The gas exchange of birds in flight is carried out thanks to. Respiratory system of birds
Do you know how interesting birds breathe? Their lungs don't really expand or compress. The lungs of birds are motionless and adhering to the chest. And their breathing is not "two-stroke", as in humans (inhale-exhale), but "four-stroke".
More details under the cut:
Respiratory system birds, if not the most perfect, then the most complex among vertebrates. In the respiratory tract, the dead volume is limited only by the trachea, and the air moves through the lungs in only one direction, and the air completes a full cycle in two pairs of respiratory movements (inhale-exhale-inhale-exhale), the so-called double breath.
The respiratory tract of birds begins with the nostrils, continues into the nasal cavity and upper larynx, the larynx is followed by the trachea, the length and number of cartilage rings in which different birds vary greatly, then at the point of branching of the trachea into two bronchi is the lower larynx of birds (syrinx), which is the main vocal apparatus of birds. The bronchi, having entered the lung, give off secondary bronchi, which partially extend beyond the lung and form air sacs located in various parts of the bird's body. The secondary bronchi communicate with each other by numerous parabronchi, braided with a network of blood capillaries.
- Trachea
- main bronchus
- secondary bronchi
- parabronchi
- abdominal pouch
- Dorsal thoracic sac
- Ventral thoracic sac
- Brachial bone
- Neck bag
- Interclavicular sac with outgrowths
- To the air sac in the sternum
- Outgrowths of the cervical vertebrae
Air bags are the only effective cooling system for birds. Being in the most "hot places", between and around the working muscles, in the abdominal cavity, etc., the air sacs are filled with air having a temperature environment(and given the high temperature in birds, which different types ranges from 38° to 43.5°C, the temperature of the environment in most cases will be lower), while the liquid evaporates from the walls of the bags, which contributes to the cooling of their walls, thus cooling the body. And in flight, when muscular work intensifies, and hence heat production, the work of the heart also becomes more frequent and external respiration intensifies, increased respiration will contribute to intense heat transfer. They can also be thermal insulators, preventing heat exchange between the tissues they share, in particular, these are internal organs and integumentary tissues.
There are five pairs of air sacs and one unpaired. They are also divided into front and rear. Anterior: cervical, interclavicular and prothoracic, posterior: posterior, abdominal and interclavicular (unpaired). The rear bags are larger than the front.
The main feature of the breathing of birds is the lungs, which are not subject to stretching, enclosed in a rigid chest, which does not change its volume. Therefore, the lungs are blown with air through the bronchial system, and the movement of air is provided by a change in the volume of the breathing bags.
When inhaling, air enters the trachea and primary bronchi mainly into the posterior sacs, while exhaling it moves into the lungs. On the second inhalation, air from the lungs enters the anterior sacs, and on the second exhalation, it exits.
It is noteworthy that no valves were found in the airways of birds, so all the bizarre air movements occur according to the laws of hydrodynamics.
- main bronchus
- Lung
- abdominal pouch
- Dorsal thoracic sac
- Ventral thoracic sac
- Front bags
- Neopulmo
Birds extract 40 ml of oxygen from 1 liter of air (mammals - 30 ml), while the oxygen tension in arterial blood is greater, and carbon dioxide is less than in exhaled air!
Let's try to schematically show how the countercurrent system provides such excellent gas exchange.
Gas exchange in birds
Above - parabronchus, below - capillary, the direction of air and blood flow is indicated by arrows. The red and blue circles represent, respectively, oxygen and carbon dioxide. When air and blood come into contact through the air-blood barrier, the oxygen concentrations in the air and in the blood tend to equalize. The same applies to carbon dioxide. Pay special attention to the difference between the results of gas exchange - exhaled air and arterial blood. This difference in the ratios of gases was discussed earlier.
Gas exchange in mammals
Here, the alveolus of the lung and the capillary are schematically depicted. The direction of blood flow, as well as air during inhalation (left) and exhalation (right) is indicated by arrows.
