Question

Answer the questions below regarding the Histology:

1. Key characteristics of epithelial tissues

2. what simple refers to? stratified refers to? Preustratified refers to? squamous and cuboidal cells refers to?

3. Explain how many layers, shape of cells, in which organ can be found,what is the function of each tissue of Simple Squamous epithelium, simple cubodial epithelium, simple columnar epithelium, stratified squamous epithelium, pseudostratified columnar epihelium, transitional epithelium.

4. Explain the exocrine and endocrine gland in pancreas. a.Locate the islets of langerhans(secret hormones) in endocrine gland. explain its function a bit.

b. Locate the acinar portion in exocrine gland. Explain a bit its function.

You can post some images for or draw for illustration of each too. but dont skip any part please.

thank you.

Answer 1

Epethelium tissue is the covering or protective tissues in the animal body. most of the organs and cavities within the body are covered by Epithelium.

the key features of epithelium

Epithelium is a closely packed, flattened cells. There is little intercellular material between the cells. The main function of the tissue is to cover and protect our boady.

There are no without blood vessels in the tissue (avascular). Nutrient and waste exchange occurs through neighboring connective tissues by diffusion.

The upper surface of epithelium is exposed to the outside of the body or to an internal body cavity. The basal surface rests on connective tissue. A thin, extracellular layer called the basement membrane forms between the epithelial and connective tissue.

Simple epithelium: it has only one cell layer. every cell is in direct contact with the underlying basement membrane. as it is fragile in nature, this type of epithelium is found inside the body.it forms the lining of the body cavities, blood and lymph vessels, heart and respiratory system etc.

stratified epithelium: it consists of  multiple layers. where only the bottom layer of cells is in contact with the extracellular matrix.

Pseudostratified epithelium: a single layer of cells of different sizes, giving the appearance of multilayer. It contains epithelial cells that appear to be arranged in layers but which are all in contact with the extracellular matrix.

squamous epithelial cell: It is a large flattened cell with abundant cytoplasm and small round central nucleus. It is generally flat kind of epithelium. it is mainly found in urinary tract, lungs alveoli etc. where where transportation of substances occurs through a selectively permeable surface.

Cuboidal epithelium: it is  cube‐ or hexagon‐shaped with a central, round nucleus. Main function of it is to provide mechanical support. it forms the lining of kidney tubules and ducts of salivary glands.

Simple Squamous epithelium: it is a single layered epithelium. it is found in Air sacs of the lungs and the lining of the heart, blood vessels and lymphatic vessels. it allows  materials to pass through by diffusion and filtration, and secretes lubricating substances

simple cubodial epithelium:  it is a single layered epithelium, cells are cuboidal in shape. it is found in  ducts and secretory portions of small glands and in kidney tubules. Secretion and absorbtion are the main function of it.

simple columnar epithelium : it is a single layered epithelium eith tall cells. it is found in Ciliated tissues including the bronchi, uterine tubes, and uterus,etc. absorbtion is the main function of it. it also secretes mucous and enzymes.

stratified squamous epithelium: it is multi layered. squamous cells are seen apically but cuboidal or columnar cells are found in basel layer.  it is found in  Lines the esophagus, mouth, and vagina.the main function is  Protection against abrasion.

pseudostratified columnar epihelium : Pseudostratified columnar epithelium is a type of epithelium that appears to be stratified but instead consists of a single layer of irregularly shaped and differently sized columnar cells.  it is found in Ciliated tissue lines the trachea and much of the upper respiratory tract. the main function of it is Secretion of mucous and ciliated tissue moves mucous.

transitional epithelium: Transitional epithelium is a type of stratified epithelium. it consists of multiple layers of epithelial cells. it has cells with shapes that fall between cuboidal and squamous. it is found in walls of the bladder, urethra and ureters. it allows the urinary organs to expand and stretch.