Vertebrate skeleton formed not only by bones: it includes cartilage and connective tissue, and sometimes it includes various skin formations.

In vertebrates it is customary to distinguish axial skeleton(skull, chord, spine, ribs) and limb skeleton, including their belts (shoulder and pelvic) and free departments. Snakes, legless lizards and caecilians lack the skeleton of limbs, although some species of the first two groups retain their rudiments. In eels, the pelvic fins corresponding to the hind limbs have disappeared. Whales and sirens have no external signs hind legs there are also none left.

Scull. Based on their origin, there are three categories of skull bones:

• replacing cartilage,
• integumentary (overlay, or skin)
• visceral.

In sharks and their relatives, it may once have contained bones, but now its box is a single monolith of cartilage with no seams between the elements. Bony fish have more different types of bones in their skulls than any other class of vertebrates. In them, like all higher groups, the central bones of the head are embedded in cartilage and replace it, and therefore are homologous to the cartilaginous skull of sharks.

Visceral elements of the skull- derivatives of cartilaginous gill arches that arose in the walls of the pharynx during the development of gills in vertebrates. In fish, the first two arches have changed and turned into maxillary and sublingual apparatus. In typical cases, they retain 5 more gill arches, but in some genera their number has decreased. The primitive modern sevengill shark (Heptanchus) has as many as seven gill arches behind the jaw and hyoid arches. In bony fishes, the jaw cartilages are lined with numerous integumentary bones; the latter also form gill covers that protect the delicate gill filaments. During the evolution of vertebrates, the original jaw cartilages were steadily reduced until they disappeared completely. If in crocodiles the remainder of the original cartilage in the lower jaw is lined with 5 paired integumentary bones, then in mammals only one of them remains - the tooth, which completely forms the skeleton of the lower jaw.

The skull of ancient amphibians contained heavy integumentary plates and was similar in this respect to the typical skull of lobe-finned fish. In modern amphibians, both applique and replacement bones are greatly reduced. There are fewer of them in the skull of frogs and salamanders than in other vertebrates with bony skeleton, and in last group many elements remain cartilaginous. In turtles and crocodiles, the skull bones are numerous and tightly fused to each other. In lizards and snakes they are relatively small, with the external elements separated by wide intervals, as in frogs or toads. In birds, the skull bones are thin but very hard; in adults they have fused so completely that several sutures have disappeared. The orbital sockets are very large; the roof of the relatively huge braincase is formed by thin integumentary bones; the light jaws are covered with horny sheaths. In mammals, the skull is heavy and includes powerful jaws with teeth. The remains of the cartilaginous jaws moved to the middle ear and formed its bones - the hammer and the incus.

In birds and reptiles, the skull is attached to the spine using one of its condyle(articular tubercle). In modern amphibians and all mammals, two condyles located on the sides of the spinal cord.

Spine, in embryonic development it is always preceded by chord, which persists for life in lancelets and cyclostomes. In fish, it is surrounded by vertebrae (in sharks and their closest relatives - cartilaginous) and looks clear-shaped. In mammals, only rudiments of the notochord are preserved intervertebral discs. The notochord is not transformed into vertebrae, but is replaced by them. They arise during embryonic development as curved plates that gradually surround the notochord in rings and, as they grow, almost completely displace it.

A typical spine has 5 sections:

• cervical,
• thoracic (corresponding to the chest),
• lumbar,
• sacral
• tail.

Number cervical vertebrae varies greatly depending on the group of animals. Modern amphibians have only one such vertebra. Small birds can have as few as 5 vertebrae, while swans can have up to 25. The Mesozoic marine reptile plesiosaur had 72 cervical vertebrae. In mammals there are almost always 7 of them; the exception is sloths (from 6 to 9). The first cervical vertebra is called atlas. Mammals and amphibians have two articular surfaces, which include the occipital condyles. In mammals the second cervical vertebra ( epistrophy) forms the axis on which the atlas and skull rotate.

TO infant Ribs are usually attached to the vertebrae. Birds have about five, mammals have 12 or 13; snakes have a lot. The bodies of these vertebrae are usually small, and the spinous processes of their superior arches are long and inclined backwards.Lumbar vertebrae usually from 5 to 8; in most reptiles and all birds and mammals they do not bear ribs. The spinous and transverse processes of the lumbar vertebrae are very powerful and, as a rule, directed forward. In snakes and many fish, the ribs are attached to all the trunk vertebrae, and the border between the thoracic and lumbar regions difficult to carry out. In birds, the lumbar vertebrae are fused with the sacral vertebrae, forming a complex sacrum, which makes their backs more rigid than those of other vertebrates, with the exception of turtles, in which the thoracic, lumbar and sacral regions are connected to the shell.

