All questions of Tissues (BIO) for MCAT Exam

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.

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.

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.

Ends of two long bones connected by ligaments.
But muscle and bone are connected by tendons.so option C.

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.

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.

Prothrombin is a component of blood which helps in blood coagulation .It is mainly synthesised by the liver . Prothrombin of blood plasma is converted to thrombin in the presence of thromboplastin and calcium ion during blood clotting . Albumin is a globular protein , produced by the liver . Fibrinogen is a glycoprotein complex that circulate in the blood of vertebrate

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.

Thrombin converts fibrinogen into fibrin
the inactive form of thrombin is prothrombin

Epithelial tissue is a type of tissue that covers the surface of the body and lines various organs and cavities. It has several functions that include protection, secretion, and absorption. However, it does not perform the function of conduction.

Protection
Epithelial tissue serves as a protective barrier against physical, chemical, and biological damage. It protects the underlying tissues and organs from injury, abrasion, and invasion by microorganisms.

Secretion
Epithelial tissue also secretes various substances such as mucus, enzymes, and hormones. For example, the epithelial cells in the stomach secrete hydrochloric acid and digestive enzymes that aid in the digestion of food.

Absorption
Epithelial tissue is involved in the absorption of nutrients, water, and other substances from the external environment. For example, the epithelial cells in the small intestine absorb nutrients from digested food and transport them to the bloodstream.

Conduction
Epithelial tissue does not perform the function of conduction. Conduction refers to the transmission of nerve impulses from one nerve cell to another. This function is performed by nervous tissue, which is a separate type of tissue.

In conclusion, epithelial tissue performs several important functions such as protection, secretion, and absorption, but it does not perform the function of conduction.

Cartilage is avascular it means that there is no vessels to carry the blood to the cartilage tissue. It lies in the space called as lacunae with upto eight chondrocytes located in each. Cartilage is a flexible connective tissue that differs from the bones in several ways . It is also aneural i.e. lacks nerves.

6000 to 8000 according to ncert

The mesothelium is a membrane composed of simple squamous epithelium that forms the lining of several body cavities: the pleura (thoracic cavity), peritoneum (abdominal cavity including the mesentery), mediastinum and pericardium (heart sac).

Yes Immature RBC's are Known as reticulocytes.They are devoid oF nucleus Just like Mature RBC.

Loose connective tissue is a category of connective tissue which includes areolar tissue, reticular tissue, and adipose tissue. ... Cells called fibroblasts are widely dispersed in this tissue; they are irregular branching cells that secrete strong fibrous proteins and proteoglycans as an extracellular matrix.

White fibrous connective tissue are of 2 types:
1) Regular
2) Irregular
Tendons belong to dense regular white fibrous connective tissue as it is made up of collagen fibres and having no intercellular spaces , arranged in regular manner containing macrophage nd mast cells in abundant amount .

Epithelial tissue is a type of tissue that covers the surface of the body and lines the cavities and organs within the body. It is composed of tightly packed cells that are specialized to perform specific functions. There are several types of epithelial tissue, including simple squamous, simple cuboidal, simple columnar, stratified squamous, and transitional.

Thin flat cells appearing like packed tiles are characteristic of simple squamous epithelium. This type of epithelial tissue is found in areas where rapid diffusion or filtration is necessary. The correct option in this case is option D, which is the inner lining of the cheek.

Explanation:

The inner lining of the cheek is composed of a thin layer of squamous epithelial cells that are tightly packed together. These cells are flat and appear like packed tiles when viewed under a microscope. This type of epithelial tissue is ideal for the inner lining of the cheek because it allows for rapid diffusion of nutrients, oxygen, and waste products.

The inner lining of the ovary is composed of a layer of cuboidal epithelial cells that secrete hormones and support the development of eggs. The inner lining of the stomach is composed of a layer of columnar epithelial cells that produce mucus and digestive enzymes. The inner lining of the fallopian tubes is composed of ciliated columnar epithelial cells that help move the egg from the ovary to the uterus.

