KIN 3304 1nd Edition Lecture 15 Outline of Last Lecture I The Cardiac Cycle II Conduction of Contractions III Steps of Contraction IV Sequence V Nodal Cells VI Sinoatrial Node VII Conducting System Outline of Current Lecture I CDV System II Lots of Tubing III Normal Layers of Arteries IV 3 Layers of Artery and Vein Walls V Layering Gives Strength VI Differences Between Arteries and Veins VII Different Types of Arteries Veins VIII Elastic IX Muscular Arteries X Arterioles These 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 Capillaries XII Sinusoids XIII Veins XIV Venous Valves XV Distribution of Blood XVI Arteriosclerosis Current Lecture Give saline to push pressure up I CDV System a Closed System b Circulates blood throughout body c 2 Circuits Pulmonary and Systematic II Lots of Tubing a Pulmonary trunk aortal systematic have diameter at 2 5 cm III Normal Layers of Arteries a Intima b Media c Adventitia IV 3 Layers of Artery and Vein Walls a Intima i Inner most layer ii Thick in largest artery iii Endothelial lining larder of CT with elastic fibers 1 Internal elastic membrane 2 The difference between arteries and veins is the internal elastic membrane b Media middle layer i Smooth muscle in framework of CT ii 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 BP c Adventitia Fig 22 1 i Thick layer collagen some elastic fibers 1 Fibers blend into adjacent tissues 2 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 space V Layering Gives Strength a A combo of smooth muscle and elastic components permits variations in diameter during changes in blood flow volume b Vessel walls too thick to allow for diffusion between blood stream and tissues i Arteries veins supply instead ii They re just blood delivering devices that s it VI Differences Between Arteries and Veins a Usually lay side by side within narrow CT band b Arterial walls are thicker i Arterial media contain more smooth muscle elastic fibers than do venous media ii Allows for resistance against cardiac pressure c Arterial walls contract without pressure i Dissociated look smaller collapse ii Cut open arteries circular strong veins flat collapse d Veins bring blood to the heart e Arteries take blood away from the heart VII Different Types of Arteries Veins a Arteries i Aortic ii Muscular iii Arterioles iv Capillaries b Veins i Large vein ii Medium sized vein iii Venule iv Fenestrated capillary VIII Elastic conducting a Large up to 2 5 cm i Pulmonary carotid etc b Very resilient lots of elastic fibers c Tolerate high pressure changes during cardiac cycle d During ventricular systole BP increases elastic fibers stretching e During ventricular diastole BP decreases fibers return IX Muscular Arteries a Transports blood to skeletal muscle internal organs b Brachial a of arms femoral a of thighs etc c Sympathetic division of ANS can control diameter i Can regulate blood flow to individual organs muscles X Arterioles a Very small 30 micrometers b Poorly defined adventitia media not complete c Change diameter in response to local conditions or to endocrine stimulation d Control blood flow between arteries and capillaries XI Capillaries a Smallest blood vessel i Diameter of 8 micrometers size of 1 RBC b Only vessel that permits exchange between blood and interstitial fluid i Diffusion by crossing capillary walls by diffusion ii Or via gaps between endothelial cells c Continuous or Fenestrated i Fenestrated is like poking holes in a hose ii Fig 22 4 XII Sinusoids a Similar to fenestrated capillaries except have larger pores thinner basal lamina b Flattened irregular follow contours of organs c Permits extensive exchange of fluids large solutes i Blood moves slowly here allows for maximum absorption 1 Ex food truck simile d Found in liver bone marrow suprarenal glands XIII Veins a b c d Collect blood from all tissues organs Thinner less elastic then arteries Much greater structural variation Generally larger in diameter than corresponding arteries XIV Venous Valves a Blood pressure in venules medium sized veins is too low to oppose force of gravity b In limbs veins contain 1 way valves i Similar to heart valves prevent backflow of blood ii Movement muscles pushes blood toward heart c Called a skeletal muscle pump i Not found in vena cava changes in thoracic cavity allow for blood to move toward heart ii Muscle pump is when blood flow resists gravity through a series of 1 way valves iii Giraffes have a reverse skeletal pump XV Distribution of Blood a Is not even b Heart arteries capillaries 30 35 of blood i 1 5 L c Venous System contains the rest 70 75 i 3 5 L d Veins have less smooth muscle more distensible i Stretch 8x that of arteries ii 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 distribution XVI Arteriosclerosis 2 types a Focal calcification i Gradual degeneration of smooth muscles deposition of Ca2 salts b Atherosclerosis i Damage to endothelial lining formation of lipid deposits in media ii Most common form of arteriosclerosis