The anatomical structure of the rabbit. We study the internal structure of the rabbit together What departments does the rabbit body consist of?

Rabbit anatomy has a lot in common with the internal structure of other mammals, but there are also fundamental differences. In this article, we will figure out what the skeleton of a rabbit consists of, as well as how its vital organs are located.

The skeleton of a rabbit is in many ways similar to the skeletons of other mammals, but has distinctive features

Performs supporting and protective functions. It includes 212 bones. In an adult pet it takes 10% of the body weight, in small rabbits - 15%. Cartilage, tendons and muscles link bones together. Subdivided into axial and peripheral.

Interestingly, meat rabbits have a smaller skeleton than their skin breeds..

Peripheral

Includes limb bones.

Subdivided into:

• Pectoral limbs (front legs)... Presented by the shoulder blades (belt), humerus, forearm, hand. The latter, in turn, consists of 9 short carpal bones, 5 metacarpal bones and 5 fingers, consisting of phalanges (the first has 2 phalanges, the rest - 3);
• Pelvic limbs (hind legs)... Includes the pelvis, ilium, pubic and ischial bones, thighs, shins, feet, 3 phalanges of 4 fingers.

The collarbone connects the sternum and shoulder blades together, allowing the rodents to jump. Their leg bones are thin, hollow inside, rabbits lack a strong spine. For these reasons, they often have paw fractures, and spine injuries are possible if careless.

The structural features of the skeleton allow him to jump to great heights

Axial

Includes major bones such as the skull and ridge.

Structure:

• Skull (brain and facial regions)... The bones are mobile, connected with special sutures. The cerebral section includes 7 bones (occipital, parietal, temporal and others). The facial includes the maxillary, nasal, lacrimal, zygomatic, palatine bones, etc. The skull of a rabbit is elongated, outwardly similar to the skull of other mammals. Most of it (3 \\ 4) is occupied by the respiratory and digestive organs;
• Torso (vertebral column, sternum, ribs)... The vertebral column or ridge consists of 5 parts, which will be discussed below. Flexibility of the spine is given by the menisci that hold the vertebrae together.

Wide vertebrae are characteristic of fleshy breeds. Knowing this property helps breeders select the right species.

The cervical spine includes 7 vertebrae. The thoracic region is represented on 12-13. They are held together by ribs to form the ribcage, where the heart and lungs are located. The number of vertebrae in the lumbar region varies from 6 to 7, in the sacral their number is 4. The caudal region is represented by 15 vertebrae.

The skeleton of a rabbit has 212 bones, wide vertebrae define the meat breed

Muscular system

The taste of meat and the appearance of pets are determined by the muscular system. Under the influence of impulses, muscles tend to contract.

Types of muscles:

• Body musculature... It is represented by striated muscle tissue. This includes all muscles;
• Musculature of internal organs... Consists of smooth muscle tissue. For example, the walls of the respiratory system, digestion, vascular walls.

The lifestyle of rabbits does not involve strong physical activity, as a result of which their muscles are insufficiently saturated with myoglobin and sarcoplasm. The meat has a white-pink hue, the color on the legs is darker than on the rest of the body. At birth, the muscular system of babies is poorly developed, accounting for no more than 20% of the total weight. With age, this number increases to 40%.

The muscles of eared pets are not very saturated with myoglobin, the meat is white-pink

Interestingly, the meat of an adult is higher in calories than the meat of a small rabbit.

Nervous system

Subdivided into:

• Central (brain and spinal cord);
• Peripheral (nerves of skeletal muscles, skin and blood vessels).

The brain is divided by a groove into 2 hemispheres (left and right), located inside the rabbit's skull. Scientists conditionally divide it into the following sections (middle, back, oblong, etc.), each of them performs a separate function. So, for example, oblong is responsible for the respiratory and circulatory system.

The spinal cord is located in the vertebral canal, which begins in the brain and ends in the region of the seventh cervical vertebra. Weighs about 3.64 grams. It consists of gray matter, which resembles the letter "H" in outline, and white matter surrounding the gray.

It is customary to refer to the peripheral section as cranial and spinal nerves, nerve endings.

The spinal cord of a rabbit weighs 3.64 grams and consists of gray and white matter

The cardiovascular system

It includes everything that is somehow connected with blood: hematopoietic organs (spleen), lymphatic system, arteries, veins, capillaries, etc. Each of them performs its own specific function: the spleen, whose weight does not exceed 1.5 grams, regulates blood pressure. The bone marrow is responsible for the production of red blood cells.

The thymus gland stimulates blood formation, its weight in newly born rabbits is only 2.3 grams, over time this volume decreases.

Up to 280 ml of blood circulates in the mammalian body. The body temperature of a healthy rodent in winter is 37 ° С, in summer it is 40-41 ° С. When the temperature rises to 44 ° C, the animal dies.

The anatomy of the rabbit heart has been studied for a long time, it is four-chambered, subdivided into 2 ventricles and 2 atria (chambers), weighs about 6.5 grams, and is located in the pericardial serous cavity. The normal heart rate is 110-160 beats per minute.

A 6.5 g rabbit heart has 4 chambers, where up to 280 ml of blood circulates

Digestive system

With its help, the rabbit processes food, thereby prolonging its life. The foods he consumes pass through the gastrointestinal tract within 72 hours.

The baby bunny has 16 teeth at birth. After two and a half weeks of life, deciduous teeth are replaced by molars. In adults, there are 28 of them, in other mammals there are more. They grow continuously throughout life. Rabbits have large incisors with which they gnaw through solid food; with the root teeth located below, the baby crushes his food.

