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Arteries/ arterioles are more like veins/ venules (thin walled, with large lumens)oArterial resistance and pressure are low (24/8 mm Hg)Blood flow: heartDuring ventricular systole oCoronary vessels are compressedoMyocardial blood flow ceases
oStored myoglobin supplies sufficient oxygenAt rest, control is probably myogenicDuring strenuous exerciseoCoronary vessels dilate in response to local accumulation of vasodilators oBlood flow may increase three to four timesAlterations in blood pressureHypotension: low blood pressureoSystolic pressure below 100 mm HgoOften associated with long life and lack of cardiovascular illnessoBelow 60 mm HgHigh concernHypertension: high blood pressureoSustained elevated arterial pressure of 140/90 or higherChronicBorderline 130/85May be transient adaptations during fever, physical exertion, and emotional upsetOften persistent in obese people Homeostatic imbalance: hypertensionProlonged hypertension is a major cause of heart failure, vascular disease, renal failure, and stroke.oTreating BPoAtherosclerosis oAfterload: increase work load on heartVentricular hypertrophy Primary or essential hypertensiono1stproblem o90% of hypertensive conditionsodue to several risk factors including heredity, diet, obesity, age, stress, diabetes mellitus, and smokingsecondary hypertension is less common odue to identifiable disorders, including kidney disease, atherosclerosisand endocrine disorders such as hyperthyroidism and cushing’s syndromekidney disease: ability to reduce blood volumeresult: retain more wateroincreased blood volume and increased blood pressure oanother heart problem started first resistanceoarterioles decrease resistanceomedication that promotes vasodilationlowers blood pressureblood volumeoincrease urine outputlittle less water in blood volumedecrease blood volume; lowers blood pressurediuretics Chapter 22: The Respiratory System Part ARespiratory system: functional anatomy Some medications combine the two
major organs (most of parts are conducting zone)onose, nasal cavity, and paranasal sinuses opharynxolarynxotracheaobronchi and their branchesolungs and alveoli conditioned airowarm, filtered, humidify LOOK AT DIAGRAM****Functional anatomyRespiratory zone:site of gas exchange (diffusion) omicroscopic structures: respiratory bronchioles, alveolar ducts, and alveoli(presence) Conducting zone: conduits to gas exchange sites (nasal, pharynx, larynx, trachea, bronchi, upper/ middle lungs)oMoves air up and down, in and out of lungs and conditions airoIncludes all other respiratory structures Respiratory muscles: diaphragm and other muscles that promote ventilation The nose and nasal cavityFunctions oConditioningoProvides an airway for respiration oMoistensand warmsthe entering airoFiltersand cleans inspired airoServes as a resonating chamber for speechoHouses olfactory receptorsThe noseNasal cavity: in and posterior to the external noseoDivided by a midline nasal septumo