Cardiac_rev (1).ppsx

Cardiac System A N AT O M Y 1 1 1 0 H T T P S : / / Y O U T U. B E / U D R G V Z J S L P Q Happy Vet Tech Week https://youtu.be/kMU0GzbD6SQ Objectives Discuss the anatomy of the cardiovascular system    Identify the heart chambers and valves Label and Identify the coverings of the heart I...

Cardiac System A N AT O M Y 1 1 1 0 H T T P S : / / Y O U T U. B E / U D R G V Z J S L P Q Happy Vet Tech Week https://youtu.be/kMU0GzbD6SQ Objectives Discuss the anatomy of the cardiovascular system    Identify the heart chambers and valves Label and Identify the coverings of the heart Identify the major blood vessels associated with the heart Discuss flow of blood through the heart Review Pleura Review Anatomy of thorax Discuss what the Coronary system  Anatomy Location  Lies within the thoracic cavity within the mediastinum Canine  Ovoid shape  3rd and 6th intercostal space Long axis lays at a 45 degree angle to the sternum  Base is directed craniodorsally  Apex lies to the left of the midline of the diaphragm and sternum  Heart is almost completely surrounded by the lungs Feline  Extends from the 3rd to 4th and to the 6th and 7th ribs  The angle of the heart in the thoracic cavity is more acute Membranes Pericardium  Fibrous Sternopericardiac ligament  Serous  Epicardium The layer between the fibrous and serous layer is called the Pericardial cavity  Myocardium Endocardium Chambers and Valves Four chambers Right and left atria Accept blood pumped to heart  Foramen ovale-(fetal)   opening between right & left Atria Right and left ventricles  Pumps blood away from the heart Divided in to right and left halves by the interatrial and interventricular septum Vessels Artery Veins Aorta Vessels Associated with Right Side of the Heart Pulmonary artery- associated with right ventricle Vena cava-associated with right atrium Right Atrium Receives unoxygenated blood from the cranial and caudal vena cava It holds the unoxygenated blood until it is pumped to the right ventricle  Right atrioventricular valve (AV) or tricuspid valve Triscupid During ventricular contraction (systole) the valve closes (AV/tricuspid) The valve consists of:  Three leaflets  Papillary muscles Right Ventricle Pumps unoxygenated blood into the low- pressure pulmonary circulation Pulmonic Valves Semilunar valve Pulmonary artery delivers unoxygenated blood from the right ventricle to the lungs It branches to form left and right pulmonary arteries that go to the respective lung lobes  They have corresponding bronchi Fetal Blood flow Ductus arteriosus connects the pulmonary artery to the descending aorta   By passing the lungs & left side of the heart (atrium & ventricle) Connects the left branch of the pulmonary artery to the descending aorta, after birth it closes and becomes (fibrosed) and becomes the ligamentum arteriosum after birth  Patent ductus arteriosus  Birth defect Left Atrium Receives and hold oxygenated blood from the pulmonary veins  Located on left dorsocaudal aspect of the heart base above the left ventricles Valve Left AV or mitral During diastole the left AV/Mitral valve opens  Diastole- Relaxation   Systole contraction phase Mitral valve has 2 leaflets Malfunction of the Left AV/Mitral valve is the most common cause of congested heart failure in a dog  Cardiomyopathy Left Ventricle Pumping chamber Largest structure of the heart  2-3 times thicker than the right ventricle Conical in shape Normal Heart Sounds (“lub-dub”) lub”: S1   Closure of the mitral and tricuspid valves at the beginning of ventricular systole Mitral valve is loudest on the left side of the chest; tricuspid valve is best heard on the right “dub”: S2   Closure of the semilunar valves at the beginning of ventricular diastole Easiest to hear on the left side of the chest Aortic Valve Semilunar cusp Second most common congenital heart defect problem is aortic stenosis Aorta Largest artery in the body - largest diameter and thickest vessel walls Artery wall layers are similar to the walls of the heart Aorta and pulmonary arteries - middle layer contains more elastic fibers than muscle fibers  Allows vessels to stretch slightly as they receive highpressure blood from the ventricles Aorta Three segments: Ascending Aortic arch Descending https://media.giphy.com/media/oStBM1A Nst52U/giphy.gif Sinoatrial Node (SA node) Specialized area of cardiac muscle cells located in right atrium Generates electrical impulses that trigger repeated beating of the heart Coronary System Coronary arteries arise from the aorta  Arteries that supply oxygenated blood to the myocardium https://www.lbah.com/word/heart-anatomy-phy siology/ https://www.lbah.com/word/canine/heart-diseas es-and-their-treatment/ Blood Vessels Arteries-carries blood away from the heart Aorta and pulmonary arteries consist mainly of elastic fibers (aids in propelling) Arterioles   Smaller arterioles composed of mainly smooth muscle Diameter is controlled by autonomic nervous system Veins Constructed like arteries Largest veins have a small amount of smooth muscle Venules Capillaries Smallest blood vessels Only have one layer and that is the endothelium Sites of exchange between the blood and tissues Vessels Smaller arteries continue to split into smaller and smaller vessels and then arterioles Blood flows through arterioles into tiny, thin- walled capillaries.  Capillaries have no muscle layer in their walls. Blood travels back to the heart through small venules which merge to form vein Vascular Anatomy and Physiology Blood in the systemic circulation is under higher pressure than blood in the pulmonary or coronary circulation. Higher pressure is needed to carry blood throughout the body.  Blood in systemic circulation encounters more resistance to flow Vascular Anatomy Venous blood is under lower pressure than arterial blood. Veins have thinner walls than arteries. Valves in veins ensure that blood travels only in the direction of the heart. Smooth muscle in walls of most blood vessels Constriction and relaxation allows the vascular system to direct blood to different regions of the body under different circumstances. Venous Collection The capillary beds connect the venules which form the larger veins which take the blood back to the heart  Cranial vena cava collects blood:    Head and neck from the jugular veins Forelimbs from the right and left subclavian veins Caudal vena cava collects blood: from the pelvic viscera, hind limbs and abdominal organs from the various veins that run alongside the arteries and deposits the blood into the right atrium Vascular Anatomy Main trunk of the aorta arches dorsally then travels caudally  Numerous branches emerge in the thoracic and lumbar areas Branches of the Aorta Brachiocephalic trunk supplies blood to the head and neck through a pair of common carotids The right subclavian artery supplies the right forelimb Left subclavian artery supplies blood to the left forelimb Venipuncture Cephalic vein: craniomedial aspect of forelimb Saphenous vein: medial aspect of hind limb of Cat Saphenous: lateral aspect of hind limb dog Venipuncture  Jugular Veins   Ventral aspect of each side of the neck in the jugular groove Close to the carotid arteries  Care must be taken to avoid accidental injection into the carotid artery Review Identify the heart chambers and valves Identify the coverings of the heart Identify the major blood vessels associated with the heart What is the Pulmonary and the Coronary systems What are the different types of blood vessels Identify major blood vessels Feline