Rabbits have 2 incisors at the bottom and top for crunching solid food

Interestingly, rabbits do not have fangs.

Chewed food first goes into the throat, and then into the esophagus and stomach. The latter is a hollow organ with a volume of up to 200 cm3, it produces gastric juice. It must be said that the activity of rabbit gastric enzymes is higher compared to the enzymes of other animals. The fiber consumed by the eared ears is not digested here, and in an unprocessed form it immediately enters the intestine, which completes the digestion process. It, in turn, is divided into:

• Small intestine . It breaks down substances, some of which (for example, amino acids) are sent directly into the blood;
• Colon... It is characterized by fermentation processes. Undigested and undigested food is excreted in the form of feces (up to 0.2 grams per day). Moreover, during the day it has a solid form, and at night it is soft. The stool, secreted at night, the individuals tend to eat, due to this property the body is saturated with the necessary proteins, vitamins of group B and K.

Rabbit stomach digests food more actively than other mammals

Respiratory system

The nose, pharynx, trachea, and lungs belong to the respiratory system. They provide the body with oxygen. The inhaled air is warmed up, filled with moisture, and cleansed of impurities in the nasal cavity. From there it enters the pharynx, then the trachea, and finally the lungs.

It is important to know that rabbits breathe more often than other mammals. Normally, the individual takes 282 breaths per minute. They have a fairly active gas exchange: when 478 cm3 of oxygen is consumed, 451 cm3 of carbon dioxide is released.

Furry pets breathe more often than other mammals, they normally take 282 breaths per minute

Sense organs

Babies have developed the following senses:

• Smell. It is carried out by receptor cells located deep in the nasal cavity. On their surface, there are from 10 to 12 hairs that react to various scents. With its help, the rabbit can find her cub among strangers, easily finds food, chooses a male for mating, etc.;
• Taste. It is carried out thanks to the taste buds located on the tongue;
• Feeling. It is realized with the help of sensitive skin in the area of \u200b\u200bthe eyelids, lips, back and forehead. It helps pets to navigate in space, avoid temperature fluctuations, respond to pain irritation;

Rabbits have an excellent sense of smell, sensitive hearing and excellent eyesight even in the dark.

Antennae help animals move in complete darkness, and hairs above the eyes tell you when to duck to avoid collisions.

• Vision. Rabbits see the world in color. The animal's eye is a globular eyeball that connects directly to the brain. The peculiarity of the sight of rabbits is farsightedness and the ability to see in the dark;
• Hearing. A distinctive feature is large auricles, thanks to which animals have sensitive hearing. The rabbits communicate with each other with high frequency sounds. To pick up the correct sound signals, animals turn their ears in different directions.

Genitourinary system

Represented by the genitals and urinary organs. The latter remove decay products from the body. The volume of urine is directly proportional to the age and nutrition of the animal. Its daily rate does not exceed 400 ml. The urinary canal itself is placed in close proximity to the reproductive apparatus.

Mammals have 2 oval buds. They take place in the lumbar region, promote the breakdown of proteins, mineral salts and other substances. Urine is formed continuously, it makes its way from the kidneys to the ureters, then to the bladder, which for some time accumulates fluid, and then reflexively removes it outside. Normally, it has a yellow straw tint. A bright yellow or even brown color is a sign of a disease.

Genitals

The genitals of males and females are different. In the first, the reproductive apparatus is represented by paired testes, vas deferens, accessory glands, and the penis. The uterus, ovaries, oviduct, vagina and genital opening make up the female reproductive system. The eggs mature in the ovaries and, during ovulation, enter the oviducts. The shape of the uterus is two-horned. Ovulation occurs 10-12 hours after intercourse.

The peculiarity of the rabbit's uterus - it consists of two horns

Endocrine glands

These include the thyroid gland, pituitary gland, pineal gland, adrenal glands, pancreas, testes and ovaries. Hormones go directly into the bloodstream, since they have no excretory pathways.

The adrenal glands regulate water and fat metabolism. The pituitary gland produces the largest number of hormones and is involved in many life processes. If the glands in the body for some reason become insufficient, this can lead to a deviation in growth and development..

Summary

The skeleton of a rabbit matches the description of the internal structure of other mammals. Knowledge in this area allows the owners of farms to properly care for their pets, recognize the disease in time, and, if necessary, contact a veterinarian to prescribe appropriate treatment.

Musculoskeletal system. The skeleton of mammals consists of the same sections as in other terrestrial vertebrates: the skull, spine, trunk skeletons, girdles and free limbs (Fig. 193).

Figure: 193. The skeleton of a mammal: 1 - upper jaw; 2 - the lower jaw; 3 - skull; 4 - teeth; 5 - cervical vertebrae; 6 - thoracic vertebrae; 7 - lumbar vertebrae; 8 - caudal vertebrae; 9 - ribs; 10 - scapula; 11 - shoulder; 12 - forearm; 13 - brush; 14 - pelvic bone; 15 - thigh; 16 - drumstick; 17 - foot

The bones of mammals are strong, many grow together. The skull is large, consists of fewer bones than in reptiles, since many grow together in the embryonic period. The jaws are strong, armed with teeth, which are located in the recesses - the alveoli.

The spine consists of the following five sections: the cervical (seven vertebrae), thoracic (twelve vertebrae), lumbar (six to seven vertebrae), sacral (four merged vertebrae), and the caudal section from a different number of vertebrae in different mammals. The vertebrae are massive, with flattened body surfaces. The ribs are attached to the vertebrae of the thoracic region, some of them are connected to the sternum, forming the chest. The belt of the forelimbs consists of paired clavicles and paired shoulder blades. Coracoids (crow bones) are reduced in most animals. In horses and dogs, in which the legs move only along the longitudinal axis of the body, the collarbones are also reduced. The hindlimb girdle (pelvic girdle) consists of two large pelvic bones. Each of them arose during the fusion of the pubic, ischial and ilium bones. The pelvic bones fuse with the sacrum.