In conclusion, thin flat cells appearing like packed tiles are characteristic of simple squamous epithelium, which is found in areas where rapid diffusion or filtration is necessary. The correct option in this case is the inner lining of the cheek.

Mast cells are occur in connective tissue like blood they release histamine to dilate the blood vessels which makes them permeable for entry of WBC. They rush to site of infections. Connetive tissue are surrounding blood cells, smooth muscles, mucous etc.
So option " A " is correct answer.

Here the answer is B- Connective tissue it is mesodermal in origin.Connective tissue has three main components: cells, fibers, and ground substance. Together the ground substance and fibers make up the extracellular matrix.

Direct ncert 11th book page number 281

Blood is a fluid connective tissue as WBC r components of blood they are considered as part of connective tissue this may help u..

Cuboidal epithelium is a type of tissue that consists of cube-shaped cells. It is found in various parts of the body where secretion, absorption, and protection are required. However, there are certain places where cuboidal epithelium is not found. One such place is the vas deferens.

The vas deferens is a part of the male reproductive system that is responsible for transporting sperm from the epididymis to the urethra. It is a muscular tube that is lined by a different type of epithelial tissue known as pseudostratified columnar epithelium.

The pseudostratified columnar epithelium is characterized by its tall column-shaped cells that appear stratified but are actually single-layered. This epithelium is well-suited for the functions of the vas deferens as it provides a larger surface area for absorption and secretion. Additionally, it contains specialized cells called cilia that help in the movement of sperm.

The presence of pseudostratified columnar epithelium in the vas deferens instead of cuboidal epithelium is essential for its function. The movement of sperm requires the coordinated action of the muscles in the vas deferens, and the pseudostratified columnar epithelium allows for efficient absorption and secretion of fluids needed for sperm transport.

In contrast, cuboidal epithelium is found in other parts of the male reproductive system, such as the ducts of glands. It is also found in the tubular parts of the nephron in the kidneys, where it plays a role in reabsorption and secretion. Additionally, cuboidal epithelium is present in the germinal epithelium of the gonads, which is responsible for the production of gametes.

In conclusion, the cuboidal epithelium is not found in the vas deferens. Instead, the vas deferens is lined by pseudostratified columnar epithelium, which is better suited for its function in sperm transport.

Hey student, In this lesson, we will cover

0:6a very important respiratory pigment,

0:9which is haemoglobin. Haemoglobin, it is a

0:13very, very important respiratory pigment,

0:15which is present in the RBC's. So, each

0:19molecule of RBC, it contains around 26

0:24crores of haemoglobin molecules in them.

0:27Now when we talk about haemoglobin, if we see its

0:30composition, we see that it has 2 parts.

0:33The first , in here, we can see is the

0:36haem.

0:38This is a haem and next to it, is the

0:43globin. So, these are the two parts of

0:48haemoglobin. Now, when we talk about

0:51haem, haem basically refers to the iron.

0:54So, haem is formed of again two

0:56components, which is iron and a

1:3porphyrin. So, porphyrine, it is a ring like

1:8structure in which the iron is present

1:11in here. Now, when we talk about the iron,

1:14we see that the iron which is present

1:16in the haemoglobin, it is present in the

1:19form of ferrous meaning fe2 plus but the

1:25haemoglobin which is present in the

1:27muscle cells, it is called myoglobin. And

1:30in myoglobin, this iron is present in

1:33the form of ferric which is Fe 3 plus. So

1:38myoglobin has fe 3 plus form of iron and

1:41haemoglobin has fe 2 plus form of iron. Now,

1:46when we are talking about the porphyrin

1:47ring, we say that, it is made up

1:50of two parts, the first is the acetic

1:56acid and it is also containing the

2:1glycine amino acid. So, we have seen

2:7that the haem part of haemoglobin, it

2:10contains iron and porphyrin. In the

2:13ring of porphyrin, iron is located in

2:15the center. So it contains this iron part

2:19and the porphyrin ring is made up of

2:22acetic acid and glycine amino acid.

