All questions of Structural Organisation in Animals for NEET Exam

Anal styles are present only in male cockroach

The luminal surface of the tonsils are covered with a stratified squamous epithelium (in common with the oral epithelia). ... The epithelial cells are able to phagocytose bacteria, and transfer them to macrophages, which then present the foreign antigens to B-cells, which are activated (with the help of T cells).

The ependyma is made up of ependymal cells called ependymocytes, a type of glial cell. These cells line the CSF-filled ventricles in the brain and the central canal of the spinal cord. These are nervous tissue cells with a ciliated simple columnar shape much like that of some mucosal epithelial cells.

Simple columnar cells are found In major organs like stomach as it plays a very important role in secretion and absorption.

Larynx is lined by ciliated pseudostratified columnar epithelium except vocal cords (lined by stratified squamous epithelium). The wall of larynx is reinforced by cartilage tissue. Large cartilages (cartilago thyroidea, cartilago cricoidea) and part of cartilago arytenoidea are composed of hyaline cartilage.

Ciliated pseudostratified columnar epithelia are found in the linings of the trachea as well as the upper respiratory tract. Non-ciliated pseudostratified columnar epithelia are located in the membranous part of male vas deferens. Most of the respiratory passageways, from the nasal cavity through the bronchi, are lined by ciliated, pseudostratified columnar epithelium with goblet cells.

Transitional epithelium is a type of tissue consisting of multiple layers of epithelial cells that contract and expand. This tissue structure type is found in urothelium, including that of the urinary bladder, the ureters and the superior urethra and gland ducts of the prostate. Transitional epithelium is stretchable and waterproof. The cells of transitional epithelium are highly keratinized and contain tight junctions or virtually impenetrable junctions, that seal together the cellular membranes of neighboring cells. This barrier prevents reabsorption of toxic wastes and pathogens by the bloodstream.

Tessellated epithelium is another term used for simple squamous epithelium also called as pavement epithelium due to it's flat appearance. It is mainly present in the alveoli and blood capillaries and performs the function of diffusion.

The compound epithelial tissue consists of two or more layers of cells. They form stratified layers. In the skin, they have a protective function. They do not have much of a role in absorption and secretion. Their function is to provide protection against any form of mechanical or chemical stress. The compound epithelium can be found on the dry surface of the skin, buccal cavity, pharynx, the lining of the salivary glands ducts and pancreatic ducts.

Ciliated Epithelium

Ciliated epithelium refers to a type of epithelial tissue that consists of cuboidal or columnar cells with cilia. Cilia are hair-like structures present on the surface of these cells that play a crucial role in various physiological processes.

Structure of Ciliated Epithelium

- Cell Shape: The cells of ciliated epithelium are typically cuboidal or columnar in shape.
- Cilia: These cells bear numerous cilia, which are microtubule-based structures extending from the cell surface. Cilia are composed of a central pair of microtubules surrounded by nine pairs of microtubules in a ring-shaped structure called the axoneme.
- Basal Body: Each cilium arises from a basal body, which is a modified centriole located at the base of the cilium.
- Function: The cilia in ciliated epithelium have rhythmic beating movements that facilitate the movement of various substances across the epithelial surface.

Functions of Ciliated Epithelium

Ciliated epithelium serves several important functions in different parts of the body:

- Mucociliary Escalator: In the respiratory tract, ciliated epithelium lines the airways and helps in the clearance of mucus and foreign particles. The coordinated beating of cilia propels the mucus upward, away from the lungs, preventing the accumulation of debris and pathogens.
- Oocyte Transport: In the female reproductive system, ciliated epithelium in the fallopian tubes helps in the transport of oocytes from the ovaries to the uterus. The beating of cilia creates fluid currents that aid in moving the oocytes towards their destination.
- Cerebrospinal Fluid Circulation: Ciliated epithelium lines the ventricles of the brain and the central canal of the spinal cord. The rhythmic beating of cilia in these regions facilitates the circulation of cerebrospinal fluid, which helps in maintaining the brain and spinal cord environment.
- Smell and Taste Sensation: Cilia on the olfactory receptor cells in the nasal cavity and taste receptor cells in the taste buds help in detecting and transmitting sensory signals related to smell and taste.

In conclusion, cuboidal or columnar cells with cilia are called ciliated epithelium. These cells play vital roles in various physiological processes such as mucociliary clearance, oocyte transport, cerebrospinal fluid circulation, and sensory perception.

Epididymitis care involves rest for 1 – 2 days with the scrotum raised if possible. The aim is to get the inflamed area above the level of the heart. This helps blood flow, which lowers swelling and pain, and helps with healing. Putting ice on the scrotum now and then can also help.

The sarcolemma is the cell membrane of the striated muscle fibre cell. It is also known as the myolemma. The function of the sarcolemma is similar to the function of the plasma membrane of eukaryotic cells. The plasma membrane covering the muscle fibre is known as the sarcolemma.

A brush border (striated border or brush border membrane) is the microvilli-covered surface of simple cuboidal epithelium and simple columnar epithelium cells found in certain locations of the body.

