The heart, blood vessels and circulation Flashcards
Define systolic pressure
When the ventricles contract, blood is forced into the arteries, and the pressure reaches a maximum value called the systolic pressure.
Define diastolic pressure
When the ventricles relax, blood pressure in the arteries falls to a mimimum value called the diastolic pressure.
What is an embolus?
Material that is blocking circulation, brought with the blood from a different location in the body.
What counts as hypertention stage 1?
From 140 mm Hg systolic and 90 mm Hg diastolic - to 159 mm Hg systolic and 99 mm Hg diastolic
So from 140/90 to 159/99
(p. 365)
What is End-Diastolic Volume (EDV)?
The volume of blood in the right or left ventricle at the end of filling.
What is End-Systolic Volume (ESV)?
The volume of blood in the right or left ventricle at the end of contraction.
How do you calculate Stroke Volume (SR)?
EDV-ESV
How do you calculate Cardiac Output?
Stroke volume x heart rate
Describe atrial systole.
During atrial systole, the atria contracts, forcing additional blood to flow into the ventricles to complete their filling. The pressure rises in the atria at first during contraction, then as the blood flows into the ventricles, the pressure decreases in the atria.
Atrial repolarization is represented by the P-wave. Atrial contraction starts shortly after the P-wave.
Describe isovolumetric contraction and ventricular systole.
After the blood has been pushed from the atria to the ventricles, the pressure in the ventricles increases. The ventricles contract, causing blood to push against the atria, causing the AV-valve to close. This is the isovolumetric contraction stage - as the ventricles contract within a closed space, and the blood volume stays the same.
This ventricular de-polarization is represented by the Q-R-S complex.
As ventricular systole continues, the increasing pressure in the ventricles exceeds that of the pulmonary trunk and the aorta. This forces the semilunar valves open, and blood is ejected out of the ventricles. As the blood is ejected, the pressure in the ventricles fall, and the semilunar valves close.
Describe isovolumetric relaxation and ventricular diastole.
The ventricles are done ejecting blood and the semilunar valves have closed. As ventricular diastole continues, the pressure in the ventricles will continue to decline, until the pressure in the atria is greater than in the ventricles. This will cause the AV valves to open, allowing blood to seep into the ventricles, slowly filling them. This will be followed by atrial systole, restarting the cycle.
The T-wave appears in an ECG as the pressure in the ventricles is starting to decline, after reaching the peak.
What are the letters in an ECG, and what order do they come in?
P - Q-R-S - T
The pericardium consists of two layers, the ____ pericardium and the ____ pericardium.
fibrous and serous
The serous pericardium consists of two parts with pericardial fluid between them, the ____ pericardium and the ____ pericardium.
parietal and visceral
The right atria receives blood from…
The inferior and superior vena cava, and the coronary sinus.
