Fisiología Respiratoria

Good morning, we are going to develop the class of respiratory physiology. The physiology or respiratory apparatus or respiratory tract forms a system responsible for the gas exchange in animals. Its function is the obtaining of oxygen and the elimination of carbon dioxide, that is,

to incorporate the oxygen needed to produce the combustion and from that combustion to obtain energy through the combustion of nutrients and of course the result will be the carbon dioxide. The respiratory apparatus

It is composed of the respiratory tree, the nasal cavity, the pharynx, the larynx, the trachea, the bronchioles, the bronchiolos, the bronchiolos principales and the alveolos.

Once we talk about bronchioles, we are already talking about inside the lung. Meanwhile, up to that level, we are talking about conduction pathways, that is, from the nasal fossa to the bronchioles, practically, or let's say, they are conduction pathways, so what they do is conduct the air and prepare it. There is still no type of exchange.

And then comes the gaseous exchange zone, where the breathing is already produced, which is an involuntary, automatic process through which the body cells will take the oxygen and will eliminate the carbon dioxide. It is a gaseous exchange between the atmosphere air and the organism.

As for the physiological anatomy of the circulatory system, the lung has three circulations, one in the pulmonary, another in the bronchial and another in the lymphatic. This is given by the blood vessels, the pulmonary artery that carries blood to the capillaries that surround the alveolar sacs, oxygen and carbon dioxide exchange,

bronchial arteries that run through the wall of the bronchial tree with oxygenated blood, and the pulmonary and bronchial veins that return blood to the heart. Pulmonary circulation is given by that pulmonary artery, which is a thin, elastic wall, which provides the pulmonary artery with great distensibility.

This distensibility is what allows these pulmonary arteries to accumulate about two-thirds of the systolic gas in the right ventricle. Pulmonary veins have characteristics of similar distensibility to those of the veins of systemic circulation, that is, very similar. As for bronchial circulation,

The flow is approximately 1 to 2% of total cardiovascular waste. The oxygenated blood of the bronchial arteries will irrigate the conjunctival tissue, the small and large bronchi.

Since bronchial blood is emptied into the pulmonary veins instead of the right heart, the right ventricular expenditure is 1-2% lower than the left ventricular expenditure. And finally, we have lymphatic circulation, which is found in these vessels in all the tissue supporting the lung.

The particles that penetrate the alveoli are eliminated by these conducts and the plasma proteins that are filtered from the pulmonary capillaries are also eliminated, which helps to avoid edema. As for the pressures in the pulmonary system, blood pressure in the pulmonary circulation is low compared to the systemic pressure. Pressure in the pulmonary artery in animals

The systolic pulmonary pressure is on average about 36 mmHg, it can go from 21 to 46. The diastolic pulmonary arterial pressure is about 21 mmHg, it can vary from day 28. And the average pulmonary arterial pressure is 26 mmHg. It varies or has its extreme between 10 and 35 mmHg.

The average capillary pressure is calculated by indirect methods at about 7 mmHg. This is important because it is also what allows the exchange. The pressure in the left and venous pulmonary auricula, this average pressure in that auricula and in the main pulmonary veins is on average 4 mmHg.

The pressure of the left auricle can also be calculated by means of pressure of pulmonary cavities, for example. But that is much more practical, so we will continue with the effects that hydrostatic pressure gradients have on the blood flow in the pulmonary region. Being erect, the animal

The distance between the highest point of the lungs and the lowest is approximately 30 centimeters, which is a 23 mmHg blood pressure difference. This gradient has a great effect on the blood flow through the different pulmonary areas. That is why the hydrostatic pressure gradients in the lung create different zones

of pulmonary blood flow under different normal and pathological conditions of the lung and there we can find any of these three possible blood flow zones. They are a zone, let's say, a first zone or a superior zone, this superior zone, which is the

that has no blood flow due to the fact that the local capillary pressure is never higher than the alveolar pressure. In this area, the alveolar pressure is higher than the arterial pressure and higher than the venous pressure. Therefore, the capillaries are compressed. Zone 1 only occurs in abnormal conditions. It can occur when the pulmonary arterial pressure drops, for example, in a hemorrhage.

or when the alveolar pressure increases, for example in a ventilation with positive pressure. The second zone, or mid zone or intermediate zone, as you want to call it, the blood flow is intermittent during the systole when the arterial pressure is higher than the alveolar pressure, but not during the diastole when the arterial pressure is lower than the alveolar pressure.

The blood flow here is determined by the difference in blood pressure and alveolar pressure. And finally, the third zone or the lower zone, the lower part of the lung, the blood flow is high and continuous due to the fact that the capillary pressure remains above the alveolar pressure throughout the cardiac cycle.

So that will make the distribution of blood and air different. We will have that in the upper part it will be well aerated, but it will have little blood, that is, there will be little red blood cells that can take that available oxygen.

The second zone, the intermediate zone, is more balanced, it is well irrigated and well ventilated, it has enough oxygen available. And finally, the lower zone, the third zone, the lower zone, is more irrigated, but it is not well,

Let's say that there is a lot of red blood cells for the amount of oxygen available in this area. Is this understood? Then there will be a first area where there is a lot of oxygen available, but there are no red blood cells to transport it. The intermediate zone, which is the one that is balanced, and a lower zone where there is a lot of red blood cells in comparison with the availability of oxygen.

That distribution is not homogeneous and of course it will change with the posture. As for the vascular resistance of the lung,

This will decrease in an intense exercise. During the exercise, the blood flow through the lungs increases from 4 to 7 times and this additional blood flow is accommodated in the lungs in practically two ways. One by increasing the number of open capillaries, sometimes up to 3 times, and the other by lowering all the capillaries and increasing the flow rate through each capillary to more than double.

In a normal animal, these two alterations together decrease the vascular-pulmonary resistance so much that the pulmonary arterial pressure increases very little, even when there is maximum effort. How do liquids move? How is the capillary dynamics in the lung?