Again, when air and blood come into contact through the air-blood barrier, the concentrations of oxygen, as well as carbon dioxide, in the air and in the blood tend to equalize. However, contact with air occurs only once and the concentrations of gases in the arterial blood and in the exhaled air are equal.
This is an illustrative scheme, although very roughly illustrating the mechanism of gas exchange. In particular, it can be concluded from the scheme that when inhaling, the inhaled air immediately appears in the alveoli, which is not at all the case (the air in the alveoli does not move at all, only diffusion of gases occurs between the inhaled and alveolar air).
The frequency of respiratory movements, as well as the heart rate, is greater, the smaller the weight of the bird. In mallard ducks at rest - 10-16, in small passerines - 60-100 breaths / min.
Unlike mammals, the respiratory system in birds has structural and functional features. Structural features. Nasal openings in birds are located at the base of the beak; nasal air passages are short.
Under the external nostril there is a scaly fixed nasal valve, and around the nostrils there is a feather-corolla that protects the nasal passages from dust and water. In waterfowl, the nostrils are surrounded by a waxy skin.
Birds lack an epiglottis. The function of the epiglottis is performed by the back of the tongue. There are two larynxes - upper and lower. There are no vocal cords in the upper larynx. The lower larynx is located at the end of the trachea at the point of its branching into the bronchi and serves as a sound resonator. It has special membranes and special muscles. Air passing through the lower larynx causes the membrane to vibrate, which leads to the appearance of sounds of different heights. These sounds are amplified in the resonator. Chickens are capable of making 25 different sounds, each of which reflects a particular emotional state.
The trachea in birds is long and has up to 200 tracheal rings. Behind the lower larynx, the trachea divides into two main bronchi, which enter the right and left lungs. The bronchi pass through the lungs and expand into the abdominal air sacs. Within each lung, the bronchi give rise to secondary bronchi, which run in two directions - to the ventral surface of the lungs and to the dorsal. Ecto- and endobronchus are divided into a large number of small tubules - parabronchi and bronchioles, and the latter are already passing into many alveoli. Parabronchi, bronchioles and alveoli form the respiratory parenchyma of the lungs - the "spider web", where gas exchange takes place.
The lungs are elongated, maloelastic, pressed between the ribs and firmly connected to them. Since they are attached to the dorsal chest wall, they expand in a way that the lungs of mammals that are free in the chest cannot. The weight of the lungs in chickens is approximately 30 g.
Birds have the rudiments of two lobes of the diaphragm: pulmonary and thoracic. The diaphragm is attached to the spinal column with the help of a tendon and small muscle fibers to the ribs. It is reduced in connection with inspiration, but its role in the mechanism of inhalation and exhalation is insignificant. In chickens, the abdominal muscles take a great part in the act of inhalation and exhalation.
The breathing of birds is associated with the activity of large air sacs, which are combined with lungs and pneumatic bones.
Birds have 9 main air sacs - 4 paired, located symmetrically on both sides, and one unpaired. The largest are the abdominal air sacs. In addition to these air sacs, there are also air sacs located near the tail - posterior trunk, or intermediate.
Air sacs are thin-walled formations filled with air; their mucous membrane is lined with ciliated epithelium. From some air sacs there are processes to the bones that have air cavities. There is a network of capillaries in the wall of the air sacs.
The air sacs perform a number of roles:
1) participate in gas exchange;
2) lighten body weight;
3) ensure the normal position of the body during flight;
4) contribute to the cooling of the body during flight;
5) serve as an air reservoir;
6) act as a shock absorber for internal organs.
Pneumatic bones in birds are the cervical and dorsal bones, tail vertebrae, humerus, thoracic and sacral bones, vertebral ends of the ribs.
The lung capacity of chickens is 13 cm 3, ducks - 20 cm 3, the total capacity of the lungs and air sacs, respectively, is 160 ... 170 cm 3, 315 cm 3, 12 ... 15% of it is the respiratory volume of air.
functional features. Birds, like insects, exhale when the respiratory muscles contract; in mammals, the opposite is true - when the muscles of the inhalers contract, they take a breath.
