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Evolution of the musculoskeletal system of vertebrates. The musculoskeletal system of animals (the evolution of the structure). The evolution of the musculoskeletal system»

07.12.2020

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EVOLUTION OF THE MUSCLE-MOTOR SYSTEM FUNCTIONS OF ODS: Movement of the body, Support and protection of internal organs Assignment according to §37 1. Write down the organs of the ODS in invertebrate animals. 2. What animals have an external skeleton, what are its shortcomings? 3. What animals have an internal skeleton, what are its advantages? 4. What parts do the skeletons of Chordates consist of. Read the text "Did you know that..."

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EVOLUTION OF THE MUSCLE-MOTOR SYSTEM FUNCTIONS OF ODS: Movement of the body, support and protection of internal organs Evolution of the organs of support and movement of invertebrates Protozoa - cell membrane, flagella, cilia Intestinal - dermal-muscular cells Flatworms - KMM Roundworms - KMM Annelids - KMM Type Mollusks - muscular legs Type Arthropods - external skeleton - chitinous cover. The muscles are attached from the inside to the cover. The external skeleton has diversified movements in various habitats, but it is not extensible and limits the size of the body.

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CHORDIATE ANIMALS HAVE AN INTERNAL SKELETON THE SKELETON IS A COMPLETE OF BONES, CARTILAGES, LIGANS AND JOINTS. MUSCLES ARE ATTACHED TO THE SKELETON. lancelets - chord + musculature FISH - skull + spine of 2 sections + skeleton of fins + musculature Amphibians - skull + spine of 3 sections + skeleton of limbs + muscles of REPTILES, BIRDS, MAMMALS - skull + spine of 5 sections + chest + limb skeletons + muscles.

The phylogenesis of motor function underlies the progressive evolution of animals. Therefore, the level of their organization primarily depends on the nature of motor activity, which is determined by the peculiarities of the organization of the musculoskeletal system, which has undergone major evolutionary transformations in the Chordata type due to a change in habitats and changes in the forms of locomotion. Indeed, the aquatic environment in animals that do not have an external skeleton suggests uniform movements due to the bends of the whole body, while life on land is more conducive to their movement with the help of limbs.

Skeleton. Chordates have an internal skeleton. According to the structure and functions, it is divided into axial, skeleton of the limbs and head.

Axial skeleton. In the subtype Cranial there is only an axial skeleton in the form of a chord. It is built from highly vacuolated cells, tightly adjacent to each other and covered on the outside by common elastic and fibrous membranes. The elasticity of the chord is given by the turgor pressure of its cells and the strength of the membranes.

Throughout life in vertebrates, the notochord is preserved only in cyclostomes and some lower fish. In all other animals, it is reduced. In humans, in the postembryonic period, the rudiments of the notochord are preserved in the form of nuclei of the intervertebral discs. Preservation of an excess amount of chordal material in case of violation of its reduction is fraught with the possibility of developing tumors in humans - chordomas arising on its basis. In all vertebrates, the notochord is gradually replaced by vertebrae developing from somite sclerotomes and is functionally replaced by the vertebral column. The formation of vertebrae in phylogenesis begins with the development of their arches, covering the neural tube and becoming places of muscle attachment. Starting with cartilaginous fish, cartilage of the notochord membrane and growth of the bases of the vertebral arches are found, as a result of which the vertebral bodies are formed. The fusion of the upper vertebral arches above the neural tube forms the spinous processes and the spinal canal, which contains the neural tube. Replacement of the chord with the spinal column - a more powerful support organ with a segmental structure - allows you to increase the overall size of the body and activates the motor function. Further progressive changes in the spinal column are associated with the replacement of cartilaginous tissue with bone, which is found in bony fish, as well as with its differentiation into sections. Fish have only two sections of the spine: trunk and tail. This is due to their movement in the water due to the bends of the body. Amphibians also acquire the cervical and sacral regions, each represented by one vertebra. The first provides greater mobility of the head, and the second - support for the hind limbs. In reptiles, the cervical spine lengthens, the first two vertebrae of which are movably connected to the skull and provide greater head mobility. The lumbar region appears, still slightly delimited from the thoracic, and the sacrum already consists of two vertebrae. Mammals are characterized by a stable number of vertebrae in the cervical region, equal to 7. The lumbar and thoracic regions are clearly separated from each other. In fish, all trunk vertebrae bear ribs that do not fuse with each other and with the sternum. In reptiles, part of the ribs of the thoracic region fuses with the sternum, forming the chest, and in mammals, the chest contains 12-13 pairs of ribs.

The ontogenesis of the human axial skeleton recapitulates the main phylogenetic stages of its formation: in the period of neurulation, a notochord is formed, which is subsequently replaced by a cartilaginous and then a bone spine. A pair of ribs develops on the cervical, thoracic and lumbar vertebrae, after which the cervical and lumbar ribs are reduced, and the thoracic ribs fuse in front with each other and with the sternum, forming the chest. Violation of the ontogeny of the axial skeleton in humans can be expressed in such atavistic malformations as nonunion of the spinous processes of the vertebrae, resulting in the formation of a defect in the spinal canal. In this case, the meninges often protrude through the defect and a spinal hernia is formed. Violation of the reduction of the cervical and lumbar ribs underlies their preservation in postnatal ontogenesis.

Head skeleton. The continuation of the axial skeleton in front is the axial, or cerebral, skull, which serves to protect the brain and sensory organs. A visceral or facial skull develops next to it, which forms a support for the anterior part of the digestive tube. Both parts of the skull develop differently and from different rudiments. At the early stages of evolution and ontogenesis, they are not connected with each other, but later this connection arises. Phylogenetically, the brain skull went through three stages of development: membranous, cartilaginous and bone. In cyclostomes, it is almost all membranous and does not have an anterior, non-segmented part. The skull of cartilaginous fishes is almost completely cartilaginous, and includes both the rear, primarily segmented, part, and the front. In bony fish and other vertebrates, the axial skull becomes bone due to the processes of ossification of the cartilage in the region of its base and due to the appearance of integumentary bones in its upper part. Widely known in humans are such anomalies of the brain skull as the presence of interparietal, as well as two frontal bones with a metopic suture between them. They are not accompanied by any pathological phenomena and are therefore usually discovered by accident after death.