These alveolar walls are covered with a number of capillaries that in most areas, these almost touch each other, therefore, the blood flows in the alveolar walls like a sheet, not as a duct, because there is practically no space between capillary and capillary. And the exchange of liquid capillary in the lungs and the dynamics of the pulmonary intervascular liquid

allows for that quick exchange of liquid through the pulmonary capillaries, which is qualitatively equal to that of peripheral tissues. However, there are quantitative differences that lead to

that this happens in this way. One is the low pulmonary capillary pressure, remember we talked about it before, which was about 7 mmHg, compared to a higher capillary pressure in the peripheral tissues, which is around 17 mmHg. Another is the pressure in the intertissue of the lung, which is slightly negative,

than the subcutaneous and peripheral tissue and the values there will vary in negative values between -5 and -8 mmHg. Another is the capillary permeability, which is high.

which allows additional amounts of protein to leave the capillaries in this way. The colloidal pressure of the interstitial liquid is also high, around 14 mmHg compared to the 7 mmHg of average in many peripheral tissues. The alveolar walls

They are thin, the epithelium that covers the alveolar walls is so weak that it breaks when the interstitial pressure increases above the atmospheric pressure, that is, more than 0 mmHg, which allows the interstitial space liquid to flood the alveoli, let's say, to enter the alveoli and flood it.

The average filtration pressure in the pulmonary capillaries is 1 mmHg, that is, a positive value. And this value is obtained taking into account the total output force, that is, about 29 mmHg. The forces that tend to cause the liquid to come out of the capillaries are that capillary pressure that we have been mentioning, 7 mmHg,

The colloidal pressure of the interdicial liquid of 14 mmHg and the pressure of the interdicial liquid, which is of minus 8 mmHg.

The total input force is 28 mmHg, the difference is 1 mmHg. The only force that tends to absorb liquid into the capillaries is the colloidal plasma pressure, the pressure exerted by the proteins, which is 28 mmHg. So the net filtration pressure is +1, that is, 1 mmHg, as the total output force,

29 mmHg is slightly higher than the input of 28 mmHg, the net filtration pressure is slightly positive, of 1 mmHg as we have mentioned. This net filtration pressure produces a continuous loss of liquid in the capillaries. Here we have graphed how

the liquid, the hydrostatic and osmotic forces that are going to come into play, of what we were talking about. Assuming there is a failure, the retention of the liquid is going to occur and that is known as post-mortem edema, which occurs in the same way as in the rest of the body, that is, there is a liquid transbase, it accumulates, there is no one who can remove it and

The most common causes of this edema, that is, of this liquid filling the lungs, are mainly due to two processes. One is left cardiac insufficiency or mitral valvulopathy, with the consequent great increase in pulmonary capillary pressure and the flooding of the interstitial spaces and the alveoli.

and the other is the lesion of the pulmonary capillary membrane produced by infections or by inhalation of harmful substances, which produces rapid release of plasma liquid and protein outside the capillaries. When the volume of pulmonary interstitial fluid increases by more than 50%, the liquid enters the alveoli, therefore the edema liquid enters the alveoli, except in the cases of milder edema.

There are other safety factors that prevent pulmonary edema, so that this edema occurs. All the following factors must be overcome to produce pulmonary edema. One is the normal negativity of the pressure of the interstitial fluid, lymphatic pumping, which is the one that takes

or the liquid that enters the intervascular spaces is dry, and the other is the lower pressure with the intervascular fluid, produced by a greater loss of fluid in the pulmonary capillaries.

As for the type of breathing in animals, we have those animals that live in humid or aquatic environments, such as certain anelids, some arthropods, amphibians, which also have lungs, breathe through the skin. It is the cutaneous breathing. This type of breathing needs the skin to be fine, permeable to gases, and it must also be continuously wet.

Branch breathing. Branch breathing is characteristic of aquatic animals such as some anelids, mollusks, crustaceans, equinoderms and fish. These branches are nothing more than a projection of the external surface of the body or of the internal layer of the intestine towards the outside of the animal. Pulmonary breathing

The lungs are invaginations of the respiratory surface surrounded by blood capillaries. They are thin bags, walls that serve to make the exchange of gases for what is connected to the outside through a series of conducts. And so we have that, as the animal scale is made, the lungs increase their internal surface

from amphibians whose lungs are sacs without any tabication, so that this breathing is complemented with what occurs through the skin, that is, the cutaneous, to the birds and mammals, whose lungs are the most developed due to the aerial sacs and the birds and the alveoli in mammals.

The mechanism that respiratory physiology has to produce this pulmonary respiration, that gaseous exchange of the body with the exterior, mainly presents two stages. One is the inspiration and the other is the exhalation.

What are the functions of the respiratory system? Air distribution, gas exchange, oxygen and carbon dioxide, as well as filtering, heating, and humidifying the air we breathe, regulating the pH by retaining or eliminating carbon dioxide, regulating the temperature by water loss, by evaporation, for example,

conversion or production of some hormones in the lung and also production of sounds, the oral language that allows each species to communicate with each other. As for the concept of breathing, we have cellular breathing, that cellular breathing is what will produce

the intracellular interaction of oxygen with molecules to produce mainly carbon dioxide, water and energy. That is, it will arrive by a path, by a respiratory tract, for example, oxygen

and by another apparatus, the digestive apparatus, the solute will arrive, which will be combustion inside the organism to produce that energy, which is what the cell will need to fulfill all its metabolic functions.

And then we have external breathing, which is the movement of gases between the environment and the cell of the organism and is carried out precisely by this respiratory system and also by the circulatory system. That circulatory apparatus will be in charge of transporting the

of transporting the oxygen that comes, that exchanges the lung with the exterior and therefore, once it is available there, by pressure difference, it will enter the red blood cell and the red blood cell will distribute it to the whole body. As for the stages of

In the respiratory stage, we have a first stage, or an air exchange between the atmosphere and the alveoli. We know it as ventilation, an air exchange between the atmosphere and the pulmonary alveoli. A second stage is the exchange of oxygen and carbon dioxide between the alveoli and the blood. And a third stage is the transportation of gases into the blood,

either by pulmonary circulation or systemic circulation and the fourth which is the exchange of oxygen and carbon dioxide between blood and cells. Regarding the functions of the respiratory system, we had talked about that one of them was the respiratory function, that is, the exchange of oxygen and carbon dioxide. Another function is

maintain the acid-base balance. That is, it is one more mechanism that the organism has to maintain the balance of the acids and bases within itself. What will happen there? There will be retention or expulsion of carbon dioxide. That

the pH, what it will do is move according to the amount of carbon dioxide, and that compensation is what we expect in this case, if the imbalance is given by the pulmon, we expect that

the balance is caused by the metabolic system. We hope that the kidney solves the problem. Undoubtedly, and vice versa, if the problem is renal, acid retention, for example, what we expect is that the lung activates or brings the balance back.