Birds have relatively frequent breathing: chickens - 18 ... 25 times per minute, ducks - 20 ... 40, geese - 20 ... 40, turkeys - 15 ... 20 times per minute. The respiratory system in birds has great functionality - under load, the number of respiratory movements can increase: in agricultural birds up to 200 times per minute.
The air entering the body during inhalation fills the lungs and air sacs. Airspaces are actually spare containers for fresh air. In the air sacs, due to the small number of blood vessels, oxygen uptake is negligible; in general, the air in the bags is saturated with oxygen.
In birds, the so-called double gas exchange occurs in the lung tissue, which occurs during inhalation and exhalation. Due to this, inhalation and exhalation are accompanied by the extraction of oxygen from the air and the release of carbon dioxide.
In general, breathing in birds occurs as follows.
The muscles of the chest wall contract so that the sternum is raised. This means that the chest cavity becomes smaller and the lungs contract to the point where carbon dioxide-laden air is forced out of the breathing spaces.
As air exits the lungs during exhalation, new air from the air spaces passes forward through the lungs. During exhalation, air passes predominantly through the ventral bronchi.
After the muscles of the chest have contracted, the exhalation has taken place and all the used air has been removed, the muscles relax, the sternum moves down, the chest cavity expands, becomes large, a difference in air pressure is created between the external environment and the lungs, and inhalation is carried out. It is accompanied by the movement of air mainly through the dorsal bronchi.
The air sacs are resilient, like lungs, so when the chest cavity expands, they also expand. The elasticity of the air sacs and lungs allows air to enter the respiratory system.
Since muscle relaxation causes air to enter the lungs from the environment, the lungs dead bird, whose respiratory muscles are usually relaxed, will be inflated, or filled with air. In dead mammals, they are dormant.
Some diving birds can remain submerged for a significant amount of time, during which time air circulates between the lungs and air sacs, and most of the oxygen passes into the blood, maintaining an optimal oxygen concentration.
Birds are very sensitive to carbon dioxide and respond differently to increases in its content in the air. The maximum allowable increase is not more than 0.2%. Exceeding this level causes inhibition of respiration, which is accompanied by hypoxia - a decrease in the oxygen content in the blood, while the productivity and natural resistance of birds decreases. In flight, breathing slows down due to improved ventilation of the lungs even at an altitude of 3000 ... 400 m: in conditions of low oxygen content, birds provide themselves with oxygen with rare breathing. On the ground, birds die under these conditions.
The respiratory system of birds is considered the most complex among all animals.
This is understandable: a flying lifestyle requires an exceptionally developed respiratory mechanism and its well-functioning work.
Diagram of the respiratory tract
The respiratory tract of birds is a complex system consisting of several parts:
- nasal and oral cavities;
- Upper and lower larynx (pharynx and syrinx);
- Trachea;
- Bronchi;
- Air bags.
The bronchi form the backbone of the lungs. At the same time, birds have only one trachea, unlike mammals. Inhalation and exhalation with such a system are carried out in a more complicated way. Light birds are designed so that the air passes through them through.
At the same time, only 25 percent of the air remains in them, the rest is collected in air bags. When you exhale, the rest of the oxygen enters the lungs. This system is called double breathing and is distinctive feature birds.
The air sacs of a bird are the main “carrier of oxygen” and resolve the “bird paradox”, which consists in the fact that birds need to breathe much more than mammals and humans, but their lungs are much smaller in relative size, inactive and attached to the bones of the spine and ribs.
Birds do not have a diaphragm, and air movement is created by changing the pressure in the air sacs, which are stretched and compressed by the pectoral muscles. The air bag acts as a pump.
the structure of the respiratory system of birds photo
Expanding it, the bird forces outside air into it (some of which, as already mentioned, settles in the lungs through a branch in the trachea); then she compresses it, and the air passes through another path - through the lungs, from where it exits into the trachea and out.
Such breathing becomes more intense during the flight; air is forced into and out of the air sac by itself during the flapping of the wings. The more intensely the bird flaps its wings, the more deeply it breathes.
