Ch. 13 Lecture 3Veins• Have a lower pressure than arteries• Return blood to the hearto Skeletal Muscle Pumps: Muscles surrounding the veins help pump blood• Venous Valves: Ensure one directional flow of bloodo Can lead to abnormalities for people that stand up a lot. Results in varicose veins• Breathingo Flattening of the diaphragm at inhalation increases abdominal cavity pressure in relation to thoracic pressure and moves blood towards the heartAthersclerosis• Responsible for 50% of the deaths due to heart attack and strokeo You build up plaques that occlude the lumen of the blood vessel and restrict blood flowo Mostly happens in the arteries, not veins• Forms in response to damage to the endoghelium of a blood vessel• Caused by smoking, high bp, high cholesterol• Lipid filled macrophages/lymphocytes accumulate in the region and engulf lipids• Layers of smooth muscle are added • Then connective tissue caps the cmooth muscle, lipids, and cellular debris• High Cholesterolo LDLs, Low density lipoproteins, carry cholesterol to arteries o People who consume or produce a lot of cholesterol have more LDLs High LDL is associated with increased atherosclerosiso HDLs carry cholesterol away from the arteries to the liver to be metabolized Takes cholesterol away from sources of plaque development Statin drugs elevate HDL levels Diet and exercise also helpo Inflammation Arthlerosclerosis is thought to be an inflammatory disease C-reactive protein might be a good predictor for atherosclerosis Antioxidants might be future treatments bc oxidized LDL might be high risk• Ischemic Heart Disease o Condition due to inadequate oxygen due to reduced blood flowo Mostly caused by atherosclerosiso Associated with increased production of lactic acid and resulting paino Associated with increased production of lactic acid and resulting pain: Angina Pectoriso Eventually, Necrosis of some areas of the heart occurs, causing a: Myocardial infarction (Heart Attack)o Detecting Ischemia Depression of the S-T segment of an EKG Plasma concentration of blood enzymes• Creatine phosphokinase, lactate dehydrogenase, troponin I and T• Heart Arrhythmiaso Abnormal Heart rhythmso Bradycardia: Slow heart rate, below 60bpmo Tachycardia: Fast heart rate, above 100bpm Abnormal tachycardia can occur due to drugs or fast ectopic pacemakers These HR are normal if someone is active, but not at resto Ventricular tachycardia occurs when pacemakers in the ventricles make them contract out of sync with the atria Very dangerous. Can lead to ventricular fibrillation and sudden death Heart isn’t really beating, just vibratingo Flutter Extremely fast 200-300bp Still coordinated contractions, but some issues in efficiencyo Fibrillation Completely uncoordinated between atria/ventricles Each cardiac cell acting independently o Atrial Fibrillation Can result from atrial flutter Often from an ectopic pacemaker Atrial muscles can’t effectively contract. AV Node can’t keep pace with speed of atrial contractions but some stimulation is passed on Reduces cardiac output by 15% Associated with increased risk of stroke and heart failureo Ventricular Fibrillation Ventricles can’t pump blood and victim dies Need CPR or Electrical Defibrillation to reset the rhythm• Brings all the cells to the same membrane potential in hopes of getting them back in synco AV Node Block AV node allows the delay between atrial and ventricular contraction Can be seen in changes in the PR interval of an ECG• 1st Degree: Impulse conduction exceeds .2 seconds• 2nd Degree: Not every p wave has a QRS complex. o Not every electrical wave passes to the ventricles• 3rd Degree: No stimulation gets through the AV nodeo Pacemaker in the Purkinje fibers takes over but is slow (20-40bpm)Functions of the Lymphatic System• Transports excess lymph from tissues to veins• Produces and houses lymphocytes for immune response• Transports absorbed fats from intestines to blood • Lymphatic Capillarieso Smallest, found within most organso Picks up Interstitial fluids, proteins, microorganism and fat• Lymph Ductso Formed from merging capillarieso Similar to veins in structureo Lymph is filtered through the lymph nodes • Thoracic Trunk and Right Lymphatic Trunko Form merging lymphatic ductso Deliver lymph into right and left subclavian veins• Organs of Lymphatic Systemo Tonsils, thymus, spleeno Sites of lymphocyte productiono These can be used to move cancer
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