>> The importance of the musculoskeletal system, its composition. Bone structure

§ 10. The importance of the musculoskeletal system, its composition. Bone structure

What qualities of bone ensure its lightness and strength?
Why is bone tissue classified as connective tissue?

Microscopic structure of bone. The compact substance of bone consists of microscopic cells and tubules through which numerous blood vessels and nerves enter the bone from the periosteum. The walls of the bone tubules are lined with rows of radially located bone plates (Fig. 19). This is the noncellular substance of bone. The presence of noncellular substance is characteristic of any connective tissue. The bone cells that form these plates are located along the outer perimeter of these rings.

Types of bones.

Based on the type of structure, there are tubular, spongy, and flat bones.

Tubular bones have the appearance of cylinders with thickened marginal ends. They serve as long, strong levers, thanks to which a person can move in space or lift weights. The tubular bones include the bones of the shoulder, forearm, femur and tibia. Tubular bones are covered with periosteum, with the exception of the articular surfaces. Behind the periosteum is a layer of compact, dense substance. In the terminal areas of the bone, the compact substance becomes spongy, which fills the ends of the bones. In the middle part of the bone there is no spongy substance; there is a bone marrow cavity filled with yellow bone marrow. Red bone marrow is stored in the spongy substance at the end of the bone.

Tubular bones grow in thickness due to the periosteum. However, bone mass increases only slightly because the walls of the medullary cavity contain cells that dissolve bone. Thanks to the complex and coordinated work of both cells, optimal bone strength is achieved with minimal weight and material consumption.
Growth in length of tubular bones occurs due to growth zones and is completed by 20-25 years. The growth zones are located near the ends of the bones. They consist of cartilage tissue, which is replaced by bone tissue as the bone grows.

Spongy bones have a rather thin compact substance on the surface, under which there is spongy substance filled with red bone marrow. Spongy bones include the bones of the vertebral bodies, sternum, small bones of the hand and foot. Basically, spongy bones have a supporting function.

Flat bones perform a mainly protective function.

They consist of two parallel plates of a compact substance, between which a spongy substance is located crosswise, like beams. Flat bones include the bones that form the cranial vault.

Skeleton, muscles, periosteum, compact, spongy bone, medullary cavity, red bone marrow, yellow bone marrow; bone tissue, bone plates, cells that form bone and dissolve bone; types of bones: tubular, spongy, flat; growth zones of tubular bones.

Why are the skeleton and muscles classified as a single organ system?
What are the supporting, protective and motor functions of the skeleton and muscles?
What is the chemical composition of bones? How can you find out the properties of its components?

Explain why bone bends are more common in children, and fractures more common in older people.
Consider Figure 18, A, B and C. Compare it with a preparation of a cut of natural bone. Find the periosteum, compact substance, spongy substance, medullary cavity.

1. Consider Figure 18, B and C. Explain why the crossbars of the cancellous substance are oriented in the direction of the forces of compression and tension of the bone.

Laboratory work

Microscopic structure of bone

Equipment : microscope, permanent preparation “Bone tissue”.

Work progress

1. Examine bone tissue at low magnification using a microscope. Using Figure 19, A and B, determine: are you considering a transverse or longitudinal section?

2. Find the tubules through which the vessels and nerves passed. In cross section they look like a transparent circle or oval.

3. Find the bone cells that are located between the rings and look like black spiders. They secrete plates of bone substance, which are then saturated with mineral salts.

4. Think about why a compact substance consists of numerous tubes with strong walls. How does this contribute to bone strength with the least amount of material and bone mass required? Why is the airframe made from durable duralumin tubular structures, and not from sheet metal?

Kolosov D.V. Mash R.D., Belyaev I.N. Biology 8th grade
Submitted by readers from the website

“Musculoskeletal system. Structure, composition and properties of bones"

Objective of the lesson: study the composition and functions of the musculoskeletal system, chemical composition, structure and properties of bones.

Lesson objectives:

• educational: to develop knowledge about the composition and functions of the musculoskeletal system; to form in students knowledge about the characteristics of the chemical composition, structure and properties of bone, ensuring the performance of the functions of the musculoskeletal system.
• developing: develop the ability to analyze, compare, and draw conclusions; develop logical thinking (establish cause-and-effect relationships, confirming on given subject material the dependence of the properties of an object on its composition and structure);
• educational: to foster a sense of responsibility for maintaining one’s health (to form students’ ideas about the need to monitor their posture and nutrition).

Equipment: cuts of tubular bones, microscope, ready-made microspecimen “Bone tissue”, calcined and decalcified bones, presentation for the lesson, student technological maps

Lesson progress

1. Organizational moment.

2. Updating students’ knowledge, motivation.

3. Explanation of new material.

3.1.1. Composition and functions of the musculoskeletal system.

3. 2. Chemical composition of bone. Demonstration of experience.

3.3. Bone structure.

3. 3.1. Macroscopic structure of bone.

Working with saw cuts.

3. 3.2. Microscopic structure of bone. Laboratory work “Microscopic structure of bone.”

4. Consolidation and generalization of the material covered.

5. Homework.

1. COMPOSITION AND FUNCTIONS OF THE MUSTOCULAR SYSTEM

Teacher.“Movement is life,” noted Voltaire. We make many different movements, move in space, run, walk, jump, swim. We perform many thousands of different straightening, bending, and turning movements. The musculoskeletal system provides all this.