In addition to the respiratory function, air sacs perform additional functions: they lighten body weight, contribute to the release of excess heat, and in waterfowl they also provide buoyancy.
Efficiency
The described structure of the respiratory tract of birds allows for more efficient gas exchange compared to the lungs of mammals, and even more so reptiles and amphibians. Fresh air enters the lungs during both inhalation and exhalation.
At the same time, the exhaust air cannot immediately leave the body: there is an anterior air sac between the lungs and the trachea, and during the first exhalation, unnecessary air remains there. During the second exhalation, the air from there finally comes out, and its place is filled with a new portion that has passed from the main - the posterior air sac through the lungs.
The set of air sacs in birds is quite extensive and is not limited to the two considered. There are cranial sacs, which include the clavicular, cervical and cranial. The abundance of these cavities provides the bird with a light body capable of long-term flight.
However, the functions of the respiratory system of birds are not limited to breathing itself. She is also responsible for singing. Air passes through the lower larynx - the syrinx, which is also a distinctive feature of the bird class. The trachea plays the role of a resonator and can increase in volume during singing.
These and other changes in the shape of the vocal apparatus allow birds to reproduce a huge number of sounds, including imitating human speech. Based on the size of the trachea, we can say that in small birds the whole organism is responsible for resonating.
1 option
1. The body shape of birds is shaped like:
a) streamlined;
b) flat
c) spherical.
2. The beak of birds consists of:
a) horny jaws; b) ridge scales; c) bone jaws.
3. The contour feather of birds consists of:
a) rod, core; b) rod, fan, beard; c) rod, fan, chin, beard.
4. What forms the chest of birds:
a) thoracic vertebrae; b) thoracic vertebrae, ribs, sternum; c) thoracic vertebrae, keel, ribs.
5. What bone forms the tail section of the bird:
a) pelvic; b) coccygeal; c) crow.
6. The belt of the forelimbs in a bird consists of:
a) two elongated shoulder blades, two fused pelvic bones; two crow bones;
b) two coccygeal bones, two elongated shoulder blades; two crow bones;
c) two crow bones, two elongated shoulder blades, two clavicles fused at the bottom.
7. The most developed fingers of a bird:
a) 2 front; b) average; c) back.
8. The skeleton of the hind limbs consists of:
a) femur, 2 fused bones of the lower leg, tarsus, bones of the fingers;
b) femur, tarsus, finger bones, crow bone;
c) femur, tarsus, finger bones.
9. Goiter is:
a) expansion of the esophagus; b) expansion of the pharynx; c) intestinal expansion.
10. When lowering the sternum in birds, the air from the lungs passes:
a) into the lungs and posterior air sacs; b) in the anterior air sacs; c) into the lungs.
11. The following enters the lungs of birds:
a) arterial blood; b) mixed blood; c) venous blood.
12. In birds, only:
a) right ovary b) both; c) left ovary.
13. Birds have:
a) coccygeal gland; b) sacral; c) breast.
14. Heart of birds;
a) 4-chamber; b) 2; c) 3rd.
15. The lungs of birds look like:
a) bags b) nets; c) spongy bodies.
16. Bird excretory organs:
a) kidneys; b) kidneys and ureters; c) cloaca.
17. Testes of birds have:
a) bean-shaped; b) pea-shaped; c) curved.
18. What is more connected with high level metabolism in birds (compared to reptiles):
a) with perfect breathing, rapid digestion of food;
b) with perfect breathing, rapid digestion of food, perfect blood circulation, improvement of the digestive system;
c) with perfect breathing, blood circulation, rapid digestion of food.
19. What is the development of the midbrain connected with:
a) with the coordination of a complex movement; b) with the perfection of the organs of vision.
20. What is the importance of bird protein:
a) Protection against mechanical damage;
b) Protection against mechanical damage and water source;
c) Source of water.
