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

Give source organism of the dna polymerase used in pcr, a) Mention the numb...

a) Mention the number of primers needed in each cycle of polymerase chain Reaction (PCR) . Write the role of primers and DNA polymerase in PCR. b) Give the characteristic fea

Mitral valve, This valve has the same basic features as  of the Tricuspid V...

This valve has the same basic features as  of the Tricuspid Valve. It has an anterior and a posterior cusp. The anterior cusp is larger and is attached on the upper right part of t

Alfieri repair-technique of operation, Alfieri Repair: This is advised ...

Alfieri Repair: This is advised for ischaenlic mitral regurgitation. In the area of prolapse, the anterior and posterior leaflet edges are approximated with one or two mattress

What are the four types of weak bonds, What are the four types of weak bond...

What are the four types of weak bonds, and how do they differ from each other and from covalent bonds?

Define about the cellulose acetate electrophoresis (cae), Define about the ...

Define about the Cellulose acetate electrophoresis (CAE)? If the hydroxyl groups in cellulose are reacted with acetic anhydride, cellulose is acetylated to form the raw materia

Endosperm with chalazal haustorium, Endosperm with Chalazal Haustorium ...

Endosperm with Chalazal Haustorium In Grevillea robusta, a member of Proteaceae the endosperm is of the free nuclear type. The upper part of endosperm becomes cellular, where

What are blood stem cells, What are blood stem cells? Stem cells are un...

What are blood stem cells? Stem cells are undifferentiated cells able to distinguish into other types of specialized cells. The stem cells of the bone marrow create the diff

What are the three main parts of a eukaryotic cell, Q. What are the three m...

Q. What are the three main parts of a eukaryotic cell? The eukaryotic cell can be separated into two major portions: the cell membrane that separates the intracellular space fr

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