Animal eye tissues come in two main varieties: one common to many invertebrates, and the other to vertebrates such as fish or humans. The main difference between them is that they increase the light-collecting surface of the sensitive sensor differently.

Chapter 32. Features of metabolism in nervous tissue The human brain is the most complex of all known living structures. The nervous system and, first of all, the brain play a vital role in coordinating behavioral, biochemical, physiological

Energy metabolism in nervous tissue Characteristic features of energy metabolism in brain tissue are: 1. Its high intensity in comparison with other tissues.2. High rate of consumption of oxygen and glucose from the blood. Human brain, part

Lipid metabolism in nervous tissue The lipid composition of the brain is unique not only in the high concentration of total lipids, but also in the content of their individual fractions. Almost all brain lipids are represented by three main fractions: glycerophospholipids,

Chapter 33. Biochemistry of muscle tissue Mobility is a characteristic property of all forms of life - the divergence of chromosomes in the mitotic apparatus of cells, air-screw movements of bacterial flagella, bird wings, precise movements of the human hand, powerful work of the leg muscles. All

Muscle tissue proteins There are three groups of proteins: 1. myofibrillar proteins – 45%;2. sarcoplasmic proteins – 35%;3. stromal proteins – 20%. Myofibrillar proteins. This group includes: 1. myosin; 2. actin;3. actomyosin; as well as so-called regulatory proteins: 4. tropomyosin;5.

Chapter 34. Biochemistry of connective tissue Connective tissue makes up about half of the dry mass of the body. All types of connective tissue, despite their morphological differences, are built according to general principles: 1. Contains few cells compared to others

Animal tissue is a collection of cells that are connected by an intercellular substance and are intended for a specific purpose. It is divided into many types, each of which has its own characteristics. Animal tissue under a microscope can look completely different, depending on the type and purpose. Let's take a closer look at the different types.

Animal tissue: varieties and features

There are four main types: connective, epithelial, nervous and muscular. Each of them is divided into several types, depending on the location and some distinctive features.

Animal connective tissue

It is characterized by a large amount of intercellular substance - it can be either liquid or solid. The first type of this type of tissue is bone. The intercellular substance in this case is solid. It consists of minerals, mainly phosphorus and calcium salts. Cartilaginous animal tissue also belongs to the connective type. It differs in that it is elastic. It, in turn, is divided into types such as hyaline, elastic and fibrous cartilage. The most common type in the body is the first type; it is part of the trachea, bronchi, larynx, and large bronchi. Elastic cartilages form the ears, and the bronchi are medium-sized. Fibrous are part of the structure of the intervertebral discs - they are located at the junction of tendons and ligaments with hyaline cartilage.

Connective also includes blood and lymph. The first of them is characterized by specific cells called blood cells. They come in three types: red blood cells, platelets and lymphocytes. The first are responsible for the transport of oxygen throughout the body, the second are responsible for blood clotting in case of damage to the skin, and the third perform an immune function. Both of these connective tissues are special in that their intercellular substance is liquid. Lymph is involved in the metabolic process; it is responsible for returning various chemical compounds from tissues back into the blood, such as all kinds of toxins, salts, and some proteins. Connective ones are also loose fibrous, dense fibrous, and the latter is distinguished by the fact that it consists of collagen fibers. It acts as the basis for internal organs such as the spleen, bone marrow, lymph nodes, etc.

Epithelium

This type of tissue is characterized by the fact that the cells are located very closely to each other. The epithelium mainly performs a protective function: it makes up the skin, it can line organs both externally and internally. It comes in many types: cylindrical, cubic, single-layer, multi-layer, ciliated, glandular, sensitive, flat. The first two are so called because of the shape of the cells. Ciliate has small villi; it lines the intestinal cavity. All glands that produce enzymes, hormones, etc. consist of the following type of epithelium. The sensitive one acts as a receptor; it lines the nasal cavity. located inside the alveoli and blood vessels. Cubic is found in organs such as kidneys, eyes, and thyroid gland.

Nervous animal tissue

It consists of spindle-like cells called neurons. They have a complex structure, built from a body, an axon (long outgrowth) and dendrites (several short ones). These formations connect tissues to each other, and signals are transmitted through them, like wires. Between them there is a lot of intercellular substance, which supports neurons in the desired position and nourishes them.

