The organ that receives reduced flow of blood during vigorous exercise is the

Step 1: Analyze the question During vigorous exercise, the body redistributes blood to the organs that need more oxygen and nutrients. We need to find the organ that gets less blood flow, or at best no increase.

Step 2: The concept During exercise:

• Skeletal muscles (limbs) need more oxygen and glucose for respiration, so blood flow to them increases a lot.
• The heart (cardiac muscle) works harder, so its coronary blood flow increases.
• The lungs receive the entire cardiac output and take in more oxygen, so blood flow through them increases.
• The brain is a vital organ, and its blood flow is kept roughly constant by the body. Even so, in terms of the share of cardiac output, it receives a smaller proportion. Its blood supply does not rise like the others.
• The digestive system and kidneys have blood flow reduced (vasoconstriction), but they are not among the options.

Step 3: Compare the options

• A. Brain: its flow stays about the same, and its share of the total output drops. Among the options, it is the one that does not gain extra flow.
• B. Heart: increased flow, since it pumps faster and harder.
• C. Lung: increased flow, since more blood is pumped through to take up oxygen.
• D. Limb: greatly increased flow to the working muscles.

Step 4: Answer The brain is the organ that does not receive increased blood flow during vigorous exercise. Its relative share falls, while the heart, lungs, and limbs get more.

Exam tip: Remember "exercise = more blood to muscles, heart, and lungs; less to digestion, kidneys, and (relatively) other organs." When all the options are active in exercise, pick the one that is not directly involved in movement or gas exchange.