PART B
1. Birds are warm-blooded animals.
2. The skin of birds has a large number of glands.
3. The coccygeal gland secretes the fat necessary to lubricate the feather cover.
4. Birds have sharp eyesight.
5. Birds have a three-chambered heart.
6. Birds have sharp teeth.
7. According to the method of movement, birds are divided into three groups: running, swimming and flying.
8. Riteless birds include all chicken.
9. Perhaps the first birds appeared on Earth about 1 million years ago.
10. The jaw of birds is represented by a beak.
Explain the meaning of the expression "Water off a duck's back."
Control work "Bird class"
Option 2
1. The bone jaws of the bird are covered with:
a) a horny sheath; b) a bony sheath; c) a keratinized sheath.
2. Outside the bird's body is located:
a) flight feathers; b) tail feathers; c) contour feathers.
3. Large contour tail feathers are:
a) steering; b) flywheels; c) downy.
4. What fluid accumulates in the coccygeal gland:
a) watery; b) oily; c) coccygeal.
5. What forms the sacrum of a bird:
a) the last thoracic vertebra, all lumbar, sacral and anterior caudal;
b) all lumbar, sacral, anterior caudal, femoral,
c) the last thoracic vertebra, sacral and anterior caudal.
6. What is the hind limb belt formed by:
a) 2 pairs of pelvic bones; b) 3 pairs of pelvic bones; c) pelvic and sacral bones.
7. The skeleton of the hind limbs consists of:
a) femur, 3 fused bones of the lower leg, tarsus, finger bones;
b) femur, 2 fused bones of the leg, bones of the fingers,
c) femur, 2 fused bones of the lower leg, tarsus, bones of the foot and fingers.
8. In the glandular part of the stomach, there are:
a) glandular juices; b) digestive juices; c) enzymes.
9. Importance of bird air sacs:
a) participation in respiration; b) decrease in body density, respiration,
c) protection of internal organs from overheating during flight, reduction of body density, participation in respiration.
10. When lifting the sternum, air containing carbon dioxide passes:
a) into the trachea; b) into the artery; c) into the lungs.
11. Open into the small intestine:
a) ducts of the pancreas, bile ducts of the liver and gallbladder;
b) ducts of the pancreas, bile ducts of the liver and gallbladder, duodenum 12;
c) ducts of the liver and gallbladder.
12. The high metabolic rate of birds is associated with:
a) with more perfect breathing, blood circulation, rapid digestion of food;
b) with more perfect breathing, rapid digestion of food;
c) with more perfect breathing, with a more developed digestive system.
13. Reproductive organs of birds:
a) testes; b) testes and ovaries; c) ovaries.
14. Why is the germinal disc facing up:
a) because the upper part of the yolk is heavier; b) the lower part of the yolk is heavier,
c) the yolk is in the center.
15. Cords consist of:
a) protein; b) water; c) nutrients.
16. The development of the cerebellum in birds is associated with:
a) the perfection of the organs of vision; b) with the coordination of the complex movements of the bird.
17. Bird excretory organs:
a) kidneys; b) kidneys and ureters; c) ureters.
18. When lowering the sternum, air from external environment goes to:
a) posterior air sacs; b) posterior air sacs and lungs; c) lungs.
19. The following enters the body organs of birds:
a) venous blood; b) arterial, c) mixed.
20. What provides constant temperature birds:
a) a high level of metabolism; b) feather cover,
c) a high level of metabolism and feather cover.
PART B
1. Write down the numbers of the correct statements.
The strength of the bird skeleton is achieved by the fusion of many bones in the early stages of individual development. In birds, the thoracic vertebrae bear ribs that are movably connected to the sternum. In many birds, the sternum does not have a keel. In birds, the hind limb girdle is formed by three paired bones: crows, shoulder blades and collarbones. The increase in brain volume is associated with the development of the forebrain hemispheres and the expansion of motor activity, the complication of behavior. Arterial blood, coming from the lungs through the pulmonary vein, pours into the left atrium, and from there into the right ventricle and aorta. The lungs have a spongy structure, the bronchi entering them branch out and end with the thinnest blind bronchioles. In some birds, the long esophagus forms an extension, as a goiter, where food accumulates and begins to be digested. The ureters open into the bladder, as in reptiles. Embryonic development of chicks begins with the release of egg membranes.
