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RESPIRATION. Respiration. Respiration : the oxidation of food substances in the mitochondria of cells to release energy Two types of respiration : Aerobic respiration - the respiration that uses energy Anaerobic respiration – takes place in the absence of 0 2. Cell respiration.
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Tr.Rez@SB2013 Respiration • Respiration : the oxidation of food substances in the mitochondria of cells to release energy • Two types of respiration : • Aerobic respiration - the respiration that uses energy • Anaerobic respiration – takes place in the absence of 02
Tr.Rez@SB2013 Cell respiration • Is also called internal respiration or tissues respiration • Involves the oxidation of glucose molecules to produce energy, CO2 and H2O • Takes place in the mitochondria of living cell of plants & animals
Tr.Rez@SB2013 Gaseous exchange • Also known as breathing or external respiration • Process of transferring O2 from the surrounding medium (air or water) to cells & the elimination of the products of respiration (H2O & CO2) to the surrounding medium • Involves the mechanical process of inhalation & exhalation of air into & out of our lungs
Tr.Rez@SB2013 Aerobic Respiration • Takes place in all living cells of plants, animals & in certain microorganisms • Production of energy in the presence of Oxygen • Takes place in mitochondria • Produce 2898 Kj energy
Tr.Rez@SB2013 Anaerobic respiration • Breakdown of glucose to produce energy in the absence of oxygen • Inefficient because only a small amount of energy is released • Occurs both in animal cells & plant cells
Tr.Rez@SB2013 • Anaerobic respiration of glucose in animals produces lactic acid & energy • Energy produced (210 kJ) • Anaerobic respiration of glucose in plants produces ethanol, carbon dioxide & energy • Energy produced (210 kJ)
Respiratory structures & breathing mechanisms in humans & animals
Tr.Rez@SB2013 Respiratory structures & adaptations • Respiratory structure: • The way the different parts of a respiratory system are organised or arranged • Respiratory surface: • Actual exchange of respiratory gases takes place • Consist of a thin & moist membrane where O2 diffuses into the body & CO2 diffuse out
Tr.Rez@SB2013 • Common characteristics of the respiratory surface: • A large surface area to maximized exchange of gases • A moist respiratory surface for gases to dissolve in first before diffusing across the respiratory surface • A thin respiratory surface for effective diffusion of gases • A network of blood capillaries beneath the respiratory surface (except for protozoa & insects)
Tr.Rez@SB2013 Breathing • Is to maximise the process of gaseous exchange • Involves pumping movements to ventilate respiratory surface • Does not take place in simpler, smaller, organisms
Tr.Rez@SB2013 Respiratory structure of protozoa CO2 O2 • Have no specific respiratory structure • Has high surface area : volume ratio – makes diffusion very efficient • No breathing mechanism necessary
Tr.Rez@SB2013 • An amphibian exchanges gases in 3 ways: • Cutaneous respiration • Buccal respiration • Pulmonary respiration
Tr.Rez@SB2013 Cutaneous Respiration
Tr.Rez@SB2013 Buccal Respiration
Tr.Rez@SB2013 Pulmonary Respiration
Tr.Rez@SB2013 • Consist of: • Nose and nasal cavity • Pharynx • Larynx • Trachea • Bronchi & bronchioles • Lungs – left & right
Tr.Rez@SB2013 • Trachea • Strengthen by C-shaped cartilage rings which provide structure & keep trachea open
Tr.Rez@SB2013 • External intercostal muscle • Pull the ribs together, raising the rib cage during inspiration • Internal intercostal muscle • Lower the rib cage during expiration
Tr.Rez@SB2013 Mechanism of respiration • Consist of: • Inhalation • Exhalation
Gaseous exchange across the respiratory surfaces and transport of gases in humans
Tr.Rez@SB2013 • Characteristics of the respiratory surface in the alveoli are: • Large surface area • Thin one cell thick & moist epithelial surface • Underlying capillary network • Exchange of gases is through diffusion • Gases diffuse down their partial pressure gradients
Tr.Rez@SB2013 Gaseous exchange in alveolus
Tr.Rez@SB2013 Transport of oxygen & carbon dioxide
Tr.Rez@SB2013 Transport of oxygen • Oxygen is transported from the lungs in two ways: • As oxyhaemoglobin in RBC (99%) • In lungs (high PO2 ) • In tissue • As dissolved gas molecules in the plasma Hb + 402 Hb (O2)4 (Haemoglobin) (oxygen) (oxyhaemoglobin) Hb (O2)4 Hb + 4 O2 Oxyhaemoglobin Haemoglobin oxygen
Tr.Rez@SB2013 Transport of CO2 from the lungs • As bicarbonate ion (85%) • Formation of bicarbonate ion • When deoxygenated blood reaches lungs: CO2 + H20 → H2CO3 → HC03- + H- (Carbonic acid) (Bicarbonate ion) HCO3- + H+ → H2CO3 → CO2 + H2O (Carbonic acid)
Tr.Rez@SB2013 Hb + CO2 HbCO2 • Combines with RBC to form carbaminohaemoglobin • Formation of carbaminohaemoglobin • High P CO2 • When reaches lungs • Low P CO2 HbCO2 Hb + CO2