RESPIRATION• DEFINITION : - The breaking down of food ( substrate – mainly glucose ) in the presence or absence of oxygen to release energy in the form of ATP and carbon dioxide in the cells of the organism is termed RESPIRATION.• TYPES :-a) Aerobic respiration- requires presence of oxygenb) Anaerobic respiration – does not require presence of oxygen
AEROBIC & ANAEROBIC RESPIRATIONAEROBIC RESPIRATION ANAEROBIC RESPIRATION• It utilizes oxygen • It occurs in the absence of oxygen.• occurs in the mitochondria • It also occurs in the mitochondria• Involves the process of • It also involves the process of glycolysis in cytoplasm ‘glycolysis’ where glucose is • Pyruvate then enters different broken down to ‘pyruvic pathways and forms different acid’. products . • 2 types of anaerobic respiration• Pyruvate is converted to CO2, are: H2O, and ENERGY by kreb’s • Fermentation - leads to formation of alcohol in yeast cycle. • anaerobic respiration in human• 38 ATP are generated. muscles - leads to formation of lactic acid.
BREATHING & AEROBIC RESPIRATION• Aerobic respiration requires the presence of oxygen which is internalized by the living system by the process of breathing.• Breathing in humans involves the rhythmic intake of oxygen (by inhalation) and release of carbon dioxide (by exhalation) .• The terms breathing and respiration are not synonymous.
THE HUMAN RESPIRATORY SYSTEMDiagram : - The respiratory tract • nose and nostrils • nasal cavity • pharynx • larynx • glottis and epiglottis • trachea • lungs • primary bronchi • secondary bronchi • bronchioles • Alveoli/alveolar sac
THE RESPIRATORY TRACT• The nose and the nostrils are the openings which allow the passage of air in and out of the body.• The nostrils are lined with small hair and the nasal passage is internally covered with a thick layer of mucus.• The cavity has the presence of ciliated columnar epithelium.• The nasal cavity is separated from oral cavity with a bony Palate.
THE UPPER RESPIRATORY TRACT • It consists of nasal cavity, pharynx and larynx.DIAGRAM • The Pharynx - It is a narrow opening where the buccal cavity ends and the trachea and the esophagus start. • The end region where the pharynx joins the trachea has an opening called GLOTTIS. • The glottis always remains open, except during swallowing it is closed by a flap like structure called EPIGLOTTIS. • The larynx or the voice box follows the next.
THE LOWER RESPIRATORY TRACT • It consists of :DIAGRAM • Trachea • Primary bronchi • Secondary bronchi • Bronchioles lungs • Alveoli
• The trachea is the organ which communicates between the upper and the lower respiratory tract. It is protected by semi circular cartilageneous rings.• The trachea further divides into primary , secondary and tertiary bronchioles which connect the alveoli .• The alveoli are air sacs with thin walls composed of moist non-ciliated squamous epithelial cells. They are richly supplied by blood capillaries.
LUNGS• The organs from primary bronchi to alveoli are covered up inside the organ called LUNGS.• The lungs are called the ‘Respiratory organs ’ in the Human body, which has two lungs – The left and the right lung.• Different organisms have different organs for breathing E.g.: Fish – gills, Frog - moist skin and lungs.
• In the humans the Lungs are very delicate organs located in the “Thoracic Cavity” .• They are supported by the “Diaphragm” which is a muscular organ and also separates the abdominal cavity from the thoracic cavity.• Externally the lungs are protected by the ribcage. They are covered by membranes called ‘PLEURA’
Mechanism of Breathing • BREATHINGINHALATION EXHALATION breathing in air breathing out air( rich in oxygen) ( rich in carbon dioxide) Both inhalation and exhalation are involuntary processes. It does not require any energy except to contract and relax the respective muscles.
INHALATION• The diaphragm lowers down and becomes flat (contracts) and at the same time the ribs and sternum are pulled outwards (with the help of intercoastal muscles) which leads to the enlargement of the thoracic cavity.• This leads to the expansion of lungs & hence the air pressure inside the lungs decreases, to balance the pressure the fresh air hence moves into the lungs .• On reaching the alveoli the exchange of gasses occurs due to difference in the concentration of gasses in the air and blood. The exchange occurs through diffusion.
EXHALATION• Once the exchange of gasses has occurred the diaphragm relaxes and returns to it’s original curved position ( ie it is pushed upwards) and at the same time the ribs are also pushed inwards, resulting into decrease in area of thoracic cavity and increasing the air pressure inside the lungs.• This leads to pushing the air out of the lungs passively.
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