Mammals have a complex muscle system. The most developed are the muscles that move the limbs. They start on the bones of the girdles and attach to the bones of the free limb. Long tendons fit the bones of the foot and hand, which provides good mobility of the limbs, expanding their adaptive (adaptive) capabilities.

The intercostal respiratory muscles are well developed, the contraction of which raises and lowers the chest. There are muscles that connect to the skin: for example, facial muscles, the contraction of which causes twitching of the skin, movement of the coat, vibrissae.

In all mammals, the chest cavity is separated from the abdominal muscular septum - the diaphragm. It enters the chest cavity with a wide dome and adjoins the lungs.

Laboratory work No. 10

Topic. The structure of the skeleton of mammals.

Purpose. To study the structural features of the skeleton of mammals.

Equipment: tweezers, magnifying glass, skeleton (and parts thereof) of a rabbit (cat, rat).

Working process

1. Consider the general structure of the skeleton. Find its parts: skeletons of the head, torso, limbs. Pay attention to the connection between the bones.
2. Examine the skeleton of the skull. Pay attention to the size of the cerebral box, bone joints, differentiated alveolar teeth.
3. Determine the parts of the spine and their structural features.
4. Consider the structure of the chest, remember its meaning for the animal.
5. Consider the structure of the skeletons of the girdles and free limbs - front and back. Find and name their main parts. Consider the muscle attachments.
6. Find similarities and differences in the skeletal structure of mammals and reptiles.
7. Write your conclusions in a notebook, draw the necessary drawings.

Nervous system. The central nervous system of mammals consists of the same sections as in other vertebrates (Fig. 194). The most developed is the forebrain, which has large hemispheres. The surface of the hemispheres is formed by several layers of nerve cells - the so-called cortex.

Figure: 194. The mammalian nervous system: A - general plan of the structure: 1 - brain; 2 - spinal cord; 3 - peripheral nerves; B - rabbit brain: 1 - olfactory lobes of the forebrain; 2 - forebrain hemispheres; 3 - convolutions of the cortex; 4 - diencephalon; 5 - midbrain; 6 - cerebellum; 7 - medulla oblongata

In mammals with relatively simple behavior (rabbits, mice), the hemispheres are smooth, while in carnivorous mammals and primates with complex behavior, the cerebral cortex has numerous convolutions (folds) and grooves that increase their surface. The large hemispheres of the forebrain cover the diencephalon and midbrain from above. The cerebellum is well developed, where the centers of coordination of movements are located.

The peripheral nervous system, like other vertebrates, is represented by twelve pairs of cranial nerves (branching off from the brain) and numerous nerves branching off from the spinal cord. Powerful nerve trunks travel from the spinal cord to the front and rear limbs.

Of the sense organs, animals have the most developed sense of smell, hearing, and sight. The brain regions associated with the olfactory, auditory and visual analyzers are well developed.

The more complex structure of the musculoskeletal and nervous systems of mammals in comparison with reptiles testifies to their progressive development, further differentiation in a series of vertebrates and enormous adaptive capabilities.

Digestive system in mammals it is more complex than in reptiles (Fig. 195). The mouth is surrounded by fleshy lips that make it easier to grasp and hold food. The teeth are differentiated (subdivided into groups) into incisors, canines, premolar and molars. In representatives of different families, they are developed in different ways, depending on the way of feeding and the nature of the feed. So, in rodents and hares, incisors are well pronounced, in predators - canines, etc.

Figure: 195. Internal structure of a rabbit (female): 1 - trachea; 2 - esophagus; 3 - heart; 4 - lungs; 5-stomach; 6 - cecum; 7 - liver; 8 - spleen; 9 - small intestine; 10 - pancreas; 11 - kidney; 12 - large intestine; 13 - ovary; 14 - uterus; 15 - oviduct; 16 - bladder

The vestibule of the mouth is located between the teeth and lips. Rodents and monkeys have cheek pouches in which they carry food. Animals tear off food and chew with their teeth, abundantly wetting with saliva. Saliva enzymes act on complex sugars (starch, fiber), breaking them down to simpler compounds. The food lump passes into the pharynx, esophagus and enters the stomach (Fig. 196, A). Most mammals have a simple stomach: it consists of one chamber. Its walls contain glands that secrete digestive substances and acid that digest proteins.

Figure: 196. Diagrams of the structure of the digestive systems of mammals: A - general plan of the structure (rabbit): 1 - mouth; 2 - oral cavity; 3 - pharynx; 4 - esophagus; 5 - stomach; 6 - liver; 7 - pancreas; 8 - small intestine; 9 - large intestine; 10 - cecum: 11 - rectum; 12 - anus; B - the structure of the stomach of a ruminant artiodactyl: 1 - scar; 2 - mesh; 3 - book; 4 - abomasum

In ruminant artiodactyls, the stomach is complex, consisting of four sections - scar, mesh, book and abomasum (Fig. 196, B). Only the last of these is the stomach itself. The previous divisions represent the expansion of the esophagus and serve to ferment food. Here, under the influence of protozoa, bacteria and yeast, indigestible fiber is processed. A cow per day secretes up to 50 liters of saliva, and food from the stomach is periodically belched and chewed by the teeth (hence the name "ruminants"). In the intestine, food is exposed to enzymes secreted by the digestive glands located in the intestinal walls and coming from the liver and pancreas. They affect all food groups: proteins, fats and sugars. Digested food is absorbed in the small intestine, and undigested residues enter the large intestine, where feces are formed and removed to the outside.

