2. The respiratory system is situated In the thorax and it responsible for gaseous exchange between the circulatory system and the outside world .Air is it taken in via the upper air ways ( the nasal cavity, pharynx & larynx ) through the lower air ways ( trachea, primary bronchi and bronchial tree ) and into the small bronchioles and alveoli within the lung tissue .The lungs are divided into lobes; the left lung is composed of the upper lobe, the lower lobe and the lingual (a small remnant next to the apex of the heart), the right lung is composed of the upper, the middle and the lower lobes. To take a breath in, the external intercostals muscles contract, moving the ribcage up and out the diaphragm moves down at the same time, creating negative pressure within the thorax .The lungs are held to the thoracic wall by the pleural membranes, and so expand outwards as well. This creates negative pressure within the lungs, and so air rushes in through the upper and lower air ways.3. Pulmonary ventilation is the amount of air that enters and leaves the lungs in one minute. It is the product tidal volume and respiratory rate. It is about 6 liters / minuet with a normal tidal volume of 500ml and the respiratory rate of 12/minute. During exercise hyperventilation occurs which includes increase in rate and force of respiration. In mode exercise respiration rate is about 30/ minute and tidal volume increase to about 60 liters /minute during moderate exercise. In severe muscular exercise, it rises up to 100 liters /minute Various factors are involved in increasing the pulmonary ventilation during exercise .1. Higher centers 2. Chemoreceptor3. Propriceptors 4. Body temperature 5. Acidosis 4. Pulmonary function can be examined by the spirometry technique. Spirometers are the traditional tools of the respiratory physiologists. The Subject breathes into closed system in which air is trapped (bell). As the subject breathes air movement into or out of the mouthpiece causes the bell to rise (inspiration) or fall (expiration). Corresponding movements of an attached pen register the changes in volume or a rotating drum recorder. From such a recording we could measure Tidal Volume (TV):- volume of air inhaled or exhaled with each breath during normal breathing (0.5L).Inspiratory Reserve Volume (IRV):- maximal volume of air inhaled at the end of a normal inspiration (3L).Expiratory Reserve Volume (ERV):- maximal volume of air exhaled at the end of a tidal volume (1.2 L). Inspiratory Capacity (IC):- Maximal volume of air inhaled after a normal expiration (3.6 L) (TV + IRV).Functional Residual Capacity (FRC):- The volume of gas that remains in the lung at the end of a passive expiration (2- 2.5L or 40% of the maximal lung volume (ERV +RV).Residual volume (RV):- The volume of gas remains in the lung after maximal expiration (1-1.2L).Total Lung Capacity (TLC):- The maximal lung volume that can be achieved voluntarily (5.6L) (IRV+ERV+TV+RV).Vital capacity (VC):- the volume of air moved between TLC and RV. 5. Pulmonary Ventilation: - is a cyclic process by which fresh air enters the lungs and equal volume of air is exhaled. It is the volume of air moving in and out of lungs per minute. It is also called Respiratory minute volume (RMV). It is the product of tidal volume (TV) and the rate of respiration (RR).Thus, Pulmonary ventilation = Tidal volume X Respiratory rate = 500ml x 12 / minute = 6,000 ml (6liters /min). Alveolar ventilation: - is different from pulmonary ventilation. It indicates the volume of air, which is utilized for gaseous exchange. There are certain parts in respiratory tract where gaseous exchange does not take place. These parts are collectively called dead space. The air present in the dead space is called dead space air. Normally it is about 150ml.So, the alveolar ventilation is defined as the amount of air utilized for gaseous exchange every minute.Thus, alveolar ventilation:= (Tidal volume - Dead space volume) X Respiratory rate = (500-150) x 12 = 4,200ml (4.2 liters)/ min 6. Dead space the volume occupied 5% gas which does not participate in gas exchange in lung Anatomical dead space - the volume of the condacting airways of the nose mouth, trachea down to the level of alveoli representing dead portion of inspired gas unavailable of exchange of gases with pulmonary capillary blood.Alveolar dead space- is the space occupied by gas which is transported to the alveoli but does not meet blood across the alveolar capillary membrane. 