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ANSC 2340 (44)

Cardiovascular and Respiratory Systems.docx

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Animal Science
ANSC 2340
Ira Mandell

Cardiovascular and Respiratory Systems 3 cavities in trunk of animal: - Thoracic cavity  thorax or chest cavity (1) - 2 pleural cavities (closed space) for lungs - Mediastinum, located between left and right pleura Contains pericardial cavity, trachea and esophagus - Bony cavity formed by sternum, ribs, costal cartilage and thoracic vertebrae - Protects organs - Contains trachea, esophagus, lungs, heart, large blood vessels, nerves, lymphatics and lymph nodes - Organs and structures in the thoracic cavity are lined by a thin membrane called pleura - Pleura has two layers visceral (inner, covers lungs and adjoining structures) and parietal (outer, attached to chest wall) - Contains pleural fluid which allows pleurae to slide against each other in ventilation - Boundaries of thoracic cavity are dorsally, thoracic cavity… laterally, ribs and intercostal muscles… and ventrally, sternum. - Abdominopelvic cavity  abdominal (2) and pelvic cavities (3) - Separated from thoracic cavity by diaphragm - Abdominal cavity - Stomach, intestines, liver, spleen - Pelvic cavity - Pelvis, bladder, repro organs, rectum - 13 rib is used as a landmark to show where thoracic cavity ends and abdominopelvic cavity begins Cardiovascular system: - Includes heart, blood and blood vessels - Heart and blood vessels deliver blood to the bodies tissues - Blood used for transport (nutrients and waste), thermoregulation, immunity and acid-base balance - Blood type of connective tissue where materials are suspended in non- living liquid matrix - Transports gases, nutrients, hormones, heat, waste products (to kidneys, liver and gall bladder) - Regulates pH, body temperature, osmotic pressure - Immunity via phagocytosis, antibodies and blood clotting Heart: - Located in mediastinum - Surrounded by membrane called pericardium - 2 layers - Outer fibrous layer anchors the heart, inner serous membrane - Functions - Limits motion of heart - Prevents over expansion - Reduces friction when heart is beating - Heart wall has 3 layers - Epicardium outer most layer which includes connective tissue - Myocardium middle layer made up by cardiac muscles - Primary heart muscle - Endocardium inner layer of connective tissue (CT) - Lines chambers Cardiac Muscle: - Involuntary, striated - Versus skeletal muscles which are voluntary - Differs from skeletal muscle also in - Length - Number of nuclei - Number and size of mitochondria - Stimulation for contraction - Autorhythmic cells - One cardiac cell stimulates next 4 Chambers of Heart: - 2 atria - Located anteriorly and superiorly (directed upward) - Receives blood and pumps to ventricles - Atria separated by interatrial septum - 2 ventricles - Located posteriorly - Pumps blood away from heart - Separated by interventricular septum Atria: - Small and thin-walled - Passive flow (low pressure) and not as much contraction as ventricles - Reservoir for blood volume - Right atrium - Superior (anterior, cranial) vena cava brings blood from body regions in front of diaphragm - Thoracic cavity, head/neck, forelimbs (front legs and wings) - Inferior (posterior, caudal) vena cava brings blood from body regions in back of diaphragm - Abdominopelvic cavity - Coronary sinus, collects blood draining the myocardium - Part of coronary circulation - Blood passes from right atrium to right ventricle through the tricuspid valve (3 cusps, flaps, or leaflets) - 4 pulmonary veins bring blood from lungs to left atrium - Left atrium to right ventricle via bicuspid (mitral) valve which as 2 cusps - Classes of veins - Venule - Small/medium vein - Large vein Ventricles: - Majority of heart tissue - Right ventricle thinner than left - Only pushing blood a short distance to lungs, left ventricle is pushing blood to entire body via aorta - Contains muscle bundles called papillary muscles - Attachments for chordate tendinae attach to atrioventricular valves to assist in valve function Circulation: - Pulmonary circuit blood to and fro from lungs - Deoxygenated blood… RARVpulmonary artery (PA)pulmonary capillaries (gas exchange, blood now oxygenated)pulmonary veinLA - Systemic circuit delivering blood to tissues - Oxygenated blood arrives at LA - LALVaorta (pumps to body)systemic arteriesarterioles capillaries - Coronary circuit supplies myocardium - Coronary arteries deliver oxygenated blood - Coronary veins collect venous blood to coronary sinus when empties into RA Atrioventricular Valves: - LHS (between left A & V): mitral or bicuspid valves - RHS (between right A & V): tricuspid valves - Valves open cusps pushing into ventricles to allow blood flow from A to V - Papillary muscles and chordae tendinae are relaxed - Ventricles contract pressure increase pushes cusps towards atria, closing valves - Pap muscles contract and pull on chordae tendinae to prevent valve cusps from inverting into the atria Right Ventricular Hypertrophy (RVH) in Poultry (Ascites): - Broiler eating machine - High biological oxygen demand with high growth rates - CV system tries to keep up - Thin walled RV becomes distended due to increased work load get dilation out of the right ventricle (RVH) - AV valve (tricuspid) starts to fail and blood flows back into the atria and eventually the liver - Backflow into atria causes RV failure - Impacts liver - Liver congestion - Plasma leaks from liver into body cavity - 1-2% mortalities - Controlled by management - Environmental influences - High altitudes (low oxygen tension) - Cool temperatures (cant make enough energy to heat body) Semilunar Valves: - Aortic and pulmonary SL valves (3 cusps) allow blood to pass from ventricles to PA or aorta - Ventricles contract pressure results in blood flowing into the blood vessels - Ventricles relax backflow of blood catches the cusps and closes them shut so blood doesn’t flow back into atria Cardiac Cycle: - A complete contraction and relaxation of the heart is one cycle - Systole contraction stage - Blood ejected from atria to ventricles - Blood ejected from V to blood vessels (RV:PAlungs… LV:aortatissues) - Diastole relaxation stage - Atria and ventricles refill with blood to be ejected in the next systolic contraction Conduction System in the Heart: - Specialized cardiac fibers can generate an action potential (AP) on their own to stimulate contraction - Vs. skeletal muscle which replies on input from NS to stimulate them to contract - Autorhythmic cells (specialized cardiac fibers) act as a pace maker - AP travels throughout heart - Conduction system for these A
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