Another function is thermoregulation, the elimination of water vapor and jade in some species, not all. Another very important is phonation, as we said, which is given by the larynx and the vocal cords, which is what allows the animal to communicate with its congeners. Another is olfaction, whether it is given by

in conjunction with the nasal pituitary, the nasal ovum organ, which are where the nerve terminals are located that are going to take the different smells, that is, the different odor particles that are going to cause the particular smell of each substance. Within the metabolic, we have synthesis functions such as the surfactant,

the histamine, the calicrein, the prostaglandin, which are the ones that will have to do with, let's say, that change in volume that can then be exchanged with the lung, because it can even produce vasoconfliction and in that way, in the vessels, and change the functionality of the organ. Another metabolic function is activation.

hormonal activation, for example, angiotensin, it transforms angiotensin I into angiotensin II, it has to do with the regulation of blood pressure, also of the hydroelectrolytic balance. Another function is the removal. The removal is done by

remove substances that already fulfilled their function such as bradykinin, serotonin, noradrenaline,

acetylcholine, dimethyl selenium, substances that, as you can see, are all, most of them, chemical mediators. Once the chemical mediator acts, it is deactivated, let's say, either by the lung itself or the lung can remove that substance from the body.

that result, those substances that remain as the metabolic result. Another function is the defensive. Within the defensive we have the elimination of gases that have nothing to do with oxygen and carbon dioxide, such as carbon monoxide or in the case of rumiantes, mainly fermentative.

Another is the antithrombotic action, that is, the production of profibrinolicin. Do you remember when we saw coagulation? And the other is the preparation of the air, whether it is the warming at body temperature, the humectation, so that it has a similarity with the internal air, a pressure,

of water that is in 47 mmHg, another is the purification that is done through the histological characteristic of the conduction pathways, mainly in the first part of the respiratory apparatus, where there is

a epithelium that has cells that produce mucus, that produce cilia, that have macrophages, that produce immunoglobulins, lysosomes, and in addition to that they have the reflexes, the reflex of the cough and the sneeze, which are the ones that allow cleaning the pathways of the respiratory system. Well, we said, within the functions of the respiratory system,

To observe here, we say olfaction and absorption, phonation, where in addition to the larynx, there must be an articulation of tongue and lips, resonance, which is given by the nasal cavity, the paranasal and thoracic nerves, which allows to produce a sound that allows to contact or communicate with their congenital.

We were talking about preparation of the air, heating, body temperature, and here we have a graph of an epithelium where we see the different components that make up that aspect of what we were talking about, the purification of the different components of that apparatus.

The olfactory system or olfactory apparatus is the sensory system used to detect pain through sensory chemical perception. This system is often considered, along with the taste system,

as well as the sensory chemical senses, since both turn the chemical signals into perception and electrical impulses that go to the brain. The olfactory system has several purposes, it can be to detect and orient itself to a nutrient source, that is, to look for food, to evaluate the type, quality and nutrition of the nutrient source, to detect a match for mating,

recognize a territory marked odorificamente, detect information from the environment such as repulsion of unpleasant odors, dangers, predators, prey, humidity level, other species that are surrounding, create a representation of the smell, determine the concentration of the smell,

distinguish a new smell from among the environmental smells in the background, identify smells in different concentrations, relate the smell with the memory of what it represents. And here we have a graph where we see how the olfactory apparatus is, where we have the different types of cells, cells that are responsible for

First, we have the olfactory cells, which are characterized by having many dendrites, so they will perceive, they will enter into contact with the different particles. Then we have the olfactory actions, which are the ones that will take the information to these glomerules, passing through the

the bone, that part with many perforations that the hermaphrodite has, therefore they will come into contact with these glomerules, which are the ones that actually go through a union of that mechanism

already sensitive to that level, that is, of a nervous style, and through the periglomerular cells, they will lead to the cells of the olfactory tract, to the granulosa cell, and that already leads to the cortex, the information.

Well, the inhalation of smells, here we have a graph of how the air circulates and why the dog can perceive better than other species.

We have brachycephalus, like bulldog, dolicocephalus, like Lebrele, and mesocephalus, like the German shepherd, the border collie, which are the ones with the best development of this type of epithelium, since they have many more cells per square centimeter compared to any other species.

and that is what allows us to use these animals to detect, find or identify anything that not only has to do with the smell itself, but with legal processes. Another thing that we also have to take into account are the mechanisms by which

In addition to what we saw in the first portion of the respiratory tract with epithelium, there are particles that undoubtedly, due to their size, will pass that barrier, and they will have other types of mechanisms, the organism, to be able to continue removing them from the inspired air.

For example, we will have to have for those particles that due to their size, we say that they are large, like being 5 mm, they will impact the nasopharynx. Assuming that there are particles in that air-inspired of smaller size, it will no longer be due to impact, the mechanism will be sedimentation and the

Partículas van a ser de tamaño medio, de 1 a 5 mm. Sobre todo en la vía respiratoria pequeña, en la bifurcación de la tráquea, en la bifurcación de los primeros bronquios se produce eso. Y por último,

we will have particles that due to their size are still smaller, that go up to 0.1 nanometer. And that will already enter the alveoli and there they will be removed by diffusion or attacked by the different macrophages that are at that level. In the alveoli, then, the gaseous exchange is carried out. This in the case of mammals, for example, the case of counting with

because of the fact that it has lungs with alveoli, provides them with 50% more oxygen than any other system. As long as there is no type of inconvenience in the air that reaches that level, it can exchange without any inconvenience with the air that is in the alveoli, in this case with the capillary.

We said that there are mainly two important processes that are related to each other in the process of breathing. One is lung ventilation, which is the process through which the air enters and leaves our lungs. Lung ventilation is performed in two phases. One is the entry, the inspiration, the lungs widen and the air enters their interior, this is due to pressure difference.