Number sacral vertebrae varies from one in amphibians to 13 in birds.Structure tail The department is also very diverse; in frogs, birds, apes and humans it contains only a few partially or completely fused vertebrae, and in some sharks it contains up to two hundred. Toward the end of the tail, the vertebrae lose their arches and are represented by only bodies.

Ribs first appear in sharks in the form of small cartilaginous processes in the connective tissue between muscle segments. In bony fishes they are bony and homologous to the haemal arches located below on the caudal vertebrae. In four-legged animals, such fish-type ribs, called lower, are replaced by upper ones and are used for breathing. They are laid in the same connective tissue partitions between muscle blocks as in fish, but are located higher in the body wall.

Skeleton limbs. The limbs of tetrapods developed from the paired fins of lobe-finned fish, the skeleton of which contained elements homologous to the bones of the shoulder and pelvic girdle, as well as the front and hind legs.Originally in shoulder girdle there were at least five separate ossifications, but in modern animals there are usually only three: scapula, clavicle and coracoid. In almost all mammals, the coracoid is reduced, attached to the scapula, or absent altogether. In some animals the scapula remains the only one functional element shoulder girdle.

Pelvic girdle includes three bones:

• ileum,
• ischial
• pubic

In birds and mammals they completely merged with each other, in the latter case forming the so-called innominate bone. In fish, snakes, whales and sirens, the pelvic girdle is not attached to the spine, which therefore lacks the typical sacral vertebrae. In some animals, both the shoulder and pelvic girdles include accessory bones.

Bones anterior free limb and in quadrupeds they are basically the same as in the back, but are called differently. In the forelimb, if you count from the body, first comes humeral bone behind it radial And ulna bones, then carpals, metacarpals And phalanges of fingers.

IN hind limb they correspond femoral, then tibia and tibia, tarsal, metatarsals and phalanges of fingers. The initial number of fingers is 5 on each limb. Amphibians have only 4 toes on their front paws. In birds, the forelimbs are transformed into wings; the bones of the wrist, metacarpus and fingers are reduced in number and partially fused to each other, the fifth finger on the legs is lost. The horses only have middle finger. Cows and their closest relatives rest on the third and fourth toes, and the rest are lost or reduced. Ungulates move on their toes and are called phalanges. Cats and many other animals, when walking, rely on the entire surface of their fingers and belong to finger-walker type. When moving, bears and humans press their entire sole to the ground and are called plantigrade.

Exoskeleton. Vertebrates of all classes have an exoskeleton in one way or another. The head plates of scutes (extinct jawless animals), ancient fish and amphibians, as well as the scales, feathers and hair of higher tetrapods, are skin formations. The shell of turtles is of the same origin - a highly specialized skeletal formation. Their skin bone plates(osteoderms) approached the vertebrae and ribs and merged with them. It is noteworthy that the shoulder and pelvic girdles parallel to this have shifted inward chest. In the crest on the back of crocodiles and the shell of armadillos there are bone plates of the same origin as the shell of turtles

In case of veterinary-sanitary or forensic examinations the doctor has to determine the type of animal by the carcass, corpse, their parts or individual bones. Often the decisive factor is the presence or absence of some detail or shape feature. Knowledge of comparative anatomical features The structure of the bones allows us to confidently draw a conclusion about the type of animal.

CERVICAL VERTEBRA - vertebrae cervicales.

Atlas - atlas - first cervical vertebra (Fig. 22).

At the large cattle the transverse processes (wings of the atlas) are flat, massive, set horizontally, their caudolateral acute angle pulled back, dorsal arch wide. The wing has an intervertebral and alar foramen, but no transverse one.

The ovine caudal margin of the dorsal arch has a deeper, gentle notch, and there are also only two openings on the wing.

Rice. 22. Atlas cows (I), sheep Ш), goats (III), horses (IV), pigs (V), dogs (VI)

In goats, the lateral edges of the wings are slightly rounded, and the caudal notch of the dorsal arch is deeper and narrower than in sheep and cattle, and there is no transverse foramen.

