Cardiovascular Anatomy (UCLan) PDF

Cardiovascular Anatomy Kris Phillips – Lecturer in Anatomy [email protected] Where opportunity creates success ➢ Macro Learning Outcomes: • • • • • 29 Outline the embryonic development of the cardiovascular system 29 Describe fetal circulation, gas exchange across placenta (and changes ass...

Cardiovascular Anatomy Kris Phillips – Lecturer in Anatomy [email protected] Where opportunity creates success ➢ Macro Learning Outcomes: • • • • • 29 Outline the embryonic development of the cardiovascular system 29 Describe fetal circulation, gas exchange across placenta (and changes associated with birth) 29 Describe the gross anatomical structure and function of the mammalian cardiovascular system (including vasculature and microcirculation) 29 Describe the vascular supply and innervation of the CV system (alpha & beta receptors) 29 Compare and contrast the structure and function of cardiovascular systems of the common small animal domestic and exotic species (i.e. open, closed, single, double/amphibians, reptiles, birds, fish). Learning Outcomes Right-Side View of Dog Thorax & Abdomen Left-Side View of Dog Thorax & Abdomen Heart Structure 1. From the image, identify the structures A-M. Letter Structure Letter Structure A Cranial vena cava H Descending/thoracic aorta B Pulmonary valve I Papillary muscle C Right pulmonary artery J Bicuspid/Mitral valve D Right pulmonary vein K Left pulmonary vein E Tricuspid valve L Aortic valve F Chordae tendineae M Left pulmonary artery G Caudal vena cava 2. What is the function of the structure labelled F? • During ventricular contraction the pressure in both ventricles increase and close the valves, the chordae tendineae tense to keep the valves closed and prevent the valves prolapsing into the atria. Heart Structure & Blood Flow 3. On the image opposite, use arrows to show the direction of blood flow, distinguishing between oxygenated and deoxygenated blood. 4. Why is the myocardium of the left ventricle thicker than the right ventricle? • The left ventricle is responsible for pumping blood to all areas of the body so needs to have more muscular power. The right only pumps blood to the lungs. Heart Valves 5. Why are the openings to the coronary arteries at the base of the ascending aorta? • When the aortic valve opens, the openings to the coronary arteries are covered, this means high pressure blood does not go into them. • Once the pressure of blood leaving decreases, the aortic valve starts to close and the lower pressure backflow of blood then trickles into the coronary arteries to supply them. 6. The act of the valves in the heart closing gives it its distinctive beating sound. What are the sounds, and which are the corresponding valves to each sound? • Lub-dub • Lub: Tricuspid and Mitral valves • Dub: Aortic and pulmonary valves Aortic Branches 7. From the image, identify the arteries A-F. Letter Artery Region Supplied A Descending Aorta Thorax, abdomen, pelvis, hind limbs B Aortic arch Whole body C Brachiocephalic trunk Head, neck, brain, thorax and right forelimb D Right Subclavian artery Right Forelimb, thorax, brain E Left subclavian artery Left Forelimb, thorax, brain F Right Common carotid artery Head, neck, brain Pericardium The image opposite is a schematic illustration of the pericardium surrounding the heart. 8. Identify each layer of the pericardium. Structure Number Heart 1 Great Vessels 2 Visceral Pericardium 3 Fibrous Pericardium 6 Parietal Pericardium 5 Mediastinal Pleura 7 Pericardial Cavity 4 Sternopericardial Ligament 8 Pericardium 9. What is the function of the fluid within the pericardial cavity? • Lubrication for the unimpaired movement of the heart. 10.If too much fluid accumulated within the pericardial cavity, what could occur? • Compression of the heart (if acute) – usually compresses atria first due to less muscular walls. • Pericardial effusion (fluid build up) can lead to cardiac tamponade (impairment of heart). • If fluid build up is slow, pericardium can stretch accommodate some of it. Circulatory System 11.Some arteries can be subdivided into elastic arteries or muscular arteries. a. What is the benefit of elastic arteries? • Accommodate high pulsatile forces b. What is the benefit of muscular arteries? • Allows contraction (vasoconstriction) or relaxation (vasodilation). 12.Arteries have 2 receptors (alpha and beta) associated with them. What are their functions? • Alpha – Contraction; Beta – Relaxation Circulatory System 13.Where can arterial pulses usually be felt? Think about the structures – not location on the body. • Wherever an artery lies close to the surface, over bone, and/or over firm structures. 14.Veins, like the heart, often have valves – what is the function of having valves? • Prevent the backflow of blood. 15.What is a potential benefit of veins lacking a strong muscular wall? • Allow for greater capacitance – hold more blood without increasing blood pressure. 16.In the body many areas are supplied or drained by multiple vessels. This is called collateral circulation. • Why is this important? • If a blood vessel is damaged or blocked it allows blood supply to be maintained to the particular area. Fetal Circulation Three vascular shunts exist in the fetal circulation to allow blood to mostly bypass the liver and non-functioning lungs. • Foramen ovale: • Between the atria. • Blood bypasses the pulmonary circulation. • Closes shortly after birth usually. • Ductus arteriosus: • Links the distal arch of aorta with the pulmonary trunk. • Blood bypasses the pulmonary circulation. • Becomes ligamentum arteriosum after birth. • Ductus venosus: • Shunts umbilical blood from the primitive liver, to the IVC to ensure enough oxygen reaches the developing brain. • Involutes by or just after birth. Gas and nutrient exchange for fetus happens across the placenta. Conduction System 17.On the image opposite, draw and label the conduction system of the heart including: • SA node • AV node • Internodal branches • Bachmann’s bundle (interatrial band) • Bundle of His • Right bundle branch • Left bundle branch • Purkinje fibres