The visceral skull also appears for the first time in lower vertebrates. It is formed from mesenchyme of ectodermal origin, which is grouped in the form of thickenings, having the shape of arches, in the intervals between the gill slits of the pharynx. The first two arches are particularly strongly developed and give rise to the jaw and hyoid arches of adult animals. In cartilaginous fish, in front of the jaw arch, there are usually 1-2 more pairs of premaxillary arches, which are of a rudimentary nature. Amphibians in connection with the transition to terrestrial existence have undergone significant changes visceral skull. Gill arches are partially reduced, and partially, changing functions, are part of the cartilaginous apparatus of the larynx. The lower jaw of mammals is articulated with the temporal bone by a complex joint, which allows not only to capture food, but also to perform complex chewing movements.

limb skeleton. In chordates, unpaired and paired limbs stand out. Unpaired are the main organs of locomotion in non-cranial, fish, and to a lesser extent in caudal amphibians. Fish also have paired limbs - pectoral and ventral fins, on the basis of which paired limbs of terrestrial tetrapods subsequently develop.

In modern amphibians, the number of fingers in the limbs is five or their oligomerization to four occurs. Further progressive transformation of the limbs is expressed in an increase in the degree of mobility of bone joints, in a decrease in the number of bones in the wrist, first to three rows in amphibians and then to two in reptiles and mammals. In parallel, the number of phalanges of the fingers also decreases. Also characteristic is the lengthening of the proximal limbs and the shortening of the distal ones. In human ontogenesis, numerous disorders are possible, leading to the formation of congenital malformations of the atavistic limbs. So, polydactyly, or an increase in the number of fingers, inherited as an autosomal dominant trait, is the result of the development of bookmarks of additional fingers, which are normal for distant ancestral forms. The phenomenon of polyphalangy is known, characterized by an increase in the number of phalanges, usually thumb brushes. A serious malformation is a violation of the heterotopia of the belt of the upper extremities from the cervical region to the level of the 1st-2nd thoracic vertebrae. This anomaly is called Sprengel's disease or congenital high standing of the scapula. It is expressed in the fact that the shoulder girdle on one or both sides is several centimeters higher than the normal position.

Muscular system . In representatives of the Chordata type, the muscles are subdivided according to the nature of development and innervation into somatic and visceral. Somatic muscles develop from myotomes and are innervated by nerves, the fibers of which exit the spinal cord as part of the abdominal roots of the spinal nerves. The visceral musculature develops from other parts of the mesoderm and is innervated by the nerves of the autonomic nervous system. All somatic muscles are striated, and visceral muscles can be either striated or smooth

Selection by database: 5fan_ru_Electrical injury. Drowning. Heat and sunstroke. Eno, 16. What causes the action of one body on another.docx, 1. Introduction. Nature. Man is part of nature. bodies and substances. Thu , Foreign bodies of the larynx, nose and ear.pptx , Seminar evolution.docx , Amorphous bodies.docx , 5. evolution and systematics of agnathans.docx , Rationale for the method of basal body temperature.docx , 13. Emergency care for aspiration of a foreign body in p , 2. test on the origin and evolution of the biosphere.docx .
The evolution of the integument of the body.

In invertebrates, integuments develop from the ectoderm. The evolution of the integument followed the path of transformation of the ciliated epithelium (ciliary worms) into a flat epithelium, devoid of cilia, with the formation of a cuticular layer outside. Already in invertebrate animals, the cover performs not only the function of protection, but also many others (perception of mechanical and chemical irritations, touch, defeat of the victim, scaring off enemies).

In chordates, the cover is not a homogeneous structural formation, but consists of two parts - the epidermis and the dermis, which are closely related to each other, but differ in origin: the epidermis develops from the ectoderm, the dermis from the mesoderm. The evolution of the integument followed the path of replacing a single-layer cylindrical epithelium and a poorly developed dermis (lancelet) with a stratified squamous keratinized epithelium and a well-developed dermis (vertebrates).

Further evolution of the integument in a series of vertebrates led to the division of the epidermis into the upper protective stratum corneum and the lower growth layer. The cells of the stratum corneum, as they approach the surface, flatten, fill with fibrillar protein-keratin, die and desquamate, which is important in conditions of constant terrestrial existence.

In all higher vertebrates, due to the modified stratum corneum of the epidermis, specialized structures are formed: scales, claws, horns, feathers, nails, hair. It should be noted that in the ancestors of mammals, the body was covered with scales, which is preserved on the limbs and tail of a number of modern mammals (rodents, insectivores, marsupials). In many amniotes, in which teeth are reduced, the skin along the edges of the jaws becomes keratinized, forming a beak. The nails and hooves that arose in mammals are a modification of the claws.

The appearance of hair in mammals provided thermal insulation, species-specific coloration of the skin (together with pigment cells of the epidermis and dermis), improved touch, aero- and hydrodynamic properties of the body.

Functions of the integument of the body.

1.Protection against mechanical, physical and chemical influences.

2. Barrier - a barrier to the penetration of bacteria and other microorganisms.

3. Thermal insulation (skin, hair, feathers).

4. Participation in heat exchange between the body and the environment.

5. Participation in the regulation of the body's water balance.

6. Participation in the excretion of end products of metabolism (gland).

7. Participation in respiration (O2 absorption and CO2 release).

8. Metabolic function (storage of energy material, formation of vitamin D, milk).

9. An important role in intraspecific relationships: skin and hair pigments provide species-specific skin coloration; the totality of the secrets of the odorous, sebaceous, sweat glands makes it possible to distinguish individuals of one's own and other species, and facilitates the meeting of a male and a female.