2. Which birds correspond to the listed signs.
3. Write down the numbers indicating the organs that perform the functions:
Explain the meaning of the expression "The crane flies high, but does not depart from the river."
Test work on the topic "Class Mammals"
Word puzzle. Put the letters and syllables correctlyTOL + PORRIDGE
FIELD + GIFT
Mark +/- true and false statements:1. The stomach of most animals is single-chamber
2. Food in the mouth is wetted by saliva
3. All mammals are covered with hair
4. The ancestors of mammals were animal-toothed lizards
5. In all mammals, babies are born already able to move.
6. Fertilization in females occurs inside the body
7. Mammals have a well-developed midbrain and cerebellum
8. The heart in mammals is four-chambered.
9. There are convolutions in the forebrain
10. The forelimbs consist of the thigh, lower leg and foot
11. Thoracic spine, ribs and sternum form the chest
12. The length of the neck of mammals depends on the number of vertebrae
13. The skull of mammals consists of more bones than reptiles.
14. Teeth are divided into incisors, canines and molars
15. The most developed back muscles
16. There are highly branched bronchi in the lungs.
18. Circulatory system consists of 3 circles of blood circulation
19. External fertilization
20. All mammals make nests
21. Marsupials give birth to underdeveloped babies
22. Platypus - one of the representatives of egg-laying
23. Echidnas carry eggs in a fold of skin on their stomach - a bag.
Choose the correct answer:1. A hallmark of mammals
1. Live birth
2. Fur body
3. Mammary glands
4. Presence of teeth
1. Mammals are descended from
1. Ancient reptiles
2. Animal-toothed lizards
3. Archeopteryx
4. Seymouria
1. The body cover of mammals is formed
1. Hairline and undercoat
2. Awn, undercoat, claws
3. Awn, undercoat, horny scales
4. Claws, wool
1. In the skin of mammals
1. No glands, dry skin
2. One coccygeal gland
3. Sweat and sebaceous glands
4. Sweat, sebaceous, milky, odorous glands
1. Unlike other vertebrates, mammals have
2. Vibrissae
3. Ears
1. The belt of the forelimbs consists
1. 2 collarbones, 2 shoulder blades, 2 crow bones
2. 2 collarbones, 2 shoulder blades
3. Sternum, 2 collarbones, 2 shoulder blades, 2 crow bones
1. The length of the neck of mammals depends on
1. Lengths of the vertebral bodies and their shapes
2. Number of vertebrae
3. The number of vertebrae and the length of their bodies
4. Not at all dependent
1. The heart in mammals
1. Three-chamber with a partition
2. Three-chamber without partition
3. Four-chamber
4. Five-chamber
1. GM has the most developed
1. Midbrain and cerebellum
2. Cerebellum and medulla oblongata
3. The cerebral cortex of the forebrain and the cerebellum.
Answer the questions:1. Name several organs of animals that provide them with thermoregulation of the body
2. How do animals get energy for their existence
3. What adaptations to environmental conditions do underground mammals have
4. Name the most valuable species of wild mammals, indicate their value.
Test
on this topic
Option 1
1. In most mammals in the cervical spine:
A) 6 vertebrae; C) 7 vertebrae;
B) 9 vertebrae; D) 12 vertebrae.
2. Which part of the mammalian brain is the most developed:
A) medulla oblongata B) cerebellum;
B) forebrain; D) midbrain.
3. Aperture is:
A) skin fold B) the outer cover of the lungs;
B) an opening between the thoracic and abdominal cavities; D) muscular septum;
4. The systemic circulation begins:
A) in the right atrium B) in the left ventricle;
B) in the right ventricle; D) in the left atrium.
5. The most changing department in the skeleton of mammals of different species is:
A) a skull B) tail;
B) cervical; D) chest.
6. A fertilized egg is:
A) zygote; B) gamete
B) spermatozoon; D) an egg.
