4:33 AM
Respiratory is the breakdown of absorbed food with the help of oxygen. During this process, carbon dioxide (CO2) and water (H2O)are released as waste and a lot of energy is produced. This energy is made available to the cells of the body.
Food + oxygen g carbon dioxide + water + energy
C6H12O6 + 6O2 g 6CO2 + 6H2O + energy
In this process, glucose is oxidized slowly in the cells and energy is released. The energy is released in the form of ATP (Adenosine triphosphate), This a complex compound. This process of cellular respiration takes place in mitochondria of every cell of the body. Since every cell needs energy to work and this process takes place within cells of the body, it is also called internal respiration or tissue respiration. As, it occurs in the presence of oxygen, it is also called aerobic respiration.
In certain micro-organisms like fungi, yeast and bacteria glucose is partially broken down into ethyl alcohol or lactic acid and carbon dioxide in the absence of oxygen. This type of respiration which occurs in the absence of oxygen is called anaerobic respiration.The carbon dioxide released during this process and the intake of oxygen is carried out by lungs. This process of transport of oxygen to the body tissues in animals for the purpose of respiration and the removal of carbon dioxide is called breathing or external respiration.
Blood plays an important role in respiration. Oxygen needed for respiration and carbon dioxide produced during respiration are transported by blood. Blood transports oxygen after combining with hemoglobin to tissues and transports carbon dioxide from tissues to the lungs. Hemoglobin is a respiratory pigment present in the blood cells. The blood also transports the molecules of glucose to each cell and tissues.
The various respiratory organs are:
1. Nostrils
2. Nasal cavity
3. pharynx
4. trachea
5. bronchi
6. lungs
1. Nostrils:
Nostrils are the apertures in the nose through which air enters the nasal cavity.
2. Nasal cavity:
It has fine hair and a sticky substance called mucus. Hair and mucus prevent dirt, dust and germs from entering the respiratory system. It also cools or warms the inhaled air to the body temperature to avoid sudden change in temperature in the lungs.
3. Pharynx:
The common passage of the nasal cavity, mouth cavity, trachea and oesophagus, is called pharynx. Air from the nasal cavity enters the pharynx. The pharynx has a pair of tonsils on the right and the left sides. The lower part of the pharynx has low apertures, one opening into the windpipe (trachea) and the other opening into the oesophagus. The aperture of the trachea is termed glottis. It is guarded by a flap like structure called epiglottis which closes the glottis. The function of the epiglottis is to prevent the entry of food into the windpipe.
4. Trachea:
The trachea or windpipe is a tube supported by rings of cartilage. It has a mucus lining.
The trachea has two main functions:
a) The cartilaginous rings of the trachea help in
keeping air passage all the time.
b) The mucus lining catches the dust particles present
in the inhealed air.
Air entering trachea first passes through larynx or voice box. It helps in producing sound.
5. Bronchi:
The trachea is divided into two bronchi. A bronchus is a tube which connects trachea with the lungs.
6. Lungs:
The bronchi also have cartilaginous rings to keep thin passages open in the lungs. Each bronchus divides further into smaller branches termed bronchioles. Each bronchiole ends in a tiny chamber called air sac. The air sac has a large number of microscopic cavities called alveoli. The alveoli have extremely thin walls surrounded by thin capillaries.
The alveoli are the structures in the lungs where the exchange of gases (oxygen and dioxide0 takes place.
We breath in air rich in oxygen. The air goes in through nostrils to a pipe called windpipe or trachea. The pipe divides into two branches called bronchi which finally enter the lungs. From the lungs, oxygen enters the blood.
Carbon-dioxide and water formed in respiration are released into lungs. These are removed from the lungs with the air we breathe out.