2:25Now, coming to the globin part, in

2:29the globin part we see that it is the

2:31protein part. And each molecule of this

2:35protein, it is made up of four types of

2:38polypeptide chains. Now let's see what

2:42are these polypeptide chains? So, if I

2:45show you, in here, there are four types of

2:49polypeptide chain.

2:51The first one is called alpha

2:53polypeptide chain, the next is the beta

2:56polypeptide chain,

2:58next we see it is gamma and lastly is

3:2the delta. So, alpha, beta, gamma and delta

3:6polypeptide chains. They form a

3:9single molecule of protein. Now, in alpha

3:14polypeptide chain, basically, there are

3:16present 141 amino acids, whereas in

3:22all the rest three, there are present

3:25around 146 amino acid. So, this is the

3:32composition of these polypeptide chains.

3:35Now on the basis of, you know, these four

3:38polypeptide chains, there can be found

3:40three types of haemoglobin. Let's see what

3:44are they. So, the first one is the HbA

3:49meaning the adult haemoglobin.

3:53So this adult haemoglobin, it is found

3:56approximately like 95 to ninety-seven

3:59percent in a human adult and it is formed

4:3of two polypeptide chains of alpha

4:7plus two polypeptide chains of beta.

4:12So, this is the haemoglobin of an

4:15adult,

4:16okay? or we call it adult haemoglobin. So the next

4:19is HbA2, so this is the

4:25second type of a adult haemoglobin which is found

4:28to be like 2 to 3 percent only.

4:30Now, this is formed of two alpha

4:35polypeptide chains plus two Delta

4:39polypeptide chain. So this is the second

4:42type of adult haemoglobin. The third

4:45type is HbF, meaning the fetal haemoglobin.

4:49Now, this fetal haemoglobin, it is formed of

4:52two polypeptide chains of alpha plus two

4:58polypeptide chains of gamma. So we have

5:1seen, that the globins, these are the

5:4protein molecules and they can be formed

5:7of the four types of polypeptide chains.

5:9These can be HbA, HbA 2 and HbF, which

5:14are the three types of haemoglobin and

5:17these three types, we have seen that the

5:19composition is somewhat like this. Now

5:23moving forward if we talk about

5:24haemoglobin ,its function basically, so the

5:27basic function of haemoglobin is to, it

5:30carries the oxygen. So a single molecule

5:33of haemoglobin, it carries 4 molecules

5:36of oxygen and also if we see one gram of

5:42haemoglobin, we will write HB, it carries around 1.34

5:50ml of O2,

5:52okay? So one gram of haemoglobin, it carries

5:55around 1.3 ml of O2. Now, we see that

6:1hundred ml of blood, how much haemoglobin

6:7is present in hundred ml of blood ? It is

6:915 gram, approximately 15 gram, So, now

6:15can we find out that hundred of ml of

6:17blood will have how much amount of

6:19oxygen ?

6:20It will be simple, multiplying

6:251.34 into 15 grams, which

6:29will make it somewhere up to 20 ml of

6:33oxygen. So this way, we have found out

6:37that when one gram of haemoglobin carries

6:401.34 ml of oxygen, we see that hundred ml

6:45of blood carries 20ml of oxygen because

6:49hundred ml of blood has 15 gram of

6:52haemoglobin present in it . Now it is very,

6:55very important for you to note, that the

6:57haemoglobin F which is the fetal

6:59haemoglobin. It has higher affinity of

7:1oxygen towards itself as compared to

7:4the haemoglobin of an adult. So students,

7:8in this lesson you have learned that the

7:10haemoglobin has two parts, the haem and

7:13the globin. Haem is basically the iron

7:16and porphyrin and globin is the

7:18protein part. On the basis of the

7:21different polypeptide chains, there can

7:22be three types of haemoglobin and the

7:25major function of haemoglobin, as it acts

7:28like a respiratory pigment is to carry

7:31oxygen.

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