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

What is the choice of a prophylactic agent, Choice of a prophylactic agent ...

Choice of a prophylactic agent An effective prophylactic regimen should be directed against the most likely infecting organisms, but need not eradicate every potential pathogen

Mycoplasmosis, Mycoplasmosis Mycoplasmas are the aetiological agents o...

Mycoplasmosis Mycoplasmas are the aetiological agents of bovine pleuropneumonia in cattle caused by Mycoplasma mycoides subsp. mycoides, caprine pleuropneumonia in goats cause

Chuck darwin knew blending theory, Chuck Darwin knew BLENDING THEORY, but h...

Chuck Darwin knew BLENDING THEORY, but he also knew that if it was true his NOT work because

Explain about the amino acids and proteins, Explain about the Amino Acids a...

Explain about the Amino Acids and Proteins? We shall now study the properties of amino acids which we know are the building blocks of proteins.  In this practical, we shall car

Explain the nonpolar molecular attractions, Explain the Nonpolar Molecula...

Explain the Nonpolar Molecular Attractions in basic chemistry? Nonpolar Molecular Attractions :  Van der Waals forces and hydrophobic interactions are weak (not as strong

What is the main nitrogen waste of humans, Q. What is the main nitrogen was...

Q. What is the main nitrogen waste of humans? Human beings excrete largely urea eliminated with the urine.

Determine energy expenditure for climbers, Determine energy expenditure for...

Determine energy expenditure for Climbers? The energy expenditure of 3250 Kcal/ day is reported in climbers to Mt. Everest using doubly labeled water teaching. Out of this, 161

Why photoperiodism affect the flowering of some plants, How does the photop...

How does the photoperiodism affect the flowering of some plants? Flowering is a typical and simple to observe instance of photoperiodism. Most flowering plants flower only duri

Structure and fate of endosperm, Structure and Fate of Endosperm The ...

Structure and Fate of Endosperm The cells of endosperm are usually thin-walled, large isodiametric and devoid of pits and store large amount of food materials. The starch alo

How is the nervous system of nematodes organized, Q. How is the nervous sys...

Q. How is the nervous system of nematodes organized? Where are the neural chords located in their body? Roundworms have a ganglial nervous system with an anterior neural ring r

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