In horses, on significantly developed, thinner, inclined wings, in addition to the alar and intervertebral foramina, there is a transverse foramen. The caudal edge of the dorsal arch has a deep, gently sloping notch.

In pigs, all cervical vertebrae are very short. Atlas has massive narrow wings with thickened rounded edges. The wing has all three openings, but the transverse one can be seen only along the caudal edge of the atlas wings, where it forms a small canal.

In dogs, the atlas has widely spaced lamellar wings with a deep triangular notch along its caudal margin. There are both intervertebral and transverse foramina, but instead of the alar foramen there is an alar notch - incisure alaris.

Axis, or epistropheus, - axis s. epistropheus - second cervical vertebra (Fig. 23).

Rice. 23. Axis (epistrophe) of a cow (1), sheep (II), goat (III), horse (IV), pig (V), dog (VI)

Rice. 24. Cervical vertebrae (middle) cow* (O, horses (II), pigs (III), dogs (IV)

In cattle, the axial vertebra (epistropheus) is massive. The odontoid process is lamellar, semi-cylindrical in shape. The crest of the axial vertebra is thickened along the dorsal edge, and the caudal articular processes at its base project independently.

In horses, the axial vertebra is long, the odontoid process is wide, flattened, the crest of the axial vertebra bifurcates in the caudal part, and on the ventral side of this bifurcation lie the articular surfaces of the caudal articular processes.

In pigs, the epistrophy is short, the odontoid process in the form of a wedge has a conical shape, and the ridge is high (increases in the caudal part).

In dogs, the axial vertebra is long, with a long wedge-shaped odontoid process; the crest is large, lamellar, protrudes forward and hangs over the odontoid process.

Typical cervical vertebrae - vertebrae cervicales - third, fourth and fifth (Fig. 24).

In cattle, the typical cervical vertebrae are shorter than in the horse, the fossa and head are well defined. In the bifurcated transverse process, its cranioventral part (costal process) is large, lamellar, extended downward, the caudodorsal branch is directed laterally. The spinous processes are round, well defined and directed cephalad.

Horses have long vertebrae with a well-defined head, fossa and ventral ridge. The transverse process is bifurcated along the sagittal plane, both parts of the process are approximately equal in size. There are no spinous processes (in their place there are scallops).

Pig vertebrae are short, the head and fossa are flat. The costal processes are wide below, oval-rounded, drawn down, and the caudodorsal plate is directed laterally. There are spinous processes. An additional cranial intervertebral foramen is very typical for the cervical vertebrae of pigs.

Dogs have typical cervical vertebrae that are longer than pigs, but the head and fossa are also flat. The plates of the transverse costal process are almost identical and bifurcate along the same sagittal plane (as in the horse). Instead of spinous processes there are low ridges.

Sixth and seventh cervical vertebrae.

In cattle, on the sixth cervical vertebra, the powerful plate of the costal process extended ventrally has a square shape; on the body of the seventh there is a pair of caudal costal facets; the transverse process is not bifurcated. The lamellar spinous process is high. There is no transverse hole, like the horse and pig.

In horses, the sixth vertebra has three small plates on the transverse process, the seventh is massive, does not have a transverse foramen, is shaped like the first thoracic vertebra of a horse, but has only one pair of caudal costal facets and a low spinous process on the body.

Rice. 25. Thoracic vertebrae of a cow (I), horse (II), pig (III), dog (IV)

The sixth vertebra of the pig has a wide, powerful oval-shaped plate of the transverse process extended ventrally; on the seventh there are double intervertebral foramina and the spinous process is high, lamellar, and set vertically.

In dogs, the sixth vertebra has a wide plate of the costal process beveled from front to back and downwards; on the seventh, the spinous process is set perpendicularly, has an awl-shaped shape, caudal costal facets may be absent.

Thoracic vertebrae - vertebrae thoracicae (Fig. 25).

Cattle have 13 vertebrae. In the area of ​​the withers, the spinous processes are wide, lamellar, and caudally inclined. Instead of a caudal vertebral notch, there may be an intervertebral foramen. The diaphragmatic vertebra is the 13th with a vertical spinous process.

Horses have 18-19 vertebrae. In the area of ​​the withers, the 3rd, 4th and 5th spinous processes have club-shaped thickenings. The articular processes (except the 1st) have the appearance of small contiguous articular surfaces. Diaphragmatic vertebra - 15th (sometimes 14th or 16th).