Explanation:The Membrane of Krause, also known as the Z line, bisects the I band or isotropic band. Here's a brief explanation of the different components involved:- I band or isotropic band: - The I band is a lighter, less dense region in a sarcomere. - It contains only thin (actin) filaments. - The I band bisected by the Z line, dividing it into two equal halves.- Z line (Membrane of Krause): - The Z line is a dark membrane that appears in the middle of the I band. - It serves as the attachment site for the thin filaments and helps maintain the structure of the sarcomere. - The Z line plays a crucial role in muscle contraction by anchoring the thin filaments and transmitting the force generated during contraction.- A band or anisotropic band: - The A band is a darker, more dense region in a sarcomere. - It contains both thin (actin) and thick (myosin) filaments. - The A band remains constant in length during muscle contraction.- Henson's line: - Henson's line, also known as the M line, is situated in the middle of the A band. - It consists of proteins that help to hold the thick filaments in place and maintain the structure of the sarcomere.- Sarcomere: - The sarcomere is the functional unit of a muscle fiber, responsible for contraction. - It is composed of various bands, lines, and filaments, including the A band, I band, Z line, and Henson's line. - Sarcomeres are organized in series within a muscle fiber, and their coordinated contraction results in the overall shortening of the muscle fiber and generation of force.In summary, the Membrane of Krause or Z line bisects the I band or isotropic band, dividing it into two equal halves and providing attachment sites for the thin filaments within the sarcomere.

Transitional epithelium is a stratified tissue made of multiple cell layers, where the cells constituting the tissue can change shape depending on the distention in the organ. When the organ is filled with fluid, cells on the topmost layer of this epithelium can stretch and appear flattened. Alternately, they can also appear cuboidal with a rounded shape when the fluid pressure is low.


This epithelium is found lining the urinary bladder, ureters and urethra, as well as in the ducts of the prostrate gland.

The image shows a cross section of the bladder with an inset displaying the histology of the epithelium, the underlying connective tissue (lamina propria) and submucosa.

Simple Epithelial Tissue

Simple epithelial tissue is a type of tissue that is composed of a single layer of cells. These cells are tightly packed together and cover a surface or line a cavity. Simple epithelial tissue is classified based on the shape of the cells.

Types of Simple Epithelial Tissue

a) Squamous epithelium - This type of simple epithelial tissue is composed of flat, thin cells that allow for the rapid diffusion of substances. Squamous epithelium is found in areas where rapid diffusion is necessary, such as the alveoli of the lungs.

b) Cuboidal epithelium - This type of simple epithelial tissue is composed of cube-shaped cells that are involved in secretion and absorption. Cuboidal epithelium is found in the glands and tubules of the kidney.

c) Columnar epithelium - This type of simple epithelial tissue is composed of tall, elongated cells that are involved in absorption and secretion. Columnar epithelium is found in the lining of the stomach and intestines.

d) Compound epithelium - This is not a type of simple epithelial tissue. Compound epithelium is composed of multiple layers of cells and is found in areas that require protection, such as the skin.

Conclusion

Simple epithelial tissue is an important type of tissue that plays a crucial role in the functioning of many organs and tissues in the body. It is classified based on the shape of the cells and includes squamous, cuboidal, and columnar epithelium. Compound epithelium is not a type of simple epithelial tissue.

The free surface may have microvilli. They are present in the lining of the stomach and intestine. Its functions include absorption and secretion. Ciliated Epithelium – When the columnar epithelial tissues have cilia, then they are called the ciliated epithelium.

The corneal epithelium is the outermost layer of the cornea. It is composed of a single layer of basal cells and 4-5 cell layers of nonkeratinized, stratified squamous epithelial cells, which are held together by tight junctions, to form an effective barrier against fluid loss and pathogen penetration.

The term epithelium was introduced in 18th century by Duth Anatomist Ruysch to refer to the fact that these tissue grow upon other tissues.

The basement membrane is composed of two layers, the basal lamina and the underlying layer of reticular connective tissue. The clear layer closer to the epithelium is called the lamina lucida, while the dense layer closer to the connective tissue is called the lamina densa.

Endothelium refers to cells that line the interior surface of blood vessels and lymphatic vessels, forming an interface between circulating blood or lymph in the lumen and the rest of the vessel wall. It is a thin layer of simple, or single-layered, squamous cells called endothelial cells.

The cellular covering of internal and external surfaces of the body, including the lining of vessels and other small cavities. It consists of cells joined by small amounts of cementing substances. Epithelium is classified into types on the basis of the number of layers deep and the shape of the superficial cells. Cuboidal epithelium epithelium whose cells are of approximately the same height and width, and appear square in transverse section.

The gland is composed of columnar epithelium, and ducts are lined by stratified squamous epithelium and transitional cell epithelium. ... The Bartholin complex consists of a duct that is lined by squamous epithelium as it enters the distal vagina.

Yes..this is really a good question Saurabh.In infants brown fat is nearly 5% and located on the back,along the upper half of the spine and toward the shoulders.It is present because it over comes lethal cold(hypothermia)which is a main cause for death of infants.Hope my answer is useful..any queries if I can,I will answer.

The inability of the heart to generate tetanic contractions is the result of the long absolute refractory period of cardiac muscle, defined as the period during and following an action potential when an excitable membrane cannot be re-excited. The refractory period lasts almost as long as the contraction.

VitB12 and folic acid required for maturation of rbc.Haemoglobin required for transporting co2 and o2.

Astrocytes contribute to induction and maintenance of the blood–brain barrier through paracrine interactions with the pericytes and endothelial cells. Astrocytes secrete classes of factors with either barrier-promoting or barrier-disrupting effects depending on signals received from neurons and/or endothelial cells.

The blood-brain barrier restricts the passage of pathogens, the diffusion of solutes in the blood, and large or hydrophilic molecules into the cerebrospinal fluid, while allowing the diffusion of hydrophobic molecules (O2, CO2, hormones) and small polar molecules.[4] Cells of the barrier actively transport metabolic products such as glucose across the barrier using specific transport proteins