MEDICAL ACADEMY NAMED AFTER S.I. GEORGIEVSKY DEPT. OF BIOLOGY TOPIC - THEORY OF

THEORY OF PHYLOEMBRYOGENESIS – ARKHALLAKSIS PHYLOGENESIS OF VASCULAR SYSTEM OF CHORDATES.DEVELOPMENTAL

DISORDERS OF VASCULAR SYSTEM OF HUMANS. SCIENTIFIC RESEARCH ADVISOR – SVETLANA SMIRNOVA MADE BY – VIDUSHI VERMA & DHRUV VASHISTH

THEORY OF PHYLOEMBRYOGENESIS

1) Arkhallaksis
2)Phylogenesis of phylum chordata vascular system
3)Development of disorders of the vascular system in humans

embryological parallelism—often expressed using Ernst Haeckel's phrase :
“Ontogeny recapitulates phylogeny”
BIOGENETIC

LAW (grech, bios life of genetikos belonging to the birth, an origin) — a complex of the theoretical generalizations describing communication between individual and historical development of live organisms.
 It was formulated in 1866 it. zoologist E. Gekkel (E.N. Haeckel):
«A number of forms through which there passes the individual organism at the development, beginning from an ovum and finishing quite developed state, is the short, compressed repetition of the long line of forms passed by animal ancestors of the same organism or patrimonial forms of its look since the most ancient times of so-called organic creation, up to the present», i.e. «ontogenesis is bystry and short repetition of phylogenesis»

Theory of phyloembryogenesis

beginning + Greek allaxis, from allasso – to change, change)

– phylogenesis type, is characterized by the fact that change of an initial laying of body is observed at early stages of an embryogenesis and changes the further course of ontogenesis.
 a mode of progressive evolution — arkhallaksis, or change of primary rudiments of bodies:
Arkhallaksis is characterized by transformation of the earliest stages of ontogenesis, since its bookmark (a1, a2, a3) that can lead to emergence of the new, being absent at ancestors bodies (E1, E2, E3) — primary arkhallaksis, or to radical reorganization of ontogenesis of body without essential changes of its definitivny structure — secondary arkhallaksis. At this way of evolution reconciliation is absent.

Arkhallaksis

bodies. Distinguish two types of a reduction: rudimentation (underdevelopment) and

afaniziya (complete disappearance). At a rudimentation the body which is normally developed and functioning at ancestors loses the functional value at descendants. In this case, according to A. N. Severtsov, the reduction is carried out by a negative arkhallaksis: a bookmark at descendants is less and more weakly, than at ancestors, develops more slowly and does not reach an ancestral definitivny stage. As a result the body of descendants is underdeveloped. At an afaniziya the reduced body not only loses the functional value, but also becomes harmful to an organism. Ontogenesis of such body, as a rule, begins and a nek-swarm time proceeds the same as at ancestors, but then there is a negative anaboly — the body resolves, and process goes as it should be, the return to development, up to disappearance of the bookmark.

this classification dates back to ca 500 BC. During the ancient Hindi

era, Charaka distinguished between the Jarayuja (invertebrates) and Anadaja (vertebrates). In the ancient Greek era, Aristotle (ca 300 BC) recognized animals with blood (Enaima, or vertebrates) and those without (Anaima, or invertebrates). This recognition persisted even until Linnaeus . It was Lamarck who first explicitly proposed the vertebra-based division of animals, ‘Animaux vertèbrès’ and ‘Animaux invertèbrès’, in place of Enaima and Anaima, respectively.

Aristotle had already recognized solitary ascidians as Tethyon around 330 BC. Carolus Linnaeus was a botanist who devised a system for naming plants and animals. In his book Systema naturae (12th edn, vol. 1) , ascidians were included among the molluscs. Following anatomical investigations of ascidians by Cuvier and others, Lamarck recognized these as Tunicata, namely animals enclosed with a tunic (tunica, in Latin, meaning garment). On the other hand, cephalochordates (lancelets) were first described in mid-to-late eighteenth century as molluscs. Although Yarrell had already noticed that lancelets have an axial rod, calling it ‘a lengthened internal vertebral column, although in a soft cartilaginous state’, it was Alexander Kowlevsky's discovery that both tunicates and lancelets possess notochords and dorsal neural tubes during embryogenesis, indicating that they are close relatives of vertebrates.

