自由潜水相关circulation and gas exchange

1、How long can you hold your breath?Brett LaMaster - constant ballast free diving record 266 ft., 2 minutesFrancisco Ferreras (Pipin) - no limits free diving record 439 ft.; two breath record 515 ft, 2 minutesHow long can you hold your breath?Brett LaMaster - constant ballast free diving record 266 ft

2、., 2 minutesFrancisco Ferreras (Pipin) - no limits free diving record 439 ft.; two breath record 515 ft, 2 minutesMartin Stepaneck - first person to hold his breath underwater on purpose 8 min; his record = 8 min. 6 secondsChapter 42Circulation and Gas Exchange1 mm rule: Diffusion is an effective me

3、ans oftransporting substances (e.g.,gases) only when the distance is 100 m from a capillaryFig. 42.9Capillaries connect to venulesFig. 42.9Venules connect to veinsFig. 42.9Veins have valves that help prevent backflowWhat is blood? Blood is the fluid that carries nutrients, gases, hormones and wastes

4、 around the body Blood consists of: plasma (the liquid part)55% of volume cellular components45% of volume(red blood cells, white blood cells, platelets) Average adult human has 5 to 6 L of blood (about 8% of body mass)What is blood?Plasma is a straw-colored liquid that contains dissolved proteins,

5、salts, minerals, and hormonesWhat is blood?Red blood cellsWhite blood cellsPlateletsWhat is blood?Red blood cells = erythrocytesThese are the most numerous cells in the bloodTheir dimpled shape gives them extra surface areaThey are packed full of the pigment hemoglobinWhat is blood?HemoglobinFour su

6、bunit polypeptide chainsEach subunit polypeptide chain has an iron-rich heme groupEach heme group can reversibly bind one O2 moleculeWhat is blood?HemoglobinCarries 70 times more O2 than dissolves in the plasmaAlso carries CO2, but with much less affinity than for O2What is blood?Red blood cells = e

7、rythrocytesProduced in the bone marrowLive 120 daysDead and damaged cells are removed from circulation by the liver and spleenWhat is blood?White blood cells 5 types of leukocytesProduced by the bone marrowCollective function is to fight infectionFig. 42.16What is blood?PlateletsFragments that bud o

8、ff of larger cells in the bone marrowThey are especially valuable in the clotting responseA clot forms as platelets, RBCs, and a fibrin network stick togetherThe lymphatic systemCapillaries are leaky, and much fluid passes out of them into the interstitial spacesFig. 43.5The lymphatic systemThe flui

9、d is taken up by lymph capillaries, at which point the fluid is referred to as lymphFig. 43.5The lymphatic systemLymph vessels are valved and empty into main veins of the circulatory systemFig. 43.5The lymphatic systemLymphocytes are also important components of lymphFig. 43.5The lymphatic systemLym

10、phocyte-rich nodes help filter the lymph and serve as sites of attack on microbial invadersFig. 43.5The lymphatic systemStructures labeled in the figure are especially active traps of microbial invadersFig. 43.5The lymphatic systemLymphocytes develop in the thymus and bone marrowFig. 43.5Elephantias

11、is caused by a parasitic worm, most common in parts of Africa, reduces the lymphatic systems ability to take up fluids that leak out of capillariesThe lymphatic systemJust like other organ systems, the lymphatic system can malfunctionFig. 42.23The respiratory systemEach lung contains 2 million alveo

12、li, with a total surface area of 75 m2Fig. 42.23The respiratory systemAlveoli have thin, moist walls and are surrounded by capillariesFig. 42.23The respiratory systemOxygen diffuses from the air in the air spaces of the alveoli into the blood of the capillariesFig. 42.23The respiratory systemCarbon

13、dioxide diffuses from the blood of the capillaries into the air of the air spaces of the alveoliFig. 42.23The respiratory systemWhen the diaphragm contracts, the chest cavity expands, and the lungs fill with airThe respiratory systemWhen the diaphragm contracts, the chest cavity expands, and the lun

14、gs fill with airFig. 42.24Birds have especially efficient respiratory systemsWhen a bird inhales, some of the air passes through its lungs and some fills its air sacsFig. 42.25Birds have especially efficient respiratory systemsWhen a bird exhales, air continues to move in the same direction through

15、the lungs, as the air sacs emptyFig. 42.25Birds have especially efficient respiratory systemsThe microscopic, tube-like chambers of gas exchange in bird lungs are known as parabronchiFig. 42.25Cardiovascular diseasesDisorders of the heart and blood vesselsLeading causes of death in the USA ( 1 milli

16、on people each yr)Hypertension (high blood pressure), often caused by constriction of the arteries and arterioles, can strain the heartHypertension often results from plaque buildupPlaques are thickened artery and arteriole walls; smooth muscle infiltrated by lipids (especially low-density lipoprote

17、ins, LDLs, the “bad cholesterols”)Cardiovascular diseasesAtherosclerosis is the condition in which plaques impair circulationArteriosclerosis is a more advanced condition in which plaques become hardened by calciumdepositsCardiovascular diseasesPlaques are often sites of clotting within vessels; thr

18、ombus (clot formed & found at the site of blockage) or embolus (clot transported within the blood to its site of blockage)Cardiovascular diseasesCardiovascular diseasesRestricted blood flow within the coronary arteries (which deliver blood to heart tissues) may cause chest pains (angina) Cardiovascu

19、lar diseasesBlockage from a thrombus or embolus of coronary arteries is one cause of heart attackA similar blockage in the brain is a cause of strokeCardiovascular diseasesExercise, low-fat diet, and abstinence from smoking and alcohol abuse all promote a healthy heartSmoking and healthA gratuitous

20、public-service announcementNicotine in tobacco smoke is a powerfully addictive drugSmoking and healthEach yr 430,000 people die in the U.S. from smoking related diseasesSmoking costs U.S. tax payers about $100 billion annually in health care for the uninsured and losses of productivityPrincipal causes of death are lung cancer, emphysema, chronic bronchitis, heart disease, strokes, and other cancersSmoking and healthToxins in tobacco smoke inhibit the cilia that line the respiratory tract so that they cannot remove particulatesToxins also i