially lead to cancerous transformations.
Step 4: Note that epithelial tissues are often exposed to carcinogens. For example, skin epithelium is exposed to UV radiation, lung epithelium to inhaled toxins, and colon epithelium to dietary carcinogens, all of which can damage DNA and promote cancer development.
Step 5: Conclude that the combination of high cell turnover, exposure to environmental carcinogens, and the critical functions of epithelial tissues explains why over 90% of adult cancers arise in epithelial cells, leading to carcinomas and adenocarcinomas.
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Video duration:
1mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Epithelial Cell Proliferation and Turnover
Epithelial tissues have a high rate of cell division and turnover to maintain protective barriers and organ function. This frequent cell replication increases the chance of DNA replication errors, making epithelial cells more susceptible to mutations that can lead to cancer.
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Transitional Epithelia
Exposure to Environmental Carcinogens
Epithelial surfaces, such as skin and lung lining, are directly exposed to environmental carcinogens like UV radiation, tobacco smoke, and chemicals. This exposure increases DNA damage risk, promoting mutations that can initiate carcinogenesis in these tissues.
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Glandular Epithelium and Adenocarcinomas
Glandular epithelia produce secretions and have specialized functions, but their active metabolism and cell division make them prone to malignant transformation. Adenocarcinomas arise from these tissues, reflecting how functional demands and cellular activity influence cancer development.
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01:53Glandular Epithelial Tissue Example 1
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