When the thoracic cavity is widened, the lungs accompany that widening and therefore produce a negative pressure on the exterior, then the air enters. And the other is the exit, the exhalation. The lungs narrow,

the air goes out to the outside because undoubtedly, as the chest and the lungs narrow again due to their fiber-elastic characteristic, they return to their state of rest, the air is expelled by pressure and goes beyond the outside and therefore, it comes out in this way. And the other is the gas exchange. After the inspiration, a gas exchange occurs between blood and air that has entered the lungs.

part of the oxygen from the air passes to the blood that reaches the lungs and also the carbon dioxide that the blood has collected in the cell as a waste substance passes to the blood and then in the alveoli passes to the air and in that way in the cyclicity of the respiration it is expelled to the exterior. So that you have an idea, inspiration and expiation, analyzing the compression of the air,

We have air-inspired and exhaled, in terms of nitrogen it is the same, but look at oxygen, it already changes completely. The amount of oxygen that the air-inspired carries is 20% and the air-expired is only 16%, so it means that there is a 4% that enters the exchange. Carbon dioxide in the air-inspired is very low, 0.04%.

while the air is 4%. The water vapor is very little in the air-inspired and a lot in the air-inspired. So, to make some difference between air and water. As for the respiratory mechanics, that is, the pulmonary ventilation, it is mainly due to the characteristic of the lung, of its viscoelastic structure that we were talking about, where a

A respiratory cycle that lasts 5 seconds, 2 seconds and is an active process, corresponds to the inspiration and 3 seconds, which is a practically passive process in most species, except in the dog and the horse, where there is a large portion of that, of that lapse of inspiration that is active and that is what a cycle represents.

and that input and output obeys the changes in the thoracic box caused by the respiratory and inspiratory muscles, mainly. If we take into account how many cycles occur per minute, as you see here in the example, if we take into account that

in one minute we divide it by the five seconds that a whole cycle lasts, it will give us 12 revolutions or cycles per minute and that is the normal frequency, for example, for the equinox, which has a frequency of 12 cycles per minute but it can go from 8 to 16, for the bovine it is 20 but it can go from 12 to 30, the canine is also 20 but it can go from 10 to 30.

The respiratory type is abdominal cost and that has a semiological importance, especially because if some pathology or some abdominal pain occurs, the animal will try not to move the abdominal muscles or what they have on the continent

not feel the pain and then it will be done postally. And the same thing happens vice versa. If we have any problem at the level of the thoracic box, undoubtedly to relieve the pain, the animal will try to move only the abdomen. So we are talking about respiratory type, the physiological is abdominal cost, but it can be done postally and it can also be done abdominal.

Well, in terms of the different movements, that is, cycles per minute of frequency, we can talk about apnea when it is normal, tachypnea when it is increased, bradypnea when that respiratory frequency is decreased. We are going to talk about dyspnea when there is raleigh, when there is some difficulty.

We talk about amnesia when there is no respiratory movement. And the jadeo, which is in some species, it does not occur in men, but it can be in the dog, in the bird, in the deer, in the ruminant. And undoubtedly, where you will notice it the most is in the dog. Where the dog, because it does not have many glandular or oriparous,

heat can not be exchanged, then it is almost a main way that is the respiratory system increasing the frequency and that heat can reach 200 cycles per minute to be able to eliminate heat.

Well, when the diaphragm is relaxed, the air comes out because it decreases the thoracic volume. If the diaphragm is contracted, the air will enter because the thoracic volume increases. If we put this in an animal, we will see that when the diaphragm is relaxed, what it will do is that all the weight,

of the intestinal mass, that is, of the abdominal cavity, let's say, it will take that diaphragm forward and therefore it will not shrink the thoracic cavity. Now, when the diaphragm is contracted, it will have to remove all that

that mass that invaded the thoracic box, again to the abdominal and therefore will increase the thoracic box. Undoubtedly, the airway is also helped by the contraction of the abdominal muscles and the elastic cut of the lungs.

because we have to take into account the structure of the lung that spreads through the large air intake, but when it does not have the air pressure, it tries to return to its resting state. Here we have how the diaphragm would be in the inspiration and how the diaphragm would be in the exhalation.

contracted, then this length is increased and here it is relaxed, therefore it pushes and shrinks the thoracic box and the air is exhaled.

Well, as for the respiratory muscles, we have the inspirators and the expirators. Within the inspirators we have the diaphragm, which goes down to the floor of the thoracic jaw, let's say, if we are up or it goes back, if we are talking about animals. External intercostals that pull the ribs up and out, the other would be forward and out, in animals.

the deltoid, from previous times, that raises the ribs and leads them forward, the scalenum, which also leads forward the first two ribs, and the sternocleidomastoid, which will pull the sternum. All of this makes the trachea enlarge and then air will enter. As for the expiratory muscles,

We have the abdominals that pull the ribs down, compress the viscera, in the case of the animal it would be inwards, the posterior serratum that lowers the ribs and the internal intercostals that pull the ribs down and inwards, that is, backwards and inwards, and all that makes the thoracic box shrink.

How is the unit formed, let's say, the capillary alveolus, which is the place where the gas exchange is performed, that is, the respiratory membrane, and it has, let's see the alveolus,

The alveoli, which will have type 2 and type 1 cells. We have the capillary, where here we have a thin layer that separates the alveoli from the capillary. Within that capillary, for example, we will have the red blood cell. And then the red blood cell practically has, or sorry, the oxygen or the carbon dioxide, practically have to go through that

the capillary wall, the interstitial wall and the alveolar wall. It is a very thin layer that allows the diffusion of these ganses. There we have marked what we know as the respiratory membrane, which is what forms the respiratory membrane, very thin.

As for the physical concepts, we have to take into account elasticity, which is the capacity of the tissue to expand and return to its original situation without deforming or breaking. The gas mixture, which is the air, whose total pressure is the sum of the partial pressure of each one of them, this is known by the law of Dalton of biophysics.

the air moves in favor of the pressure gradient, it is also applied to the partial pressures of each gas, that is why each one exchanges for its part, and the pressure exerted by a gas is inversely proportional to the volume it occupies, and that is what the Bowling Law says. Well, we also know that the lungs are not attached to the thoracic box, so what is going to happen is that they are going to accompany us in that movement,

of the thoracic box is going to be accompanied by the lung, because the lung is covered by a membrane, that membrane that covers the lungs is the one that has two layers, inside it there is a cavity, but then we are going to talk about

that this pleura is formed by two membranes, one visceral and another parietal. The visceral is the one that is going to be attached to the lung and the parietal is the one that is going to be attached to the ribcage. So when, and within it there is a virtual cavity, the pleural cavity, which normally does not exist, that is, it is virtual, like the classes that we are doing now.

because there should not be or should not accumulate gas or liquid and that is thanks to that movement, to those gradient concentrations on both sides, but undoubtedly that can lose the physiological state and for some problem this virtual cavity can become a real cavity.

