Chapter 13 Cardiovascular SystemPrincipal BranchesVeins from the Abdominal VisceraChapter 13 Cardiovascular System Cardiovascular System: The cardiovascular system consists of the heart, and vessels, arteries, capillaries and veins. What is the function of the CV system? Heart: The heart is a hollow, ________________-shaped, muscular pump within the ________________ cavity. The average adult heart is _______ cm long and ___________ cm wide. The heart lies in the __________________ under the sternum; its apex extends to the ________ intercostal space. Pericardium: It is made of two layers: the outer, tough connective tissue _____________pericardium surrounding a more delicate ____________________ pericardium (also called _______________) that surrounds the heart. At the base of the heart, the inner layer folds back to become the ________________ pericardium that lines the tough outer layer. Between the two pericardia is a potential space called the ______________ cavity and filled with __________ fluid. Wall of the Heart The wall of the heart is composed of three distinct layers. The outermost layer, the _______________________, is made up of connective tissue and epithelium, and contains blood and lymph capillaries along with ____________ arteries. It is the same as the visceral pericardium. The middle layer called ________________consists of cardiac muscle and is the thickest layer of the heart wall. The inner ____________________is smooth and is made up of connective tissue and epithelium, and is continuous with the endothelium of major vessels joining the heart. Heart chambers: The heart has four internal chambers: two on top and two below. A _____________ divides the chambers on each side. Upper chambers,___________, receive blood returning to the heart and have thin walls and ear-like auricles projecting from their exterior. Below them, the thick-muscled ________________________ pump blood to the body and lungs. Heart valves: The right A-V valve called ________________ and left A-V valve called either ________________ or the _______ valve have cusps to which strings called _______________________ attach. These strings are, in turn, attached to _____________________ muscles in the inner heart wall that contract during ventricular contraction to prevent the backflow of blood through the A-V valves. Where are the semilunar valves found? What is their function? Skeleton of the Heart Rings of dense connective tissue lie surrounding the pulmonary trunk and aorta to provide attachments for the heart _____________ and ____________________. These tough rings prevent dilating of tissue in this area1Path of blood thru heart: sup. & inf. vena cava, ________________. _______________ valve, _________________, _________________ valve, _______________ lungs, ___________________, _________________, _______________ valve, ___________________, _________________, valve, ________________ body Which part is pulmonary & which is systemic? What is the function of pulmonary circulation? Of systemic circulation? Heart Blood Supply: The first branches off of the aorta, which carry freshly oxygenated blood, are the right and left _____________ arteries that feed the heart muscle itself. Branches of these arteries feed many capillaries of the myocardium. The heart muscle requires a continuous supply of freshly oxygenated blood, so smaller branches of arteries often have _____________________ as alternate pathways for blood, should one pathway become blocked. _____________________ veins drain blood from the heart muscle and carry it to the coronary ______________. Cardiac cycle: The cardiac cycle consists of the atria beating in unison (atrial_____________) followed by the contraction of both ventricles, (ventricular ________________e) then the entire heart relaxes for a brief moment (______________). During the cardiac cycle, pressure within the heart chambers rises and falls with the ________________ and ____________________ of atria and ventricles. When the atria fill, pressure in the atria is ________________________ than that of the ventricles, which forces the ________________ valves open. Pressure inside atria rises further as they contract, forcing the remaining blood into the ventricles. When ventricles contract, pressure inside them ________________________ sharply, causing ______ valves to close and the __________________ and ________________________ valves to open. As the ventricles contract, _______________ muscles contract, pulling on ____________________ and preventing the backflow of blood through the A-V valves. heart sounds: Heart sounds can be described as a "lubb-dupp" sound. The first sound (lubb) occurs as _________________ contract and ___________valves are closing. The second sound (dupp) occurs as ________________ relax and aortic and ______________ valves are closing. Conduction system: A mass of merging fibers that act as a unit is called a functional ______________; one exists in the atria and one in the ventricles. Specialized cardiac muscle tissue conducts impulses throughout the myocardium and comprises the cardiac conduction system. A self-exciting mass of specialized cardiac muscle called the __________________ node (________ node or pacemaker), located on the posterior right atrium, generates the impulses for the heartbeat. Impulses spread next to the atrial __________________, it contracts, and impulses travel to the junctional fibers leading to the __________________ node (______node) located in the septum. Junctional fibers are small, allowing the atria to contract before the impulse spreads rapidly over the ventricles. Branches of the __________bundle give rise to _______________ fibers leading to papillary muscles; these fibers stimulate contraction of the papillary muscles at the same time the ventricles contract.2ECG: The first wave, the _____ wave, corresponds to the ___________________ of the atria. The __________ complex corresponds to the ________________ of ventricles and hides the __________________ of atria. The _________ waves ends the ECG pattern and corresponds to ventricular _________________________.Heart rate control: The amount of blood pumped at any one time must adjust to the current needs of the body (more is needed during strenuous exercise). The S-A node is innervated by branches of the ________________ and __________________ divisions, so the