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Quiz Chapter 10: Transport in Humans and Animals

10 questions ยท Form 4 Biology Bab 10: Transport in Humans and Animals

Question 1 of 10Score: 0

Which structure in the human heart is known as the natural pacemaker because it initiates electrical impulses for cardiac contraction?

Full Question List & Answer Key

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1. Which structure in the human heart is known as the natural pacemaker because it initiates electrical impulses for cardiac contraction?

  1. A. Atrioventricular (AV) node
  2. B. Sinoatrial (SA) node
  3. C. Bundle of His
  4. D. Purkyne fibers
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Answer: B

The Sinoatrial (SA) node located in the right atrium generates rhythmic electrical signals that set the pace for heart contractions.

2. Which valve prevents the backflow of blood from the left ventricle into the left atrium during ventricular systole?

  1. A. Tricuspid valve
  2. B. Bicuspid (mitral) valve
  3. C. Aortic semilunar valve
  4. D. Pulmonary semilunar valve
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Answer: B

The bicuspid (mitral) valve is located between the left atrium and left ventricle.

3. Which blood component is normally present in blood plasma but absent in interstitial (tissue) fluid?

  1. A. Glucose
  2. B. Large plasma proteins (e.g., albumin, fibrinogen)
  3. C. Oxygen
  4. D. Amino acids
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Answer: B

Large plasma proteins cannot pass through the capillary wall pores due to their size, remaining inside the blood.

4. The thoracic duct drains lymph collected from most of the body back into which major blood vessel?

  1. A. Right subclavian vein
  2. B. Left subclavian vein
  3. C. Hepatic portal vein
  4. D. Inferior vena cava
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Answer: B

The thoracic duct re-enters the venous bloodstream by emptying lymph into the left subclavian vein.

5. Which two essential factors are required alongside thrombokinase to activate prothrombin into thrombin?

  1. A. Iron ions and Vitamin C
  2. B. Calcium ions (Ca2+) and Vitamin K
  3. C. Sodium ions and Vitamin D
  4. D. Potassium ions and Vitamin A
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Answer: B

Calcium ions (Ca2+) and Vitamin K act as critical cofactors for prothrombin activation.

6. Why is the circulatory system of an amphibian described as a double incomplete system?

  1. A. It has only one atrium and one ventricle.
  2. B. Blood flows through the heart only once per circuit.
  3. C. Oxygenated and deoxygenated blood partially mix in the single ventricle.
  4. D. It lacks blood vessels completely.
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Answer: C

Amphibian hearts have 2 atria but only 1 ventricle, allowing partial mixing of oxygen-rich and oxygen-poor blood.

7. What soluble plasma protein is converted by thrombin into insoluble threads during clot formation?

  1. A. Fibrinogen
  2. B. Prothrombin
  3. C. Albumin
  4. D. Globulin
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Answer: A

Thrombin hydrolyzes soluble fibrinogen into insoluble fibrin strands that trap cells to seal wounds.

8. Which animal possesses an open circulatory system where hemolymph bathes organs directly within a hemocoel?

  1. A. Earthworm
  2. B. Grasshopper
  3. C. Toad
  4. D. Salmon
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Answer: B

Insects like grasshoppers have an open circulatory system with hemolymph flowing into the body cavity (hemocoel).

9. What movement assists the flow of lymph along lymphatic vessels towards the subclavian veins?

  1. A. Pumping action of the heart
  2. B. Contraction of surrounding skeletal muscles and presence of internal valves
  3. C. High arterial blood pressure
  4. D. Active transport by epithelial cells
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Answer: B

Lymphatic vessels lack a central pump; lymph moves via skeletal muscle contractions squeezing vessels, guided by internal one-way valves.

10. During cardiac contraction, electrical impulses travel from the AV node down the septum through which specialized conducting tissue?

  1. A. Sinoatrial node
  2. B. Bundle of His
  3. C. Coronary sinus
  4. D. Bicuspid valve
Show answer

Answer: B

The Bundle of His conducts electrical signals from the AV node down the interventricular septum toward Purkyne fibers.

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