Muscle tissue

They are divided into three types, each of which has its own characteristics. The first of these is smooth muscle animal tissue. It consists of long cells - fibers. This type of muscle tissue lines internal organs such as the stomach, intestines, uterus, etc. They are capable of contracting, but the person (or animal) himself is unable to control and manage these muscles on his own. The next type is cross-striped fabric. It contracts many times faster than the first one, since it contains more actin and myosin proteins, thanks to which this happens.

Striated muscle tissue makes up skeletal muscles, which the body can control at its discretion. The last type - cardiac tissue - is distinguished by the fact that it contracts faster than smooth tissue, has more actin and myosin, but is not subject to conscious control by a person (or animal), that is, it combines some features of the two types described above. All three are made up of long cells, also called fibers, that typically contain large numbers of mitochondria (organelles that produce energy).

Comparison of the structure of tissues of multicellular organisms (for example: plants, fungi, animals and humans). Types of tissues and their functions

Laboratory work

Biology and genetics

Laboratory work No. 3 Topic: Comparison of the structure of tissues of multicellular organisms using the example of: plants, fungi, animals and humans. Types of tissues and their functions. Tissue is a group of cells and intercellular substance united by a common structure, function and origin...

Laboratory work No. 3

Subject: Comparison of the structure of tissues of multicellular organisms (for example: plants, fungi, animals and humans).Types of tissues and their functions.

Textile this is a group of cells and intercellular substance, united by a common structure, function and origin. There are four main types of tissue in the human body: epithelial (integumentary), connective, muscle and nervous.

Target : learn to find structural features of cells of different organisms, compare them with each other; study the structure of various types of tissue and determine their functions; master the terminology of the topic.

Equipment : microscopes, slides and cover glasses, glass rods, microscopic preparations of cells of multicellular animals, microscopic preparations of epithelial, muscle, connective, nervous tissue.WITH containers with water, Elodea leaf, yeast, Bacillus subculture.

Safety precautions: work carefully with a microscope; treat the rules of working with it responsibly; When turning the lens to high magnification, carefully work with the screw so as not to crush the microspecimen.

PROGRESS OF WORK

Work 1.

1. Prepare a preparation of Elodea leaf cells. To do this, separate the leaf from the stem, place it in a drop of water on a glass slide and cover with a coverslip.
2. Examine the preparation under a microscope. Find chloroplasts in the cells.
3. Draw the structure of an Elodea leaf cell. Write captions for your drawing.

1. membrane
2.chloroplasts
3.cytoplasm
4.core
5.vacuole

4. Look at Figure 1.

5.Draw a conclusion about the shape and size of the cellsdifferent plant organs

Rice. 1. Color, shape and size of cells of different plant organs

Watermelon cell structure

O - cell membrane; n - granular wall layer of protoplasm; T - strands of protoplasm; yak - nuclear pocket (accumulation of protoplasm in which the nucleus lies ( I ) with nucleolus and plastids); V - vacuoles (according to Rostovtsev and Komarnitsky).

A living cell made from a coconut shell with branched canals and a very thick lignified shell: 1 - pore canals filled with cytoplasm; 2 - core; 3 - layered cell membrane; 4 - cytoplasm.

Plant leaf pulp cell

Stinging nettle leaf hair:

1 - base of the hair, 2 - burning cell, 3 - nucleus, 4 - vacuole, 5 - cytoplasm, 6 - broken off tip of the burning cell.

Work 2.

1.Remove some mucus from the inside of your cheek with a teaspoon.

2. Place the mucus on a slide and tint with blue ink diluted in water. Cover the preparation with a coverslip.

3. Examine the preparation under a microscope.

Job 3

Consider a ready-made microslide of cells of a multicellular animal organism.

Compare what you saw in the lesson with the images of objects on the tables.

Compare these cells with each other.

Enter the comparison results in Table 1

Answer the questions:

What are the similarities and differences between cells?

All these cells have a cell membrane, cytoplasm, hereditary material in the form of chromosomes, ribosomes, and inclusions. Eukaryotes (all except bacteria) have mitochondria, EPS, Golgi complex, lysosomes, nucleus, and centrioles. Plant cells, unlike animal cells, have vacuoles, plastids and a cellulose membrane. Bacteria have the most primitive structure, consisting of a murein shell, capsule, and ribosome.