7. When inhaling, the volume of the chest cavity:
A) permanent B) is increasing.
B) decreases;
8. Which of the organs is not located in the abdominal cavity?
A) lungs; B) liver
B) stomach; D) intestines.
9. The multi-chambered stomach of ruminants is adapted for digestion:
A) animal food C) plant food.
B) mainly animal and partly vegetable food;
A) sweat; B) sebaceous;
B) odorous; D) milky.
1. Select the features characteristic of mammals:
A) there are skin glands in the skin;
B) bare skin;
C) the skin is covered with horny scales;
D) alveolar teeth;
D) are the most highly organized vertebrates;
E) the large intestine is shortened.
2. Select the features of reproduction and development of mammals:
A) fertilization is internal;
B) external fertilization;
C) most lay eggs covered with a dense shell;
D) development with transformation;
D) the development of the embryo occurs in the uterus;
E) placenta is formed in the uterus.
A) the presence of a cloaca;
B) mammary glands without nipples;
C) the presence of a placenta (children's place);
D) the presence of crow bones in the shoulder girdle;
D) oviparous;
E) cubs are born very small and poorly developed;
G) the cerebral cortex is well developed;
C) the embryonic period is very short.
group of mammals
1) First beasts
2) Marsupials
3) Placental
1. In mammals with complex behavior, the cerebral cortex has ... .
2. There are no ... in the shoulder section of the skeleton of mammals. 3. Ribs are attached to ... vertebrae. 4. Together with ... they form the chest.
A) crow bones D) chest
B) facial E) sternum
C) trunk G) convolutions and furrows
D) cerebral
Test
on this topic "Class Mammals, or Beasts"
Option 2
Task 1. Choose one correct answer.
1. Which of the bones belongs to the forelimbs:
A) shoulder blade B) thigh
B) shoulder; D) shin.
2. The development of the embryo (embryo) occurs:
A) in the placenta B) in the uterus
B) in the oviducts; D) in the umbilical cord.
3. The embryo receives nutrition for its development through the system:
A) digestion B) breathing
B) blood circulation; D) selection.
4. Saliva enzymes break down:
A) proteins B) fats
B) carbohydrates (starch); D) all of the above substances.
A) trachea; B) bronchi;
B) larynx; D) lungs.
6. In the respiration of mammals, the main role belongs to:
A) skin B) easy.
B) lungs and skin equally;
7. Horny skin derivatives DO NOT include:
A) hair B) hooves
B) claws; D) sweat glands.
8. Why did mammals get such a name?
A) their main food is milk;
B) their glands secrete milk;
C) they feed their young with milk from the mammary glands;
D) their stomach does not digest milk.
9. What is the name of a group of mammals that have many features in common with reptiles:
A) marsupials; B) placental;
B) viviparous; D) First beasts, or One-pass.
10. Name the glands of mammals, the secret of which lubricates the coat, reducing its wetting:
A) sweat; B) sebaceous;
B) odorous; D) milky.
Task 2. Choose three correct answers.
1. Select the structural features of mammals:
A) the chest cavity is separated from the abdominal diaphragm;
B) teeth are divided into groups;
C) the chord persists throughout life;
D) the presence of one circle of blood circulation;
D) the presence of a coat;
E) are cold-blooded.
2. Select the features characteristic of the reproduction and development of higher (placental) animals:
A) cubs lick milk from wool;
B) the nipples of the mammary glands are well developed;
C) the development of the embryo occurs outside the mother's body;
D) the embryo is attached to the wall of the uterus by the placenta;
D) the cubs themselves suck milk;
E) The mother injects milk into the baby's mouth.
Task 3. Match:
Features of the structure and life
A) molars have sharp tops, carnassials are well developed;
B) most of their lives are spent in water;
C) the limbs are shortened and turned into flippers;
D) outwardly similar to fish;
E) hind limbs are absent, the pelvic girdle is reduced;
E) the body is covered with thick and long hair.
Detachment of placental mammals
2) Pinnipeds
3) Cetaceans
Task 4. What words are missing in the text? Fill in the gaps with the corresponding letters (the form of the words has been changed).
