Epithelial tissue Questions in English

(D) The epithelium described is the $Simple \ Squamous \ Epithelium$.
It consists of a single thin layer of flattened cells with irregular boundaries.
It is found in the walls of blood vessels (endothelium),air sacs of lungs (alveoli),and the Bowman's capsule of nephrons.
It is primarily involved in functions like forming a diffusion boundary.
Therefore,all the given options represent locations where this tissue is found.

(D) The $Compound$ $epithelium$ is made up of two or more layers of cells and has a limited role in secretion and absorption.
Its main function is to provide protection against chemical and mechanical stresses.
It covers the dry surface of the skin, the moist surface of the buccal cavity, pharynx, inner lining of ducts of salivary glands, and of pancreatic ducts.

(C) The inner surface of the fallopian tubes (oviducts) is lined with $Ciliated$ $epithelium$.
These cells possess hair-like projections called $cilia$ on their free surfaces.
The movement of these $cilia$ helps in the transport of the ovum or egg towards the uterus.

(A) The diagram shows ciliated columnar epithelium,which consists of tall,slender cells with cilia on their free surface.
These cilia help in moving particles or mucus in a specific direction over the epithelial surface.
This type of tissue is primarily found in the inner linings of hollow organs like bronchioles and fallopian tubes.
Therefore,the correct option is the inner linings of bronchioles.

(C) Tight junctions are specialized structures that act as barriers to prevent the leakage of substances across a tissue.
They are found at the apical parts of epithelial cells and form a seal that restricts the movement of molecules between adjacent cells.
Gap junctions facilitate communication between cells by allowing the passage of ions and small molecules.
Adhering junctions perform cementing functions to keep neighboring cells together.
Therefore,the correct option is $C$.

(A) Glands are classified based on the number of cells into unicellular and multicellular glands.
Unicellular glands consist of isolated glandular cells.
Goblet cells of the alimentary canal are a classic example of unicellular glands.
Salivary,pituitary,and thyroid glands are multicellular glands,which consist of clusters of cells.
Therefore,the correct answer is $A$.

(D) Simple epithelium consists of a single layer of cells and functions as a lining for body cavities,ducts,and tubes.
$A$,$B$,and $C$ are examples of simple epithelium (ciliated,cuboidal,and squamous respectively).
The lining of the buccal cavity is composed of compound epithelium (stratified squamous epithelium),which consists of multiple layers of cells to provide protection against mechanical and chemical stress.
Therefore,the correct answer is $D$.

(B) The simple columnar epithelium is composed of a single layer of tall and slender cells.
These cells are elongated in shape.
The nuclei of these cells are typically located at the base of the cell.
Therefore,the correct option is $(B)$.

(B) The correct matches are as follows:
$1$. Simple squamous epithelium is found in the air sacs of lungs (alveoli) where it facilitates diffusion $(I-d)$.
$2$. Ciliated cuboidal epithelium is found in the lining of the Fallopian tubes, where cilia help in the movement of the ovum $(II-c)$.
$3$. Brush bordered columnar epithelium is found in the lining of the gall bladder and intestine for absorption $(III-a)$.
$4$. Urothelium (transitional epithelium) is found in the ureter and urinary bladder, allowing for distension $(IV-b)$.
Thus, the correct sequence is $I-d, II-c, III-a, IV-b$.

(D) The provided diagram shows cells of different heights where all cells touch the basement membrane but not all reach the free surface,which is characteristic of pseudostratified columnar epithelium.
Pseudostratified columnar epithelium is found in the lining of the trachea and bronchi.
Option $D$ correctly identifies the tissue type and its location in the bronchi.
Therefore,the correct answer is $D$.

(B) $(i)$ The ducts of glands are lined by cuboidal epithelium,which provides mechanical support and secretion.
$(ii)$ The fallopian tubes are lined by ciliated columnar epithelium,which helps in the movement of the ovum.
$(iii)$ The air sacs (alveoli) of the lungs are lined by squamous epithelium,which facilitates the diffusion of gases.
$(iv)$ The inner lining of the stomach is composed of columnar epithelium,which is involved in secretion and absorption.
Therefore,the correct sequence is $(A)$ Cuboidal,$(B)$ Ciliated columnar,$(C)$ Squamous,$(D)$ Columnar.

(D) Gap junctions are specialized intercellular connections that directly connect the cytoplasm of two cells.
They allow the passage of ions,water,and small molecules (such as signaling molecules and nutrients) between adjacent cells.
In some cases,they can also facilitate the transfer of larger molecules,ensuring metabolic and electrical coupling between cells.
Tight junctions primarily prevent leakage of substances across a tissue,while desmosomes provide mechanical strength and adhesion.

(D) The lining of the stomach and intestine is composed of columnar epithelium.
Columnar epithelium consists of tall,slender cells with nuclei located at the base.
This tissue is specialized for absorption and secretion,which are the primary functions of the stomach and intestinal lining.
Therefore,the correct option is $D$.