Which best describe the isovolumetric contraction phase of the cardiac cycle? Which best describe the isovolumetric contraction phase of the cardiac cycle? The pressure from the atrial contractions opens the semilunar valves. As pressure builds up in the ventricles during systole, the AV valves open and allow blood to leave the heart. As ventricular systole starts, the AV valves are closed and the semilunar valves are closed. Because the ventricles are contracting and both valves are closed, pressure increases rapidly leading to ejection. As ventricular systole starts, the AV valves close, which immediately opens the semilunar valves.

The correct answer is: As ventricular systole start, the AV valves are closed and the semilunar valves are closed. Because the ventricles are contracting and both valves are closed, pressure increases rapidly leading to ejection.

Explanation:

The heart functions like a bomb that pumps blood to every part of the body, which is fundamental for the proper function of every organ.

The cardiac cycle has two main phases: the diastole and the systole. During the diastole, blood returns from the body through the vena cava and is deposited in the right atrium of the heart. When the pressure in the right atrium becomes bigger than the pressure in the right ventricle, the tricuspid valve opens and the blood flows to the left atrium.

During systole, the atria suffer a depolarization that makes the atria's muscle contract. Thanks to this, the blood goes through the atria to the ventricles.

During isovolumetric contraction, the ventricles contract but the pulmonary and aortic valves remain closed. When the ventricular muscle contracts, the semilunar valves open.

question#1

ans:

cell is the basic unit of organization of all living things. cells are often called the building block of life and it is the smallest unit of life. the study of cell is called cell biology. cell consists of cytoplasm enclosed within membrane, which contain bio-molecules such as proteins and nucleic acid.

two third of cell is water, which means that two-third of your whole body is water. the rest is the mixture of molecules, mainly proteins, lipids and carbohydrates.

question#2

ans:

organ:

an organ is a group of tissues specialized to form a functional unit. an example is the heart in animals.

organ system:

an organ system is a group of several organs whose functions are synchronized to release an effective action in a living organism. an example is digestive system.

question#3

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#4

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system—working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#5

our body works because of the interactions that happen between organs and organ systems.  

for example:  

the heart to regulate blood flow throughout the body. the blood carries oxygen and nutrients to the cells and carries carbon dioxide and waste away from the cells. body systems work together in maintaining a constant internal environment. when this balance is disrupted, the body systems may not function properly, and human health can suffer.   you start to feel bad.