7. A) Transport of Oxygen 97% of oxygen transported from the lungs to the tissues is carried in chemical combination Hemoglobin in the red blood cell.The remaining 3% is transported in the dissolved state in the water of the plasma and cells. Thus, under normal conditions, oxygen is carried to the tissues almost entirely by hemoglobin. b) Transport of carbon dioxide Carbon dioxide is transported by the blood from tissue to the alveoli. In the arterial blood, the volume of carbon dioxide is 48 % and the partial pressure of CO2 is 40 mmHg. In venous blood, the volume of carbon dioxide is 52 % and the partial pressure is 46mmHg. Carbon dioxide is transported in the blood in the following ways :- 1. As dissolved from- Co2 diffuses into blood and dissolves in the fluid of plasma forming a simple solution. Only about 3ml of Co2 is transported as dissolved state in blood. This is about 7% of total Co2 in the blood. 2. As carbonic acid- part of dissolved co2 in plasma, combines with the water to form carbonic acid. Though Co2 is transported in this from, this reaction is very slow and it is negligible.3. As bicarbonates - about 63% of Co2 is transported as bicarbonate from plasma, the Co2 enters the RBC. Inside the RBC Co2 Combines with water to form carbonic acid. The reaction inside red blood cells is very rapid, the rapid formation of carbonic acid inside the red blood cells is due to the presence of an enzyme called carbonic anhydrase. This enzyme accelerates the reaction carbonic anhydrase is present only inside the red blood cells and not in the plasma. That is why the carbonic acid is formed at least 200 to 300 times more in the red blood cells than in plasma. 4. As Carbamino compounds About 30% of carbon dioxide is transported as carbamino compounds. Carbon dioxide is transported in blood in combination with hemoglobin and plasma proteins. Co2 combines with hemoglobin to form carbamino hemoglobin or carbhemoglobin. And, it combines with plasma protiens to form carbamino proteins. The carbamino hemoglobin and carbaminon protein are together called carbamino compaunds. The Co2 combines with protein or hemoglobin with a loose bond so that , Co2 is easily released into alveoli, where the partial pressure of Co2 is low. Thus, the combination of Co2 with proteins and hemoglobin is reversible one. Only a very small amount of Co2 is transported in combination with plasma proteins than with hemoglobin. This is because the quantity of proteins in plasma is only half of the quantity of hemoglobin. 5. Transpnt of Co2 by the blood is not nelanly so grat a problem as transpnt of O2 ble even in the most abnromd conditions Co2 can usully be transported in far greate quantitre than can O2 Haween the amount of Co2 in the blood does have much to do in acid base blance of the body flivd under normal restrl anditin s an averale of 4 milites of CO2 one transported from the tissue to the lungs in each 100 millilites of blood Pulmany uventilati :- is a cyclic process by w/h fresh air enters the lungs an etud volume of air is exhuled it is the volume of air moul in oot of lungs pen minule it is also called Respiratry minute volume ( RmU ) it is the product of tidal volume the rate of respiration (RR) Thus Pulmanary ventilation = tidal volume X Rispiratory rate = 500ml x 12 / minute 6,000 ml ( 6 lities /min Alveolar ventilator :- is different from pulmonary vemtilatim it indicates the volume of air which is utilized for gaseovs exchange there are centain parts in respiratra tract where gaseous exchange doesnot take place these parts are collectively called dead space the air present in the dead space is called dead space air normale it is about 150ml So the alveola ventilation is defined as the amunt of air utilized for gaseous exchange every minute thus alveola ventilatin = ( tidal volume Dead space voume )X Resparet = (500-150) x 12 = 4,200ml ( 402 lites ) min 7 b) transpnt of Co2 Co2 is transported by the blood from tissue is to the alveoli in the arterial blood the volume of Co2 is 48 % is the partral pressure of CO2 is 40 mmlty in venous blood the volume of Co3 is transported in the blood in the following ways :_ 6. As dissolved from Co2 diffuses into blood is dissolves in the fluid of plasma formial a simple solution only about 3rd of Co2 is transported as dissolved state in blood this is about 7% of total Co2 in the blood 7. As carbonic acid part of dissolved co2 in plamc conebnes is the water to form carbonic acid though Co2 is transpated in this from this reaction is very slow it is negligible 8. As bicarbonates :_ aboust 63% of Co2 is transpoted as bicarborate from plasma the Co2 enters the RBC inside The RbC Co2 Combines with water to form carbmic acid the reacin inside red blood cells is very rapid the rapid formation of corbmic acid inside the red blood cells is due to the presence of an enzyme called carbmic anhydrage this phzyme accelerates the reaction carbmic anlydrase is presnt only inside the red blood cells and not in the plasmic that is why the carbonic acid is formed at least 200 to 300 times more in the red blood cells than in plasma 9. As canbmino compounds :- about 30% of Co2 is transported as canbmino campounds Co2 is transpoted ascanbamino capounds Co2 is transpoted in blood in comination with hemoglobir and plasma proteins Co2 combines is hemoglobin to form can bamino hemoglobin or carbhemoglosir and it canbines with plasma protems to form can bamino proteins the carbamino hemoglobin and can baminon protein are together called canbamiro compwnds The Co2 combres with protein or hemoglobin with a loose band so that Co2 is easily released into alveolis where the partial pressure of Co2 is low trvs the combiraion of Co2 with protems and hemoglobin is arevesible one only a very small amount of Co2 is transpoted in combination with plasma proteins than with hemoglobin this is because the quanfity of protins in plasma is only half the quantity of hemoglobin 8 Respiratry centers classified into two groups part of the medulla oboungtc it is alos called dorsal group of respiratory neurons this is formed by the nucleus of tractous solitaries and some neuron surrounding this Function Inspiratory center is cuncemed with inspiration the nucleus of tractus solitaivs recrives sensory impuises from peniphenal barore cuprous chemdrecepturs and pulmmany recepturs through vagus and glossopharyngel nevees these smpulses from periphery help the center in the legulation of respiratrn Effect of stimulation Electrical stimulation of the inspiratry center in animals by using neele electrode couses contraction of inspiatory muscles and prolonged inspiration A.2 Expiratory center Situation The expiratory center is situated in medulla oblongata and lateral to the inspiratory center it is alos called the venterd group of respiratory neurons the neurons of this center form nucleus ambiguous anteriurly and nucleus retro ambiguous posteiorly Function Normally this center is inactive during fuiet breathinal and the inspiratiry center is the active center Expiratory center becomes active durng forced breating or when the inspiratrry center is inhibited But during quiet breating expiration is a passive process and is due to the reculing propenty of thorapic cage and lungs Effect of stimulation Stiulation of preumotaxic center does not produce acne typical effect except slight promulgation of expiration by inhibit it the inspiratiory center The sinsu nerue is also called Herings nerve the chemarecepturs in aortic body are supplied by aortic nerve whcich is abrach of vagus nerve 11. the exchange of respiratory gases b/n fetu blood and maten blood occurs mostly because of pressue gradient the particat pressue of oxygen in the paitial pressure of Oxygen I s 30 mhg This pressure gradient of 20 mmhg cause the diffrsion of oxygen into the fetal blood This pressare gradient is very low companed to the gradient exitinl b/n partical pressare of oxygen in arterial blood and alveoli in adults still an adequct quantity of oxygen is ovalilable for fetus this is because of the following reasms 1. The hemoglobin in feto blood has got 20 times more affintity oxygen the adult Hemuglob 2. The concentration of hemoglobin is about 50% more in feto blood than in adolt blood Bohrs effect Increased car bon dioxide tension reduces the affmity of hemoglobin for oxygen this is called Bohrs effect on the othen hand when the can bandiuxide tensim is decreased the affrity for oxygen is increased all the metabolic end product includly can ban divxde are completely excreted from felus into the mateanl blood the developd low partical pressare of Co2 in feto blood