Skip to main content

Renin Angiotensin Mechanism.

Compound Microscope.

 Compound Microscope.

Introduction:

  • Generally an object smaller than 0.1 mm cannot be seen by our eyes. Therefore, to observe an object smaller than this, an instrument is used called “Microscope”. 

  • Microscope was first invented by a Dutch spectacle maker, Zaccharias Janssen. 

  • Different types of Microscopes are available today which offer different functionalities and greater magnification.

  • Compound microscopes are generally used in the laboratories. 

Parts of a Compound Microscope.

  • The parts of a compound microscope can been divided into 4 main parts: 

  1. Base : 

    • This is the U-shaped lower portion of the microscope on which the other parts of the microscope are placed. 

    • Above the U-shaped portion, there is a perpendicular portion known as the pillar. 

    • On the top of this, another arm is fixed, this is known as inclination joint. 

    • An inclination joint can be used to tilt the microscope at a desired angle.

  2. Arm : 

    • It supports the body tube and base of the microscope. 

    • This portion is used to hold or carry the microscope. 

    • On the basis of this, the stage is fixed. 

    • On the top of the arm body tube of the microscope is fixed and two knobs are fitted. 

    • One is for the coarse adjustment and the other for the fine adjustment. 

    • These are used for focussing the body tube.

  3. Body Tube : 

    • This is attached to the knob of the arm. 

    • It has one lens on the upper end known as an eyepiece. 

    • This lens can be changed according to the required magnification. 

    • On the bottom of this tube there is a nose piece. 

    • Two to four lenses can be fitted in this nose piece. 

    • Because the lenses are fitted on the objective, these are known as objective lenses. 

    • These are fitted in the body tube, known as the objective lens body. The objective lens body is fitted into the noise piece. 

  4. Stage : 

    • It is a platform having a circular hole in the centre to allow the passage for light from below. 

    • It is fixed to the base by the stand. 

    • One mirror is fixed to the stand, it is known as a reflecting mirror. 

    • Below the stage is a condenser through which a concentrated beam of light passes. 

    • Iris diaphragm is also attached to the condenser. 

    • The reflecting mirror reflects the light upward through the iris and diaphragm. This beam of light passes through the hole in the stage and provides light to the object kept on the slides.

    • There are two clips for holding the slide above the hole on the stage.

Operating the Compound Microscope.

  1. To use the microscope first of all rotate the nosepiece until the low power objective is in line with the body tube and clicks into position. 

  2. Open the iris diaphragm. 

  3. Look through the eyepiece, adjust the mirror and diaphragm to set a complete field of vision. 

  4. Place the slide you want to examine on the stage of the microscope and by the help of the clip fix it. 

  5. Move the slide till the object comes roughly to the centre of the hole or the stage. 

  6. Bring the object into focus using the coarse adjustment knob. 

  7. Turn the fine adjustment knob to bring the object into sharp focus. 

  8. The multiplication of magnification of eyepiece and nosepiece denotes “Magnification Power” of the microscope.

Maintenance of Compound Microscopes:

  • Microscope is a costly equipment & should be handled carefully. 

  • Always keep the microscope in an upright position while moving it from one place to another. 

  • Carry it holding the arm by one hand and supporting the base by another hand.

  • As far as possible don’t tilt the arm. 

  • Clean the lenses of the microscope with the lens paper or muslin cloth, never use the filter or any other kind of paper. 

  • If you are using the high power objective lens then after the observation is over, turn the nose piece and bring a low power objective lens in line with the hole in the stage. 

  • Objective lenses should be kept at least 1 cm above the stage. 

  • After using the microscope, always keep it in the box. 

  • Take care to see that the stage of microscope, the eye piece, the objective lens are dry and clean. No chemical should stick to these. 

  • Adjustment knobs and joints should be protected from rusting by applying petroleum jelly.
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