PLEASE HELP!!

List all the electrical and mechanical events that occur within 1 heartbeat (in order). Also be able to state which are occurrin

eimsori [14]

Answer:

Phases of the Cardiac Cycle are Diastole and Systole

Explanation:

<h2>Cardiac Cycle Phases </h2>

(First Phase) Atrial contraction

This is the phase of atrial contraction.

In this fase, 80% of ventricular filling has been done passively even before the onset of atrial contraction, and the remaining 20% of ventricular filling is due to atrial contraction. The active filling of ventricles becomes valuable during physical activity.

When pressure in the atrium increases, blood rush into the ventricles through the opened mitral valve. During left atrium contraction, pressure and volume are transferred into left ventricle through opened mitral valve. Aortic valve is closed because pressure in aorta is greater than the pressure in left ventricle at this moment.

(Second Phase) Isovolumetric Contraction

The early phase of ventricular systole. When ventricles contract, there is a progressive increase in intraventricular pressure. This wil leads to closure of mitral valve. That produces first heart sound (S1) and little bulging of mitral valve into atrium causing the slight increase in the atrial pressure.

Intraventricular pressure progressively increases upto 80mmHg altought it is not competent enough to open the aortic valve.

At this moment ventricle is contracting with closed mitral and aortic valves. Meanwhile, intra atrium pressure is gradually increasing due to accumulation of blood returning from lungs into the left atrium. During the same phase, aorta pumps whatever blood it contains into more peripheral part of arterial tree due to its elastic nature.

This is the stage of ventricular contraction when backward valves are closed yet the forward valves are not opened. Ventricle is contracting as a closed chamber without any change in volume and size of the ventricle. We call it isovolumetric contraction of early part of ventricular systole.

(Third Phase) Rapid Ventricular Ejection

When pressure reaches to 81mmHg, aortic valve opens. This starts third phase of cardiac cycle. Ventricles keep on contracting, and there is a progressive increase in intraventricular pressure upto 120mmHg. During this phase, aortic valve opens and blood is ejected quickly into the aorta. At this point left ventricle and aorta behave as a single chamber.

The pressure changes occurred in the ventricles results in the transmission of pressure to aorta. Meanwhile left atrium continues receiving blood from the lungs.

(Fourth Phase) Slow Ventricular Ejection

In this phase atrium is still behaving as reservoir of blood and the pressure is keep on building. Mitral valve is closed. Ventricles are still contracting but intraventricular pressure starts falling, due to ejection of blood . Hence, pressure in aorta also starts falling, but intraventricular pressure is still more than aortic pressure.

Aortic valve remains open leading to slow ejection of blood into aorta. Elastic aorta keeps on squeezing the blood and pumps it into peripheral arterial tree.

(Fifth Phase) Isovolumetric Relaxation

In this phase ventricles start relaxing. Intraventricualr pressure falls quickly. In the beginning, as soon as the ventricular pressure becomes less than pressure in aorta, aortic valve closes.

Even though pressure in ventricle is falling, it is still high enough compared to pressure in atrium. Ventricle is relaxing with closed valves and it is known as isovolumetric relaxation. During this phase atrium is still behaving as reservoir of blood.

(Sixth Phase) Rapid Passive Ventricular Filling

When left ventricle start relaxing, pressure in left ventricle start dropping until it reaches the point where pressure in the ventricle becomes less than the pressure in atrium, leads to opening of mitral valve. Blood which was previously accumulated in atrium will rush into ventricle. This quick filling is done without atrial contraction.

(Seventh Phase) Slow Passive Ventricular Filling

As atrioventricular valve open, blood coming to atrium rushes into the ventricle. Here atrium is not acting as reservoir.

7 0

4 years ago

Sinanthropus pekinenis was victim of cannibalism

Tom [10]

Yes he was he was a victim on cannibalism

5 0

3 years ago

All organisms possess a genetic system based on what

ozzi

Answer:

DNA

Explanation:

Deoxyribonucleic acid or DNA is defined as the genetic material in all the living organisms responsible for all the genetic activities in an organism.

DNA carries genetic instructions that are inherited from one generation to another generation. The DNA comprises of genes having specific genetic code that encodes the sequence of amino acid residues in proteins. DNA undergoes the process of replication and form several copies of it which are passed on to next generation.

Hence, the correct answer is "DNA".

5 0

3 years ago

What is the relationship between the curve seen in the graph and the environmental health of the oceans?

enyata [817]

Answer:

As the population increases, more demands are put on the ocean to support human life.

Explanation:

Many countries rely on the ocean for transport and as food sources. Over fishing has continuously been a growing problem as more and more fish are required to sustain populations as well as support more gourmet markets. A higher population will also lead to higher trade rates as more materials that aren't available in one country will need to be imported from others.

8 0

2 years ago

Aluminum makes up 8.0% of the weight of the Earth's crust. This metal is used to make aluminum cans such as soda cans. How can t

Likurg_2 [28]

you can recycle the cans to reuse the aluminum to reduce the amount of deaths in the mines and the amount of mines there are

6 0

4 years ago