Presentation on theme: "Respiratory System Exchange of oxygen and carbon dioxide between the blood and the muscle tissues Exchange of oxygen and carbon dioxide between the lungs."— Presentation transcript:
1 Respiratory SystemExchange of oxygen and carbon dioxide between the blood and the muscle tissuesExchange of oxygen and carbon dioxide between the lungs and bloodThe breathing of air into and out of the lungs
3 Mechanics of Breathing Inspiration:External intercostals muscles contract during inspirationDiaphragm contracts (downwards and flattens)This pulls the rib cage upwards and outwardsThese actions cause the thoracic cavity size to increaseThis decreases the pressure inside the thoracic cavityGases move from areas of high pressure to low pressure areasTherefore oxygen moves from the atmosphere (higher pressure) into the lungs (now low in pressure)During exercise, a more forceful inspiration is required so extra muscles are involved in this process – sternocleidomastoid and pectoralis minor
4 ExpirationUsually a passive processAs the intercostals muscles relax the rib cage moves downwardsThe diaphragm relaxes and returns to its dome shapeThis decreases the size of the thoracic cavityThis causes the pressure to increase in the thoracic cavity (smaller volume)Therefore gases move out of the lungs (high pressure) into the atmosphere (lower pressure)During exercise breathing rate is increased, expiration is aided by the internal intercostal muscles and the abdominal muscles,This pulls the rib cage down more quickly and with greater force
7 Gaseous Exchange Key Terms: Gaseous Exchange – the process of exchanging O2 and CO2Partial Pressure - the pressure a gas exerts in a mixture of gasesDiffusion - The movement of gases from areas of higher partial pressure to lower partial pressureDiffusion Gradient - The difference between high and low pressure of gases. The bigger the gradient the greater the diffusion.
8 External RespirationInvolves the movement of oxygen and carbon dioxide between the alveoli of the lungs and capillaries surrounding the alveoli.The aim of external respiration is to oxygenate the blood returning from the tissuesAs blood circulates through the capillaries surrounding the alveoli oxygen is picked up and carbon dioxide is dropped off to be expired
9 Internal RespirationInvolves the movement of O2 and CO2 between the capillaries surrounding the muscles and the muscle tissuesThe aim of internal respiration is to oxygenate the muscles and collect CO2 to return it to the alveoliThese processes can only happen if a diffusion gradient is present.
10 External and Internal Respiration Showing Changes in O2 and CO2
11 Oxygen-Haemoglobin Dissociation Curve Shows us how much haemoglobin is saturated with oxygenSaturated – when haemoglobin is loaded with oxygenDissociation – where oxygen is unloaded from the haemoglobinThe higher the partial pressure of oxygen, the higher percentage of oxygen saturation to haemoglobin
13 Oxygen associates with haemoglobin at the lungs and dissociates at the muscles (because PP of O2 is high at lungs and low at muscles)During exercise a greater amount of dissociation of O2 at the muscles is required, therefore less saturation at the muscles has to occurFour factors happen in our bodies during exercise to allow this to occur
14 Factors Affecting the saturation of oxygen to haemoglobin Increase in temperature – in the blood and muscles during exerciseDecrease in PP of O2 – within the muscles during exercise, therefore creating a greater diffusion gradientIncrease in PP of CO2 – therefore causing a greater CO2 diffusion gradientIncrease in acidity – lowering the pH of the blood through production of lactic acid (more hydrogen ions produced). This is known as the BOHR SHIFTAll four of these factors (which occur during exercise) increases the dissociation of oxygen from haemoglobin, which increases the supply of oxygen to the working muscles and therefore delays fatigue.
16 Exam Style Question:What happens to the oxygen-Haemoglobin Dissociation Curve during exercise? (6 marks)It shifts to the rightBecause during exercise there is an increase in blood/muscle temperatureDecrease in PP of O2 in the musclesIncrease in PP of CO2 in musclesIncrease in acidity (more lactic acid)Known as Bohr Effect/Shift
17 Myoglobin Has a higher affinity for O2 than haemoglobin Therefore acts as a store of O2Even at very low partial pressures of 02 (the muscles when exercising) it remains saturatedThis means that myoglobin still has O2 available to supply the working muscles.
18 Respiratory Adaptations to Training Reduction in breathing rate during sub-maximal exercise,System is more efficient therefore lessbreaths required,No changes in lung volumes exceptVital capacity – amount of air that can be forcibly expired after maximal inspiration – increases slightly, largely due to stronger respiratory musclesTherefore spirometer traces are not good predictors of training or fitness because lung size/volume do not determine fitness (these are largely genetic and not adapted due to training)
19 Gaseous exchange becomes efficient External Respiration - increased capilliarisation surrounding alveoli – more opportunity for gaseous exchange to occur, more O2 enters the bloodInternal Respiration – increase in myoglobin within the muscles (this carries O2 to mitochondria), therefore leading to improved efficiency of energy production.
21 Describe the chemical, physical and neural changes that cause a change in our breathing rate. Increase in CO2, increase in acidityDetected by chemoreceptorsPhysical –Movement of muscles and jointsDetected by proprioreceptorsAlso stretch receptors in lungs, temperature receptors detect changesNeural –Nervous controlMessages sent to the medulla (respiratory control centre)Messages to send respiratory muscles via sympathetic nervous system.
22 Respiratory System so far . . . What is the Oxygen-Haemoglobin Disassociation Curve?What happens to the curve during exercise?What causes this to happen?What are the effects of the curve shifting to the right?What changes occur to the respiratory system as a result of training?
23 Lung Volumes (Average male) ** Learn Volume NameDescriptionValue at Rest (ml)Change during ExerciseTidal Volume (TV)Amount of air breathed in or out per breath500IncreasesInspiratory Reserve Volume (IRV)Maximal amount of air forcibly inspired in addition to tidal volume3100DecreasesExpiratory Reserve Volume (ERV)Maximal amount of air forcibly expired in addition to tidal volume1200Vital Capacity (VC)Maximal amount of air exhaled after a maximal inspiration(TV + IRV + ERV)4800SlightResidual Volume (RV)Amount of air left in the lungs after a maximal expirationNoneTotal Lung Capacity (TV)Vital Capacity plus residual volume(TV + IRV + ERV + RV)6000none
24 Effects of Exercise on Volumes At rest, lungs are ventilated at approx. 6 Litres per minuteDuring “steady state” endurance exercise maximal ventilation is about Litres per minute (males) and Litres per minute (females) – smaller lungs!Brief maximal exercise (800m race) rates may increase to Litres per minuteBREATHING RATES – rise from 12 per minute to 45 per minute during strenuous exerciseDepth of respiration can increase from 0.5 litres per breath to 2.5 litres per breathTraining will usually result in little or no change in pulmonary function. However, swimmers may experience some increase in vital capacity and maximal breathing capacity (breathing against resistance of the water)Comparison of marathon runners and sedentary subjects showed no difference in actual lung functions (FEV1, etc)
25 SummaryThe respiratory system functions to deliver O2 to the lungs and remove CO2The system consists of the nose, trachea, larynx, bronchial tree and lungsInspiration occurs when air is drawn into the lungs by the reduction of the pressure caused by an increase in the size of the thoracic cavityExpiration occurs when the pressure increases as the size of the thoracic cavity decreases and air is forced outDuring normal breathing inspiration is produced by the activity of the diaphragm and intercostal musclesDuring exercise both the rate and depth of breathing increaseRespiration is controlled by the MEDULLA of the brainTotal Lung Capacity = Tidal Volume + Inspiratory Reserve Volume + Expiratory Reserve Volume and Residual Volume (6000ml)