10. Passive protection - adaptive coloration (protective, warning, dismembering, mimicry) ensures the adaptation of the organism to the environment.

Evolutionary transformations of integument in chordates.

Expansion of the number of functions performed - in addition to protection, integuments take part in gas exchange, thermoregulation, in the removal of end products of metabolism;

Change of function - placoid scales on the jaws turned into teeth;

The intensification of the body's defense function led to the differentiation of the integument: the development of the dermis due to the growth of connective tissue, the division of the epidermis into two layers (horny and growth); the formation of specialized derivatives of the skin, multicellular glands of several types;

The appearance of new structural elements of the skin - hairline;

The appearance of specialized derivatives of sweat glands - the mammary glands.

Onto-phylogenetically determined malformations of integument in humans.

1. Lack of sweat glands (anhidrosis dysplasia).

2. Excessive hairiness of the skin (hypertrichosis).

3. Polymammary (polythelia).

4. Increased number of mammary glands (polymast).
The evolution of the musculoskeletal system.

One of the main properties of animal organisms - movement (locomotion) - is carried out due to the musculoskeletal system. The supporting formations of invertebrates are varied and can be of ecto-, entho-, and mesodermal origin. So, in intestinal cavities, the supporting function is performed by the mesoglea, locomotion by the epithelial-muscular cells of the ecto- and endoderm; the skeleton of coral polyps develops from the ectoderm. Most invertebrates have an external skeleton. In chordates, the skeleton is internal (ento- and mesodermal origin). We are the basis of their body

neck-chordal complex (myochord), consisting of a chord (axial elastic cord) and metameric muscles adjacent to it. The notochord is laid in the embryonic period of all chordates and performs a morphogenetic role - under the influence of the chordo-mesodermal rudiment, the neural tube, spine develop, and the somites differentiate.

In the process of progressive evolution of chordates, the following occurred: the replacement of the notochord by the vertebral column, consisting of vertebrae; the acquisition by the vertebrae of procoelity (anterior concavity) and plasticity (anterior and posterior surfaces of the vertebrae are flat); skull formation; loss of the metameric structure of the muscles and the appearance of specialized muscle groups; change in the location of the limbs and the type of their attachment. Adaptations to different habitat conditions led to the formation of diverse types of movement, which expanded the possibilities of obtaining food, escaping from enemies, searching for optimal habitats, and settling by chordates in almost all biotopes of land, water, and the lower layers of the atmosphere.

Functions of the musculoskeletal system.

1. Preservation of a certain body shape.

2. Protection of organs from influences.

3. Support for the entire body weight, lifting it above the ground.

Division of the common atrium and common ventricle into right and left sections

Displacement of the heart from the cervical region to the chest to establish optimal relationships with the lungs (heterotopia)

Reduction of the cardinal veins and Cuvier ducts, their transformation into hollow, jugular veins and coronary sinus.
The evolution of the excretory system.

The excretory system arose in animals in connection with the need to maintain the constancy of the internal environment by removing dissimilation products from the body. In unicellular animals and sponges, the function of excretion and osmoregulation is performed by contractile vax "olis. In the intestinal cavity, special excretion organs have not been identified. In more highly organized invertebrate animals, due to the complication internal structure and the formation of dense outer covers, complex and diverse excretory organs are formed. Despite the differences in their structure, the principle of the release of dissimilation products in all invertebrates is similar and is carried out due to two main processes: ultrafiltration and active transport of substances. During ultrafiltration of the liquid, proteins and other large molecules do not pass through the semipermeable membrane of the excretory organs. Active transport occurs in two opposite directions: with the help of active secretion, substances are transferred from the internal environment of the animal to the lumen of the excretory organ, and with active reabsorption, their transport occurs in the opposite direction.

The kidneys of all classes of vertebrates also work on the principle of filtration - reabsorption and secretion. At the same time, 99% of the filtrate is reabsorbed and less than one percent is excreted in the form of urine. In an evolutionary sense, this method of isolating dissimilation products turned out to be the most beneficial, since as a result of ultrafiltration, any foreign and most of the toxic substances remain in the urine and are excreted from the body. The latter enables animals to expand and change their habitat and food sources without creating a special mechanism for the elimination of each new, possibly toxic substance that has entered the body with food.

functions of the excretory system.

1 - excretory - removal of dissimilation products and toxic substances;

2 - maintenance of water-salt homeostasis;

3- maintaining acid-base balance, glucose levels, ionic composition;

4- excretion of reproductive products (gametes);

5- participation in the regulation of blood pressure.

Evolutionary transformations in the excretory system of vertebrates.

1. Substitution - replacement of the pronephros by the primary, and in higher vertebrates by the secondary kidney;

2. Polymerization of homogeneous structures - an increase in the number of nephrons from 6 - 12 in the pronephros, up to several hundred in the primary and up to one million or more in the secondary kidney;

3. Strengthening the main function of the kidneys is manifested in a significant increase in the level of glomerular filtration and tubular reabsorption. This is achieved by a number of transformations:

a) an increase in the number of nephrons;

b) the formation of the renal corpuscle and the reduction of the funnel, which leads to the establishment of direct contact of the excretory tubules with the circulatory system and to the loss of communication with the whole;

c) an increase in the size of the renal corpuscles and an increase in renal blood flow;

d) elongation and differentiation of convoluted tubules, obrazo-; loop of the nephron.

4. Separation of functions.

Formation of the oviduct from the paramesonephric canal and the vas deferens from the mesonephric cord.
Onto-phylogenetically determined malformations of the excretory and reproductive systems in humans.