8 Film screening (1 minute)

The musculoskeletal system is often called the musculoskeletal system. Why? Because the musculoskeletal system includes bones, connective tissues and muscles that connect them. The bones of the skull, torso and limbs form the skeleton (from the Greek “skeleton” - “dried”).

The bones of the skeleton make up passive

?Teacher . Guys, what does “passivity” mean?

Suggested answer . Lack of own actions

Teacher. That's right, the bones are not moved by themselves, but by the contraction of the muscles attached to them.

Muscles make up active part of the musculoskeletal system.

The skeleton and muscles function together. They determine the shape of the body, provide support, protective and motor functions.

1.Mechanical functions.

Support function

? Teacher . Guys, what is a support?

BY. Support

Teacher. What does the musculoskeletal system support?

BY. Human body

Teacher. That's right, the musculoskeletal system provides support for the body as a whole, as well as for all its parts and organs. Supportive function - manifests itself in the fact that the bones of the skeleton and muscles form a strong frame that determines the position of the internal organs and does not allow them to move.

Motor function carries out movement of the body and its parts in space. Motor function is possible only if the muscles and bones of the skeleton interact, since the muscles set bone levers in motion.

Protective function.

Skeletal bones protect organs from injury. Thus, the spinal cord and brain are located in a bone “case” - the brain is protected by the skull, - the spinal cord. The rib cage covers the heart and lungs, airways, esophagus, and major blood vessels. The abdominal organs are protected from behind by the spine, from below by the pelvic bones, and in front by the abdominal muscles.

2.Biological functions.

Along with mechanical functions, the skeletal system performs a number of biological functions. The bones contain the main supply of mineral salts: calcium, phosphorus. They are used by the body as needed, so the skeletal system takes a direct part in mineral metabolism. The bones contain red bone marrow, which is involved in hematopoietic processes.

2. CHEMICAL COMPOSITION OF BONE

Teacher. Everyone knows about the existence of bones in our body. Crossbones and a skull were used by pirates as a sign to scare away those who were overly inquisitive. There are a lot of skulls and skeletons in fiction. Most often they introduce an atmosphere of mystery into the story. The skeleton also works in fairy tales. The Old Slavonic word “koshch” (“kosht”) means “dry.” From him came the word “bone” and the name of the character in Russian fairy tales - Koschey the Immortal. It is not by chance that this name was given to it - bones “outlive” a person for a long time and are sometimes preserved in the ground for thousands of years, almost unchanged.

Study the data and draw a conclusion about the strength of bone tissue “as a building material” of the human skeleton

Conclusion: Surprisingly, bone is second in strength only to hard types of steel and turns out to be much stronger than granite and concrete, which have become examples of strength.

Let's find out step by step what features of the chemical composition and structure give bones such unique properties.

Teacher. The substances that make up bone can be divided into two groups: organic and inorganic.

? Teacher . Remember what mineral elements make up bone?

BY. Calcium, phosphorus, magnesium

Teacher. That's right, the composition of bone mainly includes calcium and phosphorus salts.

Teacher. What organic substances can be part of bone tissue?

BY. Proteins, fats, carbohydrates.

Let's see which properties are given to bone by inorganic substances and which by organic substances.

Demonstration of experience

Teacher. Two days ago I placed a chicken bone in a 10% hydrochloric acid solution. It is a chicken bone, because... it is smaller than, for example, cow's milk and dissolving the salts that make up its composition will require less acid and time.

Acids affect not only inorganic, but also organic compounds, so I chose hydrochloric acid as a milder acid. So that its effect on the organic substances of bone tissue is minimal.

So, I remove the bone from a glass with 10% hydrochloric acid solution, remove the remaining acid with filter paper, and check the properties of the bone. She is able to bend in all directions.

? Teacher.

BY. Organic substances give bones firmness and elasticity .

Teacher: Now let's solve the problem of how to remove organic matter from bone.

BY. They can be burned.

Teacher: That's right, organic matter burns well. When we studied the chemical composition of the plant organism, we said that plant remains (fallen leaves, dry branches, stems, etc.) burn well. Ash always remains at the site of the fire - these are mineral salts (i.e. inorganic substances), and all organic substances burn.

The bone was charred. Charring is a sure sign that organic matter has burned. The bone is hard but brittle. It crumbles in your hands.

? Teacher. What conclusion do the results of the experiment lead us to?

BY. Inorganic (insoluble calcium and magnesium salts) give bones hardness.

So, organic substances (proteins) give elasticity to bones, and inorganic substances (insoluble calcium and magnesium salts) give bones hardness. The combination of hardness and elasticity gives bone strength.

It is also necessary to know the proportions of organic and inorganic substances. Because if there are more inorganic substances in the bones, they will be hard but brittle. And if there is an excess of organic matter, then the guests will be too flexible.

Nature, creating the bone skeleton, found a golden mean (3:1). Therefore, human bones are strong enough to perform the functions assigned to them.

The composition of human bone tissue changes throughout a person's life.

? Teacher . How does bone chemistry change with age?

Reading a textbook. Page 47, article “Chemical composition of bones”, third paragraph

BY. With age, the content of inorganic substances in bone increases and the content of organic substances decreases.

? Teacher . Why do children often experience bone curvatures, and older people often experience fractures? Why do you need to constantly monitor your posture at your age?

BY. Children's bones contain more organic matter. Their bones are more resilient and elastic. With age, the salt content in the bones increases. In old age, bones become brittle due to the fact that their content of inorganic salts significantly exceeds the content of the elastic component.

