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Return of systemic blood to the heart is impeded by the pressure inside the chest. The output of the heart is reduced, and stroke volume falls. This occurs from 5 to about 14 seconds in the illustration. The fall in stroke volume reflexively causes blood vessels to constrict with some rise in pressure (15 to 20 seconds).
Vertebral artery dissection is one of the two types of cervical artery dissection.The other type, carotid artery dissection, involves the carotid arteries.Vertebral artery dissection is further classified as being either traumatic (caused by mechanical trauma to the neck) or spontaneous, and it may also be classified by the part of the artery involved: extracranial (the part outside the skull ...
Cervical artery dissection has been noted to be a common cause of young adult strokes, with some sources indicating a prevalence of up to 20% in this young adult population with annual incidence rates between 2.6 and 2.9 per 100,000, although these incidences may be misleading with true incidences being higher because clinical presentations can vary, many being minor or self-limited, and thus ...
The carotid arteries are major blood vessels in the neck that branch into smaller vessels called the external and internal carotid arteries. [3] In carotid artery dissection, a tear in the arterial wall allows blood to flow between the layers of the artery, leading to potential narrowing, reduced blood flow, or clot formation, which may cause a ...
External bleeding is generally described in terms of the origin of the blood flow by vessel type. The basic categories of external bleeding are: Arterial bleeding: As the name suggests, blood flow originating in an artery. With this type of bleeding, the blood is typically bright red to yellowish in colour, due to the high degree of oxygenation.
Portal venous congestion causes venous blood leaving the stomach and intestines to be diverted along auxiliary routes of lesser resistance in order to drain to systemic circulation. With time, the small vessels that comprise a collateral path for porto-caval circulation become engorged and dilated.
The narrowing of blood vessels leads to an increase in peripheral resistance, thereby elevating blood pressure. While vasoconstriction is a normal and essential regulatory mechanism for maintaining blood pressure and redistributing blood flow during various physiological processes, its dysregulation can contribute to pathological conditions.
Needless to say, this would be extremely dangerous in real life. Even under ideal, clinical conditions, a cricothyrotomy is difficult and requires specific tools, preparation and a practiced knowledge of anatomy. There are many major blood vessels and nerves in the neck and cutting there carries a high risk of harming the patient.