1. Gartner's canal - the preservation of the mesonephric canal in women - the source of cysts and malignant changes. In 30% of girls, it obliterates

2. Various anomalies in the development of the uterus and vagina (double, saddle-shaped, bicornuate, divided, asymmetrical uterus; double or septate vagina)

3. Cryptorchidism - undescended testicles. Non-closure of the inguinal canal - a predisposition to hernias

4. Non-separation of the cloaca (normally in the seventh week it is divided into the urogenital sinus and rectum) - various fistulas between the rectum and the genitourinary system - rectovesical fistula; rectovaginal fistula.

5. Pelvic position of the kidney.
Kidney development in human ontogeny

In human embryogenesis, all three types of vertebrate kidneys are laid in turn: the pronephric kidney functions from the third to the sixth week, the primary kidney - from the sixth to the eighth week of embryonic development. The nephrons of the secondary kidney are laid at 7-8 weeks and complete the formation by 32-36 weeks of intrauterine development. The final formation of the kidneys occurs in postnatal development. In the regulation of water-salt metabolism in the fetus, its kidneys, placenta and amnion participate. In this case, there is a constant circulation of water and osmotically active substances: the fetus swallows the amniotic fluid, part of which is absorbed in the gastrointestinal tract, enters the bed, is removed from there through the placenta or is filtered by the kidneys of the fetus. In newborns, the nephrons are functionally immature. They are characterized by:

a) low glomerular filtration rate;

b) reduced ability to concentrate urine;

c) limited ability to remove excess water;

5. Common forebrain ventricle

6. Non-closure of the back seam neural tube spinal cord

7. Absence of the corpus callosum

Endocrine system.

It arose on the basis of humoral regulation inherent in all living organisms from unicellular to humans. It is associated with the ability of cells to synthesize physiologically active substances that regulate processes in the cell itself and are released into the environment through which they act on other cells.

In unicellular organisms, active substances are released for interaction with other individuals. In multicellular - they perform the function intermediaries in intercellular interactions. In the beginning, their action was limited to the nearest cells, which is why they received the name tissue or local hormones. Some of them were neurosecrets, because they were synthesized

neurons and released into the environment by their axons (adrenaline, norepinephrine, dopamine), accumulating in synapses or spreading to nearby cells. Neurosecretion is characteristic of all multicellular organisms.

In connection with the complication and differentiation of multicellular organisms, it became necessary to distant regulators that would ensure the coordinated activities of all bodies. They became true hormones, substances of various chemical nature entering the blood, transported by it and acting as chemical regulators of cellular processes.

In annelids, they first form neurohemal organs - small depots of neurosecrets, surrounded by a network of dilated blood capillaries through which neurosecretions enter the blood.

In arthropods, in the area of ​​\u200b\u200bthe “brain”, a group of cells surrounded by a membrane is distinguished, specialized for neurosecretory function -(intercerebral gland) - gland of internal secretion. At the same time, other endocrine glands (sexual) appear - the function of which is controlled by the hormones of the intercerebral gland.

Thus, in the phylogenesis of hormonal regulation in invertebrates, there is a transition from intracellular secretion of active regulatory substances to endocrine glands that synthesize neurohormones - peptides or hormones of a different chemical nature.

In vertebrates, all levels of humoral regulation are found: cellular with the help of metabolites and cAMP, tissue with the help of local hormones (prostaglandins, serotonin, dopamine, adrenaline), organ and system-organ with the help of true hormones entering the blood and acting remotely.

In vertebrates, it forms endocrine system, unifying endocrine glands, in which it occupies a special place hypothalamus. Its neurons combine the ability to conduct nerve impulses and secrete neurohormones. It connects the nervous and endocrine systems. Thanks to the hypothalamus, the endocrine system is able to respond to external and internal signals. Therefore, the hypothalamus is neurosecretory body. (Except for the hypothalamus, the ability to neurosecretion retained the pineal gland, adrenal medulla, neurons of the autonomic nervous system). The hypothalamus forms a single system with pituitary gland. Nerve impulses arriving at the hypothalamus activate secretion releasing - hormones(liberins and statins), each of which regulates the synthesis in the pituitary gland tropins, with the help of which the pituitary gland controls the activity of other endocrine glands, growth processes, etc. The neurohormones of the hypothalamus are deposited in the posterior lobe of the pituitary gland, which is essentially neurohemal organ, similar to those of invertebrates.

Many endocrine glands in vertebrates were formed by specializations cells of various tissues (thymus, gonads, pancreas, thyroid), the products of which - hormones - began to enter the blood,

The endocrine glands in vertebrates were formed from different rudiments, in different ways. In the process of phylogenesis, individual secretory cells merged into groups (thyroid gland), metamerically located sections of secretory tissue united into a common gland (thymus, adrenal medulla and cortex), endocrine cells were included in another organ (ultimobranchial glands, pancreas), a change in function (epiphysis, thyroid gland), displacement of the place of laying (thyroid gland).

In the process of phylogenesis, new departments were formed and new hormones appeared (pituitary gland, adrenal glands),

Some glands were formed by combining two parts originating from different primordia (pituitary gland, adrenal glands).

Major evolutionary transformations in the endocrine

chordate system.

1. The transition from a diffuse endocrine system to a highly specialized regulatory system that combines the endocrine glands.

2. Strengthening of the main regulatory and integrating function, an increase in the number of secretory cells, the appearance of new sections and new hormones in the glands (posterior pituitary gland, mineralocorticoids appeared in terrestrial vertebrates)

3. Change of function (transition of some glands from external to internal secretion, from the ability to perceive light signals to the secretion of hormones)

4. Oligomerization - connection of several rudiments into a large glandular mass (thymus, adrenal medulla, pancreas)

5. Heterotopia - mixing of the organ site (thyroid gland, pituitary gland)

6. Improving communication with nervous system, the formation of a single neuro-humoral regulation.

Onto-phylogenetic defects of the human endocrine system.