Pigs have 14-15 vertebrae, maybe 16. The spinous processes are wide, lamellar, vertically set. At the base of the transverse processes there are lateral openings running from top to bottom (dorsoventrally). There are no ventral ridges. Diaphragmatic vertebra - 11th.

Dogs have 13 vertebrae, rarely 12. The spinous processes in the withers area at the base are curved and caudally directed. The first spinous process is the highest; on the latter, accessory and mastoid processes. Diaphragmatic vertebra - 11th.

Lumbar vertebrae - vertebrae lumbales (Fig. 26).

Cattle have 6 vertebrae. They have a long body, slightly narrowed in the middle part. ventral ridge. The transverse costal (transverse) processes are dorsally (horizontally) located, long, lamellar, with pointed, uneven edges and ends curved cranially. The articular processes are powerful, widely spaced, with strongly concave or convex articular surfaces.

Horses have 6 vertebrae. Their bodies are shorter than those of cattle, the transverse costal processes are thickened, especially the last two or three, on which flat articular surfaces are located along the cranial and caudal edges (in old horses they often synostose). The caudal surface of the transverse costal process of the sixth vertebra is connected by a joint to the cranial edge of the wing of the sacral bone. Normally, there is never synostosis here. The articular processes are triangular in shape, less powerful, closer together, with flatter articular surfaces.

Rice. 26. Lumbar vertebrae of a cow (I), horse (I), pig (III), dog (IV)

Pigs have 7, sometimes 6-8 vertebrae. The bodies are long. The transverse costal processes are horizontally located, lamellar, slightly curved, have lateral notches at the base of the caudal edge and lateral openings closer to the sacrum. The articular processes, like those of ruminants, are powerful, widely spaced, strongly concave or convex, but, unlike ruminants, they have mastoid processes, making them more massive.

Dogs have 7 vertebrae. The transverse costal processes are lamellar and directed cranioventrally. The articular processes have flat articular, slightly inclined surfaces. The accessory and mastoid (on the cranial) processes are strongly pronounced on the articular processes.

The sacral bone is os sacrum (Fig. 27).

In cattle, 5 vertebrae are fused. They have massive quadrangular wings located almost on a horizontal plane, with a slightly raised cranial edge. The spinous processes have fused to form a powerful dorsal ridge with a thickened edge. The ventral (or pelvic) sacral foramina are extensive. Complete synostosis of the vertebral bodies and arches normally occurs by 3-3.5 years.

In horses, 5 fused vertebrae have horizontally located triangular-shaped wings with two articular surfaces - auricular, dorsal for connection with the wing of the iliac bone of the pelvis and cranial for connection with the transverse costal process of the sixth lumbar vertebra. The spinous processes grow together only at the base.

In pigs, 4 vertebrae are fused. The wings are rounded, placed along the sagittal plane, the articular (ear-shaped) surface is on their lateral side. There are no spinous processes. Interarch openings are visible between the arches. Normally, synostosis occurs by 1.5-2 years.

In dogs, 3 vertebrae are fused. The wings are rounded, set, like those of a pig, in the sagittal plane with a laterally located articular surface. In the 2nd and 3rd vertebrae the spinous processes are fused. Synostosis is normal by 6-8 months.

Tail vertebrae - vertebrae caudales s. coccygeae (Fig. 28),

Cattle have 18-20 vertebrae. Long, on the dorsal side of the first vertebrae rudiments of arches are visible, and on the ventral side (on the first 9-10) there are paired hemal processes, which on the 3rd-5th vertebrae can form hemal arches. "The transverse processes are wide, lamellar, curved ventrally.

Fig 27. Sacral bone of a cow (1), sheep (I), goat (III), horse (IV), pig (V), dog (VI)

Horses have 18-20 vertebrae. They are short, massive, retain arches without spinous processes; only on the first three vertebrae the transverse processes are flat and wide, disappearing on the last vertebrae.

Pigs have 20-23 vertebrae. They are long, arched with spinous processes, inclined caudally, preserved on the first five to six vertebrae, which are flatter, then become cylindrical. The transverse processes are wide.

Rice. 28. Caudal vertebrae of a cow (I), horse (II), pig (III), dog (IV)

Dogs have 20-23 vertebrae. On the first five to six vertebrae, the arches, cranial and caudal articular processes are preserved. The transverse processes are large, long, extended caudoventrally.

