health supports

posted by .

blood flow is maintained in the veins by?
A.blood pressure
B.valves in the veins which prevent back-flow
C.muscular pumping action of the vein walls
D.partial vacuum in the heart

my answer is b

  • health supports -

    Veins carry blood back to the heart. the blood in them is at low pressure. thus, the wall of a vein is not as thick, muscular or elastic as than that of an artery of about the same size. Most veins have valves inside them to prevent back flow of blood. the flow of blood along veins is assisted by the movements of the skeletal muscle.
    Answer A is wrong,mainly. C is wrong, as vein walls have no muscles. D is ridiculous. B is probably the best choice, but it is incomplete.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. science- blood

    In the difference between veins and arteries. it says veins rarely pulsate and mainly carry deoxygenated blood one vein is diffrent from the rest which one ?
  2. biology

    choose the correct statement concerning blood vessels. a. venules control blood flow through capillaries. b. arterioles drain blood from capillaries. c. veins have thinner walls, but more valves than arteries. d. nutrient exchange …
  3. Science

    Choose the CORRECT statement concerning blood vessels. A. Venules control blood flow through capillaries B.Arterioles drain blood from capillaries. C.Veins have thinner walls, but more valves than arteries. D.Nutrient exchange may …
  4. Bio 20

    When blood enters a vein from a venule, the blood pressure A) remains constant because of the heart's pumping action B) increases because of the size of the vein C) increases because of stretch receptor stimulation D) decreases because …
  5. Biology

    During exercise, (B) __________ muscles in the walls of the veins contract and cause the vein walls to stiffen so more blood flows to the heart and lungs.
  6. Biology

    Which of the following is the purpose of valves in the venous circulatory system?
  7. Science

    The Body's Transport System 1) Which of the following is not a function of the circulatory system?
  8. Health

    3. The muscular system allows our bones to: A. Strenthen B. Contract C. Lenghthen D. Move***** 4. This muscle helps to transport blood to and from the heart: A. Smooth Muscle***** B. cardiac Muscle C. Skeletal Muscle D. Invoulntary …
  9. Reading/Language Arts

    As Pedro scaled the ladder to the roof, he felt the blood in his c=veins pumping through his body. Vein can mean a blood vessel or a crack in a rock filled with mineral deposit. How is it used in this sentence?
  10. Science

    Which of the following describes the path of blood between the heart and the lungs?

More Similar Questions