Teacher. Children's bones are quite flexible, and incorrect posture can lead to curvature of the spine. Health is the greatest wealth of a person, and it must be protected from a young age. It has been established that moderate load on the bone increases its strength, so it is very important to engage in physical exercise. Bone health depends on many factors, and a balanced diet is important.

3. BONE STRUCTURE

3.1. MACROSCOPIC BONE STRUCTURE

Teacher. Guys, here is a preparation of cutting natural bone. Look carefully at the preparation and then at Figure 18, A and B (page 46). Compare it with a preparation of cutting natural bone. On the specimen, find the periosteum, compact substance, spongy substance, and medullary cavity.

Bones are covered with dense connective tissue - periosteum.

Vessels and nerves pass through the periosteum. The periosteum takes part in the nutrition of bone and the formation of new bone tissue.

Bones can grow in length and thickness.

Length they are growing due to cartilage cell division located at its ends

Due to cell division of the inner layer of the periosteum, bones grow
in thickness and heal when fractures occur.

Each bone has a compact (dense) and spongy substance. Their quantitative ratio and distribution depends on the place of the bone in the skeleton and on its function.

Dense (compact) substance especially well developed in those bones and their parts that perform the functions of support and movement. For example, the body of long tubular bones is built from a compact substance. The bone plates are cylindrical in shape and seem to be inserted into one another. This tubular structure of the compact substance gives the bones greater strength and lightness.

Spongy substance formed by many bone plates, which are located in the directions of maximum load. It forms thickenings of the heads of long tubular bones, as well as short flat bones. Between the plates is the red bone marrow, which is a hematopoietic organ - blood cells are formed in it. The cavities of the long bones of adults are filled with yellow bone marrow, which contains fat cells.

Over the course of a person's life, the ratio of dense and spongy bone changes. These changes depend on the lifestyle a person leads, his diet, and health status. The amount of dense matter in athletes is significantly higher than in people leading a sedentary lifestyle.

3.2. MICROSCOPIC BONE STRUCTURE

? Teacher . Guys, what groups of tissues do you know?

BY. Epithelial, muscular, nervous, connective.

Teacher . Which group does bone tissue belong to?

BY. To connecting

Teacher . What are the characteristic features of connective tissue

BY. The presence of a well-developed intercellular substance that determines the mechanical properties of the tissue.

The bones of the human skeleton are formed by bone tissue, a type of connective tissue. The compact substance of bone consists of microscopic cells and tubules through which numerous blood vessels and nerves pass from the periosteum into the bone.

The walls of the bone tubules are lined with rows of radially arranged bone plates. This is the intercellular substance of bone. The presence of intercellular substance is characteristic of any connective tissue. The bone cells that form these plates are located along the outer perimeter of these rings.

Guys, now we have to do laboratory work “Microscopic structure of bone”

LABORATORY WORK

"Microscopic structure of bone"

Equipment: microscope, permanent preparation “Bone tissue”.

Work progress:

1. Examine bone tissue at low microscope magnification

2. Find the tubules through which the vessels and nerves passed. In cross section they look like a transparent circle or oval.

3. Find the bone cells that are located between the rings and look like black spiders. They secrete plates of bone substance, which are then saturated with mineral salts.

4. Fill out the observation results in a technological map, signing parts of the drawing.

Answer the questions:

1. Bone cells secrete intercellular substance in the form of plates, which are located around the canals, forming concentric cylinders. How does this affect bone strength? 2. Why is the aircraft body made from duralumin tubes, and not from rolled sheets?

So, we are convinced that bones are strong and light at the same time. This allows them to perform supporting, protective and motor functions as part of the skeleton. This is achieved:

1. Due to the chemical composition.

2. Due to macrostructure.

3. Due to microstructure.

1. Lesson on the topic:
2. “Musculoskeletal system. Structure, composition and properties of bones"

Objective of the lesson: study the composition and functions of the musculoskeletal system, chemical composition, structure and properties of bones.

Lesson objectives:

• educational:to develop knowledge about the composition and functions of the musculoskeletal system; to form in students knowledge about the characteristics of the chemical composition, structure and properties of bone, ensuring the performance of the functions of the musculoskeletal system.
• developing: develop the ability to analyze, compare, and draw conclusions; develop logical thinking (establish cause-and-effect relationships, confirming on given subject material the dependence of the properties of an object on its composition and structure);
• educational: to foster a sense of responsibility for maintaining one’s health (to form students’ ideas about the need to monitor their posture and nutrition).

Equipment : cuts of tubular bones, microscope, ready-made microspecimen “Bone tissue”, calcined and decalcified bones, presentation for the lesson, student technological maps

1. Lesson progress

1. Organizational moment.

2. Updating students’ knowledge, motivation.

3. Explanation of new material.

3.1.1. Composition and functions of the musculoskeletal system.

3. 2. Chemical composition of bone. Demonstration of experience.

3.3. Bone structure.

3. 3.1. Macroscopic structure of bone.

Working with saw cuts.

3.2. Microscopic structure of bone. Laboratory work “Microscopic structure of bone.”

4. Consolidation and generalization of the material covered.

5. Homework.

1. 1. COMPOSITION AND FUNCTIONS OF THE MUSTOCULAR SYSTEM

Teacher. “Movement is life,” noted Voltaire. We make many different movements, move in space, run, walk, jump, swim. We perform many thousands of different straightening, bending, and turning movements. The musculoskeletal system provides all this.