Respiratory system consists of the same sections as in reptiles: pathways and lungs (see Fig. 195). The lungs of animals are more complex than those of reptiles; they have a large surface, which ensures perfect gas exchange.

The trachea is divided into two bronchi, which enter the lungs and here they branch many times. The thinnest branches are the bronchioles. They end in pulmonary vesicles, or alveoli, whose respiratory surface is 50-100 times larger than the surface of the body. The alveoli are abundantly braided with blood capillaries. This is where gas exchange takes place. Carbon dioxide from the blood is released into the alveoli due to the pressure difference, and oxygen enters the capillaries from the alveoli, combines with the hemoglobin of erythrocytes and is carried by the blood throughout the body. Ventilation of the lungs occurs through inhalation and exhalation. Inhalation occurs due to the contraction of the intercostal muscles and the diaphragm, thereby increasing the volume of the chest cavity. When the intercostal muscles and diaphragm relax, the volume of the chest cavity and the volume of the lungs decrease - exhalation occurs.

Circulatory system mammals are similar to the circulatory system of birds. The heart is four-chambered: two atria and two ventricles. In the left half of the heart is arterial blood, in the right - venous (Fig. 197).

Figure: 197. Diagram of the structure of the mammalian circulatory system: 1 - heart; 2 - left aortic arch; 3 - carotid artery; 4 - dorsal aorta; 5 - jugular vein; 6 - pulmonary artery; 7 - pulmonary vein; 8 - posterior vena cava; 9 - capillary network of internal organs

Purely arterial blood from the left ventricle moves along a large circle of blood circulation to all organs and tissues of the body. True, unlike birds, mammals retained not the right, but the left aortic arch. Venous blood from the right ventricle is sent through the vessels of the pulmonary circulation to the lungs, where it is enriched with oxygen. The rapid movement of purely arterial and purely venous blood (especially to the head through the carotid arteries and from the brain through the jugular veins) provides the body with oxygen and quickly removes harmful waste products. This ensures a fast metabolism, high and constant body temperature in mammals.

Excretory system represented by the kidneys. They are located in the pelvic region and are compact bodies. In the kidneys, protein metabolism products are filtered from the blood: urea and some salts, along with water. Through the ureters, urine flows into the bladder and is removed through the urethra (Fig. 198).

Figure: 198. The structure of the excretory and reproductive systems of mammals - male (A) and female (B): 1 - kidneys; 2 - ureters; 3 - bladder; 4 - testes; 5 - ovary; b - vas deferens; 7 - oviducts; 8 - uterus; 9 - urethra

The structure and activity of the systems of the internal organs of mammals testifies to their more perfect, progressive development: intensive metabolism, constant and high body temperature. Comparison of mammals with birds shows their independent and parallel historical development.

Exercises on the covered material

1. What are the similarities and differences in the structure of the integument of the body of mammals and reptiles?
2. List the main structural features of the skeleton of the head, trunk, limbs associated with a terrestrial lifestyle, with the type of food.
3. Explain how the structure of the cerebral cortex of predators and primates differs from the cortex of rodents.
4. Using the example of rodents and ruminants, explain the characteristic features of the structure of the digestive system.
5. What complications have occurred in the structure and activity of the systems of internal organs of mammals in comparison with reptiles?

Circulatory system

The circulatory system includes the heart - the central organ that promotes the movement of blood through the vessels - and blood vessels - arteries (distribute blood from the heart to the organs), veins (return blood to the heart) and capillaries (exchange substances between blood and tissues). Vessels of all three types along the way communicate with each other by means of anastomoses existing between vessels of the same type and between different types of vessels. There are arterial, venous or arteriovenous anastomoses. Due to them, networks are formed (especially between capillaries), collectors, collaterals - lateral vessels accompanying the course of the main vessel.

A heart - the central organ of the cardiovascular system, moving, like a motor, blood through the vessels. It is a powerful hollow muscular organ located obliquely in the mediastinum of the chest cavity, in the region from the 3rd to the 6th rib, in front of the diaphragm, in its own serous cavity.

The heart in mammals is four-chambered, from the inside it is completely divided by the interatrial and interventricular septa into two halves - right and left, each of which consists of two chambers - the atrium and the ventricle. The right half of the heart, by the nature of the circulating blood, is venous, poor in oxygen, and the left half is arterial, rich in oxygen. The atria and ventricles communicate with each other through the atrioventricular openings. The embryo (fetus) has an opening through which the atria communicate, and there is also an arterial (botalle) duct through which blood from the pulmonary trunk and aorta is mixed. By the time of birth, these holes are overgrown. If this does not happen in a timely manner, the blood mixes, which leads to serious disturbances in the activity of the cardiovascular system.

The main function of the heart is to ensure a continuous flow of blood in the vessels. In this case, blood in the heart moves only in one direction - from the atria to the ventricles, and from them to the large arterial vessels. This is provided by special valves and rhythmic contractions of the muscles of the heart - first the atria, and then the ventricles, and then there is a pause and everything is repeated from the beginning.

The wall of the heart consists of three membranes (layers): endocardium, myocardium, and epicardium. The endocardium is the inner lining of the heart, the myocardium is the heart muscle (it differs from skeletal muscle tissue by the presence of intercalated crossbars between the individual fibers), the epicardium is the outer serous membrane of the heart. The heart is enclosed in a pericardial sac (pericardium), which isolates it from the pleural cavities, fixes the organ in a certain position and creates optimal conditions for its functioning. The walls of the left ventricle are 2–3 times thicker than the right one.

