Cardiac output - circulation, Biology

Assignment Help:

Cardiac Output - Circulation

The cardiac output can be determined in a number of ways. The most common method is the Fick's principle. A. Fick a German physiologist in 1870 described a simple method of calculating cardiac output from measurement of oxygen consumption (or carbon dioxide production) and the difference between oxygen (or carbon dioxide) contents of blood entering and leaving the heart.

1961_Cardiac Output - Circulation 1.png

The volume of blood ejected by each beat of the heart is the stroke volume. The mean stroke volume is determined by dividing cardiac output by heart rate. In other words, cardiac output can be calculated if we know the values of heart rate and stroke volume. Therefore, cardiac output can be increased by increasing either the heart frequency or the stroke volume or both. However, in mammals there may be little change in stroke volume if cardiac output is to be altered, major adjustments are made in the heart rate. The distribution of blood to the various organs of the human body is given in Table You can see from the Table that kidneys, liver, heart and brain make up only 5% of the total body weight but receive more than half of the total cardiac output. Stroke volume can also be defined as the difference in volume of blood before and after contraction. Two factors influence stroke volume, one is the hormone adrenaline (epinephrine) which increases contractions thus forcing a larger volume of - blood out of the ventricles in a single stroke. The other is the amount of blood present in the ventricles before contraction.

1444_Cardiac Output - Circulation 2.png

If the returning venous blood to the heart is increased, then ventricles will be filled with more blood and following contraction more blood will be ejected out. This relationship between cardiac output and increased venous volume was discovered by the English physiologist Ernest H. Starling. This relationship will be further discussed when we talk of blood flow during exercise.


Related Discussions:- Cardiac output - circulation

How can germs can be transmitted, How can germs can be transmitted Germ...

How can germs can be transmitted Germs can be transmitted many ways, including: Touching dirty hands; Changing dirty or contaminated cloths; Through contaminated water and f

Some common air pollutants: hydrocarbon, Hydrocarbon (HC): Hydrocarbons ...

Hydrocarbon (HC): Hydrocarbons such as methane, ethylene, acetylene is present in air. Most of these are low molecular weight gases and liquids at ordinary temperature. Sour

hormonal control of osmoregulation, This process involves the regulation o...

This process involves the regulation of the concentration of the body fluids through control of water content and salt content of the blood. If a person loses water from their bloo

What are epithelial tissues, What are epithelial tissues? What are their ge...

What are epithelial tissues? What are their general function and how is that function associated to the features of the tissue? Epithelial tissues, also known as epithelia, are

List out the principles of food preservation, List out the Principles of Fo...

List out the Principles of Food Preservation? All food preservation methods are based upon the general principle of preventing or retarding the causes of spoilage caused by mic

Define about the deficiency of cyanocobalamin, Define about the Deficiency ...

Define about the Deficiency of cyanocobalamin? Malabsorption of vitamin B 12 can occur at several points during digestion. By far, the most important condition resulting in v

Oogenesis, - Oogenesis involves the formation of haploid cells from an orig...

- Oogenesis involves the formation of haploid cells from an original diploid cell, called a primary oocyte, through meiosis. - The female ovaries contain the primary oocyte. The

Nursing education, Nursing  Education   Computer-Assisted Instruction ...

Nursing  Education   Computer-Assisted Instruction (CAI) is a valuable teaching aid for health care students, testing them with frequent quizzes to ensure that the material rea

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd