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Apr 2, 2023 · The aorta is the thickest blood vessel to withstand the higher pressure of blood (120 mmHg during systole; Table 18.1) entering the systemic circulation. The aorta consists of a short ascending portion, the aortic arch, and descending thoracic aorta that continues through the diaphragm as the abdominal aorta.
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
These vessels direct blood away from the heart and towards the cells of the body. They tend to lay deep in the body tissues, partially to protect them from trauma. arteries have several layers; a tough outer layer, a middle layer of smooth muscle, and an inner layer of very smooth cells. The tough outer layer allows the artery to withstand the high...
As an artery gets further from the heart it gets smaller and eventually becomes an arteriole. An arteriole is smaller in diameter than an artery, and is found closer to the target organ. For example, a branch off of the descending aorta, called the renal artery, supplies the kidneys. As the renal artery enters the kidneys it breaks up into many sma...
At the level of the cell the arteriole branches into even smaller vessels called capillaries. They do not contain smooth muscle, and cannot selectively constrict or dilate like arteries and arterioles. They are very small in diameter, so only one red blood cell can pass at a time. In fact, the capillary is so small that red blood cells literally ha...
As the capillary leaves the individual cells it is assigned to supply, and starts the journey back to the heart, it becomes a venule. Venules are small veins, and have a job similar to arterioles, although there are many more venules than arterioles. Their numerous branches drain an organ, eventually coalescing into veins on their trip back to the ...
As the venules coalesce they eventually form veins and continue on their way through the cardiovascular system. Veins have 3 layers just like arteries, although each layer is thinner and not as strong. They don’t need to be as strong because the blood is under much lower pressure in the venous system. The blood in the veins is darker in color compa...
Jul 18, 2016 · The remainder of the aorta, from the arch to its terminal iliac branches, is the descending aorta (aorta descendens). The descending aorta may be divided further into a thoracic part (aorta thoracica) and an abdominal part (aorta abdominalis). The ascending aorta, at its origin, is slightly expanded to form the bulb of the aorta (bulbus aortae).
Coronary blood flow is determined by the difference in mean pressure between the aorta (normally 100 mm Hg) and the right atrium (normally 5 mm Hg), into which coronary blood empties. Because coronary flow is greatest during diastole, slower heart rates (which preferentially increase diastolic interval) are associated with improved myocardial oxygen delivery.
Aortic stenosis (narrowing of the opening of the aorta as it leaves the left ventricle) is an inherited condition that affects primarily large-breed dogs, such as the Newfoundland, rottweiler, German shepherd dog, golden retriever, etc. Pulmonic stenosis (narrowing of the opening of the pulmonary artery as it leaves the right ventricle) is seen in the English bulldog, beagle, keeshond ...
An aortic thromboembolism is caused by a blood clot, also known as a thrombus, getting lodged in the aorta and blocking blood flow. They often get lodged toward the end of the aorta where it divides into three vessels. This decreases or eliminates the flow of blood to the legs which can cause lameness, pain, and paralysis to the back legs ...
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What is an aortic thromboembolism?
They can be heard using a stethoscope. In dogs, 2 heart sounds can normally be distinguished. Heart murmurs are vibrations that can be heard coming from the heart or major blood vessels and generally are the result of turbulent blood flow or vibrations of heart structures, such as part of a valve. Murmurs are typically described by their timing ...