The heart rate largely depends on the condition of the animal, as well as on its age, physiological condition and ambient temperature. Under the influence of contractions of the heart (due to blood flow), there is a sequential contraction of blood vessels and their relaxation. This process is called blood pulsation, or pulse. The pulse is determined by the femoral artery or brachial artery for 0.5-1 min (four fingers are placed on the inner surface in the area of \u200b\u200bthe femoral canal or shoulder, and the thumb - on the outer surface of the thigh or shoulder). In newborn rabbits, the pulse rate is 280-300 beats / min, in an adult - 125-175 beats / min.

By its functions and structure blood vessels are divided into conducting and supplying. Conducting vessels are arteries (they conduct blood from the heart, the blood in them is red, bright, since it is saturated with oxygen, they are located deeper in the body of the animal, under the veins); veins (bring blood to the heart, the blood in them is dark, since it is saturated with metabolic products from organs, they are located closer to the surface of the body); feeding, or trophic, - capillaries (microscopic vessels located in the tissues of organs). The main function of the vascular bed is twofold - blood conduction (through the arteries and veins), as well as ensuring the metabolism between blood and tissues (links of the microcircular bed) and blood redistribution. Having entered the organ, the arteries branch many times into arterioles, precapillaries, passing into capillaries, then into postcapillaries and venules. Venules, which are the last link in the microcircular bed, merging with each other and enlarging, form veins that carry blood out of the organ. Blood circulation occurs in a closed system consisting of a large and small circles.

Blood -it is a liquid tissue that circulates in the circulatory system. This is a type of connective tissue that, together with lymph and tissue fluid, makes up the internal environment of the body. It carries out the transfer of oxygen from the pulmonary alveoli to the tissues (due to the respiratory pigment hemoglobin contained in erythrocytes) and carbon dioxide from the tissues to the respiratory organs (this is performed by salts dissolved in plasma), as well as nutrients (glucose, amino acids, fatty acids, salts, etc.) to the tissues, and the end products of metabolism (urea, uric acid, ammonia, creatine) from tissues to the excretory organs, and also transports biologically active substances (hormones, mediators, electrolytes, metabolic products - metabolites). The blood does not come into contact with the cells of the body; nutrients pass from it to the cells through the tissue fluid that fills the intercellular space. This liquid tissue is involved in the regulation of water-salt metabolism and acid-base balance in the body, in maintaining a constant body temperature, and also protects the body from the effects of bacteria, viruses, toxins and foreign proteins. The volume of circulating blood in the rabbit's body is 5-6.7% of the total live weight and depends on the age, type and breed of the animal.

Blood consists of two important components - corpuscles and plasma. The corpuscles account for about 30-40% of the total blood volume, plasma - 70%. Form elements include erythrocytes, leukocytes and platelets (Table 5).

Table 5

Healthy rabbit blood composition

Hematocrit - 34-44%

Erythrocytes - 5-7 mln / mm 3

Hemoglobin - 10-15 g / 100 ml

Leukocytes - 6-13 thousand / mm 3

Lymphocytes - 60%

Platelets - 125-250 thousand / μl

Blood count - 55–63 ml / kg live weight

Erythrocytes, or red blood cells, carry oxygen from the lungs to organs and tissues; the immunological characteristics of the blood depend on them, due to a combination of erythrocyte antigens, that is, the blood group. Leukocytes, or white blood cells, are divided into granular (eosinophils, basophils, and neutrophils) and non-granular (monocytes and lymphocytes). The percentage of individual forms of leukocytes is the leukocyte form of blood. All types of leukocytes are involved in the body's defenses. Platelets, or platelets, are involved in blood clotting.

Blood plasma is its liquid part, consisting of water (91–92%) and organic and mineral substances dissolved in it. The ratio of the volumes of blood cells and blood plasma in percent is called the hematocrit number.

This text is an introductory fragment. From the author's book

Circulatory system The circulatory system includes the heart - the central organ that promotes the movement of blood through the vessels - and blood vessels - arteries (distribute blood from the heart to organs), veins (return blood to the heart) and capillaries (exchange

From the author's book

Lymphatic System The lymphatic system is a specialized part of the cardiovascular system. It includes lymph, lymphatic vessels and lymph nodes. It performs two main functions: drainage and protective. Lymph is a transparent yellowish

From the author's book

Digestive System The digestive system of a dog consists of the mouth, pharynx, esophagus, stomach, small and large intestine, liver and pancreas. The oral cavity is formed by the upper and lower lips, cheeks, gums, teeth, soft and hard palate,

From the author's book

Respiratory system The respiratory system performs the function of gas exchange: it ensures that animal oxygen enters the body and carbon dioxide is removed from it. The breathing process occurs due to the contraction of the diaphragm. The respiratory system includes

From the author's book

Urinary System The urinary system is responsible for cleansing the body of processed waste products and removing excess water. It is formed by the kidneys, ureters, bladder, and urethra.