It can be filled with lithium, we are going to talk about hydro-toracic, it can be filled with blood, we are talking about motorac. And well, it depends on what you have inside, the pathology has its name, right? That, as we said, the importance it has is that it will depend on different pressures.

the pressures will be presented mainly by a very negative pressure of -10 mmHg, which is the pressure that allows the passage or exit of everything that can enter this pleural cavity towards the peripheral capillaries.

and it has another, another positive pressure is countered, which is that of the friction of that fluid. You have to keep in mind that as that is in motion, it is expanding and it is returning to its resting state, that is friction and that friction produces a positive pressure of 6 mmHg.

which makes a difference of 4 mm of inner mercury, which we will see that it can also vary, and that is what allows these two leaves, both the visceral and the parietal, to be in contact. So when the thoracic wall is removed, undoubtedly the

the lung is also removed or the lung accompanies the thoracic wall. We can measure it by means of a manometer. That negative pressure of 4 mmHg is what keeps the lungs dilated and of course avoids the collapse. The origin of the negative pressure that we were saying

The liquid is affected by the visceral pleura in the intrapleural space due to the low pressure of its capillaries. This or that vacancy forces the lungs to apply to the thoracic cavity and of course to continue the movement.

So we are going to talk about intraalveolar pressure generated by the compression and expansion of the lungs. We are going to have an atmosphere of 760 mmHg or 1300 hectopascals as measured today, it will be zero and for the air flow to enter the alveolus it must be negative, that is,

there must be 750 mmHg, minus one, for the inspiration to occur. And that can reach up to 80 mmHg, that is, a net of minus 80 mmHg. As for the expiration, we said

the pressure must be higher, that is, it must be positive with respect to the 760, 1 atmosphere or 1,013 hectopascals of the outside. Then it increases by 1, but it can also increase by up to 100 more that pressure and that is what will produce the exhalation, that is, the exit of the air into the outside.

The intrapleural pressure, we said, in the inspiration can reach -6 mmHg and in the expiration can reach -2 mmHg. That also means that we are talking about that average of -4 mmHg, which is what keeps the two pleura in contact.

But in a deep breath, notice that it can reach -12 mmHg in the inspiration and -6 mmHg in the exhalation. The horse is the one that can reach -30 mmHg in the inspiration and -10 mmHg in the exhalation. All expressed in mmHg. Well, the current of ventilation volume, which is the normal volume that the individual exchanges in each breath,

has an inspiration and an expiration that lasts 5 seconds as we said, then we also have the intra-alveolar pressure moving, so that the inspiration is produced, a negative pressure must be produced, that is, from 0 to -1, that intra-alveolar pressure, so that in the expiration it increases to +1.

One can reach -80 mmHg and the other to +100 mmHg, as we said before. And the intrapleural pressure, which we said that an average of 4 can be between -2 and -6, but it can also reach -12 or -30, as is the case of the horse, as we said before. The neumotor, what is the neumotor? It is the equalization of intrapleural pressure with atmospheric pressure.

It can be, for example, a trauma to the ribcage. And here you have to be very careful in the case of the horse because the horse has, they are in contact with the two pleura, that is, the two lungs, right and left. There is no separation, they are not separated like other animals. So if any type of trauma occurs to the ribcage that injuries the

that injuries those pleurae will cause the neumotorax, that is, the total collapse of the lung and will cause death by asphyxia because it does not have the possibility of continuing like the other species breathing with one of the lungs. The collapse of the lungs away from the thoracic wall

by the pneumothorax, a hemothorax, a POP, for example, an obstruction or any other pathology. The tendency to collapse is high in the lungs because 1. because 25% of the fibers are elastic, which are stretched in the inspiration and try to retract in the rest state, which would be the case of the exhalation.

and two because 75% of the surface tension of the liquids that cover the alveoli tend to shrink and contact their walls. It is higher in the smallest alveoli and is controlled through the alveolar surfactant. The alveolar surfactant is produced by type 2 cells

type 2 alveoli, which are responsible for synthesizing that dipalmitrilecytin, which is the one that will decrease the surface tension of the liquid and not allow the lung to collapse. It is also called type 2 pneumocyte, that cell, as the surfactant is composed, it has protein, it has phospholipids, the dipalmitrilecytin,

that decreases the surface tension of the liquid, it is a monomolecular layer in the air-liquid interface, reduces the surface tension by 7 to 14 times. The absence of this surfactant will make it difficult or impossible to expand the lungs,

for example, the hyaline disease, frequently in newborns, especially those premature or 7 months old who have not developed this type of cell, they do not have a surfactant and therefore they cannot breathe. This became very important in 1963, where that couple that you see, that you have to know,

President Kennedy and the United States had a baby with that problem and from there the study of this surfactant or surface tension was given a lot of attention. Another function is to maintain the dimension equality between the alveoli. Large alveoli have low surface tension because there is less surfactant, but small alveoli have high surface tension. We need more surfactant.

The result is to keep both alveoli in balance, with the same size and with the state of distended. Another thing to keep in mind is the pulmonary distensibility or compliance, which depends on the pulmonary elasticity, that is, the type of lung tissue, the superficial tension of the alveoli,

where the pulmonary subfactor plays an important role, and then the pulmonary resistances, the elastic resistance, which is the static one, which depends on the pulmonary distensibility, elasticity and surface tension, and they are the most important in normal conditions. And the other is the resistance of, let's say,

of the air resistance, which are dynamic, they depend on the diameter of the airway, the air flow, which have their importance in pathologies, especially those that produce narrowing of the airways, such as asthma, bronchitis, chronic bronchitis, bronchitis, etc. The respiratory volume and the agrelative ventilation. The respiratory volume per minute is the total amount of new air that penetrates the respiratory pathways every minute.

That is, it is equivalent to the current volume, which is the current volume of ventilation or tidal volume, which is the amount of air that moves with each normal breathing, that is, with each normal cycle, multiplied by the respiratory frequency. If the normal current volume is about 6 liters and the normal respiratory frequency is 12 breaths per minute, therefore, we multiply that and it will give us

that the volume per minute of the respiratory is an average of about 72 liters per minute. That would be a kilo. Alveolar ventilation is the rate at which the new air reaches the gas exchange zone of the lungs. During the inhalation part of that air never reaches the gas exchange airways, but occupies the respiratory pathways and this air is called the air of the dead space.

Since the alveolar ventilation is the total volume of new air that enters the alveoli, it is equal to the respiratory frequency multiplied by the amount of new air that reaches the alveoli with each respiration. Remember the ventilation volume, alveolar per minute, will be equal to the respiratory frequency per minute, due to the difference between the current volume and the volume of dead space.

Therefore, with a current volume of 6 liters, a normal dead space of 150 milliliters, a respiratory frequency of 12 respirations per minute, the alveolar ventilation will be equal to 12 times 6 liters, 6,000 minus 150, that is, 70,200 milliliters per minute.

