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Zorluk: OrtaCirculatory and Transport Systems in Animals

A major evolutionary advancement in the circulatory system of birds and mammals compared to amphibians is the complete separation of oxygenated and deoxygenated blood. Which structural feature of the heart is directly responsible for preventing the mixing of oxygenated and deoxygenated blood in mammals?

  1. A completely divided four-chambered structure with an intact inter-ventricular septumCevap
  2. B
    A three-chambered arrangement with a single undivided ventricle
  3. C
    A two-chambered configuration with one atrium and one ventricle
  4. D
    A three-chambered heart featuring a partially divided ventricle

Cevap

A completely divided four-chambered structure with an intact inter-ventricular septum is directly responsible for preventing the mixing of oxygenated and deoxygenated blood in mammals.
The mammalian heart has four distinct chambers (two atria and two ventricles). The muscular inter-ventricular septum completely divides the ventricular cavity into left and right sides, ensuring oxygenated blood from the lungs and deoxygenated blood from the body remain entirely separate.

Adım Adım Çözüm

1
Analyze the circulatory requirement
Complete separation of oxygenated and deoxygenated blood requires double circulation where pulmonary and systemic circuits do not blend inside the heart.
Mixing of blood reduces oxygen delivery efficiency to metabolically active homoiothermic tissue.
2
Compare vertebrate heart chamber evolution
Fish have 2 chambers (single circulation); Amphibians have 3 chambers (2 atria, 1 ventricle, blood mixes); Reptiles have 3 chambers with an incomplete ventricular septum; Birds and Mammals have 4 distinct chambers.
The complete inter-ventricular septum in mammals physically isolates the right ventricle (pumping to lungs) from the left ventricle (pumping to body).

Anahtar Kavram

Vertebrate Comparative Heart Structure and Double Circulation
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