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RESPIRATION
B M Subramanya Swamy M.Sc. B.Ed.
CIE Co ordinator & Examination OfficerKanaan Global School
Jakarta Indonesia
Introduction
• Energy is needed for cellular respiration• Food is in the source of energy for human• Oxygen is needed to release this energy from
food• Respiration is the process by which the body
obtains and utilises oxygen and eliminates carbon dioxide
The three process of respiration in humanProcess Mode of action
Breathing Involves external respiratory system to take in O2 and release CO2
Internal respiration
Exchange of substances between capillaries and cells
Cellular respiration
Release of energy from food substances in living cells
CELLULAR RESPIRATION
the release of energy from food substances in all living cell
Comparison of aerobic and anaerobic respiration
Aerobic AnaerobicOxygen Present Absent Energy from breakdown of food
Large amount Relatively small
Location Begins in cytoplasm and continues into the mitochondria
In cytoplasm
Efficiency Very good 36 molecules of ATP from 1 glucose molecule
Inefficient 2 molecules of ATP from 1 glucose molecule
Example of organism All organisms and some yeast
Yeast, bacteria, seals and whales ( animals that dive deep into the ocean)
Aerobic RespirationC6H12O6 + 6O2 6CO2 + 6H2O + ENERGY
Uses of aerobic respiration in humanUses of energy Mode of action
Muscle contraction For muscular contractions, cardiac muscles and peristalsis
Protein synthesis Formation of peptide bondsCell division Growth, synthesis of chromosomes, cell membrane,
etc.
Active transport Transport of substances across a concentration gradient
Growth New protoplasm, and in metabolic processes
Transmission of nerve impulse
Along the axon, and for the transport of sodium ions out
Regulation of body temperature
Energy released to keep the body warm
Anaerobic Respiration
Anaerobic respiration and its uses
Types Mode of actionAlcoholic fermentation (in plants)
• Incomplete breakdown of sugar to release energy• Glucose ethanol + CO2 + energy (2 ATP)• Economically important, e.g. in bread making, brewing of beer and wine
Lactic acid fermentation (in man and animal)
{ Some bacteria causes milk to turn sour and form yoghurt{ The bacteria feeds on sugar{ Glucose lactic acid + energy (2 ATP)
Anaerobic respiration and its usesTypes Mode of action
During rigorous muscular activity
¶During strenuous activity, breathing is not enough to provide O2 for respiration¶Muscles experience a shortage of O2, causing formation of lactic acid¶Accumulation of lactic acid causes muscular cramp and fatigue¶Muscle experiences O2 debt during periods of anaerobic respiration¶Rapid breathing helps to repay the debt by increasing O2 in the muscles, thus converting lactic acid back to glucose
GASEOUS EXCHANGE IN MAN
• Lungs are the main respiratory organ in human• They lie in the upper chest cavity• Lungs are divided into section called lobes• Air enters through nostril, into nasal passages,
pharynx, larynx, trachea, bronchi and bronchioles before entering the alveoli
Components of respiratory organs and its functionOrgans Function
Nostrils Projecting nasal hairs filter out dust and debris
Nasal cavity üDivided by septumüLined with ciliated epitheliumüBlood vessels below epithelium warms the air
Pharynx § Both air and food passage§ Warms, moistens and filters air
Glottis Guarded by epiglottis (elastic flap at entrance of trachea)
Larynx Has vocal cord
Trachea ÆCylindrical tube with rings of cartilage to provide supportÆLayer of cilia and mucus – secreting cellsÆTraps debris and sweeps it upwards towards the mouthÆDivided to form two bronchi
Components of respiratory organs and its functions
Organs Function
Lung JRich in blood supply, site of gaseous exchangeJLeft lung has two lobesJRight lung is bigger, with three lobes
Bronchus Divided into smaller tubes called bronchioles
Plural membrane Encloses each lung
Diaphragm TMuscular tissue attached to thoracic cavityTSeparates thoracic cavity from abdominal cavityTThoracic cavity changes volume to assist in breathing
Bronchiole {Connects directly to alveoli{Widens and narrows during breathing
Alveoli ØAir sacs with thin wall with a moist surfaceØA network of blood capillaries covers the alveoli
Process of breathing
inspiration expiration
Comparison of inspiration and expirationInspiration Expiration
J External intercostal muscle contractsJ Increase in volume of thoracic cavityJ Ribs swing upwards and outwardsJ Diaphragm contracts, flattens downJ An increase in thoracic cavity volume reduces air pressure in the cavity and lungs. Gases expand to fill the available space, creating a partial vacuum. This forces air into the lungs.
