Lecture 7: Blood circuits and the Heart Flashcards
What is the difference between an artery and vein
Arteries take blood away from the heart- therefore they are exiting the venticles, and Veins are carrying blood back to the heart.
Describe the path of the pulmonary circuit vs the systemic circuit
The pulmonary circuit from RV to the lung to the LV. The systemic circuit is from the LV to the systems (limbs, kidneys, brain, liver and gut) and then back to the RV.
Describe the purpose of pulmonary circuit vs the systemic circuit (what type of blood)
Pulmonary takes deoxygenated blood through P arteries to the Lungs for gas exchange and then oxygenated blood to LV. Systemic arteries deliver oxygenated blood to systems where there is gas exchange and deoxygenated blood carried by systemic veins back to the RV. For both circuits gas exchange is at a capillary bed at the organ.
Compare the blood volume and pressure of the two systems
P has medium pressure and medium resistance compared to S which has lots of vessels so high resistance and therefore high pressure.
S also has 84% of blood volume, (veins are resovoir). P has 9% of blood volume. 7% is in the Ventricles/atrium.
What is the total blood volume and output on an average person
Blood volume is 5L. Output is 5L/minute at rest
Describe the unusual venous draining of the gut
The deoxygenated blood from the gut also carries a lot of nutrients so it is delivered to the liver first for filtering- not back to the heart by its veins. They are called hepatic portal veins. As a result, Liver receives 2 supplies, deoxygenated blood from hepatic portal vein and oxygenated blood from the systemic arteries
Describe the path of blood and passages in the heart from the blood from the systemic circuit coming in
vertically positioned sup. and inf. vena cava receive deoxygenated blood from the systemic circuit which drains into the R atrium + R auricle into the R ventricle. Its pumped to the pulmonary trunk to 2 pulmonary arteries to lungs. It comes back through the two horizontal placed pulmonary veins to drain into the L atrium + L auricle + L ventricle to be pumped to the Aorta - back to the systemic circuit.
Describe the filling phase of the ventricular pump. Whats happening to volume and pressure and position of inlet and outlet valve
The Ventricle is stretching out passively, therefore increasing volume and decreasing pressure. The outlet valve is closed to prevent arterial blood from coming back into the pump and the inlet valve is open to let veinous blood in.
Describe the ejection phase of the ventricular pump. Whats happening to volume and pressure and position of inlet and outlet valve
The ventricle is squeezing inwards actively, therefore volume decreases and pressure increases. the inlet valve is closed to stop blood from going back to the veins and the outlet valve is open to let the blood out
What is the purpose of the atrium
It allows blood to accumulate in the ejection phase behind the closed inlet valve so it can enter quickly during the passive filling phase
How is the pumping capacity increased in the ventricle
The outlet and inlet of the pump lie close together on one side letting the walls of the pumping chamber shorten in length as well as width- more muscle. Adding an auricle continuous with the atrium also increases the amount of blood that can be filled in.
Compare the thickness of Left atrium and Right atrium to the maximum blood pressure
Left atrium max blood pressure is 8 mmHg vs Right atrium max blood pressure 5 mmHg. Both of these have less pressure than ventricles and therefore relatively thin (2-3 mm) with a smooth posterior wall and no inlet valves so pressure can’t be that high. The Left atrium has a higher pressure because the pressure of the blood it receives (pulmonary circuit) is dispersed over a shorter distance than the systemic circuit.
Compare the thickness of Left Ventricle and Right Ventricle to the maximum blood pressure
Left Ventricle max blood pressure is 120 mmHg vs Right Ventricle blood pressure is 27 mmHg. Both pumps pump equal amounts of blood. However Left ventricle has thickest wall because it pumps blood greater distance, to a greater resistance pathway with high pressure. Whereas Right ventricle pumps blood shorter distance in a less resistance pathway.
What are the two atrioventricular valves called and when its open is blood coming in or out
For the left atrioventricular valve it is is tricuspid, and for right atrioventricular valve it is bicuspid (mitral). When open blood is coming in.
How does the structure of two atrioventricular valves help their function
They both have 2 or 3 fibrous connective tissue flaps, with the free end of a flap attached to Chordae Tendinae which are attached to papillary muscles. During Filling, everything is relaxed and blood flows from high pressure in the atria to ventricles. During ejection phase, pressure of blood in the ventricles is higher than atria, pushes the flaps up, closing it and the papillary muscles contract, pulling on the CT to stop the flaps from suddenly flapping backward
