Skip to main content

Renin Angiotensin Mechanism.

Gas Exchanges Between the Blood, Lungs, and Tissues.

 

Gas Exchanges Between the Blood, Lungs, and Tissues:

  • The purpose of the respiratory system is to perform gas exchange.

  • It is divided into following phases:

    • External Respiration.

    • Internal Respiration.

    • Oxygen Transport.

    • CO2 Transport.

  • External Respiration:

  • Pulmonary artery carries deoxygenated blood to the lungs where it forms respiratory membranes (basement membranes of blood capillary and alveoli are fused with each other) with alveoli.

  • Because of differences in partial pressure of oxygen and CO2 in blood and alveoli, the gases move from higher concentration to lower concentration.

  • Deoxygenated blood contains less partial pressure of Oxygen than alveoli and hence oxygen diffuses in the blood.

  • Deoxygenated blood contains higher CO2 partial pressure as compared to alveoli and hence diffuses from blood into alveoli.

  • The resulting oxygenated blood is sent to the heart by pulmonary veins.

  • Internal Respiration:

  • The heart pumps oxygenated blood into the aorta which supplies oxygenated blood to the entire body through its branches.

  • The capillary carrying oxygenated blood reaches tissues where partial pressure of oxygen is less as compared to blood, this results in diffusion of oxygen from blood into tissues.

  • The partial pressure of CO2 is higher in tissues as compared to in blood capillaries, this results in diffusion of CO2 from tissue to blood capillaries.

  • Now this deoxygenated blood is collected via superior vena cava and inferior vena cava and transported to the heart.

  • The heart transfers this collected deoxygenated blood to the lungs via the pulmonary artery for oxygenation.

  • Oxygen Transfer:

    • The oxygen has little water solubility and hence dissolves in little amounts in plasma which diffuses directly into the cells.

    • Around 2% of oxygen is dissolved in plasma.

    • About 98% of oxygen in blood combines with Hemoglobin to form a complex called “Oxyhemoglobin”.

    • Oxyhemoglobin dissociates radially on reaching the cells having lower Oxygen partial pressures and oxygen diffuses in the cells.

  • Carbon dioxide Transfer:

  • Carbon dioxide is formed in the cell as an end product of many reactions and is one of the major excretory products of cells.

  • The CO2 dissolves in little amounts in the interstitial fluid surrounding the cells, which diffuses easily in the blood capillaries (around 2%).

  • Majority of CO2 diffuses directly in Red Blood Cells from tissues due to concentration differences.

  • The large concentration of CO2 (70%) reacts with water in RBC to form Carbonic Acid (H2Co3).

  • The formed carbonic acid is broken down to water and bicarbonate ions (HCO3-) ions by the action of the enzyme “Carbonic Anhydrase”.

  • The bicarbonate ions enter the plasma from RBC and maintain the pH of blood.

  • Some part of Co2 entered in RBC (20%) reacts with hemoglobin and forms a complex called “Carbaminohemoglobin”.

  • On reaching the lungs, the dissolved CO2 in plasma directly diffuses in alveoli.

  • The carbaminohemoglobin complex dissociates as partial air pressure of CO2 is higher in alveoli than in blood; the free CO2 diffuses into the alveoli for exchange with oxygen.

  • The bicarbonate ions dissolved in plasma renters RBC and combines with water to form Carbonic acid, the formed carbonic acid dissociates into water and carbon dioxide.

  • The formed carbon dioxide diffuses into alveoli.

Commonly Asked question.

  1. Write a note on Internal and External Respiration.

  2. Write in detail about Gas Exchanges Between the Blood, Lungs, and Tissues.
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 ...
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 ...
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...
Read more