8 Film screening (1 minute)

The musculoskeletal system is often called the musculoskeletal system. Why? Because the musculoskeletal system includes bones, connective tissues and muscles that connect them. The bones of the skull, torso and limbs form the skeleton (from the Greek “skeleton” - “dried”).

The bones of the skeleton make up passive

Teacher. Guys, what does “passivity” mean?

Suggested answer. Lack of own actions

Teacher. That's right, the bones are not moved by themselves, but by the contraction of the muscles attached to them.

Muscles make up active part of the musculoskeletal system.

The skeleton and muscles function together. They determine the shape of the body, provide support, protective and motor functions.

1.Mechanical functions.

Support function

Teacher. Guys, what is a support?

P.O. Support

Teacher. What does the musculoskeletal system support?

P.O. Human body

Teacher. That's right, the musculoskeletal system provides support for the body as a whole, as well as for all its parts and organs. Supportive function - manifests itself in the fact that the bones of the skeleton and muscles form a strong frame that determines the position of the internal organs and does not allow them to move.

Motor functioncarries out movement of the body and its parts in space. Motor function is possible only if the muscles and bones of the skeleton interact, since the muscles set bone levers in motion.

Protective function.

Skeletal bones protect organs from injury. Thus, the spinal cord and brain are located in a bone “case” - the brain is protected by the skull, - the spinal cord. The rib cage covers the heart and lungs, airways, esophagus, and major blood vessels. The abdominal organs are protected from behind by the spine, from below by the pelvic bones, and in front by the abdominal muscles.

2.Biological functions.

Along with mechanical functions, the skeletal system performs a number of biological functions. The bones contain the main supply of mineral salts: calcium, phosphorus. They are used by the body as needed, so the skeletal system takes a direct part in mineral metabolism. The bones contain red bone marrow, which is involved in hematopoietic processes.

1. 2. CHEMICAL COMPOSITION OF BONE

Teacher. Everyone knows about the existence of bones in our body. Crossbones and a skull were used by pirates as a sign to scare away those who were overly inquisitive. There are a lot of skulls and skeletons in fiction. Most often they introduce an atmosphere of mystery into the story. The skeleton also works in fairy tales. The Old Slavonic word “koshch” (“kosht”) means “dry.” From him came the word “bone” and the name of the character in Russian fairy tales - Koschey the Immortal. It is not by chance that this name was given to it - bones “outlive” a person for a long time and are sometimes preserved in the ground for thousands of years, almost unchanged.

Study the data and draw a conclusion about the strength of bone tissue “as a building material” of the human skeleton

Conclusion: Surprisingly, bone is second in strength only to hard types of steel and turns out to be much stronger than granite and concrete, which have become examples of strength.

Let's find out step by step what features of the chemical composition and structure give bones such unique properties.

Teacher. The substances that make up bone can be divided into two groups: organic and inorganic.

Teacher. Remember what mineral elements make up bone?

P.O. Calcium, phosphorus, magnesium

Teacher. That's right, the composition of bone mainly includes calcium and phosphorus salts.

Teacher. What organic substances can be part of bone tissue?

P.O. Proteins, fats, carbohydrates.

Let's see which properties are given to bone by inorganic substances and which by organic substances.

Demonstration of experience

Teacher. Two days ago I placed a chicken bone in a 10% hydrochloric acid solution. It is a chicken bone, because... it is smaller than, for example, cow's milk and dissolving the salts that make up its composition will require less acid and time.

Acids affect not only inorganic, but also organic compounds, so I chose hydrochloric acid as a milder acid. So that its effect on the organic substances of bone tissue is minimal.

So, I remove the bone from a glass with 10% hydrochloric acid solution, remove the remaining acid with filter paper, and check the properties of the bone. She is able to bend in all directions.

Teacher.

BY. Organic substances give bones firmness and elasticity.

Teacher: Now let's solve the problem of how to remove organic substances from bone.

BY. They can be burned.

Teacher: That's right, organic matter burns well. When we studied the chemical composition of the plant organism, we said that plant remains (fallen leaves, dry branches, stems, etc.) burn well. Ash always remains at the site of the fire - these are mineral salts (i.e. inorganic substances), and all organic substances burn.

The bone was charred. Charring is a sure sign that organic matter has burned. The bone is hard but brittle. It crumbles in your hands.

Teacher. What conclusion do the results of the experiment lead us to?

P.O. Inorganic (insoluble salts of calcium and magnesium) give bones hardness.

So, organic substances (proteins) give elasticity to bones, and inorganic substances (insoluble calcium and magnesium salts) give bones hardness. The combination of hardness and elasticity gives bone strength.

It is also necessary to know the proportions of organic and inorganic substances. Because if there are more inorganic substances in the bones, they will be hard but brittle. And if there is an excess of organic matter, then the guests will be too flexible.

Nature, creating the bone skeleton, found a golden mean (3:1). Therefore, human bones are strong enough to perform the functions assigned to them.

The composition of human bone tissue changes throughout a person's life.

Teacher. How does bone chemistry change with age?

Reading a textbook. Page 47, article “Chemical composition of bones”, third paragraph

P.O. With age, the content of inorganic substances in the bone increases and the content of organic substances decreases.

Teacher. Why do children often experience bone curvatures, and older people often experience fractures? Why do you need to constantly monitor your posture at your age?

