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Tidal race or tidal rapid is a natural occurrence whereby a fast-moving tide passes through a constriction, resulting in the formation of waves, eddies and hazardous currents. The constriction can be a passage where the sides narrow, for example the Gulf of Corryvreckan and the Saltstraumen maelstrom , or an underwater obstruction (a reef or ...
This shell prevents the heart from expanding when blood enters it. As pressure on the heart increases, the stroke volume decreases as a result of a reduction in the diastolic expansion in the chambers. [6] This results in significant respiratory variation in blood flow in the chambers of the heart. [7]
The cold water can cause heart attack due to severe vasoconstriction, [2] where the heart has to work harder to pump the same volume of blood throughout the arteries. For people with pre-existing cardiovascular disease, the additional workload can result in myocardial infarction and/or acute heart failure, which ultimately may lead to a cardiac ...
Venous return (VR) is the flow of blood back to the heart. Under steady-state conditions, venous return must equal cardiac output (Q), when averaged over time because the cardiovascular system is essentially a closed loop. Otherwise, blood would accumulate in either the systemic or pulmonary circulations.
The snake then wraps one or two loops around the prey, forming a constriction coil. The snake monitors the prey's heartbeat to ascertain it is dead. This can be a physically demanding and potentially dangerous procedure for the snake, because its metabolism is accelerated up to sevenfold and it becomes vulnerable to attack by another predator.
1. Living in the open ocean rather than coastal or inland waters (e.g. a pelagic shark). 2. Taking place in the open ocean (e.g. pelagic fishing, pelagic sealing). pelican hook. Also called a slip-hook or Davey hook. A hook with a hinge in the curve of the hook, normally held closed by a metal ring that keeps the two hinged parts together.
In medicine, Friedreich's sign is the exaggerated drop in diastolic central venous pressure seen in constrictive pericarditis (particularly with a stiff calcified pericardium) and manifested as abrupt collapse of the neck veins or marked descent of the central venous pressure waveform.
An increase in sympathetic stimulation to the heart increases contractility and heart rate. An increase in contractility tends to increase stroke volume and thus a secondary increase in preload. An increase in preload results in an increased force of contraction by Starling's law of the heart; this does not require a change in contractility.