70 liters per minute, when a normal value would be 72 liters per minute with these characteristics for this species. It is also true that there are three types of air in the human space. The anatomical dead space, which is the air in the respiratory pathways that are not involved in the vasodilator exchange.

That is, even to those routes where, according to the case, there may be some kind of exchange. That is, you take it as the anatomical dead space are the conduit routes. There is no exchange at that level.

Then we have the alveolar dead space, which is the air in the hormonal zones of vacuous exchange, but which does not participate in this exchange. It is almost null in animals in normal states. And the physiological dead space, which is the sum of the anatomical and alveolar dead spaces, that is, the total of the human space.

assuming that in some special characteristic of some pathology, the space of exchange can be reduced and then that dead-alveolar space will increase. We add that to the anatomical space, it will not give the total physiological, let's say, where there will be no vacuous exchange.

So the volume per minute of the respiratory, the amount of fresh air that enters the lungs, we are going to take into account the current volume by the frequency and that is going to give us the volume per minute. The equinox is 72 liters, the bovine is 80, the caprin is 15, the man is 6, so that you have a comparison.

and this minute volume can be compensated according to the different characteristics that are presented. For example, in the case of anesthesia, where the action of anesthesia will decrease, the respiratory frequency will decrease, the current volume will be decreased, the frequency will be decreased,

then that volume will also decrease. So what will happen? The tidal volume will have to be increased to be able to counteract that low in the respiratory frequency to be able to maintain a certain amount of air in the breathing. The breathing is slow, deep,

So, it enters more air, let's say, but the respiratory frequency is reduced. When it occurs in depressions due to the Gering-Brewers reflex, an abradimnea, a vagal stimulation, for example. What happens if the current volume is reduced? For example, a occupant mass that does not allow

In this case, the occupant mass is increasing, the physiological dead space. So, the current volume will be reduced, but the respiratory frequency will increase to maintain that air. Breathing is done quickly, superficially, and

There will be a stimulation, a reflex of Ferring Begur, there will be tachypnea and instead of vagal stimulation there will be vagal inhibition. And the other is the vigorous physical exercise, where the current volume increases, the frequency increases and of course the volume increases in the respiratory minutes, which in pure blood-carrying, for example, can reach up to 1000 liters per minute.

but there is a minimum, as in a few minutes, where everything can go down, or a maximum, also in a few minutes, as everything can increase and return to its resting state. It depends undoubtedly on the capacity of the animal. The maximum respiratory capacity is 150 liters per minute,

more respiratory force, the resistance of the path will increase, it can be by bronchial stenosis, for example, where there will be difficulty in passing air through that path with that type of inconvenience. How can we measure functionality? Through spirometry. This is what you are seeing, it is a spirometer.

which can be a water chamber that receives an inverted drum with air connected to the mouth, the drum goes up in the inhalation and down in the exhalation, and writing in the chymograph, as you can see here, a respirometer and a metabolometer that eliminate carbon dioxide by interposing the chalcedonate, which is a test that we did in practice, but well, now you don't see it.

And today, undoubtedly, these spirometers are all electric spirometers with electronic technology that is no longer used for water cameras or fenders like the ones we had in the cart.

Undoubtedly, the spirometry will be different depending on the sex, size, constitution, body composition. In cubits it will always decrease, especially due to abdominal compression. We also have the disadvantage that this type of test does not allow us to measure the residual volume.

Neither the functional residual capacity nor the total pulmonary capacity. We can measure by breathing pure oxygen and measuring the nitrogen released from the hormones, that is, indirectly.

That residual volume is what allows us to have a gaseous exchange of blood with the alveolus in a continuous and balanced way and not be intermittent as is the process of the breathing itself, of the air circulation that inspires and expires. So that there is no difference in pressures, there is this

residual volume and that is its importance. The residual volume, what it does is, let's say, the main importance is that it will allow the blood to continue to oxygenate without producing any changes in the blood, neither oxygen nor carbon dioxide.

Here we have the volumes and capacities. We have the current volume, tidal volume, which we say is what is normally exchanged in a normal respiration, in an inhalation and an exhalation. The equinox goes from 4 to 6 liters, the bovine 3 to 4 and the canine from 0 to 1 to 0.3 liters. Then we have the volume of the respiratory reserve, which is the volume

of air that can be made to enter after a normal inspiration, that is, a normal current volume, all the air that the animal can inspire over that inspiration. In the case of the equinox, it goes from 10 to 12 liters. The respiratory reserve volume. The respiratory reserve volume is the amount of air that can be exhaled after a normal exhalation.

and for the case of the equine it is also 10 to 12 liters. The residual volume in the equine is also 10 to 12 liters. Remember that the spirometer does not measure that, but we can measure it indirectly by measuring some component of the air that is being exchanged. And well, the importance is that undoubtedly that is very important to maintain the gas exchange.

Then we have the capacity, which is the sum of the volumes. The inspiratory capacity is the sum of the current volume of ventilation plus the volume of the inspiratory reserve. For the case of the equinox, if it is 6 liters, the current volume plus the 12 of the inspiratory reserve would be 18 liters. The functional residual capacity adds up the current volume of ventilation and the residual volume.

which for the case of equine is 24. If we said that the volume of the respiratory reserve was 12 and the residual volume was 12, undoubtedly the functional residual capacity is 24 liters. The total lung capacity, the sum of all the volumes in the equine, we would be talking about 40 to 42 liters, following the exemplification that we have been giving.

And we have the vital capacity, which is the capacity that is measured in the spirometer and serves as a diagnosis. The vital capacity adds up the current volume of ventilation, the volume of the respiratory reserve and the volume of the respiratory reserve, which in the equinox would be 30 liters. What are the factors that modify the resistance in the airway?

Those that increase the resistance by constriction, a parasympathetic stimulus, acetylcholine, metacholine, histamine, serotonin, or that there is a drop in the carbon dioxide pressure. And they decrease the resistance, that is, they will produce dilatation, that is, the opposite effect, the sympathetic stimulus,

beta 2 agonist, nitrous oxide, which is a very important vasodilator, the high carbon dioxide pressure or low oxygen pressure. As for the diffusion capacity of the respiratory membrane, the gas volume that diffuses through the membrane per minute for a pressure difference of 1 mmHg,

was what we explained, it will depend on oxygen and carbon dioxide and is represented by, as it is impossible to measure it by the speed with which it diffuses, especially carbon dioxide, we have to follow the Fick's law that we saw in biophysics and that takes into account the surface of the membrane, the pressure on both sides, how those gases diffuse, even the thickness of the same.