ü Internal intercostal muscle contractsü Reduction in volume of thoracic cavityü Ribs swing downwards and inwardü Diaphragm is relaxed and elevatedü A reduction in the volume of thoracic cavity increases air pressure. This forces air out of the lungs to equalise the pressure of the lungs with the atmosphere.
23-14
Alveolar Pressure Changes
Comparison of composition inhaled and exhaled air
Inhaled air Exhaled air
Oxygen 21% 17%
Carbon dioxide < 0.1% 4%
Nitrogen 79% 79%
Temperature Room temperature 37°C
Moisture Variable 100%
Dust Variable Absent
Control of Breathing• The respiratory center is located in the lower medulla
oblongata• The stimulus for the respiratory center is the
presence of CO2
• When CO2 level increases, breathing rate increases as well
• During anxiety or anger, the hormone adrenaline increases metabolic rate and breathing
• If the levels drop, it inactivates the respiratory center. This could lead to death.
Adaptations of alveoli and blood capillaries for exchange of gases
Adaptation Mode of action
Network of blood capillaries For transport of gases to and from alveoli
Large surface area Allows for increased rate of diffusion
Moist surface of alveoli Allows gases to dissolve before diffusion occurs
Concentration gradient Increased rate of diffusion
Distance between alveoli and blood capillaries
Short distance increases rate of diffusion
Wall of alveoli and blood capillaries One cell thick : faster diffusion
Internal Respiration• This is the exchange of gases between blood
and body tissues• Carbon dioxide is carried as carbamino
haemoglobin or bicarbonate ions
Hb + CO2 carbamino haemoglobin
CO2 + H2O H2CO3
H2CO3 H+ +HCO3-
Passage of Gases
Oxygen Carbon dioxide
During inspiration, O2 diffuses across the alveolus
During expiration, CO2 is expelled with water vapour from the lungs
It enters the blood stream There is a higher concentration of deoxygenated blood in this area
98% combines with blood to form oxyhaemoglobin
It is carried in the blood as bicarbonate ions and carbamino haemoglobin
< 2% enters the plasma It diffuses out of capillary into the alveoli
23-24
Pulmonary Volumes• Tidal volume
– Volume of air inspired or expired during a normal inspiration or expiration
• Inspiratory reserve volume– Amount of air inspired forcefully after inspiration of normal tidal
volume
• Expiratory reserve volume– Amount of air forcefully expired after expiration of normal tidal
volume
• Residual volume– Volume of air remaining in respiratory passages and lungs after the
most forceful expiration
23-25
Pulmonary Capacities
• Inspiratory capacity– Tidal volume plus inspiratory reserve volume
• Functional residual capacity– Expiratory reserve volume plus the residual volume
• Vital capacity– Sum of inspiratory reserve volume, tidal volume, and expiratory
reserve volume
• Total lung capacity– Sum of inspiratory and expiratory reserve volumes plus the tidal
volume and residual volume
23-26
Spirometer and Lung Volumes/Capacities
23-27
Respiratory System Functions • Gas exchange: Oxygen enters blood and carbon
dioxide leaves• Regulation of blood pH: Altered by changing blood
carbon dioxide levels Carbonic acid Buffer system• Sound production: Movement of air past vocal folds
makes sound and speech• Olfaction: Smell occurs when airborne molecules
drawn into nasal cavity• Thermoregulation: Heating and cooling of body • Protection: Against microorganisms by preventing
entry and removing them