From the author's book

The reproductive system Like many other mammals, the external and internal genital organs are distinguished in the dog. The genitals of the female (bitches) are represented by the vulva, vagina, uterus, 2 oviducts and ovaries (paired gland). External genital organs - the vulva and the vagina -

From the author's book

Circulatory system The circulatory system includes: the heart - the central organ that promotes the movement of blood through the vessels, blood vessels - the arteries that distribute blood from the heart to the organs, veins that return blood to the heart, and blood capillaries through

From the author's book

Circulatory system The circulatory system consists of the heart, blood vessels, blood and blood-forming organs. The dog's heart is located in the chest cavity. Like all mammals, it is four-chambered, consists of two atria and two ventricles, and

From the author's book

Nervous System The Caucasian Shepherd Dog must have a strong nervous system. Only in this case will she be able to perform any work entrusted to her. A strong nervous system determines the working capacity of the Caucasian Shepherd Dog, its activity and endurance. As a rule,

From the author's book

Circulatory system The circulatory system includes the heart - the central organ that promotes the movement of blood through the vessels and blood vessels - arteries that distribute blood from the heart to organs, veins that return blood to the heart, and blood capillaries through

From the author's book

Lymphatic System The lymphatic system is a specialized part of the cardiovascular system. It includes lymph, lymphatic vessels and lymph nodes. It performs two main functions - drainage and protective. Lymph is a transparent yellowish

From the author's book

Circulatory system The circulatory system includes the heart - the central organ that promotes the movement of blood through the vessels, and blood vessels - the arteries that distribute blood from the heart to the organs, veins that return blood to the heart, and blood capillaries through

From the author's book

Circulatory system The circulatory system includes: the heart - the central organ that promotes the movement of blood through the vessels, and blood vessels - the arteries that carry blood from the heart to the organs, veins that return blood to the heart and blood capillaries through the walls

From the author's book

Respiratory organs and circulatory system The canary respiratory system is very complex. From the neck to the intestines there are air sacs connected to the lungs, as well as to the cavities of the hollow and spongy bones. The lungs are arranged so that air passes through them 2 times - the first

From the author's book

Circulatory system The circulatory system consists of the heart, blood vessels and blood-forming organs. The dog's heart is located in the chest cavity. Like all mammals, it is 4-chambered, consists of 2 atria and 2 ventricles and is connected to large

To properly organize rabbit breeding, you need to know fundamentals of animal anatomy and physiology.

In the body of rabbits, the following organ systems are distinguished: voluntary movement, digestion, respiration, urination, reproduction, blood and lymph circulation, nervous system, internal secretion, and skin. Internal organs are shown in the figure.

System of organs of voluntary movement consists of passive and active organs of movement.

Bones, cartilage and ligaments are passive organs. Bones serve as levers for muscles that attach to them, ligaments connect individual bones, allowing them to move.

Muscle - active organs of movement. Contracting or relaxing under the influence of nervous stimuli, they move the bones to which they are attached, resulting in the movement of the animal or individual parts of its body.

Bones outside are covered with a membrane called the periosteum. It has holes through which nerves and blood vessels pass into the bone. The outer layer of the bone (under the periosteum) is dense, and the inner layer is made of spongy substance, as a result of which the bones are strong and light. In the voids of the spongy substance is the bone marrow, one of the functions of which is hematopoiesis.

The bones are connected with each other movably (ligaments, joints) or motionlessly (connective or cartilaginous tissue) and form a skeleton that supports the body and protects the internal organs.

The skeleton is usually divided into stem, or axial (head and trunk), and the skeleton of the limbs.

Internal organs of the rabbit:
1 - trachea, 2 - lung, 3 - heart, 4 - diaphragm,
5 - ghee, 6 - gallbladder, 7 - stomach, spleen,
9 - small intestine, 10 - cecum, 11 - large intestine,
12 - rectum, 13 - kidney, 14 - ureter, 15 - bladder

The muscles that move the rabbit are made up of striated muscle fibers. Their groups are covered with a thin connective sheath (fascia), which separates the muscles into separate muscles, which allows them to contract in a certain direction. Depending on the location and the work performed, the muscles have a different shape and size. Muscles are attached to bones by tendons, most of which are surrounded by tendon sheaths that facilitate sliding.

The musculature (and skeleton) of the hind limbs is much better developed in the rabbit than in the front. This is due to the heavier work done by the hind legs (digging holes, jumping).

The digestive system. For the growth and development of animals, proteins, fats, carbohydrates, mineral salts and vitamins are needed. They are contained in various feeds eaten by rabbits, but the body can use them only after preliminary processing, which is carried out by the digestive organs.

TO digestive organs include: the oral cavity, esophagus, stomach, intestines, pancreas, liver.

The oral cavity is the beginning of the digestive tract. It is bounded in front by the lips, on the sides by the cheeks. The upper lip is divided in the middle into two parts by a longitudinal groove, which allows the rabbit to freely chew on various objects.

A newborn rabbit has 16 teeth. There are three incisors on each side of the jaw. The change of teeth begins from the 18th day after birth. Deciduous molars fall out on the 20-28th day. After the change of teeth, the animal has 28 or 26. In the upper jaw there are 2 large incisors in front, a pair of small incisors (sometimes they are absent) tightly adjoin them behind them, at a considerable distance from them behind (after the toothless edge) on each side of the jaw - 3 false rooted and 3 root.

In the lower jaw there are 12 teeth, 2 large incisors, and behind them, after the toothless edge, on each side of the jaw there are 2 false roots and 3 molars. The rabbit's teeth protrude deep into the jaw, but have no roots.

The food crushed by teeth is moistened with slightly alkaline saliva secreted by the parotid, submandibular, sublingual, buccal, infraorbital and mandibular salivary glands. The enzyme - diastase (vtialin), contained in saliva, converts starch into a soluble form.

Intestines in rabbits 8 - 10 times the body length. Due to contractions of the stomach muscles, food in a separate lump leaves the duodenum in 7-8 hours (but not all, therefore, the rabbit's stomach is never empty). Here the feed is exposed to the juices of the pancreas, liver and intestines.