1. A different number of vertebrae in different mammals has ... department. 2. The belt of the forelimbs consists of paired shoulder blades and paired .... 3. Only mammals have ... an ear. 4. The function of touch is performed by ....
A) vibrissae D) rib
B) cervical E) external
C) caudal G) clavicle
D) average H) lips
The highest need of birds for oxygen was reflected in the structure of their airways and lungs, and also led to the appearance of air sacs.
airways in birds, they begin with nasal openings (nostrils) in the beak. The entrance to them is surrounded by a rim of feathers, which prevent the penetration of dust and water (in waterfowl, the nostrils are additionally surrounded by a wax skin) into the nasal cavity. From it, air through the choanae and the oropharyngeal cavity enters the upper larynx. There is no epiglottic cartilage here, and its function during swallowing is performed by the transverse fold of the mucous membrane and the back of the tongue. The upper larynx passes into a long trachea, which consists of a large number (from 100 to 130 in chickens, and up to 200 in geese) closed rings. At the end of the trachea is the lower, or singing larynx. It is (Fig. 3) an extension that, through two glottis, opens into right and leftmain (or primary) bronchi.
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Rice. 3. Singing larynx: 1 - trachea; 2 - expansion of the larynx; 3 - bridge; |
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The walls of the glottis during exhalation are able to vibrate with sound frequencies, and the expansion of the lower larynx enhances the resulting sound (resonator). Therefore, the lower larynx, along with the function of the airways, is able to form the voice of birds.
Each main bronchus (right and left) runs from the lower larynx to a lung on its side.
Lungs birds are located in the abdominal cavity (the birds have only the rudiments of the diaphragm) to the left and right of the spine. They are elastic (in mammals they are elastic), and their dorsal surface connected to ribs. The lungs consist of a system of tubes open at both ends, in which air moves in only one direction. These tubules are formed by the successive division of the right (in the right lung) and left (in the left lung) primary bronchi into secondary endo- and ectobronchi. In the dorsal part of the lung, predominantly formed endobronchus, and in the ventral ectobronchi. Endobronchi penetrate the lung parenchyma and there sequentially break up into many smaller ones. parabronchi and entwined with blood vessels air capillaries(Here is the exchange of gases between air and blood). Ectobronchi almost do not penetrate into the parenchyma of the lung, but leave it and form blind outgrowths called air bags.
Air bags located between internal organs, between muscles, under the skin, and some (especially in birds of prey) even connect with cavities pneumatic bones(cervical and dorsal bones, vertebrae, humerus, thoracic and sacral bones, vertebral ends of the ribs). Therefore, through their protruding fragment, the bird can breathe if the larynx and trachea are damaged. The main air sacs include four paired (cervical, prothoracic, retrothoracic and abdominal) and one unpaired (clavicular). According to their localization and contribution to external respiration, they are divided into anterior (cervical, clavicular and prothoracic) and posterior (retrothoracic and abdominal) air sacs. Their total volume is several times greater than the lungs.
Gas exchange does not take place in air sacs. their main function is to provide ventilation of the lungs(draw in and push out air). In addition, air sacs provide chilling birds,reduce the density of her body, serve as an air reservoir contribute to the normal position of the body during flight, act as a shock absorber for internal organs during sudden movements, as well as improve the passage of intestinal contents and excretion of feces.
Thus, the respiratory organs and the pulmonary circulation contribute to gas exchange between the alveoli of the lungs and the blood. Then, oxygenated arterial blood must be delivered to the cells, and the excess carbon dioxide formed in them, already with venous blood, must enter the structures that ensure its release into the environment.
Therefore, breathing in animals with a pulmonary type of breathing can be divided into the following stages:
external respiration or ventilation of the lungs;
exchange of gases between the alveoli of the lungs and the blood of the capillaries of the pulmonary circulation;
transport of gases by blood;
gas exchange between the blood of the capillaries of the systemic circulation and tissue cells;
internal (cellular or tissue) respiration.