BY. Children's bones contain more organic matter. Their bones are more resilient and elastic. With age, the salt content in the bones increases. In old age, bones become brittle due to the fact that their content of inorganic salts significantly exceeds the content of the elastic component.

Teacher. Children's bones are quite flexible, and incorrect posture can lead to curvature of the spine. Health is a person’s greatest wealth, and it must be protected from a young age. It has been established that moderate load on the bone increases its strength, so it is very important to engage in physical exercise. Bone health depends on many factors, and a balanced diet is important.

1. 3. BONE STRUCTURE

1. 3.1. MACROSCOPIC BONE STRUCTURE

Teacher. Guys, here is a preparation of cutting natural bone. Look carefully at the preparation and then at Figure 18, A and B (page 46). Compare it with a preparation of cutting natural bone. On the specimen, find the periosteum, compact substance, spongy substance, and medullary cavity.

Bones are covered with dense connective tissue - periosteum.

Vessels and nerves pass through the periosteum. The periosteum takes part in the nutrition of bone and the formation of new bone tissue.

Bones can grow in length and thickness.

They grow in length due to cartilage cell divisionlocated at its ends

Due to cell division of the inner layer of the periosteum, bones grow
in thickness and heal when fractures occur.

Each bone has a compact (dense) and spongy substance. Their quantitative ratio and distribution depends on the place of the bone in the skeleton and on its function.

Dense (compact) substanceespecially well developed in those bones and their parts that perform the functions of support and movement. For example, the body of long tubular bones is built from a compact substance. The bone plates are cylindrical in shape and seem to be inserted into one another. This tubular structure of the compact substance gives the bones greater strength and lightness.

Spongy substanceformed by many bone plates, which are located in the directions of maximum load. It forms thickenings of the heads of long tubular bones, as well as short flat bones. Between the plates there is red bone marrow, which is a hematopoietic organ - blood cells are formed in it. The cavities of the long bones of adults are filled with yellow bone marrow, which contains fat cells.

Over the course of a person's life, the ratio of dense and spongy bone changes. These changes depend on the lifestyle a person leads, his diet, and health status. The amount of dense matter in athletes is significantly higher than in people leading a sedentary lifestyle.

1. 3.2. MICROSCOPIC BONE STRUCTURE

? Teacher. Guys, what groups of tissues do you know?

BY. Epithelial, muscular, nervous, connective.

Teacher. Which group does bone tissue belong to?

P.O.K connecting

Teacher. What are the characteristic features of connective tissue

P.O. The presence of a well-developed intercellular substance that determines the mechanical properties of the tissue.

The bones of the human skeleton are formed by bone tissue, a type of connective tissue. The compact substance of bone consists of microscopic cells and tubules through which numerous blood vessels and nerves pass from the periosteum into the bone.

The walls of the bone tubules are lined with rows of radially arranged bone plates.This is the intercellular substance of bone.The presence of intercellular substance is characteristic of any connective tissue. The bone cells that form these plates are located along the outer perimeter of these rings.

Guys, now we have to do laboratory work “Microscopic structure of bone”

1. LABORATORY WORK

1. "Microscopic structure of bone"

Equipment: microscope, permanent preparation “Bone tissue”.

Work progress:

1. Examine bone tissue at low microscope magnification

2. Find the tubules through which the vessels and nerves passed. In cross section they look like a transparent circle or oval.

3. Find the bone cells that are located between the rings and look like black spiders. They secrete plates of bone substance, which are then saturated with mineral salts.

4. Fill out the observation results in a technological map, signing parts of the drawing.

Answer the questions:

1. Bone cells secrete intercellular substance in the form of plates, which are located around the canals, forming concentric cylinders. How does this affect bone strength? 2. Why is the aircraft body made from duralumin tubes, and not from sheet metal?

So, we are convinced that bones are strong and light at the same time. This allows them to perform supporting, protective and motor functions as part of the skeleton. This is achieved:

1. Due to the chemical composition.

2. Due to macrostructure.

3. Due to microstructure.

Methodological development of a biology lesson in 10th grade

on the topic: “Cytoplasm. Cell membrane."

Laboratory work

“Plasmolysis and deplasmolysis in onion epidermal cells”

Purpose of the lesson : consider the main parts of cells - the cell membrane and cytoplasm, their structure in connection with the functions they perform.

Tasks: Educational:consolidate the ability to use a microscope, prepare micropreparations and discover the structural features of plant cells

Developmental : develop the foundations of students’ creative activity

Educational : develop communication skills when working in a group.

Lesson type: lesson of generalization and consolidation of knowledge, skills and abilities.

Equipment: microscopes, slides and cover glasses, glass rods, glasses of water, filter paper, table salt solution, onions. Tables: structure of magnifying devices, structure of a plant cell.

Lesson structure:

1. Organizational moment. 2. Updating cognitive activity. 3. Learning new material:

The structure of the cytoplasm; - structure and functions of the cell membrane.

4. Consolidation: - laboratory work. Appendix No. 1. Appendix No. 2. 5.Homework.

Lesson progress

1. Organizational moment.

2. Updating cognitive activity.

1. Name the main provisions of the cell theory. 2. Prove that the cell is a structural and functional unit of living organisms.