Ribs - costae (Fig. 29, 30).

Cattle have 13 pairs of ribs. They have a long neck. The first ribs are the strongest and the shortest and straightest. The middle ones are lamellar, widening significantly downwards. They have a thinner caudal edge. The hind ones are more convex, curved, with the head and tubercle of the ribs closer together. The last rib is short, thins downward, and may be hanging. It can be felt in the upper third of the costal arch.

Synostosis of the head and tubercle of the rib with the body in young animals does not occur simultaneously and goes from front to back. The first to fuse with the body is the head and tubercle of the first rib. The articular surface of the tubercle is saddle-shaped. The sternal ends of the ribs (2nd to 10th) have articular surfaces for connection with the costal cartilages, which have articular surfaces at both ends. There are 8 pairs of sternal ribs.

Horses have 18-19 pairs of ribs. Most of them are of uniform size along the entire length, the first is significantly expanded ventrally, up to the tenth the curvature and length of the ribs increase, then begin to decrease. The first 6-7 ribs are the widest and most lamellar. Unlike ruminants, their caudal edges are thicker and their neck is shorter. The tenth rib is almost tetrahedral. There are 8 pairs of sternal ribs.

Pigs often have 14, maybe 12 or up to 17 pairs of ribs. They are narrow, from the first to the third or fourth the width increases slightly. They have articular surfaces for connection with the costal cartilages. In adults, the sternal ends are narrowed, in piglets they are slightly expanded. On the tubercles of the ribs there are small flat statutory facets; the bodies of the ribs have a faintly visible spiral turn. Sternal ribs 7 (6 or 8) pairs.

Dogs have 13 pairs of ribs. They are arched, especially in the middle part. Their length increases to the seventh rib, their width to the third or fourth, and their curvature to the eighth rib. On the tubercles the facet ribs are convex, there are 9 pairs of sternal ribs.

The breast bone is sternum (Fig. 31).

In cattle it is powerful and flat. The handle is rounded, raised, does not protrude beyond the first ribs, and is connected to the body by a joint. The body expands caudally. On the xiphoid process there is a significant plate of xiphoid cartilage. Along the edges there are 7 pairs of articular costal fossae.

In horses it is laterally compressed. It has a significant cartilaginous addition on the ventral edge, forming a ventral ridge, which protrudes on the handle, rounding, and is called a hawk. In adult animals, the manubrium and body are fused. Cartilage without xiphoid process. Along the dorsal edge of the sternum there are 8 pairs of articular costal fossae.

Rice. 29. Ribs of a cow (I), horse (II)

Rice. 30. Vertebral end of horse ribs

Rice. 31. Cow breast bone (I). sheep (II), goats (III), horses (IV), pigs (V), dogs (VI)

In pigs, like in cattle, it is flat, connected to the handle by a joint. The handle, unlike ruminants, in the form of a rounded wedge protrudes in front of the first pairs of ribs. The xiphoid cartilage is elongated. On the sides there are (7-8) pairs of articular costal fossae.

In dogs, it is in the form of a round, bead-shaped stick. The handle protrudes in front of the first ribs with a small tubercle. The xiphoid cartilage is rounded, on the sides there are 9 pairs of articular costal fossae.

Chest - thorax.

In cattle it is very voluminous, in the front part it is laterally compressed, and has a triangular exit. Behind the shoulder blades it expands strongly in the caudal direction.

In horses, it is cone-shaped, long, slightly compressed from the sides, especially in the area where the shoulder girdles are attached.

Pigs have a long, laterally compressed, height and width various breeds vary.

Dogs are cone-shaped with steep sides, the inlet is rounded, the intercostal spaces - spatia intercostalia - are large and wide.

Self-test questions

1. What is the importance of the movement apparatus in the life of the body?

2. What functions does the skeleton perform in the body in mammals and birds?

3. What stages of development in phylo- and ontogenesis do the internal and external skeletons of vertebrates go through?

4. What changes occur in the bones with increasing static load (with limited motor activity)?

5. How is bone built as an organ and what differences are there in its structure in young growing organisms?

6. What sections is the vertebral column divided into in terrestrial vertebrates and how many vertebrae are there in each section in mammals?

7. In which department? axial skeleton Is there a complete bone segment?

8. What are the main parts of a vertebra and what parts are located on each part?

9. In which departments spinal column Have the vertebrae been reduced?

10. By what signs will you distinguish the vertebrae of each part of the spinal column and by what signs will you determine species features vertebrae of each department?

