39 Find errors in the given text. Indicate the numbers of proposals in which they are accepted,
Correct the mistakes.
The appearance of the first representatives of the type Flatworms was preceded by the appearance of a number of large
Aromorphozov.
Flatworms have developed a two-layer body structure - the basis for the formation of many
Organs and organ systems.
They developed radial body symmetry, allowing them to swim freely in water.
Orientation in space was facilitated by the emergence of sensory organs and diffuse nervous
Systems.
Digestive and excretory systems appeared.
Permanent gonads were formed, which determined the most effective
Forms of sexual reproduction.
Errors were made in sentences 2, 3, 4.
2. the number of body layers is incorrectly indicated - flatworms are three-layered animals;
3. flatworms have bilateral symmetry;
Flatworms have a stem nervous system.
Find errors in the given text. Indicate the numbers of the proposals in which they were made,
Correct them.
1. Cyanobacteria (blue-green) are the most ancient organisms; they are classified as prokaryotes.
The cells have a thick cell wall.
Cyanobacteria have chlorophyll and their cells produce organic matter from
Inorganic.
Photosynthesis in cyanobacteria occurs in chloroplasts.
Proteins are synthesized in small ribosomes.
ATP synthesis occurs in mitochondria.
Errors in sentences 3, 5, 7.
In cyanobacteria, the ring chromosome is separated from the cytoplasm by the nuclear envelope.
Cyanobacteria do not have a nuclear envelope.
Photosynthesis in cyanobacteria occurs in chloroplasts. Cyanobacteria do not have membranes
Organelles, including chloroplasts.
ATP synthesis occurs in mitochondria. Cyanobacteria do not have membrane organelles, including
Number of mitochondria.
41 Find errors in the given text. Please indicate the offer numbers in
Which they are made, correct them.
Brown algae live in the seas and consist of a variety of tissues.
Along with chlorophyll, their cells contain other pigments that capture sunlight.
Algae are capable of forming organic substances from inorganic ones as in
Photosynthesis and chemosynthesis.
Algae absorb water and mineral salts using rhizoids.
Algae are the main supplier of oxygen in the seas and oceans.
Seaweed - kelp - is eaten by humans.
Errors made in sentences:-
1) 1 - brown algae do not have tissues;
2) 3 - chemosynthesis does not occur in algae;
Algae absorb water and mineral salts over the entire surface of the body, and rhizoids serve
For attachment to the substrate.
42 Find errors in the given text. Indicate the numbers of the proposals in which they were made,
Correct them.
1. Kangaroo is a representative of marsupial mammals.
They live in Australia and South America.
Kangaroos feed mainly on insect larvae.
4. After birth, the baby kangaroo crawls into the pouch, where it feeds on milk.
This method of gestation is due to the fact that kangaroos have a poorly developed placenta.
When moving, the kangaroo rests on four legs, which allows it to make long jumps.
Errors in sentences:
Sentence 2 – Kangaroos live only in Australia.
Sentence 3 – Kangaroos eat only plants.
Sentence 6 – the kangaroo hops on two legs
43 Find errors in the given text. Indicate the numbers of the proposals in which they were made,
Correct them.
Platelets in mammals they are fragments of cells that have irregular shape, surrounded by a membrane and usually lacking a nucleus. They are formed from special cells in the bone marrow. Each platelet is approximately four times smaller than a red blood cell. Platelets are necessary to start the blood clotting process. 1 mm3 of blood contains approximately 250,000 platelets. The lifespan of platelets in humans is 5-9 days; they are then destroyed in the liver and spleen.
Circulation
Generalized human blood circulation diagram is presented in the figure and is characterized by the following features.
