Question

Simple cuboidal epithelium lines all the following structures except the (a) ovary (b) pancreatic ducts (c) thyroid follicles (d) Fallopian tube.

Short answer

The Fallopian tube is not lined by simple cuboidal epithelium; it is lined by simple columnar epithelium.

Step-by-step solution

Understanding the concept of epithelial tissue

Epithelial tissue is one of the four main types of tissues in the body. Simple cuboidal epithelium consists of a single layer of cube-like cells. These are primarily involved in secretion and absorption and are found lining several glands and ducts.

Identifying structures lined by simple cuboidal epithelium

Review what structures are commonly lined by simple cuboidal epithelium. This type of tissue is commonly found in the small collecting ducts of the kidney, surface of the ovary, and lining of the thyroid follicles and pancreatic ducts.

Eliminating the structures that are lined by simple cuboidal epithelium

Knowing where simple cuboidal epithelium is found, we can eliminate options (a) ovary, (b) pancreatic ducts, and (c) thyroid follicles as structures that are lined by this type of epithelium.

Identifying the structure not lined by simple cuboidal epithelium

Determine that the Fallopian tube is not lined by simple cuboidal epithelium. It is actually lined by simple columnar epithelium, which is specialized to facilitate the movement of egg cells.

Key concepts

Epithelial Tissue

Epithelial tissue is a fundamental component of animal bodies, covering surfaces, forming glands, and creating barriers. Think of it like the body's wallpaper, coating everything from the outside skin to the internal cavities and tubes. It comes in various shapes and sizes, designed for specific functions. For instance, the simple cuboidal epithelium is made up of cells that are roughly cube-shaped and organized in a single layer.

The beauty of epithelial cells lies in their consistent regeneration ability. They have a short lifespan, which means they are continually being replaced. This is crucial as these cells often defend against wear and tear, pathogens, and other harmful substances. Beyond protection, epithelial tissue plays a significant role in how the body interacts with its internal and external environments, which includes absorbing nutrients from food in the gut, and excreting waste through sweat glands.

Secretion and Absorption

Two of the stellar functions of simple cuboidal epithelium are secretion and absorption. Imagine this tissue as a dynamic, busy marketplace where goods (molecules) are both received (absorption) and dispatched (secretion).

During absorption, the cells take in substances necessary for the body, such as nutrients from food or hormonal signals. On the flip side, secretion involves the dispatch of substances either to other parts of the body or to the outside world. This can be hormones, enzymes, or other vital proteins. The compact, single-layer structure of simple cuboidal cells maximizes their efficiency in these processes, as their uniform shape and arrangement allow for quick and organized transfer of materials.

Tissue Lining in Organs

The type of epithelium that lines an organ is meticulously matched to the organ's function, much like choosing the right type of interior finish for a room based on its use. Simple cuboidal epithelium is often found lining small passageways where its roles in secretion and absorption are essential. Examples include tiny tubes in the kidneys, where they recover vital substances from urine, and in glands where they churn out secretions.

However, not all tubes in the body get the cuboidal treatment. For example, the Fallopian tubes are lined with simple columnar epithelium, which is elongated to help transport the egg from the ovary to the uterus. The specialization of epithelial tissue types is a testament to the complexity and precision of our body's internal workings.