RESPIRATORY TRACT RESPIRATORY ORGAN
Difference between dry and wet cough Irritation of respiratory tract Due to dust or smoke Accumulation of mucus Due to infections
The respiratory tract
Tracheal epithelium
Air enters the tract through Passes through the nasal chamber Nostrils 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 At the opening of the trachea is present the larynx. Larynx is the voice box.
Pharynx and epiglo<s Passes pharynx to reach the trachea The opening of the trachea is glottis that is guarded by epiglottis
Trachea Air then enters the trachea Trachea has C shaped cartilagenous rings
Inner lining of trachea
Trachea branches to form bronchi
Bronchi branches to form bronchioles
Bronchioles terminate in sac like structures - alveoli
Alveolus
Why do we breathe?
We need oxygen for..
RespiraHon in aerobic animals The process of respiration involves two phases- External respiration Internal respiration.
Respiratory organ..the lung
Membranes of lung
lungs Hilum
ProtecHng the lung.ribcage
RIBCAGE helps in breathing
MECHANISM OF BREATHING
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.
External Respiratory exchange
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 CO 2 is transported in the plasma as bicarbonate ion. 23% of CO 2 is bound to the globin part of hemoglobin as carbaminohaemoglobin. 7% is dissolved in the plasma.
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.
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
Respirometer and spirogram 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
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. Structure of oxyhaemoglobin
Oxygen- hemoglobin dissociahon curve (oxygen dissociahon curve) The amount of oxygen that can bind with Hb is determined by O 2 tension. % of Hb that is bound with O 2 is called percent saturahon of Hb. This percentage saturahon of Hb with O 2 is expressed graphically by a curve called the O 2 - Hb dissociahon curve or O 2 dissociahon curve. This is sigmoid in shape. % O2 saturation with Hb P O2 (mm Hg)
BOHR effect: The decrease in O 2 affinity of Hb when the ph of blood falls is called the Bohr effect.
Transport of carbon- di- oxide Carbon di oxide is transported in three forms: As simple soluhon dissolved in the plasma. As bicarbonate CO 2 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% CO 2 loosely combines with the globin part of deoxyhaemoglobin.
Internal respiratory exchange CO 2 +Hb HbCO 2 Carbonic anhydrase CO 2 CO 2 CO 2 CO 2 +H 2 O H 2 CO 3 Chloride shift Cl HCO 3 Cl HCO 3 + H O 2 O 2 O 2 O 2 + H. Hb Hb.O 2 + H Tissue cell Capillary wall Red blood cell
External respiratory exchange Reverse Chloride shift Cl CO 2 +Hb HbCO 2 Cl CO 2 CO 2 CO 2 CO 2 +H 2 O H 2 CO 3 HCO 3 + H Carbonic anhydrase O 2 O 2 O 2 O 2 + H. Hb Hb.O 2 + H HCO 3 Alveolus Pulmonary capillary wall Red blood cell
Release of CO2 in lung When deoxygenated blood reaches the lung there is a difference in parhal pressure of the CO 2 in the lungs and the capillaries. A series of reachons also takes place as Hb takes up O 2, the bicarbonate reacts with H+ and forms carbonic acid, which splits into CO 2 and water. Binding of O 2 with Hb tends to displace CO 2 from the blood. This effect is called Haldane effect. Haldane effect results from the fact that combinahon of O 2 with Hb causes Hb to be a stronger acid. Thus displaces CO 2.
Respiratory diseases
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.
Occupa4onal Lung Diseases
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
Examples of inorganic dust diseases SILICOSIS
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.
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. n Occupa4onal asthma n OccupaHonal asthma is caused by inhaling certain irritants in the workplace, such as dusts, gases, fumes, and vapors.
Emphysema TGES BIOLOGY AS LEVEL
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 TGES BIOLOGY AS LEVEL
Asthma
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