Question

Assertion: Ciliated epithelium mainly present in the inner surface of hollow organs like bronchioles and fallopian tube. Reason: Cilia are microvilli.

Short answer

The assertion is correct, but the reason is incorrect. Ciliated epithelium is indeed present in the inner surface of organs like bronchioles and fallopian tubes, but cilia are not microvilli; they are different structures with different characteristics and functions.

Step-by-step solution

Understand the terms

It's crucial to know what ciliated epithelium is. Ciliated epithelium is a type of tissue found in places like the bronchioles (respiratory tract) and fallopian tubes (female reproductive system), which have tiny hair-like structures called cilia.

Analyze the assertion

There is a claim that ciliated epithelium is mainly present in the inner surface of hollow organs like bronchioles and the fallopian tubes. This is correct because the cilia serve to push substances along the epithelial surface, as seen inside the bronchioles, where it helps to move mucus and trapped particles out of the lungs, or in the fallopian tubes where it helps to move the eggs from the ovaries to the uterus.

Analyze the reason

The reason provides that cilia are microvilli. This is incorrect. Despite their similar functions in movement, cilia and microvilli are different structures. Cilia are longer, whip-like structures that move rhythmically; they can be seen in the respiratory tract and fallopian tubes. Microvilli, on the other hand, are small, finger-like projections on the cell surface; they increase the absorptive surface area of cells and are usually found in the small intestine and other areas of absorption.

Key concepts

Bronchioles

Bronchioles are small air passages in the respiratory system that extend from the bronchi and lead to the alveoli where gas exchange occurs. They are critical for transporting air in and out of the lungs.
In the bronchioles, the presence of ciliated epithelium plays an essential role. Cilia, found on the surface of these epithelial cells, work to keep the airways clear of mucus, dirt, and other particles.
This cleaning process is vital as it helps maintain healthy and efficient breathing by ensuring that the air reaching the alveoli is as clean as possible. Along with cilia, the bronchioles also contain goblet cells that produce mucus. This mucus traps unwanted particles, and the cilia then help move this mucus upwards towards the throat to be expelled.

Fallopian Tubes

The fallopian tubes form part of the female reproductive system. They act as a conduit for eggs to travel from the ovaries to the uterus.
Similar to bronchioles, the fallopian tubes are lined with ciliated epithelium. Here, cilia play a crucial role in reproductive health by facilitating the movement of the egg. As the egg is released from the ovary, the rhythmic beating of the cilia gently guides the egg down the fallopian tube towards the uterus.
This movement is not only essential for fertilization, which typically occurs in the fallopian tube but also ensures that the egg reaches the uterus, where it can implant if fertilization has occurred. It's fascinating how cilia aid in two very different systems—respiratory and reproductive—by performing similar sweeping functions.

Cilia

Cilia are tiny, hair-like projections that extend from the surface of many types of cells. They are longest at about 5-10 micrometers and have a core structure known as the axoneme. This structure allows them to move in a coordinated, whip-like fashion.
Cilia are found in various parts of the body like the respiratory tract and fallopian tubes, where they help move substances across cellular surfaces. Their primary function is movement, either moving the cell itself or moving the surrounding fluid.
There are two types of cilia, motile and non-motile. Motile cilia sweep mucus or fluid, as seen in bronchioles and fallopian tubes. Non-motile cilia, on the other hand, often act as sensory organelles, allowing cells to perceive changes in their environment. Both types of cilia are essential for maintaining cellular health and function.

Microvilli

Microvilli are tiny projections from the cell membrane that increase the surface area for absorption or secretion. They are shorter than cilia, measuring only about 1 micrometer in length, and have a core of actin filaments.
You will find microvilli predominantly in the small intestine and kidney tubules, where they maximize the surface area to improve nutrient absorption. This feature is crucial for processes like digestion, where the body needs to absorb as many nutrients as possible from the food we eat.
Unlike cilia, microvilli do not move. Instead, they offer a larger surface for various essential exchanges between the cell and its environment. Their main role is to ensure maximum efficiency in nutrient uptake, which is fundamental for sustaining life.