1. A person has two circles of blood circulation. This means that blood, passing throughout the body, enters the heart twice. The advantage of such a system is the ability to first enrich the blood with oxygen in the lungs (small, or pulmonary, circle), then return it to the heart and again push it out to the rest of the organs (large, or systemic, circle). The fact is that blood pressure in the pulmonary capillaries drops, and without an additional increase, the blood supply to most of the body would become ineffective. This pattern is not characteristic of all vertebrates. In fish, for example, blood from the heart is sent to the gills, enriched with oxygen there, then distributed throughout the body and only after that returns to the heart, i.e. in fish there is only one circle of blood circulation. Two circles of blood circulation appear in the evolutionary history of amphibians, but are completely separated only in birds and mammals. It is no coincidence that it was the last two groups of vertebrates that became warm-blooded. Warm-bloodedness requires intensive metabolism, which is only possible with a good supply of oxygen to the tissues, which is necessary for aerobic respiration (it is much more energetically beneficial than oxygen-free - anaerobic). And intensive metabolism allows you to maintain high level general activity of the body in a wide variety of environmental conditions. The presence of two completely separate circulations requires the division of the heart into two functional halves. One pumps deoxygenated blood to the lungs, and the other pumps oxygenated blood to the rest of the body. In fact, we have two hearts (right and left), which are fused together and contract simultaneously. In amphibians, the heart is not divided at all, but in reptiles it is incompletely divided (with the exception of crocodiles).
2. Blood supply organs is carried out not sequentially, but in parallel. Otherwise, the blood, passing from organ A to B, then to C, etc., would lose pressure, oxygen and nutrients, i.e., some parts of the body would sooner or later be deprived. In addition, damage to a blood vessel in any one location would cut off the blood supply to all downstream tissues.
3. Leads from the intestines to the liver portal vein. Portal veins are veins that connect two organs, neither of which is the heart (a similar system connects the hypothalamus with the pituitary gland). Thus, the intestines and liver are connected in series, and not in parallel, which entails the disadvantages mentioned above. However, they are offset by an important advantage. The fact is that the blood flowing from the intestines varies greatly in composition depending on what the individual ate or drank. And one of the functions of the liver is filtering blood in order to maintain its composition within physiologically acceptable limits. For example, here excess glucose is removed from the blood and stored as glycogen.
They have a closed circulatory system, represented by the heart and blood vessels. Unlike higher animals, fish have one circulation (with the exception of lungfishes and lobe-finned fish).
Pisces have a heart two-chamber: consists of the atrium, ventricle, sinus venosus and conus arteriosus, alternately contracting with their muscular walls. Contracting rhythmically, it moves the blood in a vicious circle.
Compared to land animals, the heart of fish is very small and weak. Its mass usually does not exceed 0.33–2.5%, on average 1% of body weight, while in mammals it reaches 4.6%, and in birds - 10–16%.
Blood pressure in fish is also weak.
Fish also have a low heart rate: 18–30 beats per minute, but with low temperatures it may decrease to 1–2; In fish that survive freezing into ice in winter, the heart pulsation stops altogether during this period.
In addition, fish have a small amount of blood compared to higher animals.
But all this is explained by the horizontal position of the fish in environment(there is no need to push the blood upward), as well as the life of fish in water: in an environment in which the force of gravity affects much less than in air.
Blood flows from the heart through arteries, and to the heart through veins.
From the atrium it is pushed into the ventricle, then into the conus arteriosus, and then into the large abdominal aorta and reaches, where gas exchange occurs: the blood in the gills is enriched with oxygen and freed from carbon dioxide. Red blood cells of fish - erythrocytes contain hemoglobin, which binds oxygen in the gills, and in organs and tissues - carbon dioxide.
The ability of hemoglobin in fish blood to extract oxygen from different types different. Fast-swimming fish that live in oxygen-rich running waters have hemoglobin cells that have a great ability to bind oxygen.
Oxygen-rich arterial blood has a bright scarlet color.
After the gills, the blood enters the head through the arteries and further into the dorsal aorta. Passing through the dorsal aorta, blood delivers oxygen to the organs and muscles of the trunk and tail. The dorsal aorta stretches to the end of the tail; along the way, large vessels extend from it to internal organs.
