The European Journal of Social and Behavioural Sciences
By Alkhawaldeh, Salem A.
“Enhancing Ninth-Grade Students’ Understanding of Human Circulatory System Concepts through Conceptual Change Approach”
Publisher:
Volume 2
Pp. 201-222
2012

Type: Empirical
Data collection method: Test
Number of subjects, range: Large — 31 or more
Grade and age of subjects: 6th-8th grade — under 13-14 years, 9th-12 grade — under 17-18 years

  • Fat is not found in plasma.
  • Vitamins is not found in plasma.
  • Uric is not found in plasma.
  • All Plasma proteins are used to meet cells’ amino acid needs.
  • All plasma protein help materials transport across capillaries.
  • All plasma proteins catalyze reactions in blood. 
  • The shape of red blood cells allows them to hold more hemoglobin.
  • The shape of red blood cells allows the to be in close contact with body cells.
  • The shape of red blood cells allows them to pass through capillary walls more easily. 
  • The thick and elastic wall of arteries helps maintain high blood pressure.
  • The thick and elastic wall of arteries helps prevent heat loss.thick and elastic wall of arteries pumps blood under high pressure. 
  • When blood pressure in the capillaries increases above normal level, tissues gets fewer nutrients.
  • When blood pressure in the capillaries increases above normal level, carbon dioxide accumulates in cells. 
  • When blood pressure in the capillaries increases above normal level, the amount of oxygen diffusing out of the capillaries increases. 
  • Heartbeat is  a reflex.
  • When the brain sends stimulus to the senatorial node to initiate heart contraction.
  • A heartbeat occurs when we breathe.
  • Ventricular filling occurs mostly during atrial contraction.
  • Ventricular filling occurs mostly during ventricular ejection.
  • Ventricular filling occurs mostly during the contraction of atrioventricular valves.
  • Veins have the lowest blood pressure compared to other blood vessels because veins have the thinnest walls.
  • Veins have the lowest blood pressure compared to other blood vessels because gravity interferes with blood flow.
  • Veins have the lowest blood pressure compared to other blood vessels because blood velocity is the lowest in the veins.
  • Low blood velocity in capillary is due to their small diameter.
  • Low blood velocity in capillary is due to material exchange through capillaries.
  • Low blood velocity in capillary is due to their long distance from the heart.
  • In the systemic circulation, percent of blood volume in the arteries, and capillaries, and veins is equal.
  • In the systemic circulation, percent of blood volume in the arteries and capillaries is equal, which is greater than that of veins.
  • In the systemic circulation, the percent of blood volume in the arteries is the highest, while the blood volume in the veins is the lowest.
  • Pressure created by the valves in the veins is one of the factors that help blood return to the heart.
  • Cohesion between blood and blood vessels is one of factors that help blood return to the heart.
  • Blood from the left and right halves of the heart goes to all parts of the body.
  • Blood from one side of the heart goes to the right side of the body. Blood from the other side goes to the left side of the body.
  • Blood goes into the heart on one side. Blood leaves the other side and goes to all pans of the body.
  • When blood reaches the cells, it leaves the tubes and bathes the cells.
  • When blood reaches the cells, some stay inside blood tubes, and some leaves the blood tubes and bathes the cells. 
  • When the environmental temperature increases, skin tacks a red appearance because the diameter of the capillaries increases.
  • When the environmental temperature increases, skin tacks a red appearance because blood pressure increases.