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 estimated percentage of water in the human body, Q. What is the...

Q. What is the estimated percentage (in mass) of water in the human body? Is this percentage expected to be larger in the adult or in the old individual? Ans. Approximatel

Explain apomictic embryos in citrus, Apomictic embryos in citrus arise from...

Apomictic embryos in citrus arise from: 1. Synergids 2. Maternal sporophytic tissue in ovule 3. Antipodal cells 4. Diploid egg Maternal sporophytic tissue in ovule

Define trace elements for school children and adolescents, Define Trace ele...

Define Trace elements for school children and adolescents? Iodine requirements peak in adolescence. Consumption of iodized salt should be ensured. Adequacy of zinc for growth i

Alleles and possible causative candidate alleles, Genome wide association s...

Genome wide association studies must account for the fact that covering the entire genome with marker loci will produce ______ associations between linked marker alleles and possib

Use of toxic amino acids, Q. Explain Use of Toxic amino acids? Lathyru...

Q. Explain Use of Toxic amino acids? Lathyrus sativus (kesari dhal) seeds contain toxic amino acid beta-oxalyl aminoalanine (BOAA), is considered to be responsible

Organic chemistry and macromolecules, identify 7 speccific ways in which yo...

identify 7 speccific ways in which you can diversify carbon-containing compounds

Explain the nutritional role of minerals in foods, Nutritional and function...

Nutritional and functional role of minerals in foods Essential elements including the main elements and a number of trace elements fulfill various functions: as electrolytes, a

Pectin, PECTIN It consists of methylated galacturonic acid, galactos...

PECTIN It consists of methylated galacturonic acid, galactose & arabinose. It is also called plant cement becuase it binds layers of cell wall. It is a structural poly

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