Breathing and Exchange of Gases Class 11 Notes

 

Breathing and exchange of gases




Introduction


· Oxygen (O2 ) is utilised by the organisms to indirectly break down nutrient molecules like glucose and to derive energy for performing various activities. 
· Carbon dioxide (CO2 ) which is harmful is also released during the above catabolic reactions. It is, therefore, evident that O2 has to be continuously provided to the cells and CO2 produced by the cells have to be released out.
· The process of exchange of O2 from the atmosphere with CO2 produced by the cell is called breathing. It occurs in two stages of alleviation and expiration. 
· During alleviation air enters the lungs from atmosphere and during expiration air leaves the lungs.
· Earthworms use their moist cuticle and insects have a network of tubes (tracheal tubes) to transport atmospheric air within the body.
· Special vascularised structures called gills are used by most of the aquatic arthropods and molluscs whereas vascularised bags called lungs are used by the terrestrial forms for the exchange of gases

Breathing and Exchange of Gases Class 11 Notes


Breathing

·   It's simply an input of fresh air and junking of foul air.
·   It's a physical process.
·   No energy is released.
·   It's an extracellular process.


Breathing and Exchange of Gases Class 11 notes for 

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Respiration

·        It's the oxidation of food to form carbon dioxide, water and energy.
·        It's a biochemical process.
·        Energy is released in form of ATP.
·        It's an intracellular process.


Respiratory Organs – Medium of breathing varies in different organism according to their body structure and niche.

 

 



 

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Humans Respiratory System

 

· Human’s respiratory system consists of a brace of nostrils, pharynx, larynx, bronchi and bronchioles that eventually terminates into alveoli.
· Nasal chamber open into pharynx that leads to larynx. Larynx contains voice box (sound box) that help in sound product.
·The trachea, primary, secondary and tertiary bronchi and original bronchioles are supported by deficient cartilaginous rings to help collapsing in absence of air.
·  Each bronchiole terminates into an irregular walled, vascularized bag like structure called alveoli.

·  The branching network of bronchi, bronchioles and alveoli inclusively form the lungs.
· Two lungs are covered with double concentrated pleura having pleural fluid between them to reduce the disunion on lung face.

 

Breathing and Exchange of Gases Class 11 notes for NEET PDF

 

Conducting parts

·  Include nostrils, pharynx, larynx and trachea. Main functions include-
·  Transport of atmospheric air to alveoli.
·  Removing foreign patches from air, humidifying it and bringing it to body temperature.
·  The exchange parts are alveoli. It's the point of factual prolixity of O2 and CO2 between blood and atmospheric air.
 

Breathing and Exchange of Gases Class 11 Notes


Steps of Respiration

·    Breathing in which Oxygen rich atmospheric air is diffused in and CO2 rich alveolar air is diffused out.

·    Prolixity of gases across alveolar membrane.

· Transport of gases by blood

·    Prolixity of O2 and CO2 between blood and tissues.

·   Application of O2 by cells to gain energy and release of CO2 (cellular respiration).

 

 Mechanism of Breathing

 

·     Breathing involves alleviation and expiration. During alleviation atmospheric air is drawn in and during expiration, alveolar air is released out.
·    Movement of air in and out takes place due to difference in pressure grade.
·    Alleviation occurs when pressure inside the lung is less and expiration occurs when pressure is more in lungs than outdoors.
·     The diaphragm and external and internal intercostal muscles between the caricatures help in developing pressure grade due to change in volume.
·     The compression of intercostal muscles lifts the caricatures and sternum causing an increase in volume of thoracic depression that results in drop in pressure than the atmospheric pressure. This causes alleviation.
·     Relaxation of the diaphragm and intercostal muscles reduce the thoracic volume and increase the pressure causing expiration.
·     The volume of air involved in breathing movements is estimated by using spirometer for clinical assessment of pulmonary functions.

 

Breathing and exchange of gases Notes PDF


Respiratory Volume and Capacities

Tidal volume ( Television) – volume of air inspired or expired during a normal respiration. It's about 500mL in healthy man.

Inspiratory Reserve Volume (IRV) – fresh volume of air a person can inspire by forceful alleviation. It's about 2500 mL to 3000mL.

Expiatory Reserve Volume (ERV) – fresh volume of air a person can expire by forceful expiration. It's about 1000 mL to 1100mL.

Residual Volume ( Caravan) – volume of air remaining in lungs indeed after a forcible expiration. It's about 1100mL to 1200mL.