Well, the alveoli and hematosis, the respiratory gas exchange is due to that exchange between the alveolar air and the blood that flows through the capillaries in order to transport oxygen and carbon dioxide to the cell and from the cell respectively. The gas exchange between the blood of the capillaries and the tissues undoubtedly depends on the, let's say,

It depends mainly on the concentration of the gases in both sides. And there we have represented the region, what happens with the amount of oxygen pressure and carbon dioxide, which is what allows it to pass to one side or another due to that gradient difference. Notice that in the air, the oxygen has 160

let's say, depression, while the dioxide has 0.3. And how does it change in the alveolus? The oxygen has 100 and the carbon dioxide has 40. In the arteries, the oxygen has 95, the dioxide has 40. But in the interstitial, the oxygen has 40 and the carbon dioxide has 45.

And in the cell, notice how important it is that there are 35 pressure cells, in millimetres of mercury, which allows that 40 that reaches the interstitium

This goes to the extent that it goes away from the alveolus, let's say, it goes down the oxygen pressure by the exchange, but well, it reaches the level of the cell that has 35 and as in the interstitial it is 40, that 5 is what allows it to pass to the cell.

This is the case with carbon dioxide, which has inside the cell 46 mmHg of pressure and in the interstitium is 45 mmHg. This gradient allows it to pass outwards and of course the blood brings it back to the lung. Well, how does it transport? Undoubtedly, as you already know, as we have already talked about hemoglobin,

oxygen is transported mainly through the red blood cell through the hemoglobin. In contrast, carbon dioxide can be in the plasma or in the erythrocyte. In both ways, for example, in the erythrocyte, 63% can be balancing, or is in continuous action through carbon dioxide,

transforming into carbon dioxide or hydrogen bicarbonate or hydrogen ion, and then exchanging with chlorine to maintain the pH. A 5% is done in the hemoglobin by amortization, and a 21% is done

joined to the hemoglobin in the form of carboamino hemoglobin. Remember that it does not compete with oxygen and is joined to the free amino terminal, epsilon free amino of the protein of the hemoglobin and therefore has no inconvenience in that transport. Then it can also be free in the plasma, 5% goes as carbon dioxide

1% is taken by a protein, a carbamine compound, and 5% goes back into the amortization, where it is transformed through carbon dioxide into carbon dioxide and water, or carbon dioxide or hydrogen bicarbonate, depending on the needs of the organism

of taking the pH to alkalinity or acidity. The control of breathing. The nervous control is done by the rachidic bulge, where there is an inspiratory center and an expiratory center. The inspiratory center acts reciprocally and are the main coordination areas that are in the bulge. And the Herring-Rayward reflex is the one that inhibits the inspiration.

That is, depending on the need of the muscle, oxygen or carbon dioxide will have to be provided, that will make the concentrations in circulation vary. Therefore, this system that will make the

the oxygen, the carbon dioxide, is transported into the blood, it maintains that acid-acid balance. From there, as you see here in the circulation, the sensors will take the concentration of oxygen, carbon dioxide and they will inform the

to the brain, the central nervous system, the bulbar rachidium, to modify the rhythm according to the organ's need. So what is it going to do? That regulator center is going to stimulate the lung, which increases or decreases lung ventilation according to the needs, therefore it is also going to modify the activity of the heart so that it changes the perfusion and changes the amount of blood transporting the different gases.

So we will have a controller in the brain, a voluntary controller, in the encephalic stem, an automatic control and the spinal cord. All this will be giving information to the respiratory muscles to modify the ventilation and therefore modify not only the pressure of the gases but also the pH. But this

These respiratory muscles have their own sectors, that is, nervous centers that receive information about the activity and inform the spinal cord to modify the activity of those muscles.

If we take into account what ventilation is, there will be pulmonary receptors and upper respiratory tract receptors that carry the information of the modification of that ventilation to the encephalic stem, which is an automatic control, and the concentration of gases and pH will be taken by peripheral and central chemoreceptors that also carry to the encephalic stem for automatic control, so that

this controller has its influence on the respiratory muscles, modifies ventilation and therefore modifies the concentration of gases. The chemical regulation will have a decrease in oxygen pressure or the increase in carbon dioxide pressure or the decrease in pH will be taken by the peripheral chemoreceptors. This will take the information to the activated respiratory center or it can also be done

by means of central chemoreceptors, the increase in the pressure of carbon dioxide and the decrease in pH also take that information to the inflammatory center, activate it, produce hyperventilation and restore the levels of gases and pH to their normal state. This regulation aims to maintain the levels of oxygen and carbon dioxide in the blood

within narrow margins that allow the cells to function. In addition, breathing must be integrated with the digestive system, sound emission and cough. The system is made up of respiratory centers that are distributed in several groups of neurons integrated in the brainstem or reactive bulge. So we will have

the cyclical pattern of breathing is modified by various types, whether it is a change in pH or the concentration of gases, or in situations such as exercise, emotions, change in blood pressure, temperature, and these modifications will be detected by the reflex centers that will take the information to the bulge.

For example, the central ones will not detect the changes in the oxygen pressure, but they will detect the carbon dioxide and also indirectly by changing the pH.

And the peripherals, whether it is the carotid or the aortic callus, detect changes in oxygen pressure and detect changes in the direct carbon dioxide pressure, not as the central ones do due to the change in pH. So, when the pH changes, the carbon dioxide pressure is modified and there I have just detected

by the central ones, not by the peripheral ones. Well, here we have that if, for example, the blood pressure decreases, the peripheral chemoreceptors will take that information, they will take it to the nervous center and

and that nervous center will make changes in the respiratory muscles and therefore will modify the ventilation. That is, it will increase the impulse at the respiratory center level, it will increase the contraction of the respiratory muscles and therefore increases the ventilation and therefore increases the amount of oxygen pressure in the artery.

and so each of the different inconveniences are corrected. We will see it again in the last class when we see balance towards the lower part. So there are upper centers that have activity on the respiratory center and on that respiratory center there

chemical receptors, chemoreceptors, which have to do with detecting the difference in oxygen pressure, in carbon dioxide in the blood, after the concentration of the pH and after the concentration of oxygen, in that order. The chemists first have difficulty with carbon dioxide, then the pH and then the oxygen.

