Respiration in Humans | Class 10 | Theory Notes

  Respiration in Humans

Aerobic Respiration	Anaerobic Respiration
1. It occurs in the presence of 02.	It occurs in the absence of O2.
2.It involves the exchange of gasesbetween the organism and outside environment.	Exchange of gases is absent.
3. It occurs in cytoplasm and mitochondria.	It occurs only in cytoplasm.
4.It always releases C02 and H20.	End products vary.

     

          The importance of Lungs

▪️Lungs is the only organ in human body which can float on water.

Left lung has a depression (Cardiac notch) where heart is placed as our heart is slightly placed toward left of chest. There are two lobes in let lungs (superior and inferior) and three lobes in right lungs ( superior , inferior and median lobe).

▪️Every lung is supported by double membrane called pleura.

▪️ It forms core of the respiratory system.

▪️ In human's respiratory system begins from nose and ends in alveoli in lungs. (Also called pulmonary respiration). 1. upper respiratory systems It consist of nasal cavity , pharynx and larynx .

A .Nasal Cavity
▪️It consist of nose with openings called nostrils also called Nares. Fine hair here in nose helps to trap any foreign particle which enter through the inhaled air. This region is called Vestibule region which defences from bacteria or other harmful particles that may enter the system.
▪️Second region after vestibule region is respiratory region – It warms the air to get it to the normal body temperature then it moistens it to make it suitable for the body.
▪️Third region is olfactory region, it is responsible for sense of smell, it contains highly sensitive cells which sends the received signal to the brain and help in identifying the smell.

B) Pharynx
▪️It is like a common connection between respiratory tract and digestive tract become this acts as a common passage of nasal chamber on top and wind pipe and food pipe just lying below.
▪️It receives food and air from respective zones.
▪️Have you thought ever how food knows to enter in food pipe each time. Why it does not enter in wind pipe. That is what pharynx is for, epiglottis present after nasal chamber folds over below to cover the wind pipe when food enter the system
▪️So, food has no only one passage and that is food pipe.

C) Larynx
It is also known a voice box. It is responsible for creating the sound. Air paases in it and when it vibrates due to air passage it creates vibration producing sound. 2. Lower Respiratory systems

a) Trachea (Wind Pipe) –
▪️It is surrounded by cartilage ( provide support from frontside , it is c shaped; 16-20 rings of cartilages are present) which provides it strength and flexibility to contract of muscles when food passes in oesophagus.
▪️Cilia (hair like structure) is presented whose movement is upward which pushes dust particles outside so that pure air enters in lungs.
▪️It is also called Pseudostratified ciliated glandular columnar epithelium

b) Bronchus –
▪️It acts as an entry point of the lungs.
▪️It gets divided into two branches called right main bronchus and left main bronchus.
▪️Bronchi enter the respective lungs to further divided into bronchioles.

c) Bronchioles –
▪️It is smaller root like structure which forms basic units of the respiratory systems.
▪️They are the actual sites of exchange of gases, exchange of oxygen and co2 between lungs and blood occurs in alveoli.
▪️One single ball in group of sacs is called alveolus.
▪️Why is there not a single ball of alveoli rather than smaller alveolus? it is because it increases the surface area for exchanges of gas so that in less time maximum gas exchange can be done.
▪️ Alveolus is a single cell membrane which makes easy to exchange gases between RBCs and alveolus