1. Underdevelopment and hypofunction of the posterior pituitary gland.

2. Ectopia of the adenohypophysis (a group of glandular cells under the mucous membrane of the roof of the mouth).

3. Persistence of Rathke's pocket (cyst of Rathke's pocket between the anterior and middle lobes of the pituitary gland)

4. Thyroid duct - a strand of cells with a cavity inside (a trace of thyroid heterotopia)

5. Ectopia of the thyroid gland and median cervical fistulas.

6. Median cysts of the neck, located in the direction of the thyroid anlages.

7. Cryptorchidism

8. Accessory lobules of the thyroid gland, individual cells synthesizing thyroxine on the ventral side of the pharynx.

9. Heterotopia of the pancreas (islets of glandular tissue in the wall of the small intestine or stomach).

Lesson topic: Musculoskeletal system of animals (structure evolution)

Lesson type: lesson learning new material

Target: to study the evolution of the structure of the ODS of animals, systematizing the knowledge about the structure of the ODS of animals from different systematic groups

Tasks:
Educational
– to identify the functions of the ODS of animals and the causes of evolutionary changes in the ODS
– substantiate the relationship between the structure and functions of the ODS of animals
– compare the structure of the ODS of animals from different systematic groups, identify complications
(unicellular - multicellular, invertebrates - chordates, non-cranial - vertebrates, different classes of vertebrates - cyclostomes, cartilaginous fish, bony fish, amphibians, reptiles, birds, mammals)
- explain the reasons for the differences and justify the adaptability of the SDS of animals to different environmental conditions, habitats
Educational
– develop the ability to work with drawings (textbook, TPE, presentation slides, demonstration tables), samples of external and internal skeletons (analyze their content, describe the structure of skeletons, compare the skeletons of various organisms ...)
- develop the ability to give examples of animals (with different types of skeletons)
- develop the ability to understand the expediency of evolutionary changes
- develop thinking, communication skills
Educational
- continue to cultivate feelings of love for nature, admiration for its wisdom, expediency
- to cultivate a sense of responsibility for the success of their studies, the desire for self-education, self-development

Basic concepts:

"musculoskeletal system", "external skeleton", "internal skeleton", "axial skeleton", "spine", "vertebra", "limb skeleton", "limb belts", "bone", "joint", "skull ".

Lesson steps:

Organizing time

Greetings, an appeal to students to assess their readiness for the lesson, adjust it if necessary

Goal setting and motivation

***Let's decide on the topic of today's lesson
*** What kind of "bridge" can be thrown from the last lesson to today?
What is the logic in the sequence of studying the educational material of our section?
What section are we studying?
— evolution of the structure and functions of organs and their systems
- from the study of external integuments we pass to the study internal systems organs (figuratively speaking, we examined the animal externally, now we are trying to look deep into)
- since the integuments are often part of the ODS (we remember the concept of "skin-muscle bag", remember that in arthropods muscles are usually attached to the external skeleton ...), it is logical after studying them to move on to this topic

***What is the main goal of our lesson?
(to study the evolution of the structure of the ODS of animals by systematizing knowledge about the structure of the ODS of animals from different systematic groups)

Knowledge update

— Prove that the body needs ODS(to move, to protect cells, tissues, organs, to support and maintain, maintain a constant body shape ...)
— Why are the skeleton and muscles, such different structures, combined into one organ system?(for the successful operation of any organ that performs a movement, it needs support)
— Explain the reasons for the evolution of the ODS, changes in it over time(the development of new territories by animals, the development of new types of food, the need to survive, actively search for food, better hide from enemies, constantly improve their adaptations to changing environmental conditions ... thus, the ODS, changing along with the body, had to provide all these evolutionary changes)

Assimilation of knowledge

***What stages, “steps” in achieving the main goal of the lesson (in studying the evolution of the ODS from one group of animals to another) can we single out?
1. unicellular - multicellular
2. invertebrates - chordates
3. non-cranial - vertebrates
4. different classes of vertebrates - fish, amphibians, reptiles, birds, mammals

***Let's name the main musculoskeletal structures of protozoa and multicellular invertebrates and trace evolutionary changes
1. unicellular - multicellular invertebrates

Conversation using presentation slides
- what supporting and motor structures does the body of protozoa have?(amoeba - cell membrane, pseudopodia, euglena - flagellum as an outgrowth on the membrane, ciliates - cilia as outgrowths on the membrane)
- what supporting and motor structures appear in intestinal cavities?(epithelial-muscular cells in the ectoderm)
- what changes are characteristic of worms?(external extensible integuments of the body, skin-muscular sac, hydroskeleton)
- in shellfish? (shells in gastropods and bivalves)
- in arthropods?(external skeleton in the form of chitinous covers of insects, arachnids, in the form of crustaceans impregnated with lime, to which muscles are attached)
- Are there any animals with an internal skeleton among invertebrates?(in cephalopods, the internal cartilaginous skeleton is the head capsule that protects the brain and eyes, but this is rather an exception, since the real internal skeleton appears only in chordates)

***Let's pay attention to the evolutionary possibilities of the internal skeleton that appeared in chordates
2. invertebrates - chordates

Individual-group work to identify the advantages and disadvantages of the external and internal skeletons (1 option is preparing to name as many advantages of the external skeleton as possible, and the second - internal) with subsequent discussion, conclusions

Chalkboard manual – “scales” with natural objects of external and internal skeletons

+ external skeleton - strength, attachment of muscles and ensuring movement, mastering new ways of moving (jumping, flying), resettlement
- external skeleton - does not grow with the animal, makes the animal defenseless during molting, limits body size (especially in land animals)
+ internal skeleton - grows with the animal, increases the speed of body movement due to greater specialization of individual muscles and their groups
CONCLUSION: more progressive is the internal skeleton

*** We remember that chordates are divided into lower and higher. What are the "minuses" of the ODS of the lower chordates and the "pluses" of the ODS of the higher chordates?
- in the lower ones - the lancelet - the chord is preserved throughout life, and in the higher ones it is replaced in the process of development by the spine, which partially or completely ossifies
- in higher - vertebrates - a skull appears
- skeletons of limbs and their belts appear in vertebrates
- Vertebrates have more complex muscles

3. non-cranial - vertebrates
The skeleton of most vertebrates is formed by bones, cartilage, tendons.
Bones are composed of organic and inorganic substances and have great strength.

