Respiratory System /biology/the-human- body/respiratory-system

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Respiratory System

Respiratory System

RespirationThe exchange of gases between the body and the outside airOxygen is drawn in and delivered to the cellsCarbon dioxide is releasedOrgans of the Respiratory System

Journey of a Breath of AirVentilation moving air into and out of the lungsNose and MouthMucus and hairs trap any particles in the airAir is warmed and moistenedPharynx Long tube that is shared with the digestive system (esophagus)Epiglottis closes when you swallowLarynx voice box (vocal cords)Journey of a Breath of AirTrachea wind pipeLeads into the chestDivides into right and left bronchiContain cartilage which keeps them from collapsingMucus traps any remaining particlesTiny hairs help move the mucus and particles to where they can be expelled through the throatAir passes from the Bronchi to the smaller passages called the bronchiolesPulmonary Gas ExchangeTakes places in the alveoli of the lungs

Gas TransportOxygen is carried from the lungs back to the heart by the circulatory system

Peripheral Gas ExchangeOxygen diffuses into the cells from the capillaries and carbon dioxide diffuses into the capillaries from the cellsGas Exchange and HomeostasisSome of the carbon dioxide dissolves in the blood and forms carbonic acid to control the pH of the bloodThis can get out of whack if we breathe too fast or two slowAs a result breathing must be regulatedHow does Breathing Occur?Comes from the contraction of the diaphragm

Control of BreathingControlled by the brain stemUses the autonomic nervous systemBrain stem monitors the level of carbon dioxide in the bloodIf too high signals diaphragm to contract more often to get rid of excess carbon dioxideIf too low the opposite

Diseases of the Respiratory SystemAsthma air passages become too narrow and too much mucusTriggered by allergens, strenuous activity, stress alveoli fill with fluidCoughing, chest pain, difficulty breathingInfection or injuryBacterial or viral in natureDiseases of the Respiratory SystemEmphysema walls of the alveoli break down so less gas can be exchangedShortness of breathUsually caused by smoking and is irreversible

Cigarette Health WarningsLarger more prominent warning in September of 2012Cigarettes are addictiveTobacco smoke can harm your childrenCigarettes cause fatal lung diseaseCigarettes cause strokes and heart diseaseSmoking during pregnancy can harm your babySmoking can kill youTobacco smoke causes fatal lung disease in nonsmokersQuitting smoking now greatly reduces serious risks to your health

The Digestive System


The GI TractConnects mouth to the anus30 feet long in adults with mucus membranes that secrete digestive enzymes and absorb nutrientsPeristalsis is the involuntary muscle contractions that move food along in waves

Accessory Organs of Digestion Food does not pass through themThey secrete or store substances needed digestionLiverPancreasGall BladderFunctions of the Digestive SystemMechanical digestionPhysical breakdown of chunks of foodTakes place in the mouth and stomachChemical digestionChemical breakdown of food into usable smaller nutrients that can be absorbed by the bloodBegins in the mouth and stomach, but takes place mainly in the small intestineAbsorption nutrients absorbed in the small intestineElimination getting rid of the waste productsDigestion as a processMouth to StomachDigestive enzymes released by the salivary glands in the mouth (chemical)Salivary amylase starch into sugarMechanical digestionsFood passes into the esophagus and then into the stomachSphincter controls the entrance of food into the stomach and from moving back upStomachChemical and physical digestion bacteria in food and give the stomach a low pH needed by the digestive enzymes to workPepsin digests proteinSphincter opens and partially digested food moves into the small intestineDigestion and Absorption in the Small Intestine23 feet long in adultsDuodenum smallest part most chemical digestion takes place hereJejunumIleumDigestive enzymes of the DuodenumEnzymeWhat it DigestsWhere It is MadeAmylaseCarbohydratesPancreasTrypsinProteinsPancreasLipaseLipidsPancreas, DuodenumMaltaseCarbohydratesDuodenumPeptidaseProteinsDuodenumLiver and Gall BladderLiverProduces bile which goes into the duodenum and the gall bladderGall bladderConcentrates and stores bile and then secretes it into the small intestineBile breaks up globules of lipidsEnzymes here need a neutral environmentCreated by the pancreas secreting bicarbonateAbsorption in the small intestineIn jejunum by villi (many capillaries)

Large IntestineCecumColon Excess water is absorbed hereRectumSolid waste eliminated as feces

The Excretory SystemExcretionThe large intestine eliminates solid wastes that remain after the digestion of foodThe liver breaks down excess amino acids and toxins in the bloodThe skin eliminates excess water and salts in sweatThe lungs exhale water vapor and carbon dioxideKidneysThe main organ of the excretory systemFilters blood to form urineNephrons are the structural and functional units of the kidneyThere are more than a million nephrons

Filtering blood and forming urineBlood enters through the renal artery and branches into the capillariesBlood pressure forces some of the water and dissolved substances to enter the Bowmans capsuleFiltered substances pass to the renal tubeSome substances are reabsorbed and returned to the bloodstream other substances are secreted into the fluidFluid passes through a collecting duct which reabsorbs some water and returns it to the bloodstreamRest remains in the collecting duct as urineExcretion of UrineUrine enters the uretersPeristalsis moves it to the bladderWhen the bladder is about half full a signal is sent to relax a sphincter muscle which allows the urine to flow into the urethraUrine passes out of the body through the urethra