Answer
Ventricular systole begins during the <u>isovolumetric contraction </u>phase of the cardiac cycle.
Explanation
1. Ventricular ejection
The forceful expulsion of blood from the ventricles into the aorta and the pulmonary arteries.
2. Isovolumetric contraction
The interval between the closing of the AV valves and the opening of the semilunar valves (aortic and pulmonary valves) is known as isovolumetric contraction. it is the beginig of systole. it is the first chamber systolic event. The myocardial muscle fibers have begun to shorten but have not developed enough pressure in the ventricles to overcome the aortic and pulmonary end-diastolic pressures and open the aortic and pulmonary valves. During this period of muscle fiber contraction, the ventricular volumes do not change.
3. Ventricular filling
In this stage AV valve is opened and the blood that has accumulated in atria flow rapidly into ventricles. The ventricular volume increase rapidly. A third heart sound known as S3 is heared during this stage.
4. Isovolumetric relaxation
It is the beginning of diastole. The AV valve are closed at beginig. The atrium in diastole has been filling with blood on top of the closed AV valve, causing atrial pressure to rise gradually. The pressure in the ventricles continues to drop. Ventricular volume is at a minimum and is ready to be filled again with blood.
Answer:
Species X and species Z belong to the domain
Explanation:
To answer this specific question,
pregnancy is an example of positive feedback. I am hoping that this answer has
satisfied your query and it will be able to help you in your endeavor, and if
you would like, feel free to ask another question.
Answer:
Plant is a common example of a Producer.
Producers are also known as autotrophs.They are organisms which make their own food. They do so by getting energy from chemicals or the sun and with the help of water convert the energy into useable forms such as sugar.
The order of Producers that colonize the land After Lichens include
Annual herbaceous plants
Perennial herbaceous plants and grasses
Shrubs
Shade intolerant trees
Shade tolerant trees.
Answer:
Solar flare
Explanation:
They are characterized by coronal mass ejections on the sun's surface. The ejected ionized particles if thrown in the direction of the earth will cause bright aurora as they colide with the earth’s ionosphere and magnetic field. These solar storms can also affect telecommunications satellites and also electricity grid systems.
