6What makes an exchange surface efficient? FeatureHow it helpsLarge surface areaLarger area for molecules to diffuseThin barrierShorter distance for diffusionPermeable membraneAllow molecules throughGood supply/removal of molecules requiredMaintain diffusion gradient
7ExamplesSmall intestineLiverLungsRoot hairsHyphae of fungi
9Lungs and breathingLabel as many parts as you can.
10Lungs and breathing Larynx Trachea Right lung Left lung Left bronchus Right bronchusBronchiolesIntercostalMusclesHeartAlveoliRibsPleural cavityPleural MembraneDiaphragmLabel as many parts as you can.
171) by blood flow on one side by air flow on the other side. The steep concentration gradient across the respiratory surface is maintained in two ways:1) by blood flow on one sideby air flow on the other side.This means oxygen can always diffuse down its concentration gradient from the air to the blood, while at the same time carbon dioxide can diffuse down its concentration gradient from the blood to the air.The flow of air in and out of the alveoli is called ventilation and has two stages: inspiration (or inhalation) and expiration (or exhalation). Lungs are not muscular and cannot ventilate themselves, but instead the whole thorax moves and changes size, due to the action of two sets of muscles: the intercostal muscles and the diaphragm.
18The flow of air in and out of the alveoli is called ventilation and has two stages: inspiration (or inhalation) and expiration (or exhalation). Lungs are not muscular and cannot ventilate themselves, but instead the whole thorax moves and changes size, due to the action of two sets of muscles: the intercostal muscles and the diaphragm.
19Describe the stages of Inhalation and exhalation Must give reference toDiaphragmIntercostal musclesVolume of chest cavitypressureExhalation is a passive process, We breathe out when our muscles relax
20Breathing is a passive process InhalationExhalationDiaphragm Contracts, moving downwards increasing the volume of the chest cavity and displacing the organs beneathThe diaphragm relaxes, the organs below move back into placeThe intercostal muscles contract moving the ribcage up and outThe intercostal muscles relax, the ribcage moves down and inThe volume of the chest cavity increases decreasing the pressure in the thorax below atmospheric pressureThe volume of the chest cavity decreases causing air pressure in the lungs to increase above atmospheric pressureAir is sucked into the lungs as a resultAir is forced out of the lungs as a result
27Total Lung Capacity- The maximum amount of air that the lungs can hold Residual Volume- The volume of air that remains in the lungs after breathing approx 1.5dm3Vital Capacity- The maximum usable lung volume (total lung capacity minus the residual volume). The average vital capacity is dm3 for men and for women.Tidal Volume- The volume of air that moves in and out of the lungs in each breath (during normal breathing). In a normal adult this is about 0.5 dm3.Inspiratory Reserve Volume- The amount of air that the lungs will hold after a normal expiration (i.e. inspiratory reserve + tidal volume).Expiratory Reserve Volume- The amount of air remaining in the lungs after a normal quiet expiration (i.e. expiratory reserve volume + residual volume).