Problem 16 - Objective Biology for NEET

Question

Which of the following is unicellular glandular epithelium? (a) Salivary gland (b) Islets of langer han's (c) Goblet cells (d) All of these

Step-by-Step Solution

Answer

The correct option is (c) Goblet cells. They are an example of a unicellular glandular epithelium.

Step 1: Understanding glandular epithelium

Glandular epithelium forms the covering or lining of organs involved in secretion. It can be unicellular, having single cell glands or multicellular, having multiple cell glands.

Step 2: Understanding the options

Salivary gland and Islets of Langerhan's are multicellular glands, thus option (a) and (b) are incorrect. Goblet cells, on the other hand, are unicellular glands that secrete mucus.

Step 3: Finalizing the Answer

Considering the unicellular and glandular characteristic, the goblet cells are the appropriate selection.

Key Concepts

Unicellular Glandular Epithelium

Unicellular glandular epithelium is a type of tissue composed of single-celled glands. This is different from multicellular glands, which are made up of multiple cells working together to perform a secretory function. Unicellular glandular epithelia are typically found in lining tissues where they can perform their role without requiring additional cellular support. Their main purpose is to secrete substances directly onto the surface where they reside.
In the human body, unicellular glands are relatively rare compared to their multicellular counterparts. Despite this rarity, they are highly important for certain bodily functions, particularly in the context of lubrication and protection. Their ability to independently secrete substances ensures that the epithelial surfaces are adequately protected against damage and pathogens. By understanding their function, one can appreciate the nuanced and well-organized structure of epithelial tissues.

Goblet Cells

Goblet cells are an excellent example of unicellular glandular epithelia. Found predominantly in the respiratory and digestive tracts, they have the unique function of producing mucus. This mucus serves several essential purposes:

• It provides a protective lining for tissues it covers.
• It helps trap foreign particles, preventing them from entering other parts of the body.
• It maintains moisture in the epithelia, preventing dehydration and damage.

Goblet cells are named for their distinctive shape, which resembles a goblet or chalice. This shape helps them store large amounts of mucus before releasing it onto the tissue surface.
The presence of goblet cells is crucial for maintaining the health of the respiratory and digestive tracts, as they play a vital role in protecting these systems from irritants and pathogens. Their strategic locations and abundant secretion of mucus make them a key component of the body's defense mechanisms.

Types of Glands

Glands are specialized organs that play a significant role in secretion. They are categorized based on their structure into unicellular and multicellular glands. While unicellular glands, like goblet cells, consist of a single cell responsible for secretion, multicellular glands are complex systems composed of multiple cells.
Multicellular glands are further classified into two main types: endocrine and exocrine glands.

• Endocrine glands: These glands do not have ducts. They release their hormones directly into the bloodstream, affecting distant organs. Examples include the pituitary and thyroid glands.
• Exocrine glands: These have ducts and release their substances directly onto an epithelial surface. Examples include salivary glands and sweat glands.

The distinction between unicellular and multicellular glands, along with the subdivision between endocrine and exocrine glands, underscores the complexity and specialization of glandular function in the body. Each type is tailored to meet specific physiological needs, ensuring the body operates efficiently and effectively.