Inspiratory Capacity (IC) – Television IRV

Expiratory Capacity (EC) – Television ERV

 Functional Residual Capacity (FRC) – ERV Caravan

 Vital Capacity (VC) – maximum volume of air a person can breathe by after a forceful expiration. ERV TV IRV

 Total Lung Capacity (TLC) – total volume of air accommodated in lung at the end of forced alleviation. Caravan ERV TV IRV or Vital capacity Residual Volume.

 

 Exchange of Gases

· Exchange of gases takes place at two sites

 

      1. Alveoli to blood
2. Between and tissues.

· Exchanges of gases do by simple prolixity due to pressure/ attention grade, solubility of the gases and consistence of membrane.

·  Pressure contributed by individual gas in a admixture of gas is called partial pressure represented by pCO2 and pO2.
·  Partial pressure of Oxygen and carbon dioxide at different part involved in prolixity varies from one part to another and moves from advanced partial pressure to lower partial pressure.
·  Solubility of CO2 is 20-25 times further than solubility of O2, so CO2 verbose important faster through membrane.
·  Prolixity membrane is three concentrated thick, that's alveolar scaled epithelium, endothelium of alveolar capillaries and basement substance between them.

 


Breathing and Exchange of Gases Class 11 Notes


Transport of Gases

 

·   Blood is the medium of transport for CO2 and O2. Utmost of oxygen (97) is transported through RBC and remaining 3 by blood tube.
·   20-25 of CO2 is transported by RBC, 70 as bicarbonate and rest 7 in dissolved state by blood tube.

 

Transport of Oxygen

 

·  Hemoglobin in RBC combines with O2 to form Oxyhemoglobin. Each hemoglobin combine with four oxygen motes.
·  List of O2 is related with partial pressure of O2 and CO2, hydrogen ion attention and temperature.
·  Chance achromatism of hemoglobin and partial pressure of oxygen forms sigmoid wind (oxygen dissociation wind).
·   In the alveoli, pO2 is more and pCO2 is less, lower H ions attention and lower temperature favour the list of O2 with hemoglobin. Where contrary condition in tissues favour the dissociation of Oxyhemoglobin.


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Transport of Carbon dioxide

 

      · Carbon dioxide is transported by hemoglobin as carbamino-haemoglobin. In tissues pCO2 is high and pO2 is lower that favour the list of carbon dioxide with hemoglobin. Contrary condition help in dissociation of carbamino-haemoglobin in alveoli.

     · Enzyme carbonic anhydrase help in conformation of carbonate ions to transport carbon dioxide.




Breathing and Exchange of Gases Class 11 handwritten Notes


Regulation of Respiration

 

· Humans beings have capability to maintain and moderate the rate of respiration to fulfill the demand of body tissues by neural system.
·   Respiratory meter centre is located in medulla region of hind brain. Pneumotaxic centre in pons moderate the function of respiratory meter centre.
·  Chemo-sensitive area near meter centre is largely sensitive to CO2 and H ions that eventually control the respiratory rate. Oxygen don't play major part in controlling rate of respiration.

 

Functions of Respiration –

 

     1. Energy product
2. Conservation of acid- base balance.
3. Conservation of temperature
4. Return of blood and lymph.


 Breathing and respiration class 11 NEET


Mountain Sickness


It is the condition characterised by the ill effect of hypoxia ( deficit of oxygen) in the tissues at high altitude generally to person going to high altitude for the first time.


Symptoms-

       · Loss of appetite, nausea, and puking occurs due to expansion of gases in digestive system.
  · Breathlessness occurs because of pulmonary oedema.
  · Headache, depression, disorientation, lack of sleep, weakness and fatigue.


Breathing and Exchange of Gases Class 11 Notes


Disorder of Respiratory System

 

Asthma – it's due to antipathetic response to foreign patches that affect the respiratory tract. The symptoms include coughing, gasping and difficulty in breathing. This is due to excess of mucus in wall of respiratory tract.

Emphysema – is the affectation or abnormal distension of the bronchioles or alveolar sacs of lungs. This occurs due to destroying of septa between alveoli because of smoking and inhalation of other smokes. The exhalation becomes delicate and lung remains exaggerated.

Occupational Respiratory Diseases – occurs due to occupation of existent. This is caused by inhalation of gas, smothers or dust present in girding of work place. This includes Silicosis, Asbestoses due to exposer of silica and asbestos. The symptom includes proliferation of stringy connective towel of upper part of lung causing inflammation.

 Pneumonia – it's acute infection or inflammation of the alveoli of the lungs due to bacterium streptococcus pneumoniae. Alveoli come acutely inflamed and utmost of air space of the alveoli is filled with fluid and dead white blood corpuscles limiting gassy exchange.


Breathing and Exchange of Gases class 11 NEET 

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