Liver has 4 main lobes: two left, right and middle. Two highly developed processes extend from the latter. On the back side of the right lobe in the depression there is a gallbladder, from which a duct departs, which flows into the duodenum. The liver weighs 80-120 g. It is located in the abdominal cavity, adjacent to the concave side of the diaphragm, to which it is connected by ligaments. The role of the liver in the body is manifold. It produces large amounts of bile (up to 10% of body weight per day), which contains bile acids, fats, enzymes, some minerals and other substances. Once in the duodenum, bile accelerates the action of enzymes (lipase, amylase), promotes the dissolution of fats and fatty acids and neutralizes the stomach contents entering the intestines, and also enhances intestinal movement.

Respiratory system. The process of gas exchange in the rabbit's body, that is, supplying it with oxygen and removing carbon dioxide, is carried out by the respiratory organs and partially by the skin.

The respiratory organs include the nasal cavity, larynx, trachea, and lungs.

When a rabbit breathes, 50-60 respiratory movements per minute occur. Within an hour, per 1 kg of weight, it absorbs 478-632 cm 3 of oxygen and emits 451-632 cm 3 of carbon dioxide. Respiration rate is determined by the movement of the chest, abdominal wall (groins), and wings of the nose.

System, organs of blood and lymph circulation. Blood and lymph are essential for the metabolism and nutrition of all cells in the body. Blood consists of a liquid part - plasma, red and white cells, and platelets. It carries throughout the body and gives the cells the nutrients that have entered it from the intestines, the oxygen absorbed by it in the lungs, and hormones secreted by the glands ... of internal secretion. From the cells of the body, it takes unnecessary and harmful waste products and removes mainly with the help of the kidneys and lungs. In addition, blood helps to distribute heat evenly throughout the body.

The total amount of blood in a rabbit is 32-67 ml (from 4.5 to 6.7% of its weight). Its movement through the blood vessels is provided by the work of the heart, which is a complex muscular organ.

The heart is located in the chest cavity somewhat to the left, in the range from the posterior edge of the 2nd to the posterior edge of the 4th rib. A longitudinal septum divides the heart into right and left halves. In each of them there is a transverse septum with a closing valve and an opening, dividing both heart halves into upper and lower parts. The upper parts are called the atria (left and right), the lower ones are called the ventricles (left and right). The activity of the heart consists in alternating rhythmic contraction and relaxation of the muscles of its ventricles and atria. As a result of this, blood constantly jerks from the heart into the blood vessels and moves through them. The number of contractions - hearts in rabbits (pulse) - 120-160 per minute. The pulse is well felt in the femoral and brachial arteries and in the front of the lower jaw. To study the pulse, the finger is usually pressed against the femoral artery.

Blood vessels are elastic branching tubes. The vessels through which blood flows from the heart are called arteries, to the heart - veins.

Reproductive system. The male genitals consist of two male sex glands (testes with their appendages), two vas deferens, a penis and accessory gonads. In adult rabbits, the testes are located in the paired scrotum, and in young animals (up to 3 months of age) they are usually found in the inguinal passages.

Physiological maturity in rabbits it occurs early in medium-sized breeds by 3-3.5 months, in large breeds - by 3.5-4 months.

Well-developed females of medium breeds can happen without harm to their further growth, as well as the quality of the offspring at 4-5 months of age, and females of large breeds - at 5-6 months.

The sexual cycle of these animals has its own characteristics. After the onset of puberty, the activity of the gonads proceeds without clearly expressed seasonal periods. Females can fertilize and produce offspring at any time of the year. They are able to fertilize from the next day after birth and completely combine the periods of fertility and lactation.

Sexual heat in females in the warm season occurs every 5-6 days, in winter it is somewhat less common. The release of eggs (ovulation) occurs 10-12 hours after mating. Each ovary leaves 3-9 eggs in the oviduct. The male, when mating, secretes 1-2 ml of sperm. After 15-20 minutes, the spermatozoa penetrate into the oviducts and after 2-2.5 hours reach their opposite end. Fertilization of eggs usually occurs in the oviduct.

Intrauterine fetal development happens very quickly: after 10-12 hours, the embryos reach 0.3 mm, on the 8th day they attach to the wall of the uterus, on the 13-15th they can be felt through the abdominal wall, on the 16th the embryos begin to move. By the 30th day (time of birth), the weight of each rabbit is from 40 to 90 g, depending on the breed of rabbits, the number of rabbits and the feeding conditions of the uterus.

Okrol in rabbits it is easy and lasts from 10 minutes to one hour. Females completely combine the period of pregnancy and lactation and can fertilize, as already mentioned, the next day after birth.

Nervous system is very important for the life of the body. It is divided into central and peripheral.

The central one includes the brain and spinal cord, consisting of gray and white medulla. The gray medulla is built from nerve cells, white - from their processes, which are pathways connecting various parts of the brain with each other, as well as the brain with the spinal cord.

Skin covering protects the rabbit from harmful external influences - traumatic injuries, penetration of microbes. In addition, the skin is an organ of touch and is involved in heat exchange, respiration and metabolism. In animals of some breeds (white giant, flanders, etc.), the skin forms a large fold on the chest - dewlap.