3. Studying new material.

Cytoplasm. The cavity of any cell is filled with cytoplasm, which contains various organelles - permanent components of the cytoplasm and inclusions - temporary components of the cell. The cytoplasm is separated from the environment by a plasma membrane (plasmalemma). The entire space between the organelles is filled with a colloidal system of hyaloplasm (cytosol) - the main substance of the cytoplasm. All metabolic processes take place in it, it ensures the interconnection of the nucleus and all organelles. There are two forms of hyaloplasm: sol - the liquid part and gel - the thick part. The chemical composition of the cytoplasm is varied. Its basis is water (60-90% of the total mass of the cytoplasm). The composition of the cytoplasm includes proteins, and may include fats and fat-like substances, and other organic and inorganic substances. The cytoplasm has an alkaline reaction. A characteristic feature of the cytoplasm is constant movement (cyclosis). If this movement stops, the cell dies.

Cell membrane. The plasma membrane is adjacent to the cytoplasm, and an outer layer is formed on its surface. In animals it is called the glycocalyx (formed by glycoproteins, glycolipids). In plants and fungi, this is a cell wall formed by fiber fibers (plants) and chitin (fungi). The cell membrane is a double layer (bilayer) of lipids, most of which are complex lipids - phospholipids. Lipid molecules have a hydrophilic (“head”) and a hydrophobic (“tail”) part. When membranes are formed, the hydrophobic portions of the molecules turn out to be facing inside the cell, and the hydrophilic portions are facing out. Proteins penetrate the entire thickness of the membrane, forming pores through which water-soluble substances pass. Cell membranes are selectively permeable. They are highly permeable to some substances and poorly (or not at all) permeable to others. Diffusion (substances always move from an area of ​​higher concentration to an area of ​​lower) is the passive transport of substances. Active transport is carried out by carrier proteins; this requires ATP energy. Large particles and macromolecules are also transported through the membrane. The process of absorption of macromolecules is called endocytosis. Phagocytosis is the capture and absorption of large particles (for example, phagocytosis of lymphocytes) and pinocytosis is the process of capture and absorption of liquid droplets with substances dissolved in it.

Functions of membranes. They separate the contents of the cell from the external environment. They regulate the metabolism between the environment and the cell. Many chemical reactions in cells take place on membranes.

In order to verify the semi-permeability of the plasma membrane, we will carry out laboratory work.

4. Consolidation . Performing laboratory work.

Laboratory work No. 2

“Plasmolysis and deplasmolysis in onion epidermal cells”

Equipment: microscopes, onion bulb, concentrated NaCl solution, filter paper, pipettes.

Laboratory assignment:

1. Prepare a microslide, examine and sketch 3-4 cells of what you see;
2. On one side of the cover glass, apply a few drops of table salt solution, and on the other side, draw off the water with a strip of filter paper;
3. Examine the microslide for a few seconds. Pay attention to the changes that have occurred to cell membranes and the time during which these changes occurred. Sketch the changed object.
4. Apply a few drops of distilled water to the edge of the coverslip and pull it off the other side with filter paper, rinsing off the salt solution.
5. Examine the slide under a microscope for several minutes. Note the changes in the position of the cell membranes and the time during which these changes occurred. Sketch the object you are studying.
6. Draw a conclusion in accordance with the purpose of the work, noting the rate of plasmolysis and deplasmolysis. Explain the difference in speed of these two processes.

To the house. In writing:1. What functions of the outer cell membrane have been established by observing plasmolysis and deplasmolysis? 2. Explain the causes of plasmolysis and deplasmolysis. 3. Define the terms - plasmolysis, deplasmolysis, osmosis, turgor, diffusion, phagocytosis, pinocytosis.5. Homework. Study § 8. Textbook “General Biology” edited 10-11. D.K.Belyaev." Answer laboratory questions in writing.

6. Literature:

Biology lessons in grades 10-11. Pimenov A.V. Textbook "General Biology" edited 10-11. D.K.Belyaev." "Biological Encyclopedic Dictionary" Ch. ed. M. S. Gilyarov; Editorial team: A. A. Babaev, G. G. Vinberg and others - 2nd ed., corrected. - M.: Sov. Encyclopedia, 1986. Internet resources:http://ariom.ru/forum/viewtopic.php?p=1116177http://www.bsu.ru/content/hecadem/bahanova_mv/cl_718/files/mzip_618_14700/index.htmhttp://dic.academic.ru/dic.nsf/dic_biology/4301/ - PLASMOLYSIS

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Stary Oskol 2011 Chemistry topic: Phosphorus

Phosphorus: structure and properties

Phosphorus atom structure

The most common modifications: red and white (yellow)

Crystal lattices Fig. 1 Structure of white and red phosphorus Fig. 2 The structure of violet (1) and black (2,3 - different projections) phosphorus

Allotropic modification Structure of matter Properties of matter Phosphorus is white (yellow) It has a cubic molecular crystal lattice, consisting of P4 molecules that can rotate freely, are connected by very weak bonds and have the shape of a tetrahedron. In its pure form it is completely colorless and transparent; the commercial product is yellowish in color and looks like wax. Brittle in the cold, soft at temp. above 15 degrees Celsius, with a characteristic odor. Light melting and volatile. Very poisonous. Insoluble in water, but soluble in carbon disulfide. Glows in the dark. Self-ignites in powder. At temp. 34oC. Therefore, it is stored under water. Red phosphorus It has an amorphous structure or an atomic crystal lattice, a polymer structure: P4 tetrahedra are linked into endless chains. “Violet phosphorus” is somewhat different, consisting of groups P8 and P9, arranged in long tubular structures with a pentagonal cross-section. The powder is red-brown in color (the name red refers to several modifications that differ in density and color from orange to dark red and even purple), and is not poisonous. It does not dissolve in either water or carbon disulfide. Doesn't glow in the dark. It lights up only when ignited, and spontaneously ignites at temp. more than 200oC Black phosphorus Crystalline form. Constructed of three-dimensional hexagons with phosphorus atoms at the vertices, connected to each other in layers (reminiscent of graphite) The least active form. Externally similar to graphite. When heated without air access, it turns into steam, from which white phosphorus condenses. Comparison of the properties of varieties of phosphorus

