Respiratory system || (STUDY - PULMONOLOGY) || Respiratory organ || Respiratory tract ||

           RESPIRATORY SYSTEM


 (STUDY - PULMONOLOGY)    
                                       
» RESPIRATION IS A CATABOLIC PROCESS INVOLVING : THE BURNING OF FOOD PARTICLES IN THE PRESENCE OF OXYGEN;ELIMINATION OF CARBON DIOXIDE PRODUCED DURING THE OXIDATION;
RELEASE OF ENERGY.  SOME OF THE ENERGY IS STORED IN THE HIGH ENERGY BOND OF ATP MOLECULES...

» Respiratry system consist of :

(1) Respiratory organ... 
(2) Respiratory tract... 

                                                                 (1)   Respiratory Organ...

On the basis of types of respiratory organ, there are following mode of respiration:

#  Skin/ cutaneous respiration - cutaneous respiration involve exchange of gases through skin, which occurs when skin is thin, moist,, highly vascular and is directly or indirectly contact with the souce of oxygen..

- This respiration can occur in both air and water...

- It is exhibited by annelids, some crustaceans and amphibians ..

# Buccopharyngeal respiration - like the skin , mucosa of bucccopharyngeal cavity in certain amphibians is idealy adapted for gaseous exchange in air..

- During this respiration , the mouth, gullet and glttis remain closed but nares remain open...

- The floor of the cavity  is alter nately lowered and raised the concertaion of pair of sternohyal and petrohyal muscles..

# Tacheal respiration - In this respiratory system is highly branched air tubes called TRACHEA..

- Through these air tubes every tissue of the animal remain in direct contact with the air, thus compensating for the absence of respiatory pigment in the blood...

-The enviromental air enters into and escape from the trachea through SPIRACLE OR TRACHEA...

It is found in all the insects, centipedes; millipedes amd some spiders...

# branchial respiration - Here the organ of respiration is GILL..

- It is a characterstics feature of aquatic animals...e.g., crustaceans, certain molluscs, bony fishes and tadpoles...


(A) On the basis of their LOCTION, gills are of two types : 

(1) External gills  

(2) Internal gills/ True giils

                                                                          (1) External gills... 

- These gills are located outside the body surface...
e.g., some annelids, some insects larvae ( Dragon and Damse fly ), tadpole larva, axolotl larva of salamandra etc.

                                                        (2) Internal gill/ True gill.

These are present inside the body and covered by operculum ...
e,g., bony fishes , unio, prawn etc.
(B) On the basis of their ATTACHMENT, gills are of following types: 

# Podobranchs.. 
# Arthrobranchs..
# Pleurobranchs..

                                                       # Podobranchs...      

- Gills are directly attached to the foot or appendages...

                                                      # Arthrobranchs.. 

- Gills are attached on the arthropodilal membrabe of joints...

                                                     # Pleurobranchia

- Gills are attached to lateral side of the wall of the body..


(C) On the basis of POSITION OF GILL FILAMENT, gills are of following types:

(a) Abranch 
(b) Hemibranch/Half gill
(c) Holobranch/Complete gill


(a) Abranch - Gill axis are without gill filament...

(b) Hemibranch/ Half gill - Gill axis have only one row of gil filament on one side of gill..

(c) Holpobranch/Complete gill - Gill axis bear two rows of gill lamella...

(d) Lung/Pulmonary Respiration...


 (NOTE) - The animal breathing in the water facing many problem in ventaling their respiratory surface  because :

# Density of water is 800 times more than air so more muscular effort are required for exchange of gases...
             
# Water contains less oxygen whose concenteration further decreases in summers...

# A rise in temp. increases the animals metabolic rate and also their demand of oxygen.. But the oxygen carying capacity of water decreases with increases in temperature...So for effecient exchange of respiratory gases these animals have following adaptations: 

- Flow of the blood in capillaries of gills in the direction opposites to that of water current i.e., SHOWING COUNTER CURRENT MECHANISM...It ensures continous contact of gill with water and rapid uptake of oxygen...  .

- Rapid circulation of water over respiratory surface.....

 # Rich blood supply to gills....

(d) Lungs/ Pulmonary Respiration - Animal like lung fishes, reptiles, amphibians, birds and mammals breathe the atmospheric air with lungs...

    The main advantage of lung in air breathing is: 
- They are situated within the body so the respiratory surface can be kept moist. 
- Density of air is less than water so the animal need less energy to move air over the repiratory surface..
- Air contains moore oxygen than water so oxygen diffuse faster through air than water....

 In amphibians, the lungs are simple sacs with smooth inner surface or low internal folds.. In reptiles, lungs have considerably inner folding to increase the surface area for  gaseous exchange ....Lungs of birds have air sacs. All mammals have spongy lungs with considerably number of alveoli..


                                                                    (2) Respiratory Tract.

# It is the path for  fresh amd foul air  where no gaseous exchange occurs...

   Respiratory system comprises of following parts:
     
(a) Nostrils/ External nares  - It is a pair of opening above the mouth separated by septum..

(b) Nasal chamber - These are pair of passage above above the palate and are separated by  anastmosis/ septum..
             
  THIS CHAMBER HAS THREE REGIONS:

1- VESTIBULAR - Lined by hair skin which prevents the entry of dust particles..
2- RESPIRATORY - Lined by respiratory epitheium. It filters, sterlises and warms the air i.e., it act as an air conditioner.

3- Olfactory - Lined by olfactory epithelium...

        Nasal chamber internally has scroll like conchae meant increase the surface area.....

(c) Internal Nares - These are the opening of nasal chamber into nasopharynx...

(d) Pharynx - It is lined with non keratinised squamous epithelium , which is ciliated in nasopharynx...Lower part                              of pharynx is  laryngopharynx , having the slit like aperture called glattis covered by cartilaginous                              flap epiglottis...

(e) Larynx / Voice box -  a sound producing organ lined with mucous membrane and cilliated epithelium. It                                                       is supported by cartilages namely thyroid, cricoid, arytenoid, and cartilage of sanitorini.                                                  Larynx enclose  vocal cord..
 
(f) Trachea - It is awind pipe supported by C - shaped cartilaginous rings. It extends upyo middle of the thoracic                             cavity...

(g) Bronchi - These are the pairs of thin walled tubular structure formed by the division of trachea .. It is also                                     supported by cartilaginous rings..  Each primary bronchus enters in their respective lungs through                             hilus where they divided into secondary bronchii, tertiary bronchii and bronchiole...

(h) Respiratory Organs - Each lung is covered by pleural membranes ....The two membranes are sepated by                                                pleural cavity filled with pleural fluid..Lungs are further divided into lobe with the help of                                                fissures.. Internally lungs are having alveoli lined with network of  blood vessels and capillaries....                                                  

                                           

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