Biology - An Illustrated Guide to Science (794127), страница 29
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This reaction is calledagglutination. For this reason, ifrecipients have anti-A in their plasma,they cannot receive blood fromgroup A● The antibodies in the donor can beignored during transfusions—only theantibodies in the recipient aresignificant. This means AB (which hasno antibodies) can receive blood fromany group and is called the universalrecipient. Blood group O is theuniversal donor because it has noantibodies.OABABABaBAaABaBA●AgglutinationAABBaAntigens and antibodiesRed blood corpu scles have proteins ontheir cell surface called an tigen s.There are two types: A and B. Bloodgroup A has antigen A on its cellsurface, B has B, AB has both, and Ohas neither.● Blood plasm a contains an tibodies,proteins the immune system uses toneutralize foreign objects, that reactwith these antigens.
Blood group Ahas anti-B, B has anti-A, O has bothanti-A and anti-B, while AB has neither.aBABABABReactions that occur when different blood groups are mixedO is universal donorAB is universal recipientAgglutination occurs if the recipient's blood contains antibodies to the donor’s antigens© Diagram Visual Information Ltd.●RecipientBloodtypesDonorOOAB= red blood corpusclewith no antigensABA= red blood corpusclewith A antigenB= red blood corpusclewith B antigenABAB= red blood corpusclewith A and B antigensa= anti-A antibodyin plasmab= anti-B antibodyin plasma= agglutinationoccursAB= agglutination doesnot occur167Respiration: respiratorysystemHUMAN BIOLOGYKey wordsalveolusbronchiolediaphragmintercostalmusclelungSection of head and thoraxLeft lung: surface viewRight lung: sectionRespiration and breathingThe terms respiration and breathingare often used to mean the samething—the moving of air into and outof lungs.● However, respiration can also meanthe chemical reactions going on in allcells that transfer energy from foodand oxygen to drive cell processes.●pharynxepiglottisesophaguslarynxcartilagetracheabronchusribintercostalmusclebronchiolepleuralmembranesright lungpleuralcavitydiaphragmheartleft lungSystem componentsThe respiratory system consists of thenose, nasal cavity, pharynx, larynx,trachea, smaller conductingpassageways (bronchi andbron chioles), and alveoli.● The lungs are found in the thoracicregion and are protected by the ribs.Immediately below the lungs is a sheetof muscle called the diaphragm thatseparates the lungs from the gut andliver.● Muscles between the ribs—thein tercostals—contract and relax tomove air into and out of the lungs.● The lungs are not attached to the ribs.They are separated by the pleuralmembrane, which produces a fluid toallow them to slide over the movingribs during breathing.● Hairs and mucus in the nose clean theair before it passes into the nasalcavity.
Air travels down through thepharynx and is passed to the trachea.● The trachea is a pipe strengthenedwith rings of cartilage to prevent itfrom collapsing. It divides into twobronchi, one for each lung. At thepoint where the trachea joins theesophagus is the epiglottis. This smallflap of tissue closes the entrance tothe lungs when food is swallowed.● Inside the lungs, the bronchi divide toform smaller and smaller bronchioles,which eventually terminate in swollenair sacs called alveoli.●© Diagram Visual Information Ltd.nasal cavity168HUMAN BIOLOGYKey wordsalveolusbronchiolegaseousexchangelungthoraxRespiration: lungsRespiratory systemBronchiole and air sacsbronchioleair sacalveolusMacrostructureThe lu n gs are large air-filled spaces inthe thorax. They are protected by therib cage and connect to the outsideworld through the windpipe, ortrachea.● The lungs are connected to thetrachea by the bronchi.
The bronchienter the lungs and branch out toform bronchial trees. The bronchidivide into smaller bron chioles, whichterminate into alveoli.●respiratorybronchiolealveoliMicrostructure●respiratory bronchiolebranch ofpulmonaryarterybranch ofpulmonaryveinbronchioleand air sacscapillarynetworkSection of alveolusepitheliumof alveolusfilm ofmoisturebranch ofpulmonaryarteryalveolusThe alveoli are swollen sacs of tissuethat have very thin walls and a verygood blood supply. A branch of thepulmonary artery suppliesdeoxygenated blood to the network ofcapillaries covering the outside of thealveolus. A branch of the pulmonaryvein drains oxygenated blood fromthese capillaries and returns it to theheart.● Gaseou s exchan ge occurs between theair in the alveolus and the blood in thecapillaries.
