Foramen of Panizza
Encyclopedia
The Foramen of Panizza is a hole with that connects the left and right aorta
as they leave the heart
of all animals of the order Crocodilia
.
Crocodilians have a completely separated ventricle
with deoxygenated blood from the body, or systemic circulation
, in the right ventricle and oxygenated blood from the lungs, or pulmonary circulation
, in the left ventricle, as in bird
s and mammal
s. Two vessels, the left aorta and the pulmonary artery, exit the right ventricle. Blood
from the right ventricle goes to the lungs through the pulmonary artery, as in mammals and birds. However, when a unique active valve leading to the pulmonary artery contracts, pressure in the right ventricle can increase and blood can leave the right ventricle, enter the left aortic arch, and therefore bypass the pulmonary circulation. The foramen of panizza connects the left and right aorta. Deoxygenated blood from the right ventricle, sitting in the left aorta, can flow into the right aorta through the foramen of panizza. When the heart is relaxed, some oxygenated blood from the left ventricle, sitting in the right aorta, can flow into the left aorta across the foramen of panizza. However, some species of Crocodilians have regulatory sphincters that prevent unwanted flow of blood through the foramen of panizza during non-diving.
Aorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...
as they leave the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
of all animals of the order Crocodilia
Crocodilia
Crocodilia is an order of large reptiles that appeared about 84 million years ago in the late Cretaceous Period . They are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria...
.
Crocodilians have a completely separated ventricle
Ventricle
Ventricle may refer to:* Ventricle , the pumping chambers of the heart* Ventricular system in the brain* Ventricle of the larynx, a structure in the larynx* Stomach of the gastrointestinal tract...
with deoxygenated blood from the body, or systemic circulation
Systemic circulation
Systemic circulation is the part of the cardiovascular system which carries oxygenated blood away from the heart to the body, and returns deoxygenated blood back to the heart. This physiologic theory of circulation was first described by William Harvey...
, in the right ventricle and oxygenated blood from the lungs, or pulmonary circulation
Pulmonary circulation
Pulmonary circulation is the half portion of the cardiovascular system which carries Oxygen-depleted Blood away from the heart, to the Lungs, and returns oxygenated blood back to the heart. Encyclopedic description and discovery of the pulmonary circulation is widely attributed to Doctor Ibn...
, in the left ventricle, as in bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s and mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s. Two vessels, the left aorta and the pulmonary artery, exit the right ventricle. Blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
from the right ventricle goes to the lungs through the pulmonary artery, as in mammals and birds. However, when a unique active valve leading to the pulmonary artery contracts, pressure in the right ventricle can increase and blood can leave the right ventricle, enter the left aortic arch, and therefore bypass the pulmonary circulation. The foramen of panizza connects the left and right aorta. Deoxygenated blood from the right ventricle, sitting in the left aorta, can flow into the right aorta through the foramen of panizza. When the heart is relaxed, some oxygenated blood from the left ventricle, sitting in the right aorta, can flow into the left aorta across the foramen of panizza. However, some species of Crocodilians have regulatory sphincters that prevent unwanted flow of blood through the foramen of panizza during non-diving.