What are the reasons for the similarities and differences between cells of different organisms?

The fact is that any living organism consists of cells, but cells perform different functions.

Job 4

I. Epithelial tissue

1. Examine a microslide of epithelial tissue. Sketch.

2. Name the types of epithelial tissue.

Classification of epithelial tissues:

1. integumentary epithelia- forming external and internal covers;
2. glandular epithelia- making up most of the body's glands.
3. Ciliated epitheliumforming the internal coverings of the respiratory tract (retains dust and other foreign bodies with the help of mobile cilia).

Morphological classification of integumentary epithelium:

• single-layer squamous epithelium, endothelium - lines all blood vessels;
• mesothelium - lines the natural human cavities: pleural, abdominal, pericardial;
• single-layer cuboidal epithelium - the epithelium of the renal tubules;
• single-layer single-row cylindrical epithelium - the nuclei are located at the same level;
• Single-layer multirow columnar epithelium - nuclei are located at different levels (pulmonary epithelium);
• stratified squamous keratinizing epithelium - skin;
• multilayered squamous non-keratinizing epithelium - oral cavity, esophagus, vagina;
• transitional epithelium - the shape of the cells of this epithelium depends on the functional state of the organ, for example, the bladder.

Glandular epithelium forms the vast majority of glands in the body. It consists of: glandular cells - glandulocytes; basement membrane.

Classification of glands according to the number of cells:

1. unicellular (goblet gland);
2. multicellular - the vast majority of glands.

According to the method of removing secretions from the gland and according to its structure:

• exocrine glands - have an excretory duct;
• endocrine glands - do not have an excretory duct and secrete hormones into the blood and lymph.

According to the method of secretion from a glandular cell:

• merocrine - sweat and salivary glands;
• apocrine - mammary gland, sweat glands of the armpits;
• Holocrine - sebaceous glands of the skin.

3. List the functions of epithelial tissue.

Functions of epithelial tissue:

• protective function against mechanical damage
• participates in metabolism, at the initial and final stages
• regulate the constancy of the internal environment of the body, metabolism, etc..

II. Connective tissue

1. Consider a connective tissue preparation. Sketch.

2. Name the types of connective tissue.

Most of the hard connective tissue is fibrous (from lat. fiber fiber): composed of fibers collagen and elastin . Connective tissue includes bone, cartilage, fat and others. Connective tissue also includes blood and lymph . Therefore, connective tissue is the only tissue that is present in the body in 4 types: fibrous (ligaments), solid (bones), gel-like (cartilage) and liquid (blood, lymph, as well as intercellular, spinal and synovial and other fluids).

3. List the functions of connective tissue.

Functions of connective tissue:

1) gives strength to organs, forming the basis of tendons and skin

2) performs a supporting function

3) Provides transportation of nutrients and oxygen throughout the body.

4) contains a supply of nutrients

III. Muscle tissue

1. Examine a microscopic specimen of muscle tissue. Sketch.

1. Name the types of muscle tissue.

Types of muscle tissue

• Smooth muscle tissueThe cells are mononuclear, located in layers in the walls of blood vessels, airways, bladder, digestive tract and other hollow internal organs.
• Transversely striated skeletal muscle tissueThe cells are multinucleated and form the muscles of the body, moving the human skeleton.
• Transversely striated cardiac muscle tissueforms the heart muscle, which contracts involuntarily.

3. List the functions of muscle tissue.

Functions of muscle tissue:

Motor. Protective. Heat exchange. You can also highlight one more function - facial (social). Facial muscles, controlling facial expressions, transmit information to others.

IV. Nervous tissue

1. Examine a microscopic specimen of nervous tissue. Sketch.

1. Name the types of nervous tissue.

Neurons - perform the main function.
Neuroglia - perform an auxiliary function (they surround neurons, protect them and provide them with support, protection and nutrition, there are 10 times more of them than neurons).

3. Function of nervous tissue.

Functions of nervous tissue:

• Excitability and conductivity. Excitation that appears under the influence of various environmental stimuli is transmitted to the central nervous system. It then ensures that the body reacts to this irritation.

Questions

1. What tissue do the glands belong to?

Glands belong to epithelial tissue.

