People float in water because the human body weighs less than the volume of water it displaces when submerged. The buoyancy of an individual depends on his or her body type, as those with more muscle tend to sink further, while those with more body fat float more efficiently.
When an object is placed into water, it is entering a cylinder of water from the surface to the bottom. It displaces some of the water in that cylinder, and the water beneath it exerts upward pressure. If the volume of water that is displaced is lighter than the object, the pressure will be insufficient to keep it afloat. If the equivalent volume of water is heavier than the object, the remaining water in the cylinder will keep it at or near the surface.
Human bodies tend to float due to stores of fat and to the volume of air stored in the lungs. However, those with very low body fat percentages may have a more difficult time managing to stay afloat. Lying horizontally can improve floating capacity, as it increases the surface area exposed to the upward pressure from the water. On the other hand, clothing can absorb water and increase in weight, possibly making the difference between floating and sinking.Learn More
The cardiovascular system interacts with the digestive system by carrying digested nutrients throughout the body via the bloodstream, explains Southwest Tennessee Community College. The digestive system also works with the excretory system to control the amount of water in the body and release undigested compounds in urine, notes Biology4Kids.com.Full Answer >
Lymph is formed when interstitial fluid comes into contact with blood. Initially, it is a watery liquid with the same consistency as interstitial fluid, according to the Journal of Lipid Research. However, lymph thickens as it accumulates additional material from blood, such as proteins and lymphocytes.Full Answer >
It requires approximately 1,100 pounds of force to fracture a human skull at its weakest points, which are located around the temples. As the human skull is so resistant to outside forces, it is much more likely for an individual to suffer serious head injuries from intracranial pressure.Full Answer >
A tortuous thoracic aorta is serpentine in its shape or path, according to Yale University School of Medicine. The thoracic aorta is the portion of the descending aorta above the diaphragm, according to InnerBody. The descending aorta begins at the posterior of the heart toward the left of the body.Full Answer >