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RESPIRATORY TRACT
RESPIRATORY ORGAN
Difference between dry and wet cough
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Irritation of respiratory tract Due to dust or smoke
Accumulation of mucus Due to infections
The respiratory tract
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Tracheal epithelium
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Air enters the tract through
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Nostrils
Passes through the nasal chamber
As it passes… 1. Warms and humidifies the inspired air. 2. Removes and traps pathogens and
particulate matter from the inspired air. 3. Responsible for sense of smell. 4. Drains and clears the paranasal sinuses
and lacrimal ducts.
Larynx
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At the opening of the trachea is present the larynx.
Larynx is the voice box.
Pharynx and epiglo<s
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Passes pharynx to reach the trachea
The opening of the trachea is glottis that is guarded by epiglottis
Trachea
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Air then enters the trachea…
Trachea has C shaped cartilagenous rings
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Inner lining of trachea
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Trachea branches to form bronchi
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Bronchi branches to form
bronchioles
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Bronchioles terminate in sac like structures -‐ alveoli
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Alveolus
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Why do we breathe?
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We need oxygen for…..
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RespiraHon in aerobic animals The process of respiration involves two phases- External respiration Internal respiration.
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Respiratory organ…..the lung
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Membranes of lung
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lungs
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Hilum
ProtecHng the lung….RIBCAGE
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RIBCAGE…helps in breathing
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MECHANISM OF BREATHING
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What happens during inspiraHon and expiraHon
INSPIRATION • External intercostal muscles
contract to make the ribcage move outwards and upwards.
• Radial muscles of the diaphragm contract to make diaphragm flat.
• Volume increases and pressure and pressure decreases.
• Air rushes in.
EXPIRATION • Internal intercostal muscles
contract so that ribcage moves downwards and inwards.
• Circular muscles of diaphragm contract to make it dome shaped
• Volume of thoracic cavity decreases and pressure inside increases.
• Air is forced out. TGESBIOLOGY ISC 11
External Respiratory exchange
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Transport of respiratory gases • 98% of oxygen is bound to
hemoglobin as oxyhemoglobin. • Each hemoglobin molecule has the
capacity to bind with four oxygen molecules.
• 70% of CO2 is transported in the plasma as bicarbonate ion.
• 23% of CO2 is bound to the globin part of hemoglobin as carbaminohaemoglobin.
• 7% is dissolved in the plasma.
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Respiratory cycle
• One inspiraHon and one expiraHon alternately is called respiratory cycle.
• Rate of respiraHon is expressed in terms of venHlaHon rate. Average-‐ 12 to 14 Hmes.
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Pulmonary air volumes • Tidal volume-‐ 500ml • IRV-‐ 2000-‐3000ml • ERV-‐ 1000-‐1500ml • Vital capacity-‐ 4500ml • Residual volume-‐ 1500ml • FRV-‐ 2500ml • Dead space • Total lung capacity-‐ 5000-‐6000ml
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Respirometer and spirogram
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Tidal volume
ComposiHon of air GAS INSPIRED AIR ALVEOLAR AIR EXPIRED AIR
Oxygen 20.96% by volume
13.6% by volume 15.7% by volume
Carbon di oxide
0.04% by volume 5.3% by volume 3.6% by volume
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Transport of oxygen • Dissolved in the
plasma: This accounts for very less amounts of oxygen.
• As Oxyhaemoglobin: oxygen diffuses into the RBC and combines with Fe ions of Haemoglobin to form oxyhaemoglobin.
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Structure of oxyhaemoglobin
Oxygen-‐ hemoglobin dissociaHon curve (oxygen dissociaHon curve)
• The amount of oxygen that can bind with Hb is determined by O2 tension.
• % of Hb that is bound with O2 is called percent saturaHon of Hb.
• This percentage saturaHon of Hb with O2 is expressed graphically by a curve called the O2-‐Hb dissociaHon curve or O2 dissociaHon curve.
