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

Define reagents required and methodology for fehling's test, Define Reagent...

Define Reagents required and Methodology for Fehling's Test? - Sugar solutions of glucose, fructose, galactose, lactose, maltose, sucrose, starch - Fehling A (Copper sulphat

Explain uristix benedicts test, Q. Explain Uristix Benedicts test? No s...

Q. Explain Uristix Benedicts test? No sugar/glucose is excreted in the urine in normal individuals. In diabetics, glucose is excreted by the kidneys when the blood sugar levels

Differance between descending thoracic or abdominal aneurysm, Differance be...

Differance between Descending Thoracic or Abdominal Aneurysm ? Descending Thoracic Aortic and Thoraco-Abdominal Aneurysm :  The approach is through n left postero-lat

Heredity and variations, HEREDITY 1.         Like begets like i.e; ever...

HEREDITY 1.         Like begets like i.e; every living organism reproduces its own kind. Frog reproduce frogs, rats reproduce rats only. 2.         Heredity includes the cha

What is the difference between anabolism and catabolism, What is the differ...

What is the difference between anabolism and catabolism? Metabolism comprises two opposing processes: anabolism and catabolism. Anabolism is a set of synthesis reactions that t

Is neuron a synapses onto neuron b, Is Neuron A synapses onto Neuron B ...

Is Neuron A synapses onto Neuron B Consider Neuron B in the frog central nervous system whose plasma membrane has a newly discovered ligand-gated ionotropic receptor, named the

Which are the heart chambers, Q. Which are the heart chambers respectively ...

Q. Which are the heart chambers respectively where the entrance and the exit of blood occur? The heart chambers through which blood enters the heart are the atria there are the

Nursing care and treatment for cleft palate, Nursing Care and Treatment  ...

Nursing Care and Treatment   The only treatment is surgical repair and child may be operated before 18 months as per the choice of surgeon so  that speech pattern of child may

Explain capillaries of the vascular system, Q. What are the capillaries of ...

Q. What are the capillaries of the vascular system? Capillaries are small blood vessels that perform exchange of substances between the tissues and blood the body Capillaries a

ALGAE., HOW ARE THE ORIGIN AND EVOLUTION OF ALGAE..

HOW ARE THE ORIGIN AND EVOLUTION OF ALGAE..

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