References

Institute of Laboratory Animal Resources, TNRC, and the National Academy of Sciences. (1996, March) Guide for the Care and Use of Laboratory Animals. National Academy Press, Wahington, DC. 2. Gross, D.R. (ed.) (1994) Animal Models in Cardiovascular Research, 2nd Ed. Kluwer Academic, Dordrecht, The Netherlands, p. 494. 3. Ettinger, S.J. (2000) Congenital heart diseases, in Textbook of Veterinary Internal Medicine. Saunders, Philadelphia, PA, pp. 737-787. 4. Haworth, R.A., et al. (1983) Metabolic...

Cardiac neural crest

Neural Crest Contribution Cardiac

Origin of the cardiac neural crest within a 34-h chick embryo. Green dots represent cardiac neural crest cells in the neural folds of hindbrain rhombomeres 6-8 (the region of the first three somites up to the midotic placode level). Fb, forebrain Mb, midbrain. fuse with the atrioventricular cushions, which also divide the left and right atrioventricular canals and serve as the source of cells for the atrioventricular valves. Prior to septation, the right atrioventricular canal and right...

Sympathetic Anatomy

Cell bodies of presynaptic sympathetic efferent neurons are found in the paired lateral horns of the spinal cord, an area identifiable between the T1 and L2 or L3 vertebrae. The axons, or nerve fibers of these cells, exit the interior of the spinal cord through ventral rootlets, which coalesce to form the larger ventral roots and eventually become the ventral rami. sympathetic fibers almost immediately divert into white rami communicantes (Fig. 1), branching from these spinal nerves, which...

Pressure Transducer System

In clinical settings, arterial and venous blood pressures and waveforms are displayed using a pressure transducer monitoring system. A typical pressure transducer monitoring system includes (1) an indwelling intravascular catheter (2) pressure tubing (3) a pressure transducer (4) a stopcock and flush valve (5) a high-pressure fluid bag and (6) a graphical display monitor and microprocessor (Fig. 12A,B). The pressure wave derived from the transducer system is a summation of sine waves at...

Comparative Cardiac Anatomy

In general, the hearts of large mammals share many similarities, and yet the sizes, shapes, and positions of the hearts in the thoracic cavities can vary considerably between species (6). Typically, the heart is located in the lower ventral part of the mediastinum in large mammals (7). Most quadruped mammals tend to have a less-pronounced left-sided orientation and a more ventrally tilted long axis of the heart compared to humans (7) (Fig. 2). In addition, hearts of most quadruped mammals tend...

Cardiac Cycle

The normal electrical and mechanical events of a single cardiac cycle of the left heart are correlated in Fig. 1. The mechanical events of the left ventricular pressure-volume curve are displayed in Fig. 2. During a single cardiac cycle, the atria and ventricles do not beat simultaneously the atrial contraction Fig. 1. Electrical and mechanical events of a single cardiac cycle of the left heart (see text for details). ECG, electrocardiogram. Fig. 1. Electrical and mechanical events of a single...

Animal Models In Myocardial Ischemia

Despite tremendous advances in treatment options, atherosclerotic coronary vascular disease remains the leading cause of death worldwide. As a result, this disease continues to be an active area of cardiovascular research. Originally defined by the Greeks as a lack of blood flow, the modern definition of ischemia emphasizes both the imbalance between oxygen supply and demand and the inadequate removal of waste products. Impaired oxygen delivery results in a reduction in oxidative...

Overview Of The Thorax

Anatomically, the thorax is typically divided into compartments there are two bilateral pulmonary cavities each contains a lung with its pleural covering (Fig. 1). The space between the pleural cavities is the mediastinum, which contains all the other structures found in the thorax. The mediastinum is divided into the superior and inferior compartments by a plane referred to as the transverse thoracic plane it passes through the mediastinum at the level of the sternal angle and the junction of...

The Pericardium

The pericardium (peri around + cardia heart) is the covering around the heart. It is composed of two distinct but continuous layers separated from each other by a potential space containing a lubricating substance called serous fluid. During embryological development, the heart moves from a peripheral location into a space called the celomic cavity. The cavity has Fig. 3. The anterior surface of the heart. The atria are positioned superior to (posterior to) and to the right of their respective...

Measuring The

Electrocardiograma

Typically, the ECG is measured from the surface of the skin, which can be done by placing two electrodes directly on the skin and reading the potential difference between them. This is possible because these signals are transmitted throughout the body. Again, as stated above, the detected waveform features depend not only on the amount of cardiac tissue involved, but also on the orientation of the electrodes with respect to the dipole in the heart. In other words, the ECG waveform will look...

Internal Anatomy Of The Heart

Lotus Edge Heart Valve

A cross section cut through the heart reveals three layers (Fig. 7) (1) a superficial visceral pericardium or epicardium (epi upon + heart) (2) a middle myocardium (myo muscle + heart) and (3) a deep lining called the endocardium (endo within, derived from the endoderm layer of the embryonic trilamina). The endocardium is a sheet of epithelium called endothelium that rests on a thin layer of connective tissue basement membrane. It lines the heart chambers and makes up the valves of the heart....

Myocardial Blood Flow

Blood containing carbon substrate and oxygen is delivered to the heart by two main coronary arteries that originate from the proximal aorta and course over the surface of the heart (epi-cardium). These arteries arborize into progressively smaller branches that turn inward to penetrate the epicardium and supply blood to the myocardium (Fig. 2). In the left ventricle, the heart muscle is typically subdivided into transmural layers these are termed the subepicardium (outer layer), the...

Examples Of Current Pharmacological Cardioprotective Therapies

Listed in this section are current examples of pharmacological therapies targeted at protecting the myocardium from damage caused by ischemia and reperfusion injury. Although activation of the Na+ H+ exchanger (NHE) in response to acidosis is a feedback mechanism that enables the myocardial cell to maintain a fairly stable pH range, NHE activation may not always be beneficial. During ischemia, there is often a buildup of metabolic products that is caused by the anaerobic breakdown of ATP the...

The Fetal Heart

Foramen Ovale Heart

By the third month of fetal development, the heart and all major blood vessels are basically formed, and the blood flow is generally the same direction as the adult. However, there are some major differences between fetal and postnatal circulation (Fig. 19). First, oxygenated blood flows toward the fetus and into the heart in umbilical veins, and deoxygenated blood flows away from the fetus in umbilical arteries. Second, the fetus obtains oxygen from the uterus through the placenta, and the...