• This is sigmoid in shape.
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% O
2 sa
tura
tion
with
Hb
P O2 (mm Hg)
BOHR effect: The decrease in O2 affinity of Hb when the pH of blood falls is called the Bohr effect.
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Transport of carbon-‐di-‐oxide • Carbon di oxide is transported in three forms:
– As simple soluHon dissolved in the plasma. – As bicarbonate – CO2 reacts with water to form carbonic acid, catalysed by carbonate anhydrase.
– Carbonic acid dissociates into bicarbonates and hydrogen ions.
– Hydrogen ions are picked up by proteins, some of the bicarbonate ions remain in the RBC whereas some comes out in the plasma. Chloride ions move in, this is called chloride shie or Hamburger shie.
– As carbaminohaemoglobin about 30% CO2 loosely combines with the globin part of deoxyhaemoglobin. TGESBIOLOGY ISC 11
Internal respiratory exchange
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Tissue cell Capillary wall Red blood cell
CO2 CO2 CO2 CO2+H2O H2CO3
CO2+Hb HbCO2 Carbonic anhydrase
HCO3+ H
Hb.O2+ H O2 + H. Hb O2 O2 O2
Cl
Cl HCO3
Chloride shift
External respiratory exchange
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O2 O2 O2 O2 + H. Hb Hb.O2+ H
HCO3+ H H2CO3 CO2+H2O CO2 CO2 CO2
CO2+Hb HbCO2
Alveolus Pulmonary capillary wall Red blood cell
Carbonic anhydrase
Cl
Cl HCO3
Reverse Chloride shift
Release of CO2 in lung • When deoxygenated blood reaches the lung there is a difference in parHal pressure of the CO2 in the lungs and the capillaries.
• A series of reacHons also takes place as Hb takes up O2, the bicarbonate reacts with H+ and forms carbonic acid, which splits into CO2 and water.
• Binding of O2 with Hb tends to displace CO2 from the blood. This effect is called Haldane effect.
• Haldane effect results from the fact that combinaHon of O2 with Hb causes Hb to be a stronger acid. Thus displaces CO2.
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Respiratory diseases
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Asphyxia and hypoxia
• Asphyxia is caused by interrupHon in the supply of oxygen to the Hssues. – Drowning, pneumonia, CO poisoning.
• Hypoxia is a condiHon of shortage of oxygen in the Hssues. – High alHtudes, anemia.
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Occupa4onal Lung Diseases
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Examples of inorganic dust diseases
• Asbestosis Asbestosis is caused by the inhalaHon of microscopic fibers of asbestos.
• Coal worker's pneumoconiosis Coal worker's pneumoconiosis is caused by inhaling coal dust. Also known as black lung disease or anthracosis, the condiHon, in severe cases, is characterized by scarring on the lungs
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Examples of inorganic dust diseases
SILICOSIS
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Examples of inorganic dust diseases • Berylliosis
Berylliosis (or beryllium disease) is caused by the inhalaHon of beryllium parHcles, dust or fumes. Its symptoms include coughing, shortness of breath, faHgue, weight loss or loss of appeHte, fever and sweaHng.
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Examples of organic dust diseases • Byssinosis is caused by dust from hemp, flax, and cojon processing. Also known as brown lung disease, the condiHon is chronic and characterized by chest Hghtness and shortness of breath.
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n Occupa4onal asthma n OccupaHonal asthma is caused by inhaling certain irritants in the workplace, such as dusts, gases, fumes, and vapors.
Emphysema
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Emphysema • Due to inflammation of infected lungs- phagocytes
enter the airways. • They secrete a protein –digesting enzyme elastase. • Elastase destroys the elastin in the wall of the alveoli. • The alveoli are unable to stretch • Bronchioles burst as a result of trapping of air. • Thus reduces the surface area. • Lung function deteriorates resulting in wheezing and
breathlessness
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Asthma
• All images have been downloaded for educaHonal purpose only
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