KIN 3304 1nd Edition Lecture 15Outline of Last Lecture I. The Cardiac CycleII. Conduction of ContractionsIII. Steps of ContractionIV. Sequence V. Nodal CellsVI. Sinoatrial NodeVII. Conducting SystemOutline of Current Lecture I. CDV SystemII. Lots of TubingIII. Normal Layers of ArteriesIV. 3 Layers of Artery and Vein WallsV. Layering Gives StrengthVI. Differences Between Arteries and VeinsVII. Different Types of Arteries, VeinsVIII. ElasticIX. Muscular ArteriesX. ArteriolesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.XI. CapillariesXII. SinusoidsXIII. VeinsXIV. Venous ValvesXV. Distribution of BloodXVI. ArteriosclerosisCurrent Lecture*Give saline to push pressure up.I. CDV Systema. Closed Systemb. Circulates blood throughout bodyc. 2 Circuits: Pulmonary and SystematicII. Lots of Tubinga. Pulmonary trunk, aortal systematic, have diameter at 2.5 cmIII. Normal Layers of Arteriesa. Intimab. Mediac. AdventitiaIV. 3 Layers of Artery and Vein Wallsa. Intimai. Inner most layerii. Thick in largest arteryiii. Endothelial lining, larder of CT with elastic fibers1. Internal elastic membrane2. The difference between arteries and veins is the internal elastic membraneb. Media – middle layeri. Smooth muscle in framework of CTii. Sympathetic activation constricts (reduces) diameter of vessels (vasoconstriction)iii. Relaxation of the smooth vessels increases the diameter of the limb (vasodilation)iv. Changing diameter of vessel changes BPc. Adventitia (Fig 22.1)i. Thick layer (collagen, some elastic fibers)1. Fibers blend into adjacent tissues2. Stabilizes, anchors vessels*Artery – sturdy; ex: rapids; same volume but smaller space; faster*Vein – floppy; ex: water does to ocean; flat; more volume in larger spaceV. Layering Gives Strengtha. A combo of smooth muscle and elastic components permits variations in diameter during changes in blood flow/volumeb. Vessel walls too thick to allow for diffusion between blood stream and tissuesi. Arteries, veins supply insteadii. They’re just blood delivering devices, that’s it.VI. Differences Between Arteries and Veinsa. Usually lay side by side within narrow CT bandb. Arterial walls are thickeri. Arterial media contain more smooth muscle, elastic fibers than do venousmediaii. Allows for resistance against cardiac pressurec. Arterial walls contract without pressurei. Dissociated, look smaller (collapse)ii. Cut open, arteries circular, strong; veins flat, collapsed. Veins bring blood to the hearte. Arteries take blood away from the heartVII. Different Types of Arteries, Veinsa. Arteries:i. Aorticii. Musculariii. Arteriolesiv. Capillariesb. Veins:i. Large veinii. Medium sized veiniii. Venuleiv. Fenestrated capillaryVIII. Elastic (conducting)a. Large (up to 2.5 cm)i. Pulmonary, carotid, etc.b. Very resilient – lots of elastic fibersc. Tolerate high pressure changes during cardiac cycled. During ventricular systole, BP increases, elastic fibers stretchinge. During ventricular diastole, BP decreases, fibers returnIX. Muscular Arteriesa. Transports blood to skeletal muscle, internal organsb. Brachial a. of arms, femoral a. of thighs, etc.c. Sympathetic division of ANS can control diameteri. Can regulate blood flow to individual organs, musclesX. Arteriolesa. Very small (30 micrometers)b. Poorly defined adventitia; media not completec. Change diameter in response to local conditions or to endocrine stimulationd. Control blood flow between arteries and capillariesXI. Capillariesa. Smallest blood vesseli. Diameter of 8 micrometers (size of 1 RBC)b. Only vessel that permits exchange between blood and interstitial fluidi. Diffusion by crossing capillary walls by diffusionii. Or via gaps between endothelial cellsc. Continuous or Fenestratedi. Fenestrated is like poking holes in a hoseii. Fig. 22.4XII. Sinusoidsa. Similar to fenestrated capillaries except have larger pores, thinner basal laminab. Flattened, irregular; follow contours of organsc. Permits extensive exchange of fluids, large solutesi. Blood moves slowly here, allows for maximum absorption1. Ex. food truck similed. Found in liver, bone marrow, suprarenal glandsXIII. Veinsa. Collect blood from all tissues/organsb. Thinner, less elastic then arteriesc. Much greater structural variationd. Generally larger in diameter than corresponding arteriesXIV. Venous Valvesa. Blood pressure in venules/medium-sized veins is too low to oppose force of gravityb. In limbs, veins contain 1-way valves i. Similar to heart valves, prevent backflow of bloodii. Movement (muscles) pushes blood toward heartc. Called a skeletal muscle pumpi. Not found in vena cava; changes in thoracic cavity allow for blood to move toward heartii. Muscle pump is when blood flow resists gravity through a series of 1-way valvesiii. Giraffes have a reverse skeletal pumpXV. Distribution of Blooda. Is not evenb. Heart, arteries, capillaries = 30-35% of bloodi. ~1.5 Lc. Venous System contains the rest = 70-75%i. ~3.5 Ld. Veins have less smooth muscle; more distensible i. Stretch ~8x that of arteriesii. Blood reservoir (liver primary reservoir)iii. “Venous Reserve” is about 1 L (21% of blood volume)e. Be familiar with the pie chart of the blood distributionXVI. Arteriosclerosis (2 types)a. Focal calcificationi. Gradual degeneration of smooth muscles, deposition of Ca2+ saltsb. Atherosclerosisi. Damage to endothelial lining, formation of lipid deposits in mediaii. Most common form of