11. What characteristic features structures have an atlas and an axial vertebra (epistropheus) in domestic animals? What is the difference between the atlas of pigs and the axial vertebra of ruminants?

12. By what feature can you distinguish the thoracic vertebra from the other vertebrae of the spinal column?

13. By what features can you distinguish the sacral bone of cattle, horses, pigs and dogs?

14. Name the main features of the structure of a typical cervical vertebra in ruminants, pigs/horses and dogs.

15. Which one is the best? characteristic feature have lumbar vertebrae? How do they differ between ruminants, pigs, horses and dogs?

In vertebrates, it is customary to distinguish the axial skeleton (skull, notochord, spine,
ribs) and the skeleton of the limbs, including their girdles (shoulder and pelvic) and
free departments. Lancelets have a notochord, but no vertebrae or
no limbs. Snakes, legless lizards, lack the skeleton of limbs, although
some species of the first two groups retain their rudiments. In acne
the pelvic fins corresponding to the hind limbs have disappeared. In whales and
the sirens also had no external signs of their hind legs.

A typical spine has 5 sections: cervical, thoracic (corresponding to the rib cage), lumbar, sacral and caudal.

The number of cervical vertebrae varies greatly depending on the group of animals. Modern amphibians have only one such vertebra. Small birds can have as few as 5 vertebrae, while swans can have up to 25. The Mesozoic marine reptile plesiosaur had 72 cervical vertebrae. In mammals there are almost always 7 of them; the exception is sloths (from 6 to 9). In cetaceans and manatees, the cervical vertebrae are partially fused and shortened in accordance with the shortening of the neck (according to some experts, manatees have only 6 of them). The first cervical vertebra is called the atlas. In mammals and amphibians it has two articular surfaces, which include the occipital condyles. In mammals, the second cervical vertebra (epistropheus) forms the axis on which the atlas and skull rotate.

Ribs are usually attached to the thoracic vertebrae. Birds have about five, mammals have 12 or 13; snakes have a lot. The bodies of these vertebrae are usually small, and the spinous processes of their superior arches are long and inclined backwards. There are usually from 5 to 8 lumbar vertebrae; in most reptiles and all birds and mammals they do not bear ribs. The spinous and transverse processes of the lumbar vertebrae are very powerful and, as a rule, directed forward. In snakes and many fish, the ribs are attached to all the trunk vertebrae, and it is difficult to draw the boundary between the thoracic and lumbar regions. In birds, the lumbar vertebrae are fused with the sacral vertebrae, forming a complex sacrum, which makes their backs more rigid than those of other vertebrates, with the exception of turtles, in which the thoracic, lumbar and sacral regions are connected to the shell.

The number of sacral vertebrae varies from one in amphibians to 13 in birds.

The structure of the caudal region is also very diverse; in frogs, birds, apes and humans it contains only a few partially or completely fused vertebrae, and in some sharks it contains up to two hundred. Toward the end of the tail, the vertebrae lose their arches and are represented by only bodies.

The limbs of tetrapods developed from the paired fins of lobe-finned fish, the skeleton of which contained elements homologous to the bones of the shoulder and pelvic girdle, as well as the front and hind legs.

Topic 1. Animal diversity

Practical work No. 5. Comparison of the structure of the skeletons of vertebrates

Target: examine the skeletons of vertebrate animals, find similarities and differences.

Work progress.