The peripheral chemoreceptors, the aortic and carotid body, as we said, what they first detect is the difference in oxygen pressure, then the pH and finally the carbon dioxide. That is, the opposite of what the central chemoreceptors do.

And the nervous ones have pulmonary mechanoreceptors that make the Herring-Greywell reflex, pulmonary mechanoreceptors and chemoreceptors, pulmonary J-receptors, which are distension receptors, that is, they activate when the wall of the lung is distended, respiratory tract receptors, tendons and joint muscles receptors,

Varus receptors, nociceptors, that is pain, and thermoreceptors, that is temperature. All of this leads information to the respiratory center, which makes it modify the respiratory cycle. So, we said, we have a central control in the encephalic trunk, the sensors carry the information, chemoreceptors, pulmonary receptors, and also

are responded to that stimulus by the effectors such as respiratory muscles, diaphragm, and abdominal intercostal muscles. And that acts on the sensors making the negative feedback and maintaining the constant pressure of oxygen and carbon dioxide in the blood.

The control areas of the encephalic trunk, the medullary center, the rhythmic area, are formed by a dorsal group and a ventral group. The dorsal group functions as an inspiration and the ventral group as an inspiration and an inspiration. In other words, the ventral is more activated in the case of exercise where the two cycles of the cycle have to increase. The neomotaxic center is the one that inhibits inspiration.

and the amniotic center stimulates the inspiration. Both modify the activity of the rhythmic area and have to do with the inspiration stopping and the inspiration begins. Here we can see where the dorsal group is, which has to do with inspiration. The different nerves are the vagus and the lumbar pharynx. The neumotaxic center, which is the inhibitor, the amniotic center, which is the stimulant,

and the different nuclei that have to do with where the information reaches the brain. The central group first and then the brain. Peripheral and central chemoreceptors, what we saw in the aortic and carotid cavity. The reflection that occurs here is to modify the ventilation to modify the pressures, as we said, of the gases in the plane.

And this will have to do with what information it receives. Assuming that the oxygen pressure in the plasma goes down, the peripheral chemoreceptors are stimulated, the action of carbon dioxide on carbon dioxide and hydrogen ion increases,

forming or transforming it into carbon dioxide first, then the hydrogen bicarbonate ion, therefore the blood pressure will be increased, right? By the increase in carbon dioxide. It can also be that the increase is due to the oxygen or carbon dioxide pressure in the liquid cephalorachidia,

that will also be taken by the central chemoreceptor stimuli that will make

there is a passage of this carbon dioxide, again always by carbon hydrate, in bicarbonate and hydrogen ion, surely always passing through carbon dioxide, which is a weak and unstable acid, and it quickly transforms according to the needs of bicarbonate or hydrogen ion. That is why it is modified when there is an increase in the pressure of carbon dioxide in the plasma.

Well, the main neurotransmitters of central chemoreceptors in the anterior ventral medulla decrease serotonin-ergic neurons, the glutamate decreases, the muscarinic receptors decrease, but the gamma-aminobutyric acid increases. The response is a decrease in the concentration of carbon dioxide. The integrated responses

For example, having the central controller as a stimulus, it can be oxygen or pH, the carotid and aortic chemoreceptors respond, the sensory neurons refer to it, the carbon dioxide, the central chemoreceptors,

in the case of humans, but also in animals, it can be, why not, the emotional and voluntary control, the upper respiratory centers, the limbic system, and there we talk about the dorsal group of inhalation and the central group of exhalation. The dorsal group are motor somatic neurons that act on the scalene, the external mastoid and external intercostal, on the diaphragm,

And the ventral group that is the aspiration, are somatic motor neurons too, but they act on internal intercostals, that is, the expiratory muscles. And the abdominal muscles, which are what help to narrow the thoracic box due to abdominal pressure, due to abdominal pressure. The pulmonary receptors, the stretching receptors that we were saying, respond to pulmonary distension, increase the expiratory time and decrease the frequency. There are slow ones,

The smooth muscle, for example, increases the respiratory time, the breathing stops, the frequency decreases, the Ferring-Gregoire reflex, there is a detachment of the inspiration. This information is also taken by mechanoreceptors and chemoreceptors. That is, that is what makes the frequency change. And then we have the rapid ones, which are in the epithelial cells, which are the ones that increase the respiratory frequency.

there is a deflation reflex, that is, the inspiration is turned on also by mechanoreceptors and chemoreceptors, that is, they are the ones that are going to continuously or with greater acidity, the inspiration is produced and in that way the respiratory frequency increases. Well, the receptors of the respiratory system, yucca capillaries or yucca alveolars, which are the

let's say, of respiration, also respond to pulmonary congestion in the capillary and alveolar walls, they produce tachypnea, dyspnea, that is, they increase the breathing or increase the respiratory difficulty. They can be irritating, they respond to either pollutants or to temperature in the upper-level epithelial cells, hyperpnea, bronchoconstriction, this has a lot to do with the

how these irritants occur, they act on the epithelium and produce the allergic state. And the superiors that respond to mechanical and chemical stimuli in epithelial cells of superior pathways, all bronchospasm, mainly for that case. Well, the gamma system that we saw of amino acid gamma butyric, sorry, the gamma system has nothing to do with GABA.

They are receptors that measure muscle elongation. They are part of the intercostal muscles, the diaphragm. This information is used to check the power of muscle contraction. They participate in the sensation of dyspnea, that is, the thirst for air, and in respiratory efforts. They have a lot to do with what we saw in muscle,

They have information, especially about pain. They have nociceptor action, mainly. Arterial varus receptors, the stimulation of varus receptors of aorta and sinus carotid, due to the increase in blood pressure, can cause hypoventilation or amniotic reflex, that is, retention of the respiration.

A decrease in the anterior pressure can cause hyperventilation, but the duration is always short, otherwise we enter a pathological case. Pain and temperature, the stimulation of the afferent nerves, cause a change in breathing. Pain causes amnesia and hyperventilation. The skin heating produces hyperventilation, it is one of the ways to lose heat. The decrease in body temperature produces a decrease in the respiratory frequency to try to maintain the heat.

The hyperventilation in the fever should be stimulated by hypotalamus thermoreceptors.

the problem with the fever is already a pathological case, therefore it changes, it is not due to the process itself, but when an infection occurs, a fever occurs, what it is doing is that the toxins from that bacteria are producing a movement of the center threshold and therefore it is believed that it has

that is cold, then it produces all the mechanisms to produce heat. Well, gentlemen, we have come this far. I hope it will be useful to you.