Independent individual work on identifying types of bone connections (last paragraph on page 194 of the textbook, task 4 in TPE on page 98), followed by a conclusion about the progressive significance of the joints

Fixed (bone fusion) and movable (with the help of a joint) connection.
The bones of the skeleton of vertebrates have special places for attaching muscles (attached to two bones of the skeleton connected through a joint, the muscle sets them in motion).

Dynamic pause (our instructor received an advanced creative task, which will help us to warm up the main joints - in our case they have a structure typical for all mammals)
(exercises to warm up the joints of the shoulder, elbow, wrist, hip, knee, ankle)

The skeleton consists of three main parts: the axial skeleton, the skeleton of the limbs and the skeleton of the head - the skull.
The axial skeleton of non-cranial is represented by a notochord, and that of vertebrates by a spine consisting of cartilaginous or bony vertebrae.

Independent individual work with a textbook and TPE to identify the structural features of the vertebra (Fig. 147 of the textbook on page 195, TPE - task 6 on page 99) followed by a conclusion about the progressive significance of the appearance of vertebrae in the axial skeleton

(consists of the body, upper and lower arches, the ends of the upper arches of the vertebrae, growing together, form a canal in which the spinal cord is located, ribs are attached to the ends of the lower arches directed to the sides)

The appearance of the vertebrae is an important progressive feature, as they give strength and flexibility to the skeleton, and are a protection for the spinal cord.

***Let's trace the changes in the skeletons of vertebrates of different systematic groups
4. different systematic groups of vertebrates - fish, amphibians, reptiles, birds, mammals

Group work with textbook, TVET and card
(5 groups reveal the features of the skeletons of fish, amphibians, reptiles, birds, mammals, perform the corresponding tasks in the cards) followed by a discussion of the conclusions about the main directions of evolution of the skeleton of vertebrates

The experts will carefully listen to the presentations of representatives of all five groups and help us draw appropriate conclusions about the main directions of evolution of the vertebrate skeleton.

Group 1. Task: to identify the structural features of the fish skeleton.
Textbook - text on pp. 195, 197-198, fig. 148 on page 196.
- the spine consists of the trunk and tail sections
- the skull is made up of many bones
- there is a skeleton of paired fins - pectoral and ventral and unpaired - dorsal, caudal, anal

Group 2. Task: to identify the structural features of the skeleton of amphibians.
Textbook - text on pp. 195, 197-198, fig. 149 on page 196.
- complication of the spine - cervical (1), trunk (7 with ribs ending freely), sacral (1 with pelvic bones attached to it) sections + tail section in caudates

Group 3. Task: to identify the structural features of the skeleton of reptiles.
Textbook - text on pages 195, 197, 198, fig. 150 on page 196.
- 5 sections of the spine - cervical, thoracic, lumbar, sacral, caudal
- movable connection of the vertebrae in the cervical region
- some have a rib cage (the ribs connect to the sternum, the rib cage protects the internal organs and provides better air flow to the lungs - makes breathing a more active process)
- there is a skull, a skeleton of limbs and their belts

Group 4. Task: to identify the structural features of the bird skeleton.
Textbook - text on pages 197, 198, fig. 151 on page 197.
— 5 sections of the spine - cervical (9-25 vertebrae connected movably), thoracic (fused thoracic vertebrae - 3-10 - and the ribs connected to the sternum form the chest; many have a keel), lumbar, sacral, caudal - 6- 9 (the last thoracic, lumbar, sacral and first caudal vertebrae fuse to form a powerful sacrum for greater strength, to support the hind limbs
- light bones (many have cavities inside)
- there is a skull, a skeleton of the limbs and their belts (the skeleton of the upper limb
(hand) modified in connection with the development of the wing - adaptations for flight)

Group 5. Task: to identify structural features of the skeleton of mammals.
Textbook - text on pp. 197-198, fig. 152 on page 198.
- 5 clearly defined sections of the spine - cervical (7 vertebrae with rare exceptions), thoracic (12-15 vertebrae), lumbar (2-9 vertebrae), sacral (usually 4 fused vertebrae), caudal
- there is a skull (brain and facial sections), a skeleton of the limbs and their belts (shoulder and pelvic)

CONCLUSION ON DIRECTIONS OF VERTEBRATE SKELETON EVOLUTION (EXPERTS):
- differentiation of the axial skeleton - spine
- movable connection of the cervical vertebrae
- the appearance and development of the chest
- differentiation of the skull but the brain and facial sections, the development of the brain section
- the appearance and development of paired fore and hind limbs and their belts - shoulder and pelvic
- the emergence and development of particular adaptations in connection with the secondary loss of limbs in snakes, in connection with flight in birds, etc.

Homework information
(before fixing the educational material of the topic and checking its assimilation, let's write down the homework in the diaries,
Let's take a look at the differentiated part

§ 37, TPO, observe the ways of movement of your pets (aquarium fish and mollusks, turtles, birds, hamsters, cats, dogs ... and maybe, for example, cockroaches, moths ...), prepare a short oral story about the ways of their movement , about whether they are able to change the way they move when conditions change, for example, when touched.