Results of the auction Name of the enterprise Substance Property Application Match factory Red phosphorus Ability to ignite by friction Part of the mixture that is applied to the match and the side surfaces of the matchbox. When friction occurs, phosphorus ignites, ignites the composition of the head, and it sets the tree on fire. Plant for the production of pyromaterials White phosphorus Easily ignites, forming tiny particles of P2O5. Production of smoke screens, incendiary and smoke shells, bombs. Non-ferrous metals plant Red phosphorus Easily reacts with various simple and complex substances when heated. In the production of non-ferrous metal alloys as a deoxidizing agent, as an alloying additive (tin bronze). Production of soft magnetic alloys and semiconductor phosphides. Phosphoric acid plant White phosphorus Reactivity Produces phosphoric acid, mineral fertilizers, sodium polyphosphates (for water softening) and red phosphorus

After a fracture, a person has to wear a plaster cast for a long time so that a bone callus forms and the fragments grow together. This often brings a lot of inconvenience; due to prolonged immobilization, venous congestion occurs in the injured limb, and muscle atrophy develops. Today, medicine uses drugs to accelerate bone healing, improve blood circulation, and promote bone tissue restoration. Regular use of these products allows you to shorten the rehabilitation period and return to normal life in the shortest possible time.

After a fracture, the body needs a long time for bone fragments and muscles to heal, innervation and blood circulation to be restored. For some people, the regeneration process does not take much time, while for others it may take more than six months to fully restore limb function. Everything depends not only on the location of the fracture, but also on age and the presence of chronic diseases.

The duration of the rehabilitation period is influenced by the following factors:

• diameter of the damaged bone and type of fracture. Non-displaced injuries to the hand, forearm or foot heal fairly quickly. For fractures of the pelvis, humerus or femur, the patient must be in a cast for several months;
• time to provide first aid. The earlier pain relief and fixation of the limb were performed, the more favorable the prognosis;
• the risk of complications is significantly reduced if reposition of the fragments with subsequent fixation is performed on the first day after the fracture;
• patient's age. In older people, blood circulation worsens, mineral metabolism is disrupted, as a result of which calcium is not completely absorbed. Therefore, the process of bone tissue regeneration takes much longer than in young people;
• general condition of the patient. Diabetes mellitus, tumor lesions of bones, vitamin deficiency, problems with the thyroid gland - this is an incomplete list of diseases for which the rehabilitation period can increase several times.

How to speed up the process of bone fusion?

In order to restore the functions of the damaged bone as quickly as possible, you must follow all the doctor’s recommendations. It is prohibited to perform physical exercises, massage, or take medications without consulting a traumatologist. This can lead to repeated displacement of fragments and improper fusion of bones.

Basic rules for successful rehabilitation:

• complete nutrition enriched with protein and calcium-containing foods. The diet should include a sufficient amount of fresh vegetables and fruits; you should also consume cottage cheese, cheese, eggs, fish and meat;
• moderate physical activity is indicated after the formation of a callus; only after a few weeks the doctor may allow you to perform the exercises;
• massage is indicated after removing the plaster. Regular sessions will help improve blood flow, reduce venous and lymphatic congestion;
• Medicines for fractures for rapid healing of bones are prescribed by the doctor according to strict indications. These could be calcium supplements, vitamins or chondroprotectors. Only a doctor can select the most effective group of drugs, dose and frequency of administration.

Calcium preparations

Today, there are many drugs on the pharmacological market that contain calcium. It would seem that this microelement is an important component of bone tissue; taking calcium during a fracture will be beneficial, and the larger the dose, the better for a person. But it's not that simple. Firstly, in some preparations calcium is in a form that is poorly absorbed by the body. Secondly, it is necessary to strictly adhere to the dosage and periodically check the level of this microelement in the blood. After all, excess calcium leads to problems with the cardiovascular system and contributes to the formation of stones in the kidneys and gall bladder. Therefore, the choice of medicine must be approached with special attention.

There are several groups of calcium-containing drugs:

• monocomponent products;
• The combination preparations include vitamin D3, magnesium and phosphorus. These components improve the bioavailability of calcium, making it more easily absorbed by the body;
• vitamin complexes with calcium.

The drug is a monocomponent and is used to heal bones in fractures. Available in the form of tablets and ampoules for injection.

Features of application:

• The tablet must be taken before meals. The frequency of administration and dose should be determined by the doctor. In most cases, the drug is prescribed 3 times a day. The maximum daily dose for adults is 9g;
• calcium gluconate can be administered intramuscularly and intravenously in a hospital setting;
• for better absorption, it is recommended to take additional vitamin D3;
• during pregnancy and lactation, the drug is prescribed if the benefits of use are much higher than the possible risks. In this case, it is necessary to monitor the level of calcium in the blood.

Pay attention! It is better to take calcium tablets with clean water. Coffee and tea impair the absorption of the active substance.

