Skip to main content

Renin Angiotensin Mechanism.

Nephron: Structural & Functional unit of Kidney.

 

Introduction.

  • Structural and functional unit of kidney.

  • Each kidney contains around “ One Million” nephrons.

  • Present in the renal cortex as well as in renal medulla. 

  • Two types:

    • Cortical Nephrons: 

      • Superficial.

      • Originate in the cortex and extend for a short distance in medulla.

      • Constitute around 80-90% of the total nephrons.

    • Juxtamedullary Nephrons:

      • Lie deeper.

      • Originate at the junction of medulla and cortex, go deeper in medulla.

      • Constitute around 10-20% of the total nephrons.

  • Each nephron consists of two units:

    • Renal corpuscle. (Filtration Unit) It is made up of,

      • Glomerulus.

      • Bowman's Capsule

    • Renal Tubule. (Transportation Unit) it is made up of,

      • Proximal Convoluted Tubule (PCT).

      • Loop of Henle.

      • Distal Convoluted Tubule. (DCT)

Renal Corpuscle:

  • It is a filtering chamber where plasma is filtered.

  • It has two components,

    • Glomerulus.

    • Bowman’s Capsule.

  • Glomerulus is a bunch of capillaries, blood enters in glomerulus via afferent arteriole and exits through efferent arteriole.

  • Afferent arteriole has a large diameter and efferent arteriole has a smaller diameter, this difference between diameters causes increase in pressure inside glomerulus which facilitates filtration.

  • Bowman's capsule is a funnel shaped part of nephron surrounding glomerulus.

  • Bowman's capsule’s outer wall called the parietal layer is separated from the inner wall called the visceral wall by a space called “Capsular Space”.

  • Bowman's capsule and glomerulus together form a “malpighian body”.

  • Juxtaglomerular apparatus is a specialized structure of cells that plays an important role in blood pressure maintenance. 

  • “Filtration Membrane” is the contact point between glomerular capillaries and Bowman’s Capsule.

  • Blood from afferent arteriole enters glomerulus and is filtered i.e. blood cells, protein molecules are retained in capillary while plasma with solutes with smaller size escape from small pores on capillaries to capsular space and then to the renal tubule.

Renal Tubule:

  • It starts from a bowman's capsule and ends at collecting tubules.

  • Anatomically it is divided into three parts,

  1. Proximal Convoluted Tubule (PCT).

  2. Loop of Henle.

  • Ascending Loop of Henle.

  • Descending Loop of Henle.

  1. Distal Convoluted Tubule (DCT).

  1. Proximal Convoluted Tubule (PCT): 

  • It starts from Bowman’s capsule and continues down the descending loop of Henle.

  • It has an inner lining of cuboidal epithelium having a microvilli brush border (just like epithelial cells in the small intestine), which increases surface area for fluid absorption.

  • It absorbs ions like Na &  Cl, water and glucose.

  • It absorbs actively hence contain very large number of mitochondrias to produce ATPs

  1. Loop of Henle:

  • It is divided into two parts,

    • Descending Loop of Henle. (part going downwards)

    • Ascending Loop of Henle. (part going upwards)

  • It is present between PCT and DCT and has a sharp hairpin like structure.

  • It deals with maximum fluid absorption, it is more long in animals present in the desert.

  1. Distal Convoluted Tubule (DCT):

  • The highly coiled part starts after the ascending Loop of Henle.

  • It contains simple cuboidal epithelium.

  • It is shorter as compared to PCT.

  1. Collecting Duct:

  • DCT continues to form collecting ducts.

  • Collecting ducts are connected to many nephrons.

  • It contains columnar epithelium.

Commonly Asked Questions.

  1. Draw a well labeled diagram of the Nephron.

  2. With a well labelled diagram discuss the structure of Nephron.

  3. With a well labelled diagram of Nephron discuss the process of Urine formation.
Labels:

Popular posts from this blog

Rate of Drying Curve.

  Definition Drying is defined as the removal of liquid from a product usually with application of heat. Rate of Drying Curve. Drying process can be divided into three periods Initial Adjustment Period. Constant drying rate period. First falling drying rate period. Second falling rate period. Initial Adjustment Period (A-B): Also called the “ Heating up” period . In this period the substance gets heat and increases in temperature. Drying has not yet started. Constant drying rate period (B-C): During this period the temperature of the solid and the rate of drying remain constant. The moisture evaporating from the surface is replaced by water diffusing from the interior of the solid at a rate equal t o the rate of evaporation.  The moisture content at the end of constant rate (point C) is referred to as the critical moisture content (CMC).  At CMC, dry spots start appearing and drying rate starts falling . First falling drying rate period (C-D): This period is also called the period of
Read more

Heat Exchangers and Heat Interchangers.

  In pharmaceutical industries many types of equipments are used for transfer of heat, they can be classified as follows, Heat Exchangers. Heat Interchangers. Heat Exchangers: These devices are used for transferring heat from a fluid (Hot Gas or Steam) to another fluid (Liquid) through a metal wall. Heat Interchangers: These devices are used for transferring heat from a One liquid to another liquid or one gas to another gas through a metal wall. HEAT EXCHANGERS; The equipment used for heat transferring are known as heat exchangers. Some of the processes that involves heat transfer in pharmaceutical industries are: Preparation of starch paste (in steam jacketed kettle). Crystallization. Evaporation. Distillation.  Classification of heat exchangers On the basis of transfer of heat, heat exchangers are classified as: Direct transfer type:  The hot and cold fluids are separated by a metal wall through which the heat is transferred from hot fluid to cold fluid. E.g. shell and tube heater, 
Read more

Flash Distillation.

  Principle: When a hot mixture is allowed to enter from a high-pressure zone into a low pressure zone, the entire liquid mixture is suddenly vaporized. This process is known as flash vaporization .  During this process, the chamber is cooled.  The less volatile fraction is condensed and the more volatile component remains in the vapor phase .  This process requires time, hence liquid and vapor are kept in intimate contact until equilibrium is achieved. Flash distillation is also called equilibrium distillation because separation of two liquids takes place when liquid and vapor phases are at equilibrium. Equipment used for Flash Distillation: Construction: It consists of a pump, which is connected to a feed reservoir.  Pumps help in pumping the feed into the heating chamber.  The heating chamber is heat supplied by steam.  The other end of the pipe is directly introduced into the vapor-liquid separator through a reducing valve.  The vapor outlet is provided at the top of the separato
Read more