			Reptiles		Mammals
Head skeleton (skull)	The bones are immovably connected to each other. Movably connects lower jaw. There are gill arches	Skull cartilaginous	Skull bone	The bones of the skull are fused together. Has a large braincase, large eye sockets	Scull brain section, which consists of bones that grow together, facial section(jaw)
Skeleton of the trunk (spine)	Two sections: tulubovy, caudal. Tulubov's vertebrae bear ribs	Sections: cervical, thulubovial, sacral, caudal. Cervical vertebra one. No ribs	Sections (5): cervical, thoracic, lumbar, sacral, caudal. Cervical region provides head mobility. The ribs are well developed. There is a chest - thoracic vertebrae, ribs, breastbone	Sections (5): cervical, thoracic, lumbar, sacral, caudal. The cervical region has large number vertebrae (11-25). Thoracic, lumbar vertebrae, sacral regions connected motionlessly (solid base). The ribs are developed. There is a chest - thoracic vertebrae, ribs, the sternum has a keel	Sections (5): cervical, thoracic, lumbar, sacral, caudal. The cervical spine (7 vertebrae) ensures head mobility. The ribs are well developed. There is a chest - thoracic vertebrae, ribs, breast bone
Limb skeleton	Paired fins (pectoral, ventral) are represented by bony rays	Anterior - bones of the shoulder, forearm, hand. Hind - bones of the thigh, leg, foot. Limbs end with fingers (5)	Front - humerus, elbow and radius, brush. Rear - femur, lower leg, foot. Limbs end with fingers (5)	Limbs - wings. The anterior ones are the humerus, ulna and radius; the hand has three fingers. Hind - femur, tibia, foot. The bones of the foot fuse and form the forearm. Limbs end in fingers	Anterior - humerus, ulna and radius, hand bones. Hind - femur, tibia, tibia, foot bones. Limbs end with fingers (5)
Skeleton of limb belts	Muscles are attached to the bones	Girdle of the forelimbs - shoulder blades (2), crow bones (2), collarbones (2). Belt hind limbs- three pairs of fused pelvic bones	Belt of the forelimbs - shoulder blades (2), collarbones (2). Hind limb girdle - three pairs of fused pelvic bones	The girdle of the forelimbs - the shoulder blades (2), the collarbones (2) are fused together and form a fork Hind limb girdle - three pairs of fused pelvic bones
Method of transportation	Fishes swim. Movement is provided by fins: caudal - active forward movement, paired (abdominal, pectoral) - slow movement	Provides movement by jumping. Animals can swim thanks to membranes between the toes of their hind limbs	During movement, the body crawls along the substrate. Crocodiles and snakes can swim away	The main method of transportation is flight. The skeleton is characterized by lightness - the bones have cavities filled with air. The skeleton is strong - bone growth.	Different ways movement - running, jumping, flying ( terrestrial environment), dig holes in the soil (soil), swim and dive (aquatic environment)

Conclusions. 1. All vertebrates have internal skeleton, which has a general structural plan - the skeleton of the head (skull), the skeleton of the torso (spine), the skeleton of the limbs, the skeleton of the girdles of the limbs. 2. The skeleton performs protective function, serves as a site of attachment for muscles that provide animal movement. 3. The structural features of the skeletons of vertebrate animals provide certain ways for these animals to move in space.

Vertebrates are considered the highest subphylum of the Chordata phylum. While tunicates and tunicates are lower chordates. There are more than 40 thousand species of vertebrates. They are diverse in structure, size, life activity, and habitats. At the same time, they have a number of common features, especially during the period of embryonic development, which indicates the commonality of their evolutionary origin.

Almost all vertebrates have highly developed nervous system and lead active image life (looking for food and partners for reproduction, running away from danger).

The first discovered remains of vertebrates date back to the Silurian.

Vertebrates include: cyclostomes, cartilaginous and bony fish, amphibians, reptiles, birds and mammals (animals). Cyclostomes are jawless. The remaining classes of the subphylum belong to the section Gastrostomes.

Vertebrate musculoskeletal system

Aromorphoses: formation of the axial skeleton in the form of the spinal column; appearance of the skullForbrain protection; development of jaws for grasping prey and, in more highly organized animals, grinding food; the appearance of paired limbs,allowingquickly movingget onin space.

The skeleton of vertebrates is cartilaginous or bone (in most). Its main functions are to ensure the movement of the animal and protect it internal organs. In addition, the bones of the skeleton serve as a place for attachment of the muscles of the body, hematopoiesis occurs in individual bones, and a number of substances are stored.

The spine is formed on the basis of the notochord. In a number of vertebrate species (lamreys), the notochord is retained into adulthood, but cartilage develops around it to protect the spinal cord. In sturgeons, the upper and lower vertebral arches are formed around the notochord.

In most vertebrates, the spine consists of individual vertebrae that are relatively mobile relative to each other. Each vertebra has a body, an upper and a lower arch. The spinal cord passes through the superior arch canal. The vertebral arches serve as protection for the spinal cord. The ribs are attached to the vertebrae, protecting the organs of the thoracic cavity.

The vertebrate skeleton is divided into:

Axial skeleton- spine and cranium.

Visceral skeleton- gill arches and bones derived from gill arches (jaws and some others).

Skeleton of limbs and their girdles(except for lampreys and hagfish).

