It is a set of blood vessels which carry blood towards the heart from the all parts of body.These vessels are called veins.
The Portal Venous System
Yes, 65-70% of the blood volume is in the venous system.
The venous system is responsible for returning deoxygenated blood from the tissues back to the heart. It transports this blood through a network of veins, which have valves to prevent the backflow of blood. The venous system also plays a role in regulating blood volume and pressure in the body.
brachiocephalic
A frog's liver is in the digestive system
subclavian vein
lymphatic system
lymphatic system
Very simply put the venous system, the arterial system and your heart. The venous system bring blood from your organs and extremities to your heart, which pumps it and the arterial system takes it from your heart to your organs and extremities.
The integumentary system of a frog has multiple functions. The integumentary system is made up of the skin of a frog, and visually helps to protect the frog - using camouflage. The integumentary system also helps the skin to stay moist when the frog is on land and helps the frog to breathe while underwater.
I believe that the frog heart has one large chamber. When the "dirty" blood returns to the heart from nourishing the body, it mixes with the newly oxygenated blood from when the frog breathed. This type of heart is not as efficient as other animals with chambers to keep the two kinds of blood "dirty" and oxygenated separated. The frog still gets rid of waste gas and pumps fresh gas to its body but some of the waste blood gets pushed around the body too. The frog blood contains a lower concentration of pure gas blood than other animals.
blood vessel bloodstream heart liver lymph lymph gland lymph node vein vena venation venous blood system venous blood vessel