1. What is the peculiarity of the structure of connective tissue?

Feature: there is much more intercellular substance than cellular elements.

1. In the walls of which organs is smooth muscle tissue located?

They are located in layers in the walls of blood vessels, airways, bladder, digestive tract and other hollow internal organs.

4. Thanks to the contractions of which muscles does movement occur?

Due to the contraction of skeletal muscles.

5. What tissue is characterized by electrical signals?

For nervous tissue.

Problematic issues

1. What tissues are involved in wound healing?

Connective tissue, as well as epithelial

2. Which tissues lack blood vessels?

Epithelial tissues. Epithelium lines the surface of the human body, the inner surface of hollow organs and forms most of the body's glands. The epithelium can be keratinized or non-keratinized. Epithelium is a layer of cells that are located on the basement membrane. They are devoid of blood vessels and have a high ability to regenerate.Cartilage, lens, and cornea are devoid of blood and lymphatic vessels.

Conclusion:

We examined the structure of prokaryotic and eukaryotic cells. We learned to find differences between cells of different organisms and highlight their similarities, studied the structure and functions of cell organelles and the cell itself as a whole.

We examined the structure of various types of tissues of the animal body. We studied the structure and functions of nervous, epithelial, muscle and connective tissue and their location in the human body.

Tissue as a collection of cells and intercellular substance. Types and types of fabrics, their properties. Intercellular interactions.

There are about 200 types of cells in the adult human body. Groups of cells that have the same or similar structure, are connected by a common origin and are adapted to perform certain functions form fabrics . This is the next level of the hierarchical structure of the human body - the transition from the cellular level to the tissue level (see Figure 1.3.2).

Any tissue is a collection of cells and intercellular substance , which can be a lot (blood, lymph, loose connective tissue) or little (integumentary epithelium).

The cells of each tissue (and some organs) have their own name: the cells of the nervous tissue are called neurons , bone tissue cells - osteocytes , liver - hepatocytes and so on.

Intercellular substance chemically is a system consisting of biopolymers in high concentration and water molecules. It contains structural elements: collagen fibers, elastin, blood and lymph capillaries, nerve fibers and sensory endings (pain, temperature and other receptors). This provides the necessary conditions for the normal functioning of tissues and the performance of their functions.

There are four types of fabrics in total: epithelial , connecting (including blood and lymph), muscular And nervous (see figure 1.5.1).

Epithelial tissue , or epithelium , covers the body, lines the internal surfaces of organs (stomach, intestines, bladder and others) and cavities (abdominal, pleural), and also forms most of the glands. In accordance with this, a distinction is made between the integumentary and glandular epithelium.

Covering epithelium (type A in Figure 1.5.1) forms layers of cells (1), closely - practically without intercellular substance - adjacent to each other. It happens single-layer or multilayer . The integumentary epithelium is a border tissue and performs the main functions: protection from external influences and participation in the metabolism of the body with the environment - absorption of food components and release of metabolic products ( excretion ). The integumentary epithelium is flexible, ensuring the mobility of internal organs (for example, contractions of the heart, distension of the stomach, intestinal motility, expansion of the lungs, and so on).

Glandular epithelium consists of cells, inside of which there are granules with a secret (from the Latin secretio- department). These cells synthesize and secrete many substances important to the body. Through secretion, saliva, gastric and intestinal juices, bile, milk, hormones and other biologically active compounds are formed. The glandular epithelium can form independent organs - glands (for example, the pancreas, thyroid gland, endocrine glands, or endocrine glands , releasing hormones directly into the blood that perform regulatory functions in the body and others), and may be part of other organs (for example, gastric glands).

Connective tissue (types B and C in Figure 1.5.1) is distinguished by a wide variety of cells (1) and an abundance of intercellular substrate, consisting of fibers (2) and amorphous substance (3). Fibrous connective tissue can be loose or dense. Loose connective tissue (type B) is present in all organs, it surrounds blood and lymphatic vessels. Dense connective tissue performs mechanical, supporting, shaping and protective functions. In addition, there is also very dense connective tissue (type B), which consists of tendons and fibrous membranes (dura mater, periosteum, and others). Connective tissue not only performs mechanical functions, but also actively participates in metabolism, the production of immune bodies, the processes of regeneration and wound healing, and ensures adaptation to changing living conditions.

