Presentation on theme: "Chapter 18 Disorders of Blood Flow and Blood Pressure"— Presentation transcript:
1Chapter 18 Disorders of Blood Flow and Blood Pressure Essentials of PathophysiologyChapter 18 Disorders of Blood Flow and Blood Pressure
2PRE-LECTURE QUIZ True/False F HDL is known as the “bad cholesterol.” T Most abdominal aneurysms are asymptomatic.F Essential (primary) hypertension is characterized by chronic elevation in blood pressure that results from some other disorder, such as kidney disease. F Orthostatic or postural hypotension is an abnormal rise in blood pressure that occurs when assuming the standing position from the supine position.T Venous insufficiency leads to tissue congestion and edema in the lower extremities.
3PRE-LECTURE QUIZAorticThe __________ controls the transfer of molecules across the vascular wall, plays a role in platelet adhesion and blood clotting, and functions in the modulation of blood flow and vascular resistance.__________, with its associated risk for the development of atherosclerosis, is a major cause of cardiovascular disease. __________ phenomenon is a functional disorder caused by intense vasospasm of the arteries and arterioles in the fingers and, less often, in the toes. __________ dissection is an acute, life-threatening condition that involves hemorrhage into the vessel wall with longitudinal tearing or separation of the vessel wall to form a blood-filled channel. The body uses neural mechanisms and humoral mechanisms to effect the __________-term regulation of blood pressure, which occurs over minutes or hours and is intended to correct temporary imbalances in blood pressure.EndotheliumHyperlipidemiaRaynaudShort
4Artery Structure Arranged in tunics or coats Tunica intima: EndotheliumTunica media: smooth muscleTunic adventitia: collagen and elastic fibersAuthor: Add text?
6QuestionWhich vessel layer can expand to accommodate pressure changes?Tunica intimaTunica mediaTunica adventitiaTunica externa
7AnswerTunica mediaThe tunica media is composed of smooth muscle, which can stretch/expand to accommodate changes in blood pressure.Is this answer arguable?
8Vascular EndotheliumNutrients and O2 pass into tissuesWastes and CO2 pass from tissues into bloodCreates compounds that cause vasodilation or vasoconstrictionCreates growth factors that can stimulate smooth muscleForms a smooth lining of the blood vessels that resists clot formationCreates compounds to promote clot formation in injured areas
9Lipids get into the vascular endothelium AtherosclerosisLipids get into the vascular endotheliumWhite blood cells try to clear them away foam cellsWBCs and vascular endothelium release growth factors that promote plaque formationPlaques block the arteries
10The more protein, the higher the density LipoproteinsThe more protein, the higher the densityThe more lipid, the lower the density
11Lipoproteins The more protein, the higher the density The more lipid, the lower the densityi.e. protein is heavier than lipids
12QuestionTell whether the following statement is true or false. LDL is considered to be “good” cholesterol.
13AnswerFalse Rationale: LDL (low-density lipoprotein, which has more lipids and less protein) is the “bad” cholesterol. HDL (high-density lipoprotein) has more protein and less fat, and is considered “good” cholesterol.
14Lipid Transport in the Body Dietary lipids absorbed as chylomicronsAdipose and muscle cells take up lipids from chylomicronsChylomicron remnants are intermediate-density lipoproteins, IDL
15Lipid Transport in the Body (cont.) IDLs become low-density lipoproteins (“bad cholesterol”)These can deliver fat to the liver and to other tissuesLDL receptors are necessary for the liver to take them upSome LDLs are taken up by scavenger cells like macrophages
18AtherosclerosisAtherosclerosis develops because scavenger cells encounter the fatty deposits in the artery lining andTry to destroy the fats by oxidizing themOxidized fats injure the endotheliumClots form and release growth factorsSmooth muscle grows over the fatty coreTry to remove the fats by eating themBecome “foam cells” in the core of the plaque
19Lipid Transport in the Body High-density lipoproteins (“good cholesterol”) are made in the liverThey go out to the peripheral tissues and pick up lipidThen they carry it back to the liver
20ScenarioA man has several genetic defects in his lipoprotein receptors…His liver lacks LDL receptorsHis muscle cells lack receptors for the apoproteins on chylomicronsHis scavenger cells have extra LDL receptorsQuestion:Why might he develop atherosclerosis?
21Stable PlaquesHave thick fibrous capsPartially block vesselsDo not tend to form clots or emboli
22Unstable Plaques Have thin fibrous caps Plaque can rupture and cause a clot to formMay completely block the arteryThe clot may break free and become an embolus
23QuestionWhat immediate threat do unstable plaques present?Clot formation will increase pressure in the vessel.Plaque may lead to angina (chest pain).Clots may break loose and block blood flow to key organs.All of the above constitute immediate threats.
24Answerc. Clots may break loose and block blood flow to key organs. Rationale: If a clot breaks loose, becoming an embolus, it may lodge in a blood vessel to the brain, heart, or lungs. When blood flow is significantly decreased or blocked altogether, the result is tissue death—in the examples here, stroke, heart attack, or pulmonary embolus. The other choices represent more long-term/chronic problems.
25Scenario A woman complains of pain in her left leg. Her foot is cool and paleShe reports that it is often red and warm when she is sitting downThe pain occurs when she is walking to church on SundaysThe skin on her left leg is shinier than on her right legQuestion:What could have caused all this? How?
26Aneurysms Wall of artery weakens and stretches Risk of rupture and hemorrhageRisk of clot formation
29Discussion How would each of the following affect blood pressure? VasodilationDecreased stretching of baroreceptorsHypoxemiaInhibiting angiotensin-converting enzymeBeta blockersAlpha-2 agonistsCalcium-channel blockersLower resistance lowers BPReflex raises BPCalls for more blood flow raises BPBlocks formation of Angiotesion II Lowers BPSlows HR Lowers BPDecreases Sympathetic response Lowers BPDecreases vascular resistance Lowers BP
31Scenario A woman complains of pain in her left leg… Her foot is cool and paleShe reports that it is often red and warm when she is sitting downThe pain occurs when she is walking to church on SundaysThe skin on her left leg is shinier than on the right legQuestion:What could have caused all this? How?
32Aneurysms Wall of artery weakens and stretches Risk of rupture and hemorrhageRisk of clot formation