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

Explain about the primary protein derivatives, Explain about the primary pr...

Explain about the primary protein derivatives? a) Proteins: These are the insoluble products which result from the incipient action of very dilute acids or enzymes. e.g. casein

Counselling diabetic travellers, Counselling Diabetic Travellers The c...

Counselling Diabetic Travellers The counsellor needs to educate a diabetic patient and /or his family members to following issues when such patients plan to travel: ·  Plan

Care required by a hiv infected person, Care required by a HIV infected per...

Care required by a HIV infected person: 1) An HIV infected person needs acceptance and support from the family members. The home is very important place for a person with AIDS.

Explain about oral irrigation devices, Oral irrigation Devices The use ...

Oral irrigation Devices The use of oral irrigation devices has been controversial due to concerns about incomplete plaque removal and potential separation of connective issue f

test the hypothesis , A classic study of extrasensory perception tests the...

A classic study of extrasensory perception tests the ability of one person to read another's mind. The test uses five cards with different designs, all known to both participants.

What is the intermediate host of schistosoma mansoni, Q. What is the interm...

Q. What is the intermediate host of Schistosoma mansoni? Where does that host live? The intermediate host of a schistosome is a gastropod mollusc, Biomphalaria genus and a snai

Define the maxillary tuberosity, Maxillary Tuberosity Incision and refl...

Maxillary Tuberosity Incision and reflection of the mucosa overlying the areas of the maxillary tuberosity and hamular notch when taking impressions for maxillary subperiosteal

Structure of the pancreas, Describe the structure of the pancreas. How is t...

Describe the structure of the pancreas. How is the pancreas modified to carry out its various functions? How does the human pancreas compare to that of the fetal pig?

Explain the analysis of food samples, Explain the Analysis of Food Samples?...

Explain the Analysis of Food Samples? Now, in this practical, we shall deal with the endogenous and exogeneous microorganisms which are present on the food as contaminants. We

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