Connective tissue also includes adipose tissue (View D in Figure 1.5.1). Fats are deposited (deposited) in it, the breakdown of which releases a large amount of energy.

Play an important role in the body skeletal (cartilage and bone) connective tissues . They perform mainly supporting, mechanical and protective functions.

Cartilage tissue (type D) consists of cells (1) and a large amount of elastic intercellular substance (2); it forms intervertebral discs, some components of joints, trachea, and bronchi. Cartilage tissue does not have blood vessels and receives the necessary substances by absorbing them from surrounding tissues.

Bone tissue (type E) consists of bone plates, inside of which lie cells. The cells are connected to each other by numerous processes. Bone tissue is hard and the bones of the skeleton are built from this tissue.

A type of connective tissue is blood . In our minds, blood is something very important for the body and, at the same time, difficult to understand. Blood (type G in Figure 1.5.1) consists of intercellular substance - plasma (1) and weighed in it shaped elements (2) - erythrocytes, leukocytes, platelets (Figure 1.5.2 shows their photographs obtained using an electron microscope). All formed elements develop from a common precursor cell. The properties and functions of blood are discussed in more detail in section 1.5.2.3.

Cells muscle tissue (Figure 1.3.1 and types Z and I in Figure 1.5.1) have the ability to contract. Since contraction requires a lot of energy, muscle cells have a higher content mitochondria .

There are two main types of muscle tissue - smooth (type 3 in Figure 1.5.1), which is present in the walls of many, and usually hollow, internal organs (vessels, intestines, gland ducts and others), and striated (view I in Figure 1.5.1), which includes cardiac and skeletal muscle tissue. Bundles of muscle tissue form muscles. They are surrounded by layers of connective tissue and penetrated by nerves, blood and lymphatic vessels (see Figure 1.3.1).

General information on tissues is given in Table 1.5.1.

Table 1.5.1. Tissues, their structure and functions

The preservation of shape and the performance of specific functions by the tissue is genetically programmed: the ability to perform specific functions and to differentiate is transmitted to daughter cells via DNA. The regulation of gene expression as the basis of differentiation was discussed in section 1.3.4.

Differentiation is a biochemical process in which relatively homogeneous cells, arising from a common progenitor cell, are transformed into increasingly specialized, specific types of cells that form tissues or organs. Most differentiated cells usually retain their specific characteristics even in a new environment.

In 1952, scientists from the University of Chicago separated chicken embryo cells by growing (incubating) them in an enzyme solution with gentle stirring. However, the cells did not remain separated, but began to unite into new colonies. Moreover, when liver cells mixed with retinal cells, the formation of cellular aggregates occurred in such a way that the retinal cells always moved to the inner part of the cell mass.

Cell interactions . What allows fabrics not to crumble at the slightest external influence? And what ensures the coordinated work of cells and their performance of specific functions?

Many observations prove that cells have the ability to recognize each other and respond accordingly. Interaction is not only the ability to transmit signals from one cell to another, but also the ability to act together, that is, synchronously. On the surface of each cell there are receptors (see section 1.3.2), thanks to which each cell recognizes another similar to itself. And these “detector devices” function according to the “key-lock” rule - this mechanism is repeatedly mentioned in the book.

Let's talk a little about how cells communicate with each other. There are two main methods of intercellular interaction: diffusion And adhesive . Diffusion is an interaction based on intercellular channels, pores in the membranes of neighboring cells located strictly opposite each other. Adhesive (from Latin adhaesio- adhesion, adhesion) - mechanical connection of cells, long-term and stable holding them at a close distance from each other. The chapter on cell structure describes various types of intercellular connections (desmosomes, synapses, and others). This is the basis for the organization of cells into various multicellular structures (tissues, organs).

Each tissue cell not only connects with neighboring cells, but also interacts with the intercellular substance, receiving with its help nutrients, signaling molecules (hormones, mediators), and so on. Through chemicals delivered to all tissues and organs of the body, humoral type of regulation (from Latin humor- liquid).

Another way of regulation, as mentioned above, is carried out using the nervous system. Nerve impulses always reach their target hundreds or thousands of times faster than delivery of chemicals to organs or tissues. The nervous and humoral ways of regulating the functions of organs and systems are closely interrelated. However, the very formation of most chemicals and their release into the blood are under constant control of the nervous system.