The term ‘Vertebrata’ was first coined by Ernst Haeckel in 1866 , in which lancelets were of the class Acrania of subphylum Leptocardia and all remaining vertebrates were classified into the subphylum Pachycardia (i.e. Craniota). At that time, the Tunicata was still included, together with bryozoans, in the subphylum Himatega of the phylum Mollusca. Following Kowalevsky's discovery of the notochord in ascidian larvae , Haeckel moved the Tunicata from the phylum Mollusca to the phylum Vermes, which also contained enteropneusts (acorn worms), because he thought that tunicates were close relatives to vertebrates. He coined the name Chordonia for a hypothetical common ancestor of the Tunicata and the Vertebrata (including lancelets) by emphasizing the notochord as a significant diagnostic character shared by them. Later, Haeckel redefined Chordonia (i.e. Chordata) to include the Tunicata and the Vertebrata themselves.

The phylum chordata and subphylum vertebrata: their history

tissue spaces or blood channels in the tissues. They have

a heart but it is a simple tube with walls that contract to force the blood through it. Most tunicates have channels for blood flow through the gills that have a very simple structure. Lancelets have a closed circulatory system that resembles one of a primitive fish. There is no heart, blood cells, or hemoglobin.

Tunicates

vessels) but lack a central pump (heart). Instead, the blood

is propelled by pulsation (rhythmic contraction and relaxation) of several blood vessels. The blood contains no pigments or cells and is thought to function largely in nutrient distribution rather than in gas exchange and transport.

Cephalochordates

in two circuits: one through the lungs and back to

the heart (pulmonary circulation) and the other throughout the rest of the body and its organs, including the brain (systemic circulation).
Amphibians have a three-chambered heart that has two atria and one ventricle rather than the two-chambered heart of fish (figure b). The two atria receive blood from the two different circuits (the lungs and the systems). There is some mixing of the blood in the heart’s ventricle, which reduces the efficiency of oxygenation. The advantage to this arrangement is that high pressure in the vessels pushes blood to the lungs and body. The mixing is mitigated by a ridge within the ventricle that diverts oxygen-rich blood through the systemic circulatory system and deoxygenated blood to the pulmocutaneous circuit where gas exchange occurs in the lungs and through the skin. For this reason, amphibians are often described as having double circulation.

Amphibian

amphibian heart that directs blood to the pulmonary and systemic

circuits (figure c). The ventricle is divided more effectively by a partial septum, which results in less mixing of oxygenated and deoxygenated blood. Some reptiles (alligators and crocodiles) are the most primitive animals to exhibit a four-chambered heart. Crocodilians have a unique circulatory mechanism where the heart shunts blood from the lungs toward the stomach and other organs during long periods of submergence; for instance, while the animal waits for prey or stays underwater waiting for prey to rot. One adaptation includes two main arteries that leave the same part of the heart: one takes blood to the lungs and the other provides an alternate route to the stomach and other parts of the body. Two other adaptations include a hole in the heart between the two ventricles, called the foramen of Panizza, which allows blood to move from one side of the heart to the other, and specialized connective tissue that slows the blood flow to the lungs. Together, these adaptations have made crocodiles and alligators one of the most successfully-evolved animal groups on earth.

REPTILES

ventricles), with complete separation of oxygenated and de-oxygenated blood.
Birds tend

to have larger hearts than mammals (relative to body size and mass). The relatively large hearts of birds may be necessary to meet the high metabolic demands of flight.

MAMMALS & BIRDS

the Aorta (CoA)
Complete Atrioventricular Canal defect (CAVC

Congenital Defects

is a hole in the wall (septum) that divides the

upper chambers (atria) of the heart. A hole can vary in size and may close on its own or may require surgery. An atrial septal defect is one type of congenital heart defect

Atrial Septal Defect (ASD)