Functioning as a Breathing Apparatus
Besides functioning as a breathing apparatus when flying, pneumatic sac also helps enlarge the siring chamber so that it can amplify the sound, prevent loss of body heat that is too high, enveloping internal devices to prevent coldness, and changing body density in swimmers.
Changes in density by increasing or decreasing air pockets. Bird breathing is done in two kinds, namely on flying and not flying. When not flying, breathing occurs due to the movement of the sternum so that the ribs move forward and downward. As a result, the chest cavity enlarges and the lungs expand.
The expansion of the lungs causes air to enter (inspiration). In contrast to the shrinking of the chest cavity, the lungs will deflate so that the air from the air sacs returns to the lungs. So, fresh air flows through the parabronkus at the time of inspiration and expiration so that the lung function of birds is more efficient than the lungs of mammals.
When flying, active movement of the chest cavity cannot take place because the sternum and ribcage are a strong attachment base for the flight muscles. As a result, inspiration and expiration are carried out by the air sacs under the armpit, the way is by moving the wings up and down. This motion can compress and loosen the air sac so that there is an exchange of air in the lungs.
The higher the flight, the bird must move its wings faster to get more oxygen. The frequency of breathing birds is approximately 25 times per minute, whereas in humans it is only 15-20 times per minute.
To learn about blood circulation in aves, we take the example of bird blood circulation. The blood circulation of birds is composed by the heart as the center of blood circulation, and blood vessels. Blood in birds is composed of oval and nucleated erythrocytes.
The heart of the bird is cone-shaped and encased in the pericardial membrane. The heart consists of two thin-walled porches and two billicles with thicker walls.
Blood vessels are divided into arteries and veins. There are three arteries that come out of the left ventricle, namely two anonymous arteries which branch off into arteries that give blood to the head, flight muscles, and front members; and an aorta which is a remnant of the aortic arch to the right (the aortic arch to the left reduces).
These arteries then circle the right bronchus and turn towards the tail into the dorsal aorta (back artery). There are only one artery coming out of the right ventricle, the pulmonary artery (pulmonary artery), which then branches into the left and right lungs.
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Veins or veins are distinguished on:
Upper body back vessels (superior vena cava); This vein carries blood from the head, front members, and members of the pectoralis muscles to the heart.
Lower body veins (inferior vena cava); carry blood from the lower part of the body to the heart.
The return vessels come from the right lung and the left lung and carry blood to the left atrium of the heart.
Eggs can hatch when incubated by the mother. The mother's body temperature will help the growth of the embryo into a baby bird. Chicks hatch by breaking egg shells using their beaks. The newly hatched chicks are still blindfolded and cannot feed themselves, and need to be raised in nests.
Function of egg parts aves:
Embryonic point -> the part that will develop into an embryo
Egg yolk -> embryo food reserves
Kalaza -> keep the embryo shaking
Egg white -> keep the embryo from shaking
Air cavity -> oxygen reserves for the embryo
Amnion -> Amnion is a kind of membrane that protects an embryo in an egg. Those who have amniotic eggs are reptiles, poultry, and mammals so these three classes are called "amniota". Egg amnion is not found in fish and amphibia, so these two classes are called "anamniota".