Chapter 17 Outline I Cardiovascular Anatomy a SA Node b Types of Muscle in the body i Skeletal ii Cardiac 1 Unbranched cylindrical and multinucleated myocytes parallel myofiber bundles 2 Stimulated by nerves neuromuscular junction 1 Branched myocytes with 1 2 nuclei 2 Stimulated by nerves neuromuscular junction 3 Stimulates itself with the SA node then the AV node and then the Bundle of Hiss and purkinje fibers 1 Elongated non striated myocytes with a single nucleus i Sarcomere Z Line to Z Line the functional unit of cardiac ii Actin and Myosin overlap but don t touch at the resting state iii Contraction 1 Z Lines come towards each other a Overlap space A band becomes bigger A line iii Smooth c Musculature muscle d Myocytes shrinks i Divided by intercalated disks gap junctions electro signal from 1 myocyte to another like the wave e Z Line M Band I Band f Sliding Filament Theory i Ca2 into the SR ii Ca2 binds to troponin and exposes myosin binding sites on iii Myosin heads bind to actin release of P initiates power stroke iv Power stroke myosin head changes conformation filaments actin filaments slide past each other v ADP is released ATP binds to myosin causing it to release actin vi ATP is hydrolyzed and the myosin heads returns to normal conformation vii Ca2 is returned to the SR muscle relaxes g PQRST Wave i P atrial contraction ii QRS ventricular contraction iii T ventricular relaxation iv Lubdub systole pause between is diastole II Cardiovascular Physiology a Cardiac Cycle i Echo heart ultrasounda ii Systole contraction increases pressure 1 lubdub iii Diastole relaxation iv Sounds 1 1st closure of atrial vent bi tricuspid valve 2 2nd closure of pulmonary aortic valves v EEG vi EMG III Lipid Metabolism a Dietary Fat i 98 99 triglycerides ii 102 cholesterol phospholipids etc b Digestion occurs mostly in the intestine via intestinal and pancreatic lipases and bile acids where triglycerides are broken down to monoglycerides and fatty acids These are absorbed by the intestinal mucosa where they combine to reproduce triglycerides These triglycerides assemble into water soluble chylomicrons i pancreatic lipases and bile acids 1 monoglyceride and 3 fatty acids 1 triglyceride c Triglycerides i Predominant form of fat in nature ii Function provide energy to the cell iii Types of fatty acids 1 Essential cannot be synthesized by body linoleic linolenic arachidonic acids must be obtained through diet 2 Nonessential synthesized by the body iv Plasma triglycerides derived from Intestinal mucosa synthesized from dietary fat 1 2 Liver a Fasting liver releases VLDL due to triglyceride utilization by adipose tissue for energy b Post meal dietary carbs taken up by liver and converted to triglycerides then secreted as lipoproteins i Sources 15 diet 85 synthesized from acetyl CoA by the d Cholesterol liver ii Essential Functions 1 Structural components of cell membranes 2 Precursor for synthesis of bale salts steroid hormones and Vitamin D iii Cholesterol and triglycerides are insoluble in water They need to be transported to and from tissue cells bound to small lipid protein complexes called lipoproteins 1 Lipoproteins carries aldosterone cortisol e Lipoproteins i Apoliprotein markers for lipoproteins ii Contain 1 Triglycerides phospholipids cholesterol protein iii Variable Fat 1 Higher lipid percentage means lower lipoprotein 2 Higher protein percentage means higher lipoprotein density density 3 More lipids fat lighter 4 More protein heavier iv Types 1 High density lipoprotein HDL a Carries fat away from tissues and to the liver b Healthier Intermediate Density Lipoprotein IDL 2 3 Low Density Lipoprotein LDL 4 Very Low Density Lipoprotein VLDL a The worst No protein very light b High amounts 5 The best ones have high protein and low fat f Chylomicrons i Produced by the intestine 1 Bind and transport dietary lipids to hepatic and peripheral tissue 2 Enter circulation where triglyceride and cholesterol carriers esters bound to them are hydrolyzed This produces chylomicron remnant particles 3 Chylomicrom remnants are taken up by the liver ii Largest and least dense of lipoprotein particles iii All bad lipoproteins have Apo B marker for bad 1 Measured by blood tests