The venous blood of fish, depleted of oxygen and saturated with carbon dioxide, has a dark cherry color.
Having given oxygen to the organs and collected carbon dioxide, the blood flows through large veins to the heart and atrium.
The fish body also has its own characteristics in hematopoiesis:
Many organs can form blood: gill apparatus, intestines (mucosa), heart (epithelial layer and vascular endothelium), spleen, vascular blood, lymphoid organ (accumulations of hematopoietic tissue - reticular syncytium - under the roof of the skull).
The peripheral blood of fish may contain mature and young red blood cells.
Red blood cells, unlike mammalian blood, have a nucleus.
The blood of a fish has an internal osmotic pressure.
To date, 14 fish blood group systems have been established.
PHYSIOLOGY OF THE HEART AND VESSELS
The blood is enclosed and circulates in a closed circle of vessels, through which the blood flow occurs, called the circulatory system, or the circulatory system. Any system designed to circulate liquid must have a pump. Such a pump must either have valves that prevent backflow, or must pump fluid continuously. The center of this system, the source of energy that ensures the movement of blood in one direction, is the heart, and the peripheral part of the system is a network of blood vessels. Morphologically, fish have the following types of hearts: chamber hearts, tubular hearts, pulsatile hearts, ampullary and accessory hearts.
In fish, the main difference between the circulatory system and other vertebrates is the presence of one circulatory system and a two-chambered heart.
Rice. 24. Fish blood circulation diagram
In the systemic circulatory system, during the contraction of a two-chambered heart, there is one atrium and one ventricle, the venous blood filling it (with the exception of lungfishes and lobes) along the abdominal aorta, and its branches move to the gills. In the gills, the blood is saturated with oxygen and then sent to the head (by carotid arteries) and to the internal organs (along the abdominal aorta) inclusive of the capillaries that penetrate all organs and tissues of the body.
In this capillary network, everything necessary for their vital functions comes to the cells from the blood, and all the products of their vital activity, in particular carbon dioxide, go back into the blood. The presence of the latter makes the blood darker - venous, which flows from the capillaries of tissues and organs back to the heart. Venous blood enters the heart from the head and torso through the anterior and posterior cardiac veins, respectively.
In the gill filaments of fish, water and blood flow in opposite directions - the so-called countercurrent mechanism, which ensures almost complete extraction of oxygen from the water. This ends the circle of blood circulation. Thus, the blood circulation begins and ends in the heart.
3.1.1 Description of the circulatory system of cartilaginous fish . The heart (cor) consists of two chambers - the atrium and the ventricle. Blood from the veins collects in the venous sinus or venous sinus (sinus venosus). It is clearly visible and has the appearance of a thin-walled atrium (atrium), clearly visible on the sides of the ventricle. From the atrium, the blood passes into the thick-walled, muscular ventricle of the heart (ventriculus cordis). By contractions of the muscular walls of the ventricle, blood is pushed into the last part of the heart - the short arterial cone (conus arteriosus), which passes into the abdominal aorta (aorta ventralis). The walls of the conus arteriosus, like the ventricle, consist of striated muscles, and the walls of the abdominal aorta, like other blood vessels, are surrounded by smooth muscles.
Five pairs of afferent branchial arteries depart from the abdominal aorta. The anterior afferent branchial artery supplies the anterior hemibranch with blood; the second, branching off from the first, forms the first whole gill. The next three pairs of afferent gill arteries each approach one of the next three gills.
The afferent gill arteries in the gill filaments break up into a network of capillaries, through the walls of which gas exchange occurs. Oxygenated arterial blood is collected in the efferent branchial arteries, which empty into the dorsal aorta (aorta dorsalis), which passes under the spinal column. The branches of the dorsal aorta carry blood to all parts of the body.