Limbs come in two main types - fin and five-fingered limb. In the fin, the cartilage or bones of the limb move relative to its girdle as a single lever. The five-fingered limb of terrestrial animals is a series of levers that move independently relative to each other and the limb girdle.

The muscles of the body are formed striated muscles. In higher vertebrates (reptiles, birds, mammals), the muscles are divided into separate bundles. In lower vertebrates, muscles are segmented.

There are smooth muscles of internal organs. It is called visceral.

Nervous system and sensory organs of vertebrates

Aromorphoses: formation of the brain, its division into five sections,performing different functions (front, intermediate, middle, medulla oblongata and cerebellum).

The neural tube in vertebrates differentiates into the spinal cord and brain, which together form the central nervous system. In addition to it, the peripheral, sympathetic, parasympathetic and autonomic nervous systems are distinguished.

A developed brain enables complex behavior, including collective behavior. Higher nervous activity is the basis of adaptive behavior.

The neurocoelus (the cavity inside the neural tube) in the brain becomes the ventricles of the brain. 10-12 pairs of nerves depart from the brain (olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, auditory, glossopharyngeal, vagus, accessory, sublingual). Nerves emerge from the spinal cord in pairs.

The sense organs provide communication between the body and external environment. In vertebrates they are diverse and have complex structure. Eyes with a lens, the shape of which can vary in terrestrial vertebrates. In fish, the lens can move to achieve image clarity.

The organs of hearing are connected with the organs of balance. U various groups vertebrates have different structure. The olfactory cavity opens outward through the nostrils. The skin has receptors for touch, temperature, pressure, etc.

Circulatory and cardiovascular system of vertebrates

Aromorphoses: appearance of the heart,providingfast blood flow;complete separation of arterial and venous blood flow in birds and mammals, resulting in the appearance of warm-bloodedness, which allowed animals to be less dependent on unfavorable conditions of the abiotic environment.

Vertebrates, like all chordates, are characterized by a closed circulatory system.

The number of heart chambers (from 2 to 4) depends on the level of organization of the class. Lower vertebrates have one circulation. In this case, it passes through the heart venous blood, which then goes to the gills, where it is saturated with oxygen, then arterial blood spreads throughout the body. The pulmonary (second) circulation first appears in amphibians (amphibians).

The blood of vertebrates consists of plasma, which contains red and white blood cells.

Vertebrate skin

Aromorphosis: appearance dvuhsloinOuchleatherAnd.

Superficial layer of skin - multilayered epidermis. It develops various glands(sweat, sebaceous, mucous, etc.) and a number of solid formations (claws, hair, feathers, scales). Inner layer of skin - dermis, which is a strong connective tissue. Here, such hard formations as bone scales and skin (false) bones are also formed.

Digestive system of vertebrates

IN digestive system Vertebrates are divided into five divisions: oral cavity, pharynx, esophagus, stomach, small intestine, large intestine. During the process of evolution, the intestines gradually lengthened.

Digestive glands: salivary glands, liver, pancreas.

Respiratory system of vertebrates

Gills in cyclostomes, fish and amphibian larvae. Lungs - in all other vertebrates. In lower vertebrates, cutaneous respiration plays an important role.

Gills are plate-like outgrowths of the walls of the gill slits. These plates contain a network of small blood vessels.

During embryonic development, the lungs are formed as a pair of outgrowths of the pharynx. Amphibians and reptiles have sac-like lungs. In birds they have a spongy structure. In mammals, the branches of the bronchi end in alveoli (small vesicles).

Excretory system of vertebrates

The excretory organs of vertebrates are a pair of kidneys. Kidneys have different structures different groups vertebrates. There are head, trunk, pelvic kidneys. During embryogenesis, a change occurs from the head to the trunk or the trunk to the pelvis.

Reproductive system and embryonic development of vertebrates

Almost all vertebrate species are dioecious. There are paired sex glands (testes or ovaries). With the exception of cyclostomes, the rest have special ducts that excrete reproductive products.

Gastrostomes are divided into two groups: anamnesis And amniotes. Anamnias include fish and amphibians, since their larval stage lives in water, and the development of the embryo takes place without the formation of special embryonic membranes. For anamnias, external fertilization is usually more common.

Amniotes include reptiles, birds and animals. Their embryo has germinal membranes (amnion and allantois). Internal fertilization is characteristic.