Cardiac output - circulation, Biology

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.

Posted Date: 1/16/2013 12:38:16 AM | Location : United States







Related Discussions:- Cardiac output - circulation, Assignment Help, Ask Question on Cardiac output - circulation, Get Answer, Expert's Help, Cardiac output - circulation Discussions

Write discussion on Cardiac output - circulation
Your posts are moderated
Related Questions
What characteristics of fatty acids are false? (Dissolves in water, used for energy storage, used to build lipids, found in triglycerides, found in steroids)?

Which is the part of the human visual system where the receptors that sense light, i.e., the photoreceptor cells, are located? How do those cells work? The photoreceptor cells

Restricted Lung Diseases Restricted lung disease are classified into the following: Parenchymal inflammation. This can be due to infection e.g. pneumonia acute bronchi

Theories are import because they can be used to a. Test research hypothesis b. Develop questions which will facilitate more effective research c. Conduct more meaningful and useful

Complete history taking is an initial step in diagnosis. You will ask the patient about present complaints, past history, family history, any drug allergy and also the kind of diet

It is a newer agent that inhibits cholesterol absorption by the enterocyte. It reduces cholesterol absorption by the enterocyte. It reduces cholesterol absorption by 23 per cent-50

do you can write argument i will send you the article you want write from with rules please call me at 623-552-8532

Under fasting conditions, individuals with a deficiency in hepatic glucose 6 phosphatase cannot dephosphorylate glucose 6 phosphate generated from liver glycogenolysis. As a result

Functionality of CMC CMC is soluble in cold water and mainly used for controlling viscosity without gelling. As its viscosity drops during heating, it may be used to improve t

(a)What do you understand by the term 'monoculture'? (b) What is one disadvantage of a monoculture?   a) 'Monoculture' is the term applied to the growing