Venous blood from the head collects in the paired anterior cardinal veins (vena cardinalis) and the inferior jugular veins (v.jugularis inferior). Coming from the tail, the caudal vein (v.caudalis) enters the body cavity and is divided into the right and left portal veins of the kidneys (v.porta renalis), which, breaking up into capillaries in the kidneys, form the renal portal system. From the kidneys, blood is collected by paired posterior cardinal veins (v.cardinalis posterior). The jugular, as well as the anterior and posterior cardinal veins of each side merge into the Cuvier's duct (ductus cuvieri). From the ventral fins blood is flowing along the lateral veins (v.lateralis), which merge with the subclavian veins, carrying blood from the pectoral fins, and flow into the corresponding duct of Cuvier. The ducts of Cuvier on the right and left sides empty into the sinus venosus. From the stomach, intestines and spleen, blood is collected by several veins, which merge into the portal vein of the liver (v.porta hepatis), which breaks up into capillaries in the liver. The hepatic veins (v.hepotica), which carry blood from the liver, flow into the venous sinus.
3.1.2 Description of the circulatory system of bony fish . The heart in bony fish is located in the lower anterior part of the body cavity, at the base of the isthmus. Venous blood collects in the venous sinus or venous sinus (sinus venosus). From here the blood passes into the anterior (atrium) and then into the thicker-walled ventricle (ocntriculus) of the heart.
Unlike cartilaginous fish, bony fish do not have a cone arteriosus. The large abdominal aorta (aorta ventralis) departs directly from the ventricle, forming in this place an extension of the aortic bulb (bulbus aorta). The abdominal aorta gives off four pairs of afferent branchial arteries (arteria branchialis asserentia). In the gill filaments, each afferent gill artery breaks up into a system of capillaries. Gas exchange between the blood and the water washing the gills takes place through their walls. Oxygen-enriched arterial blood is collected through the capillary system into the efferent branchial arteries (arteria branctialis efferentia), which on the dorsal side flow into the paired roots of the dorsal aorta. The roots of the aorta in the posterior part of the head merge to form the unpaired dorsal aorta (aorta dorsalis); it passes under the spine and sends out numerous arterial vessels to all parts of the body.
Venous blood from the caudal region passes through the azygos caudal vein (vena caudalis), which divides into two renal portal veins entering the kidneys. In bony fish, unlike cartilaginous fish, the portal system is formed only in the left kidney. From the kidneys, blood is directed forward through the paired posterior cardinal veins (vena cardinalis posterior); at the level of the heart, the posterior cardinal veins merge with the anterior cardinal veins (vena cardinalis anteriot), which carry blood from the head. As a result of the fusion of the posterior and anterior cardinal veins, paired Cuvier ducts (ductus civieri) are formed, which flow into the venous sinus. The lower blood carrying blood from the lower parts of the head flows into it. jugular vein(v. jugularis ingerior).
From the intestine, blood through the portal vein of the liver (vena porta heratis) enters the liver, where this vein breaks up into a system of capillaries, i.e. forms the portal system of the liver. Upon leaving the portal system of the liver, the blood enters the venous sinus through the short hepatic vein (vena heratica). Bony fish do not have lateral veins, characteristic of cartilaginous fish.
In bony fishes, as in cartilaginous fishes, one vicious circle blood circulation The heart of fish contains only venous blood. Contractions of the heart direct this blood to the gills, where carbon dioxide is released and oxygenated. Oxygenated arterial blood leaving the gill system is directed through numerous arteries to various bodies and the tissues of the body, where the reverse process occurs, the release of oxygen from the blood to the tissues and the saturation of the blood with carbon dioxide, or the conversion of blood from arterial to venous. Through the venous system, venous blood returns to the heart.
The concepts of “arterial” and “venous” blood determine the qualitative differences in the gas composition of the blood. These concepts do not always coincide with the names of blood vessels. So, venous blood moves through the abdominal aorta (artery) and the afferent branchial arteries. Regardless of the composition of the blood, arteries are the vessels through which blood flows from the heart, and veins are the vessels through which blood is directed to the heart.
3.1.3 Mechanism of blood circulation, vascular system. The blood circulation pattern in bony fish is presented as follows. Venous blood filling the heart, during contractions of the strong muscular ventricle, is directed forward through the bulbus arteriosus along the abdominal aorta and rises to the gills along the afferent branchial arteries. Bony fish have four on each side of the head, corresponding to the number of gill arches.
In the gill filaments, blood passes through the capillaries and oxidized, enriched with oxygen, is sent through the efferent vessels (there are also four pairs of them) to the roots of the dorsal aorta, which then merge into the dorsal aorta, which runs along the body back, under the spine. The connection of the aortic roots in front forms the head circle, characteristic of bony fish. The carotid arteries branch forward from the roots of the aorta.
Chambered hearts in vertebrates and mollusks. The heart size of fish is small and makes up about 1% of body weight. The heart is a hollow organ, consisting of three muscular layers; endocardium - internal, myocardium - middle and external - epicardium. The endocardium is formed by elastic and smooth muscle fibers of connective tissue. Myocardium, striated muscle fibers. Epicard – educated connective tissue, surrounding the myocardium. On the outside, the heart is covered with a connective tissue membrane, the so-called pericardium, which is not adjacent to the myocardium.
Cardiac rhythm and minute volume. In fish, with one atrium and one ventricle, the blood passes through the gill vessels before entering the aorta.
Like other vertebrates, cyclostomes and fish have so-called accessory hearts that maintain pressure in the blood vessels. Thus, in the dorsal aorta of the rainbow trout there is an elastic ligament that acts as a pressure pump, which automatically increases blood circulation during swimming, especially in the muscles of the body. The intensity of work of the additional heart depends on the frequency of movements of the caudal fin. In lungfish, an incomplete atrial septum appears. This is accompanied by the emergence of a pulmonary circulation passing through the swim bladder, transformed into a lung.
A feature of the heart is continuous rhythmic activity, which is manifested in the sequential contraction and relaxation of its parts. Contraction of parts of the heart is called systole, and relaxation diastole.
The superclass Pisces belongs to the phylum Chordata. They live in water. And they have a number of features associated with life in it.
Circulatory system of fish
Like all chordates, fish have a closed circulatory system. In both bony and cartilaginous fish, blood from the heart enters the blood vessels, and from them returns to the heart. These animals have two chambers in the heart - the atrium and the ventricle. There are three types of vessels:
- arteries;
- veins;
- capillaries.
Arteries carry blood away from the heart and the walls of these vessels are thicker so that they can withstand the pressure created by the heart. Through the veins, blood returns to the heart, and the pressure in them drops, so their walls are thinner. And capillaries are the smallest vessels, the walls of which consist of a single layer of cells, because their main function is gas exchange.
Blood circulation of fish
Before considering the process of blood circulation itself, it is necessary to remember the types of blood. It can be arterial, which contains a lot of oxygen, and venous, saturated with carbon dioxide. Thus, the type of blood has nothing to do with the name of the vessels through which it flows, but only with its composition. As for fish, they have venous blood in both chambers of the heart, and only one circulation.
Let us consider the movement of blood sequentially:
- The ventricle contracts and pushes out venous blood into the branchial arteries.
- In the gills, arteries branch into capillaries. Here gas exchange occurs and the blood turns from venous to arterial.
- From the capillaries, arterial blood collects in the abdominal aorta.
- The aorta branches into organ arteries.
- In organs, the arteries again branch into capillaries, where the blood, giving up oxygen and taking away carbon dioxide, becomes venous from the arterial.
- Venous blood from the organs is collected in veins, which carry it to the heart.
- The blood circulation ends in the atrium.
Thus, although fish cannot be called warm-blooded animals, their organs and tissues receive pure arterial blood. This helps fish live in the cold waters of the Arctic and Antarctic, and also not die in fresh water bodies in winter.
