Answer:
The main factor that causes vasoconstriction is the high concentration calcium inside muscle cells.
Explanation:
When the vessels suffer vasoconstriction, the blood supply is decreased and in this way the heat of the body is maintained. The way this happens is because the blood can no longer reach the surface and therefore decreases outward heat radiation. The main factor that causes vasoconstriction is the high concentration calcium inside muscle cells. There are several factors that cause vasoconstriction, internal or external. Environment is one of the external factors, and what happens to the penguins' feet is an example for it, since they are trying to preserve body heat to survive.
Explanation:
The ribs are a set of twelve bones which form the protective 'cage' of the thorax. They articulate with the vertebral column posteriorly, and terminate anteriorly as cartilage (known as costal cartilage). As part of the bony thorax, the ribs protect the internal thoracic organs.
Most organisms are Diploid, and as a result, they will have received 2 copies of the chromosomes, or sets of chromosomes, from both their parents. This they will have 2 sets of Genes that will perform almost exact same process, except with different phenotypes.
These chromosomes need to be homologous, in order for new alleles and other genetic combinations to be made.
There are approximately 4.7 to 5.5 liters and 1.2 to 1.5 gallons of blood in a human's body.