so the affinity fetl hemoglob for oxygen is increased resultorly in diffusion of more amount of oxygen from mothers blood into fetl blood at the same time because of entrance of fetal carbandioxide into materal blood partial pressue of careban dioxide is very high in mothes blood Because of this affintity of mothers hemoglobin for oxygen is reducted leading to diffusion of more amount of oxygen into the feto blood Thos Borrs effect opencits in both fetal blood and maternal blood Hence it is know as double Bohrs effect B2 Apneustic center Situation The apneustic center is situated in reticular firearm of lower puns FunctionThis center accelenates the depth of inspiratic by actrol directly on the inspiratory center Effect of stimulation The stmultion of apneustic center increases the duratra of inspiration with short expiratirr gasp so the respiration is called gasping type of respiration Chemoreceptorrs :- are the receptors w/h give response to change in chemical can situents of blood Classified into two A. Central chemoreceptors B. Peripheral chemoreceptors A. Central chemoreceptors The chemoreceptors present in the brain are called the central chemoreceptors Situation Centrd chmore ceptors are situated in the deeper part of medulla oblongata clase to the dourg group of nevrons this area is known as chemo sensitive area and the neuron are called chemoreceptors the chemoreceptors are close carfact with blood and cerebru spinal fluid B. Peripheral chemoreceptorsThe propend chemoreceptors are in the carotid and acrticresia Situation Peripheral chemoreceptors are situated in the can otid body and aortic body carotid body is present over the internat canotid antery mean the bifurcation of comman canotid aitery into internal and extanl canotrd arteries the aortic body is situated on the arch of aorta . glossophanyngeal nerve . Dead space the volume occupied sy gas which does not participate in gas exchange in lung Anatomical dead space the voume of the caonducting airways of the nose mouth trachea down to the level of lved supresonting dead portion of inspired gas unavailave of exchange of gases with pulomary capillary blood .Aluveolar dead space is the space occupied by gas which is transported to the alveoli but does not meet blood across the alveolar capillary membrance 10. Respiratory distress syncline the most common problems of premature babies it can cawse babes to need extra oxygen shelp breating the most common symptoms of RDS - respiratory difficulty at birth that gets progressively worse - Cyanoses ( blue coloring ) - Flares of the nostrils - tachygnea - Eructing sands with breathing - chest retractions RDS occurs when there is not enough of a substance in the lungs called surfactant surfactiant is a liqid produced by the lungs that heaps the air ways ( called alveoli ) lopen making it possible for babies to breath in air after delivery it beging to be produced in the fetus at about 26 weeks of pregnancyTypes of hyoxia 1. Hypoxic hypoxia or generalized hypoxia Resurtag from an inadequate satwration of blood oxygen due to a reduced supply of oxygen in the air decreaded lung uentilation or respiratory disease Causes A high altitude where the comcentration of atmospherc oxygen is decreased The inhalation of nitrous oxide or laughing gas on arepeated basis for recreational puroses can decrease oxygen availability while increasing CO2 levels Sleep apnea or obstructive sleep apnea can interrupt air flow to the lungs Dideases guch as branchial asthma , rspiratiry arrest chronin obstructive pumary disease inadequate Demtilation of the lungs 2. Anemic hypoxia Refers to when the capacity of the blood to carry O2 is reduced & inadequate levels of oxygen are there fore circulated arovnd the body Causes Decreased amount of oxygenated hacemoglobin Carbon monoxide poisming where the receptors that usually carry oxygen are blocked by the carbon oxygen 3. Histotoxic hypoxia Refers to when oxygen is delivered to the tissues out they fail to utilize it effectively because the cells are damosed and can not extract & absorb Oxygen from circulating blood causes Overuse of alcohol or drugs Cyande poisoning cyanide disrupts cytochrome oxides an important enzyme in cell respiration 4. Stagenmt hypoxia Arises from a decrease in blood fins preventing adequate blood supply to tissues Causes Heart attack heart failure cardiac arrest