Blood flow during exercise - circulation, Biology

Assignment Help:

Blood Flow during Exercise - Circulation

Whenever we exercise or run we notice that we begin to breathe faster, the heart beats much faster than the usual average of 70 beats per minute. We know that the body at this time needs more oxygen and the heart must supply it to the muscles. There can be two ways of supplying this additional oxygen. The cardiac output can be increased or the amount of oxygen delivered by each volume of blood is increased. The arterial blood pumped out of the heart is already fully saturated but venous blood normally contains more than half the oxygen present in the arterial blood. Therefore, if more oxygen is extracted from the venous blood it can be supplied to the muscles. The total muscle of a lean person uses about 50 ml of O2 per minute which is supplied by about 1 litre of blood.

Arterial blood contains 200 ml of O2/litre and venous blood contains 150 ml of O2/litre. The oxygen extraction therefore, is only 25%. During heavy exercise, blood flow to muscles may be 20 litres per minute or even higher in atheletes and the oxygen extraction increases to 80-90%. In other words, during heavy exercise almost all the oxygen may be removed from the venous blood. The cardiac output can also be increased to deliver more oxygen. As said earlier, cardiac output can be increased by either increasing stroke volume or heart rate or both. At rest the human heart rate is 70 beats per minute and the stroke volume is 70 ml (from each side) giving a total cardiac output of 5 litres/minute. During exercise the cardiac output is increased about five-folds or more. Most of the increase is due to increase in pulse rate which may become 200 strokes per minute. Stroke volume may also increase beyond 100 ml. In a well-trained athelete the oxygen consumption may be increased as much as 100 times but this becomes possible more due to a three-fold increase in oxygen extraction from the blood.


Related Discussions:- Blood flow during exercise - circulation

Characteristic features of phylum arthropoda, Characteristic Features of Ph...

Characteristic Features of Phylum Arthropoda Well-developed muscular system along with striated muscles attached to the exoskeleton, and visceral organs having smoot

Glucose, Glucose is a six-carbon single sugar; It is the most common energ...

Glucose is a six-carbon single sugar; It is the most common energy source.

Reciprocal translocation and fusion, In chronic myelogenous leukemia, white...

In chronic myelogenous leukemia, white blood cells proliferate ceaselessly. In affected white blood cells, the BCR-ABL oncogene, the result of a gene fusion, transmits a constitu

What are the frequencies of the s, Platinum color in foxes is produced by h...

Platinum color in foxes is produced by heterozygous genotype Ss, and silver foxes are the genotype SS. The genotype ss is lethal, and the fox dies in early embryonic development. I

Discovery of the cell, Q. Describe the Discovery of the Cell? Ans: The ...

Q. Describe the Discovery of the Cell? Ans: The discovery that living organisms are composed of cells was made by an Englishman, Robert Hooke, in 1665. Hooke used the light mic

What is the significance of proteins for living beings, Q. What is the sign...

Q. What is the significance of proteins for living beings? Proteins play an essential role in nearly all biological processes. Due to their variety they can suppose many divers

Male accessory sex organs, Normal 0 false false false E...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

What are some examples of organs and tissues, What are some examples of org...

What are some examples of organs and tissues where mitosis is more frequent, less frequent or practically absent? Generally in vertebrates mitosis is more frequent in a tissue

Testes (testicles), TESTE S (TESTICLES) - 2 in number (Diarchic). P...

TESTE S (TESTICLES) - 2 in number (Diarchic). Pinkish in colour. Oval shaped. 4-5 cms long, 2.5 cm wide and 3 cm thick. Mesodermal. In embryonic stage attached to kid

Behaviour change communication - iron deficiency anaemia, Define Behaviour ...

Define Behaviour change communication - iron deficiency anaemia? In communities that are illiterate and consequently ignorant of the consequences of nutrition disorders and the

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