In rabbits, there is no strictly defined seasonal timing for the change of hairline - molting. Adult animals usually molt in the spring (March - April) and autumn (September - October). Molting proceeds gradually

1-1.2 months at first, usually on the nape and front of the ridge, abdomen, sides and rump. Areas of shedding skin become bluish due to accumulation of dye (pigment). By placing bluish spots on the skin of a rabbit (the color of the skin is clearly visible when the fur is swollen), the places where molting is taking place are determined. In white rabbits, pigment is not formed in the skin, the places where molt passes are determined by short growing hair. In addition to the spring and autumn molting, adult rabbits experience "loss of guard hairs in summer."

In young animals, the change of hair occurs differently. Rabbits are born naked. By the age of 30 days, their primary hairline reaches full development. Then the first molt begins, which lasts up to 3.5-4 months of age. The second age molt occurs from 4-4.5 to

6.5-7 months of age. It proceeds in the following stages: the first stage - the lower part of the neck begins to shed; the second, the molt extends to the scruff, forming a kind of ring around the neck; third, the entire scruff, ridge and abdomen shed; fourth - molt descends from the ridge, rises from the abdomen to the sides; the fifth - on the sides there are wide strips of old hair that has not faded; sixth - there are small areas with old hair in place of the stripes; seventh stage - molt ends on the thighs and rump.

Each stage lasts 10-15 days.

In the cold season and when the rabbits are kept outdoors, molting is more intense and the hairline grows thicker than in the warm season and when rabbits are kept in rabbitries.

The formation and growth of new hair during shedding requires a significant amount of nutrients. With a good full-fledged feeding, molting accelerates, with a bad one - it slows down, the hair grows thinner, brittle, matte. During molting, animals lose weight, and young growth is stunted. During this period, the hairline of animals becomes less dense and protects them worse from the cold. Therefore, when molting, it is necessary to increase the feeding of rabbits, to protect them from colds.

Rabbit body temperature. The skin plays an important role in thermoregulation (maintaining a certain temperature in the body), protects animals from the influence of the changing temperature of the external environment. The body temperature of rabbits fluctuates depending on the external air temperature: at 5 ° it is 37.5, at 10 ° -38, at 20 ° -38.7, at 30-35 ° - 40.5, at 40 ° -41, 6 °. Rabbit skin temperature, in addition, is not the same in different parts of the body. In cold weather, energy consumption for warming the body increases, so in winter rabbits need to be fed 30-35% more food. The body temperature of rabbits is determined in the rectum.

Rabbits are sensitive to overheating, which results in heatstroke. If the air temperature is very high (42-43 °), the animals gradually overheat, their body temperature reaches 44-45 °, and they die. At 45-degree frost, they are able to maintain normal body temperature for an hour, during which measures must be taken to warm the cells.

The heart of rabbits is the central organ of the cardiovascular system, moving, like a motor, the blood of rabbits through the vessels.

The circulatory system of rabbits includes the heart - the central organ that promotes the movement of blood through the vessels - and blood vessels - arteries (distribute blood from the heart to organs), veins (return blood to the heart) and capillaries (exchange substances between blood and tissues) ... Vessels of all three types along the way communicate with each other by means of anastomoses existing between vessels of the same type and between different types of vessels. There are arterial, venous or arteriovenous anastomoses. Due to them, networks are formed (especially between capillaries), collectors, collaterals - lateral vessels accompanying the course of the main vessel.
Rabbits heart - the central organ of the cardiovascular system, moving, like a motor, the blood of rabbits through the vessels. It is a powerful hollow muscular organ located obliquely in the mediastinum of the chest cavity, in the region from the 3rd to the 6th rib, in front of the diaphragm, in its own serous cavity.
The heart of rabbits is four-chambered, from the inside it is completely divided by the interatrial and interventricular septa into two halves - right and left, each of which consists of two chambers - the atrium and the ventricle. The right half of the heart of rabbits by the nature of the circulating blood of rabbits is venous, poor in oxygen, and the left half is arterial, rich in oxygen. The atria and ventricles communicate with each other through the atrioventricular openings. The embryo (fetus) has an opening through which the atria communicate, and there is also an arterial (botalle) duct through which blood from the pulmonary trunk and aorta is mixed. By the time of birth, these holes are overgrown. If this does not happen in a timely manner, the blood mixes, which leads to serious disturbances in the activity of the cardiovascular system.
The main function of the rabbit heart is to ensure a continuous blood flow of the rabbit in the vessels. In this case, the blood in the heart of rabbits moves only in one direction - from the atria to the ventricles, and from them to the large arterial vessels. This is provided by special valves and rhythmic contractions of the muscles of the heart - first of the atria, and then of the ventricles, and then there is a pause and everything is repeated from the beginning.
The wall of the heart of rabbits consists of three membranes (layers): endocardium, myocardium and epicardium. The endocardium is the inner shell of the heart of rabbits, the myocardium is the heart muscle of rabbits (differs from skeletal muscle tissue by the presence of intercalated beams between the individual fibers), the epicardium is the outer serous membrane of the heart. The heart of rabbits is enclosed in a pericardial sac (pericardium), which isolates it from the pleural cavities, fixes the organ in a certain position and creates optimal conditions for its functioning. The walls of the left ventricle are 2-3 times thicker than the right one. The heart rate largely depends on the condition of the animal, as well as on its age, physiological condition and ambient temperature. Under the influence of contractions of the heart (due to blood flow), there is a sequential contraction of blood vessels and their relaxation. This process is called the pulsation of blood, or the pulse of rabbits. The pulse of rabbits is determined by the femoral artery or brachial artery for 0.5-1 min (four fingers are placed on the inner surface in the area of \u200b\u200bthe femoral canal or shoulder, and the thumb - on the outer surface of the thigh or shoulder). In newborn rabbits, the pulse rate is 280-300 beats / min, in an adult - 125-175 beats / min.