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

Angiosperms, why are the microspores in groups of four?

why are the microspores in groups of four?

Diagnostic procedures for acute glomerulonephritis, Diagnostic Procedures ...

Diagnostic Procedures     Taking Clinical history    Urine analysis    Blood sample  for  estimation  of blood urea nitrogen    Antistrepto lysine  (ASO) titer

Oncogene, Oncogene is the gene in a tumor virus or in the cancerous cells ...

Oncogene is the gene in a tumor virus or in the cancerous cells which, when transferred into the other cells, can cause the transformation (note which only certain cells are susce

Define the maintenance of weight loss, Define the Maintenance of Weight Los...

Define the Maintenance of Weight Loss? Once an individual has managed to lose weight to a desirable level, it must not be assumed that the weight loss will be maintained automa

How dissimilar are intracellular and extracellular digestion, How dissimila...

How dissimilar are intracellular and extracellular digestion? What is the evolutionary benefit of extracellular digestion? Intracellular digestion is that in which the breaking

Protozoa, what are characteristics of flagellata class ?

what are characteristics of flagellata class ?

Joint, Ask question #Minimum 100 words what is joint accepted#

Ask question #Minimum 100 words what is joint accepted#

Explain the blood plasma levels of calcium, Which of the following serves a...

Which of the following serves as a controlled variable in a negative feedback system? A. Levels of hydrogen ions in the interstitial spaces of the brainstem. B. Blood plasma

Which dsdna is imprtant for dna purification, Which of the following proper...

Which of the following properties of dsDNA is imprtant for DNA purification? A. Hydrophilic B. Positively charged phosphate backbone C. Can only bind to divalent cations

Qualities of a good counsellor, It is important to know about qualities of ...

It is important to know about qualities of a counsellor because you will be counselling a diabetic patient and his family members in clinic/home/hospital and therefore, you shoul

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