Cell, fabric - these are the first levels of organization of living organisms , but even at these stages it is possible to identify general regulatory mechanisms that ensure the vital activity of organs, organ systems and the body as a whole.

A collection of cells and intercellular substance similar in origin, structure and functions is called cloth. In the human body they secrete 4 main groups of fabrics: epithelial, connective, muscular, nervous.

Epithelial tissue(epithelium) forms a layer of cells that make up the integument of the body and the mucous membranes of all internal organs and cavities of the body and some glands. The exchange of substances between the body and the environment occurs through epithelial tissue. In epithelial tissue, cells are very close to each other, there is little intercellular substance.

This creates an obstacle to the penetration of microbes and harmful substances and reliable protection of the tissues underlying the epithelium. Due to the fact that the epithelium is constantly exposed to various external influences, its cells die in large quantities and are replaced by new ones. Cell replacement occurs due to the ability of epithelial cells and rapid.

There are several types of epithelium - skin, intestinal, respiratory.

Derivatives of the skin epithelium include nails and hair. The intestinal epithelium is monosyllabic. It also forms glands. These are, for example, the pancreas, liver, salivary, sweat glands, etc. Enzymes secreted by the glands break down nutrients. The breakdown products of nutrients are absorbed by the intestinal epithelium and enter the blood vessels. The respiratory tract is lined with ciliated epithelium. Its cells have outward-facing motile cilia. With their help, particulate matter trapped in the air is removed from the body.

Connective tissue. A feature of connective tissue is the strong development of intercellular substance.

The main functions of connective tissue are nutritional and supporting. Connective tissue includes blood, lymph, cartilage, bone, and adipose tissue. Blood and lymph consist of a liquid intercellular substance and blood cells floating in it. These tissues provide communication between organisms, carrying various gases and substances. Fibrous and connective tissue consists of cells connected to each other by intercellular substance in the form of fibers. The fibers can lie tightly or loosely. Fibrous connective tissue is found in all organs. Adipose tissue also looks like loose tissue. It is rich in cells that are filled with fat.

IN cartilage tissue the cells are large, the intercellular substance is elastic, dense, contains elastic and other fibers. There is a lot of cartilage tissue in the joints, between the vertebral bodies.

Bone tissue consists of bone plates, inside of which lie cells. The cells are connected to each other by numerous thin processes. Bone tissue is hard.

Muscle tissue. This tissue is formed by muscles. Their cytoplasm contains thin filaments capable of contraction. Smooth and striated muscle tissue is distinguished.

The fabric is called cross-striped because its fibers have a transverse striation, which is an alternation of light and dark areas. Smooth muscle tissue is part of the walls of internal organs (stomach, intestines, bladder, blood vessels). Striated muscle tissue is divided into skeletal and cardiac. Skeletal muscle tissue consists of elongated fibers reaching a length of 10–12 cm. Cardiac muscle tissue, like skeletal muscle tissue, has transverse striations. However, unlike skeletal muscle, there are special areas where the muscle fibers close tightly together. Thanks to this structure, the contraction of one fiber is quickly transmitted to neighboring ones. This ensures simultaneous contraction of large areas of the heart muscle. Muscle contraction is of great importance. The contraction of skeletal muscles ensures the movement of the body in space and the movement of some parts in relation to others. Due to smooth muscles, internal organs contract and the diameter of blood vessels changes.

Nervous tissue. The structural unit of nervous tissue is a nerve cell - a neuron.

A neuron consists of a body and processes. The neuron body can be of various shapes - oval, stellate, polygonal. A neuron has one nucleus, usually located in the center of the cell. Most neurons have short, thick, strongly branching processes near the body and long (up to 1.5 m), thin, and branching processes only at the very end. Long processes of nerve cells form nerve fibers. The main properties of a neuron are the ability to be excited and the ability to conduct this excitation along nerve fibers. In nervous tissue these properties are especially well expressed, although they are also characteristic of muscles and glands. Excitation is transmitted along the neuron and can be transmitted to other neurons or muscles connected to it, causing it to contract. The importance of the nervous tissue that forms the nervous system is enormous. Nervous tissue not only forms part of the body as part of it, but also ensures the unification of the functions of all other parts of the body.