Application of knowledge (consolidation of the studied material)

Collective discussion of biological problems (CREATIVE ADVANCED TASK using INTERNET resources)
Problem 1. It is known that fish cannot turn their heads. Can frogs and newts do this? Explain the answer.
- can; frogs can only raise and lower their heads - they have one vertebra in the cervical region; newts can also turn their heads, since their vertebrae are movably connected in the cervical region

Task 2. There is no chest in the skeleton of snakes. In connection with what it was lost in these animals? (pages 125-126 of the textbook - if the students do not answer the question))
- due to the absence of limbs and the development of a special way of movement by lateral bends of the spine and ribs, which, with their lower ends, are able to move back and forth

Task 3. Any extra load would be a hindrance during the flight. What changes in connection with this occurred in the supporting structure of birds?
bones are thin, filled with air
- jaws without teeth

Task 4. The neck of mammals has different lengths: in a dog it is short, in a giraffe it is long. What determines such differences?
- it does not depend on the number of cervical vertebrae (there are 7 of them), but on the length of their bodies

Biological task:
As evidenced by the different position of the limbs relative to the body
in different classes of vertebrates?
- about the evolution of limbs from amphibians and reptiles - to birds and mammals; that a body elevated above the ground gives animals much more opportunities in terms of active movement in search of food, protection from enemies (in amphibians, the limbs rest on the ground on the sides of the body; in reptiles, too, but the body is more elevated; only in birds and mammals, the limbs support the body from below)

Answers to the questions of consolidation of educational material
Question 1. What underlies the evolutionary changes in the musculoskeletal system?
The basis of evolutionary changes in the musculoskeletal system is, first of all, the transition of animals from the aquatic environment to the terrestrial-air one. The new environment required greater strength from the musculoskeletal system and the ability to carry out more complex and varied movements. As an example, we can cite the appearance of compound paired limbs with movable (articular) joints of parts and complicated muscles in representatives of the class of amphibians - the first terrestrial vertebrates.
Question 2. What does a similar structural plan of the skeletons of different vertebrates mean?
The general plan of the structure of the skeletons of different vertebrates speaks of a common origin, evolutionary relationship. And the presence of similar private formations - that animals lead a similar lifestyle in similar environmental conditions. For example, a bone crest (keel) on the sternum is found in both flying birds and bats.
Question 3. What conclusion can be drawn, having become acquainted with the general functions of the musculoskeletal system in animal organisms?
Despite significant differences in the structure of the musculoskeletal structures in different animals, their skeletons perform similar functions: supporting the body, protecting internal organs, and moving the body in space.

Checking the level of assimilation of the educational material of the lesson

Completion of a written test task

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Hello…

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    The main thing…

    The human musculoskeletal system is a functional combination of skeletal bones, tendons, joints, which through the nervous regulation of locomotion, maintaining posture and others motor actions, along with other organ systems, forms the human body.

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    Human skeleton

    The Human Skeleton is a collection of bones, a passive part of the musculoskeletal system. It serves as a support for soft tissues, a point of application of muscles (lever system), a receptacle and protection of internal organs.

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    More about the skeleton...

    The human skeleton is made up of over 200 individual bones, and almost all of them are joined together by joints, ligaments, and other connections. Throughout life, the skeleton is constantly undergoing changes. During intrauterine development, the cartilaginous skeleton of the fetus is gradually replaced by bone. This process also continues for several years after birth. A newborn baby has almost 270 bones in its skeleton, which is much more than an adult. This difference arose due to the fact that the children's skeleton contains a large number of small bones that fuse into large bones only at a certain age. These are, for example, the bones of the skull, pelvis and spine. The sacral vertebrae, for example, fuse into a single bone (sacrum) only at the age of 18-25 years. 6 special bones (three on each side) located in the middle ear do not directly belong to the skeleton; the auditory ossicles connect only with each other and participate in the work of the organ of hearing, transmitting vibrations from the tympanic membrane to the inner ear. The hyoid bone - the only bone not directly connected to others - is topographically located on the neck, but traditionally refers to the bones of the facial region of the skull. It is suspended by muscles from the bones of the skull and is connected to the larynx. The longest bone of the skeleton is the femur, and the smallest is the stirrup in the middle ear.

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    Functions…

    The bones of the facial skull - their main function - participation in chewing food. Bones of the brain skull - the brain skull consists of eight flat bones that protect the brain, connected motionlessly. The ribs are the bones that, together with the sternum, form the chest, a necessary element of protection for the internal organs located in it. The spinal column is the axis, or support of our body, consisting of 33 or 34 vertebrae, it houses the spinal cord. The femur is the longest bone in the human body. Allows you to make a variety of movements with your foot due to its connection with the patella. The bones of the foot are a group of 26 bones, among which the largest, the calcaneal bone, forms the heel.

    Slide 8

    The tallest man in the world was an American, whose height was 2.72 m. By the time of his death, in 1940, when he was 22 years old, he was still growing. The shortest person was a 19-year-old Dutch woman: her height was only 59 cm, she died in 1895. The skeleton of a newborn child consists of more than three hundred bones, but as a result of the fact that many of them grow together in the process of growing up, only 206 of them remain in the skeleton of an adult.

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    Most long bones, about which there is information, are the bones of a brachiosaurus - a dinosaur, the remains of which were found in Colorado (USA). Its shoulder blades reached a length of 2.4 m, and some ribs exceeded 3 m. Among modern living beings, the tallest animal on Earth is the giraffe, its height can reach 6 m. only seven cervical vertebrae, the same number as a mouse. Perhaps the smallest are the temporal bones of a hummingbird - a bird whose length does not exceed 2-3 cm, but which has muscles on its wings that allow it to make up to 90 strokes per second. Hummingbirds can hover in the air when feeding on the nectar of flowers, and even fly backwards.

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    Diseases of the skeleton...

