Question

Consider the following statements (i)-(iii) and select the correct option stating which ones are true (T) and \(w\) t ones are false (F). (i) Stratified squamous epithelium covers moist surface like buccal cavity. (ii) Fibroblasts store fat in adipose tissue. (iii) Urinary bladder is lined by a stratified epithelium. (i) (i) (a) \(\mathrm{F}\) (b) \(\mathrm{T}\) (c) \(\mathrm{T}\) (d) \(\mathrm{T}\) (ii) \(\mathrm{T}\) \(\mathrm{F}\) \(\mathrm{F}\) \(\mathrm{T}\) (iiI) \(\mathrm{T}\) \(\mathrm{F}\) \(\mathrm{T}\) \(\mathrm{F}\)

Short answer

(i) True, (ii) False, (iii) True. The correct option is (i) (T), (ii) (F), (iii) (T) which corresponds to option (c)

Step-by-step solution

Analyze Statement (i)

First, identify whether the given statement (i) 'Stratified squamous epithelium covers moist surface like buccal cavity' is true or false. Stratified squamous epithelium is indeed the type of tissue that covers the moist surfaces of the mouth, esophagus, and other parts of the body, such as the vagina and the anal canal. Therefore, statement (i) is true.

Analyze Statement (ii)

Next, examine statement (ii) 'Fibroblasts store fat in adipose tissue.' Fibroblasts are cells that are primarily responsible for producing the extracellular matrix and collagen. They do not store fat; adipocytes are the cells in adipose tissue that store fat. Therefore, statement (ii) is false.

Analyze Statement (iii)

Finally, look at statement (iii) 'Urinary bladder is lined by a stratified epithelium.' The urinary bladder is indeed lined with a specialized type of stratified epithelium called transitional epithelium, which allows for expansion and contraction. Hence, statement (iii) is true.

Key concepts

Epithelial Tissue

Epithelial tissue is a type of tissue that covers the body's surfaces, lines its cavities, and forms glands. It serves several key functions including protection, secretion, absorption, and filtration. Based on the number and arrangement of cell layers, epithelial tissue is classified into two main types: simple and stratified epithelia.

Simple epithelium consists of a single layer of cells and is involved in processes like absorption and filtration, whereas stratified epithelium contains multiple layers and is mainly protective in function due to its thickness. One specific type of stratified epithelium is the stratified squamous epithelium, which covers moist surfaces such as the buccal cavity. This kind of tissue can withstand abrasion and provides a barrier against microbial invasion and physical damage.

It's essential to understand that the epithelial tissue is avascular, meaning it lacks blood vessels. Therefore, it receives nutrients via diffusion from underlying tissues. This characteristic, alongside cell division at its basal layers, allows epithelial tissue to regenerate effectively.

Fibroblasts and Adipose Tissue

Fibroblasts and adipose tissue are critical components of the connective tissue in the body.

Fibroblasts are the most common cells in connective tissue, responsible for synthesizing collagen and the extracellular matrix. This extracellular matrix forms a supportive framework for tissues and organs and plays a crucial role in wound healing. Fibroblasts are not only the architects of this matrix but also serve as its caretakers, repairing and maintaining it as needed.

On the other hand, adipose tissue is composed mainly of adipocytes—cells specialized in storing energy in the form of fat. Adipose tissue provides insulation, shock absorption, and an energy reserve for the body. Though fibroblasts are involved in the structure of adipose tissue, they do not store fat themselves. It's a common misconception that fibroblasts play a direct role in fat storage. Instead, they provide a necessary support structure for the adipocytes that do.

Transitional Epithelium in Urinary Bladder

The transitional epithelium is a unique type of stratified epithelial tissue that lines the urinary bladder, ureters, and part of the urethra. This tissue is highly specialized to accommodate the fluctuating volume of the bladder as it fills and empties.

Unlike the fixed size of most other epithelial cells, cells in the transitional epithelium can stretch and change their shape without losing integrity, which prevents the urine from leaking while holding a variable amount of fluid. When the bladder is empty, the transitional epithelium appears to have several layers of cells. However, as the bladder fills and expands, the number of visible layers decreases as cells stretch, making the epithelium appear thinner. This amazing capacity for distension is what sets the transitional epithelium apart from other types of stratified epithelia.

The structure and function of transitional epithelium embody the principle that form follows function, as its unique transitional properties are perfectly suited for the storage and expulsion of urine.