BCMB 230 1st Edition Lecture 15 Outline of Last Lecture I Types of Skeletal Muscle Fiber II Changes in Muscle Size III Smooth Muscle IV Review of Skeletal Muscle V Compare Skeletal Muscle to Smooth Muscle VI Muscle Tone VII Pain Sensory Information Outline of Current Lecture I Cardiovascular System II Blood III Heart IV Valves V Pacemakers VI Differences Between Cells Current Lecture I Cardiovascular System Three main components of cardiovascular system heart used as a pump to move the blood through blood vessels blood vessels pathway used to transport blood throughout the body to and from the heart helps regulate pressure and flow blood blood itself acts as a blood system does the work have components of blood that have specialization Two main circulatory pathways of cardiovascular system this means that the heart is acting like two separate pumps in the heart right and left are critical due to structural and physiological differences pulmonary circuit comes from right side blood gets pumped out goes to the lungs goes back to left side of heart systemic circuit comes from left side blood goes out and goes through a series of systemic pathways blood comes back through veins and back to right side of heart not just one system circuit basically there is a systemic circuit for every tissue artery blood vessel that carries blood away from heart 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 vein blood vessel that carries blood toward the heart capillaries small thin walled vessels that interact with tissues where exchange of gases between blood and tissue occurs does not happen in artery and vein II Blood Components of blood mostly water hematocrit the percent volume of packed cells which are mostly red blood cells can be found if we centrifuge blood somewhere around 45 of volume of blood is red blood cells slightly over half 55 of volume of blood is plasma red blood cells carry oxygen and carbon dioxide important with gas exchange plasma fluid component that has water proteins electrolytes salt sugar amino acids leukocytes white blood cells involved in defense against disease help provide immunity platelets involved with clotting III Heart The heart is a hollow organ has four fluid filled chambers two atria and then two ventricles atria smaller with thinner walls ventricles larger with thicker walls right and left sides of ventricles are separated in the middle by a wall called an interventricular septum left side has a thicker wall because it pushes blood all the way to the toes systematic pathways are more extensive General pattern when look at diagrams Typically red denotes oxygenated blood has been to the lungs has not reached the tissues yet typically the artery in systemic circuit veins in the pulmonary circuit Typically blue denotes deoxygenated blood oxygen has been removed by the tissue in the vein in the systemic circuit arteries in the pulmonary circuit This is not the same for all figures so be careful IV Valves in the heart and blood vessels prevent blood from flowing in the wrong direction operate without muscle control controlled through pressure does not use energy or resources are cup shaped called cusps with blood pushing on it in the right direction opens it up with blood pushing in opposite direction catches in cups and causes door to close Two types of valve Atrioventricular AV valves located between atria and ventricle allows blood to move from atria to ventricle two types tricuspid three cusps found on right bicuspid two cusps found on left Semilunar valves in main arteries leaving the heart pulmonary semilunar opens pathway to pulmonary pathway in pulmonary trunk leading to lungs aortic semilunar opens pathway to systemic pathway in aorta leading to body Three veins dump blood into right atrium Vena cava main veins bringing blood to systemic pathways Superior vena cava brings blood from vessels mostly above the heart toward head Inferior vena cava Coronary Sinus small vein from the heart muscle itself After right atrium blood flows through the tricuspid valve into the right ventricle It leaves through the pulmonary semilunar valve which then takes it to large artery called the pulmonary trunk trunk denotes a shortcut This almost immediately divides into left and right pulmonary arteries which takes us to lung capillaries which carries deoxygenated blood from heart to lungs It then travels through the pulmonary veins into the left atrium passes through the bicuspid valve into the left ventricle Then it passes into the aortic semilunar valve into the aorta the main artery for the systemic system which goes into systemic capillaries eventually leading back into the vena cava through the veins superior inferior or coronary sinus When the heart contracts the right and left ventricles contract simultaneously moving blood into both the pulmonary trunk and the aorta semilunar valve simultaneously The four valves are all in a line separating heart into two separate electrical components Cardiac muscle has lots of gap junctions similar to single unit smooth muscle connective tissue does not All atria are going to be very connected easier be very coordinated with each other Electrical signal is stopped by valves called cardiac skeleton Atria can be operated independent of ventricles because of the layer of connective tissue want atria to contract then ventricles to contract not both simultaneously To squeeze blood out want atria to contract starting at the top of the heart going to the bottom to push blood down into the ventricles want ventricles to contract to start at bottom of heart moving to the top to push blood up and out of heart either to pulmonary or systemic circuit can control this through pacemakers V Pacemakers very modified cardiac muscle cells that have unique properties allowing it to become a conducting system two main properties have a spontaneous depolarization that is intrinsic independent of external stimuli and are easier to stimulate than the typical cardiac muscle cells pacemaker potential have a preferred pathway of conduction Sinoatrial node SA node located at the top of the right atrium primary pacemaker pacemaker that is normally in use and overrides other pacemakers the fastest produces contraction of atria from top to bottom Atrioventricular node AV node located in the bottom of right atrium connects to a long series called the Bundle