    There are many diseases of the skeletal system. Many of them are accompanied by limited mobility, and some can lead to complete immobilization of a person. A serious threat to life and health is posed by malignant and benign bone tumors, which often require radical surgical treatment; usually the affected limb is amputated. In addition to the bones, the joints are often affected. Joint diseases are often accompanied by a significant impairment of mobility and severe pain. With osteoporosis, bone fragility increases, bones become brittle; This systemic skeletal disease most often occurs in the elderly and in women after menopause.

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    Muscular system...

    The muscular system is one of the main biological subsystems in higher animals, thanks to which movement in the body is carried out in all its manifestations. The muscular system is absent in unicellular organisms and sponges, however, these animals are not deprived of the ability to move.

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    More about Muscles...

    The muscular system is a collection of muscle fibers capable of contraction, combined into bundles that form special organs - muscles, or are independently part of the internal organs. The mass of muscles is much greater than the mass of other organs: in vertebrates it can reach up to 50% of the total body mass, in an adult - up to 40%. Animal muscle tissue is also called meat and, along with some other components of animal bodies, is eaten. In muscle tissue, chemical energy is converted into mechanical energy and heat.

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    There are three types of muscles in vertebrates:

    Skeletal muscles (they are also striated, or arbitrary) Smooth muscles (involuntary) Cardiac muscle. It exists only in the heart. Skeletal muscles cardiac muscle Smooth muscles

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    Muscle functions...

    Facial muscles - allow us to take on various facial expressions: laughter, anger, etc. The biceps brachii, together with its antagonist, the triceps brachii, provides flexion and extension of the forearm. External oblique abdominal muscles - allow air to be pushed out of the lungs during contraction. They perform work opposite to the work of the diaphragm, which is not visible here, since it is located inside the abdominal cavity. Quadriceps femoris - As with the upper limbs, the quadriceps femoris also has an antagonist muscle, the biceps femoris. Both flex and extend the hip.

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    Posture evolution

    The evolution of posture is one of the important aspects of "posture", the improvement of the human musculoskeletal system in the process historical development. Posture is a property inherent only to man, a product of the evolutionary process - upright posture. The main historical milestones in the evolution of posture are: upright posture (2 million years ago); the invention of the chair (XV century); mass schooling (19th century); the emergence of a new mass profession - an office worker (XXI century). The prominent Canadian physiologist Basmadzhan described the significance of this process in the following way:

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    “Among mammals, man, having once acquired an upright posture, has the most economical anti-gravity mechanisms. The expenditure of muscle energy in this, it would seem, the least comfortable position, is extremely economical. ”The S-shaped spine is a kind of shock absorber for axial loads

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    Evolution…

    In the process of human evolution, signs of upright walking gradually formed: a balanced fit of the head, an S-shaped spine, an arched foot, a wide pelvis, a wide and flat chest, massive bones of the lower extremities, and the orientation of the shoulder blades in the frontal plane. The S-shaped spine is a kind of shock absorber for axial loads. As you know, there is an forward bend in the cervical region - cervical lordosis, a back bend in the thoracic region - thoracic kyphosis, an anterior bend in the lumbar region - lumbar lordosis. Due to the natural curves, the strength of the spine to axial load increases. With sudden and excessive loads, the spine, as it were, “folds” into an S-shape, protecting the discs and ligaments of the spine from injury, and then straightens out like a spring.

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    ……….

    The upright skeleton allows humans to move, unlike other animals, on two legs, transferring weight from the heel to the forefoot, which turns each step into a balancing exercise. The load is transferred through the tibia. The fulcrum falls on the toe. The force is created by the Achilles tendon, which, when the calf muscles contract, raises the heel. The arches of the foot “extinguish” inertial loads upon landing, which reach up to 200% of body weight. Natural, balanced head posture allows the long axes of the orbits to be facing forward. This is a distinguishing feature of a person from his anthropoid "brothers", in which the head is suspended on the occipital muscles (anthropologists determine the position of the head by the structure of the base of the skull and cervical vertebrae). A balanced position of the head eliminates the stretching of the posterior ligaments of the neck and the need for constant tension of the neck muscles, mainly, unlike animals, the muscles of the upper trapezius. In the process of historical development, mankind has passed a difficult path.

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    ……..

    With the development of civilization, the requirements for the musculoskeletal system have changed. If ancient people were either in a vertical or horizontal position (hunted, gathered, fought, lay down, resting), then already in the 17th century 10% of the population performed sedentary work. In the 21st century, the number of such workers has increased to 90%. In the process of evolution, man ceased to adapt to environment and began to adapt the environment to himself, and this could not but affect his posture. The invention of the bench, chair (this is probably the 15th century) significantly changed the biomechanics of man, appeared new problem- "posture sitting on a chair." Modern man spends most of his time sitting at work, at home, in transport, working, studying, relaxing, waiting, eating. The “sitting” position, optimal for office work and training, is a severe test for the musculoskeletal system. It is in this position that posture most often suffers. It is a long sitting posture that is the cause of back pain, and the reason various diseases. The 18th century is the century of mass schooling. This progressive historical process has and reverse side

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    According to the Russian Institute of Pediatric Orthopedics, 40-80% of children have posture disorders, and 3%-10% of them have various curvature of the spine, the so-called school scoliosis. With the development of civilization, the content, organization and methods of human labor change. Office workers are a new mass profession, the number of which is more than 60% of the total working population. The need for long-term adherence to a sitting working posture (working at a computer, with documents, with clients) leads to an increase in the number of diseases of the musculoskeletal system of the adult population. The number of such diseases is steadily growing, they are getting younger, and this trend is likely to continue for the foreseeable future.

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    Thank you for your attention…

    Good Bye… Sources: BASMAJIAN, J.V. (1985) 5th Edition. Muscles Alive, Their Function Revealed by Electromyography. Williams & Wilkins, Baltimore. 1985

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