The most common side effects are constipation, nausea, vomiting, and stomach discomfort. As the dose increases, symptoms of hypercalcemia may develop: drowsiness, weakness, irritability, abdominal pain, vomiting, heart rhythm disturbances, increased blood pressure, muscle pain.

You can take medications containing calcium to heal bones during fractures only after consulting a doctor or after carefully reading the instructions. There are serious contraindications to the use of this group of drugs:

• intolerance to the components of the drug;
• tendency to form blood clots or severe atherosclerosis;
• increased concentration of calcium in the body;
• renal or liver failure.
• the presence of kidney stones.

This drug contains not only calcium, but also vitamin D3, magnesium, zinc, copper and other trace elements. This combination improves the absorption of components in the intestines and helps the body absorb calcium.

Features of application:

• the medicine is available in tablets. The dose and frequency of administration are prescribed by the doctor. It is recommended for adults to take 1 tablet in the morning and evening; for children, 1 tablet per day is enough;
• Pay attention! The drug contains vitamin D3, so there is no need to take it additionally, this can lead to an overdose;
• The main contraindications include hypercalcemia, allergies to the components of the drug, the presence of kidney stones, and an increased risk of blood clots;
• if after taking the drug nausea, vomiting, dizziness, or discomfort in the heart area occur, you should consult a doctor;
• Calcemin is allowed to be taken by pregnant women under medical supervision.

Calcium-D3 Nycomed is prescribed for fractures for rapid healing of bones. Due to the fact that the composition includes calcium and vitamin D3, the drug is well absorbed in the gastrointestinal tract and is evenly distributed in the body. Taking this drug allows you to accelerate bone regeneration and replenish the deficiency of microelements.

Special instructions:

• the medicine is available in the form of chewable tablets with orange or mint flavor, which is especially popular with children;
• The frequency and duration of administration is prescribed by the doctor, depending on the severity of the patient’s condition and age characteristics. The average dose is 2-3 tablets per day;
• a significant advantage is that the drug can be taken regardless of food;
• There are almost no side effects. Calcium-D3 Nycomed is well tolerated by patients, reviews of the drug are positive;
• during pregnancy and lactation, the drug is prescribed by a doctor according to strict indications with subsequent monitoring of calcium in the blood.

The medicine must not be taken in the following cases:

• with increased levels of calcium or vitamin D3 in the body;
• should be prescribed with caution to patients with phenylketonuria;
• an allergic reaction to the components of the drug is an absolute contraindication;
• In case of severe renal failure or sarcoidosis, it is better to avoid using the drug.

Osteogenon is one of the most effective drugs for bone fractures. It contains calcium and phosphorus, collagen, as well as non-collagen peptides. The main advantage of this remedy is that calcium is delivered directly to the bones, replenishing its deficiency, is not deposited in the kidneys, and does not aggravate urolithiasis.

Thanks to the special structure, the release of microelements occurs gradually. As a result, the risk of hypercalcemia and arrhythmias is minimal.

Main properties of Osteogen:

• regulation of calcium and phosphorus metabolism;
• stimulation of osteoblasts – bone tissue precursors;
• inhibition of osteoclast activity, thus the formation of new cells predominates in the bone;
• collagen and non-collagen peptides accelerate the regeneration process;
• Osteogenon promotes the formation of the mineral framework of the bone: calcium accumulates in the damaged area, making the tissue more dense.

To achieve results, the drug must be taken for a long time, on average 3-5 months. The daily dose and frequency of administration are determined by the doctor. It is recommended to take tablets for bone fractures 2 times a day.

Osteogenon is well tolerated by patients; it is contraindicated in the following cases:

• if you are intolerant to one of the components of the drug;
• in childhood;
• with increased levels of calcium in the body.

Drugs for rapid healing of bones during a fracture should be prescribed by a doctor. Even before purchasing vitamins or chondroprotectors, consultation with a specialist is necessary.

Chondroitin prevents further destruction of cartilage tissue, and is especially effective for intra-articular fractures. Active components promote the formation of collagen and hyaluron. Regular use of the product allows you to restore the metabolism of calcium and phosphorus and speed up the bone healing process.

The drug has several forms of release:

• capsules. You need to take the medicine for a long time, the effect occurs 2-3 months after starting treatment. The recommended dose for adults is 1 capsule 2 times a day (the intensive phase lasts 1 month), then switch to a maintenance dose of 1 capsule per day. Chondroitin is taken 20 minutes before meals;
• if necessary, the doctor may prescribe intramuscular injections. Injections are given every other day, the course of treatment averages 2 months;
• gel. A small amount of the drug should be applied to the skin at the fracture site and rubbed in a little. It is recommended to repeat the procedure daily for 2-3 months.

Teraflex

This drug is an analogue of Chondroitin and belongs to the group of chondroprotectors. Teraflex is an effective medicine for fractures, promotes the restoration of connective tissue, and prevents its further destruction. Also, the active components of the drug reduce pain and inflammatory reaction at the site of injury.

Contraindications:

• pregnancy, lactation;
• phenylketonuria;
• allergy to any of the components of the drug.

Restoring bone integrity is a difficult task. Rehabilitation in most cases takes several months. To speed up this process, doctors prefer complex treatment: calcium-containing tablets after a bone fracture, chondroprotectors, non-steroidal anti-inflammatory drugs, physical therapy and proper nutrition. Also during the rehabilitation period, mumiyos and physiotherapy are widely used.