Oxygen passes into theblood, while carbon dioxide passesfrom the blood to the alveolar air.● Muscular movements in the ribs andthe diaphragm maintain a constantsupply of fresh air to the alveoli.Alveolidirection of blood flowcapillarywallred blood cell© Diagram Visual Information Ltd.blood flowinhaled air(rich in oxygen)exhaled air(poor in oxygen)diffusion of oxygeninto bloodbranch of pulmonary veinblood plasmadiffusion of carbondioxide from blood169Respiration: breathingHUMAN BIOLOGYKey wordsBreathingBreathing in (inhalation)abdomendiaphragmintercostallungBreathing out (exhalation)ribsternumMuscles involvedFor gentle breathing, the diaphragm ,which separates the lu n gs from theabdom en , contracts and relaxes.● During heavier breathing, musclesbetween the ribs—the in tercostals—are also involved, and significantlyincrease the airflow.●backboneInhalingDuring gentle inhalation, thediaphragm contracts and falls awayfrom the lungs.
The lungs are pulleddown, and air is drawn into them bysuction. The diaphragm is notphysically connected to the lungs—avacuum between the surface of thelungs and the inside of the ribs pullsthe lungs down while allowing them tomove around.● To increase inhalation, the externalintercostals muscles contract. Thesepull the ribs upward and outward toincrease the volume of the chest. Thispulls air into the lungs.●tracheaThorax section(front view)intercostalmusclesrelaxedriblungExhalationintercostal musclescontracteddiaphragm musclescontracteddiaphragm musclesrelaxedThorax section(side view)ribintercostal musclesrelaxedintercostalmusclesWhen muscles in the body wallcontract, the liver and stomach pushagainst the diaphragm.
The relaxeddiaphragm then pushes up into thechest space and squeezes air out ofthe lungs.● To increase exhalation, the internalintercostals contract and pull the ribsdownward and inward to push on thelungs.●diaphragmmusclescontractedmovement of airdiaphragmmusclesrelaxedmovement of ribsmovement of diaphragm© Diagram Visual Information Ltd.lung170HUMAN BIOLOGYKey wordsbilefecesgutmetabolismspleenureaExcretion: excretorysystemsExcretory systemsExcretionExcretion is the removal of waste andbreakdown products of m etabolismfrom the body.● Since the roughage that forms mostfeces has never been inside the body(the gu t space is regarded as outsideof the body), most of it is not anexcretory product.●Excretory productsCarbon dioxide and water made byrespiration.● Urea made by the liver from excessamino acids or broken down proteinmolecules.● Excess salts that were absorbedthrough the gut.● Bile salts made by the spleen from oldred blood cells.● Assorted chemicals absorbed by thebody or toxins that have been brokendown by the liver.●skinlungRoutes out of the bodyCarbon dioxide and a small amount ofwater leave in exhaled air.● Urea passes out in solution as urinemade by the kidneys.
Urine alsocontains waste salts, other assortedwaste products, and water.● Sweat contains water, some salts, andurea, but is not a major route out ofthe body for these substances innormal circumstances.● Bile pigments are passed into the gutand pass out in feces.© Diagram Visual Information Ltd.●kidneyintestinewater and carbon dioxide from lungswater, salts, and urea from skinurea, water, and salts from kidneybile pigments (from liver) vialarge intestine171Excretion: urinary systemHUMAN BIOLOGYKey wordsUrinary systemkidneymetabolismosmoregulationureterExcretion andosmoregulationExcretion is the removal of the breakdown products of m etabolism andother waste from the body.● Osm oregu lation is the control of thewater potential of fluids within thebody.● The kidn eys are involved in bothcrucial processes.●The kidneysHuman beings have two kidneysattached to the back of the abdominalcavity.
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