Physiology of excitable systems

 

1. The smallest stimulus force, necessary and sufficient to cause excitation.
2. The measure of excitability is the threshold of irritation. If the threshold value increases, this indicates that the excitability progressively decreases.
3. As the strength of the stimulus increases, a gradual increase in the amplitude of contractions of the skeletal muscle is observed until a maximum is reached.
4. Polarization is the difference of charges on both sides of the cell membrane. Which determines the membrane potential. Depolarization is a decrease in the magnitude of the membrane potential, and hyperpolarization is an increase. But if the membrane potential increases, then the threshold peptential increases, so excitability will decrease.
5. It is necessary to record the potential of the action that arises in the muscle, and compare their number in unity with the frequency of stimulation. If these numbers completely coincide, then the muscle responds to each stimulus.
6. There will be a depolarization of the membrane and a decrease in the membrane potential.
7. In the medullated fiber, the excitation is spreading saltatory from one Ranvier's node to another. In thick fibers, the distance between the Ranvier's node is greater, therefore the jump of the nerve impulse is longer and the excitation propagates at a higher rate. In nonmedullated fiber, excitation moves from the site to the neighboring site. Each time the arising circular current passes through adjacent parts of the membrane and subsequently depolarizes them. The thicker the fiber, the less the resistance of the axoplasm and the faster the current rises to a value sufficient for the depolarization of the membrane and the achievement of a critical level of depolarization (CLD). Accordingly, the speed of propagation of excitation increases. Therefore, in nonmedullated fiber, the dependence of the propagation speed of the AP on the fiber diameter is less showed than in the medullated fibers.
8. The greatest lability in the nerve, the smallest - in the synapse.
9. Consistently or continuously, local electric currents between the excited region and the unexcited cause membrane depolarization to a critical level of depolarization followed by generalization of the action potential.
10. Fibers consisting of myofibrils shortened. Myofilia included in myofibrils do not change their length. The restriction of myofibrmill is due to the entry of thin myofilments between the thick ones.
11. The main presence of fast muscles from slow ones is that they are more quickly shortened. With a rapid contraction, myosin bridges make more "strokes" movements per unit of time, respectively, more energy is expended on this.
12. Synapses have low lability due to the low rate of chemical processes and are highly fatigued.

 

Physiology of the nervous system

 

1. The reflex principle is based on the activity of the nervous system. Scheme of the reflex arc: Receptor - CNS - effector - feedback receptor - CNS.
2. Lachrymation, sneezing, salivation.
3. The time of the reflex depends on the number of switchings, i.e. from the number of synapses. The more intercalary neurons, the more the central time of the reflex.
4. Excitation will happen, because at a single-stage subthreshold excitation of several synapses on the postsynaptic membrane, the subthreshold quanta of the mediator will aggregate (spatial summation).
5. In order for the mediation sum to occur at the synapse, it is necessary that the interval between the stimuli be less than the time of destruction of the quantile of acetylcholine by cholinesterase.
6. Renshaw cells terminate excitation of motoneuron due to the mechanism of recurrent inhibition.
7. The reflex principle is based on the activity of the nervous system. Scheme of the reflex arc: Receptor - CNS - effector - feedback receptor - CNS.
8. Lachrymation, sneezing, salivation.
9. The time of the reflex depends on the number of switchings, i.e. from the number of synapses. The more intercalary neurons, the more the central time of the reflex.
10. Excitation will happen, because at a single-stage subthreshold excitation of several synapses on the postsynaptic membrane, the subthreshold quanta of the mediator will aggregate (spatial summation).
11. In order for the mediation sum to occur at the synapse, it is necessary that the interval between the stimuli be less than the time of destruction of the quantile of acetylcholine by cholinesterase.
12. Renshaw cells terminate excitation of motoneuron due to the mechanism of recurrent inhibition.
13. Most lability has the nerve, the smallest - in the synapse.
14. Nerve fibers according to their diameter and speed of excitation can be divided into three types: A, B, C. Fibers of type A are divided into subtypes: A-alpha, A-beta, A-gamma, A-delta.
15. Nervous centers become fatigued more quickly than muscles, therefore at the expense of disturbance of processes of coordination of movements, carried out by nervous centers. Their accuracy is violated.
16. No, it can not, if the descending inhibition system of the reticular formation is destroyed.
17. The animal will stop responding to all kinds of signals.
18. Innervation of the muscle provides not only its contractile activity, but also trophic influences. In particular, nerve impulses stimulate the activity of a number of enzymes, for example ATPhase. During denervation synthesis of proteins, etc. is violated the synthesis of proteins in the muscle, its mass decreases, and atrophy occurs.
19. When the legs are bent in the knees under the action of gravity, the quadriceps muscles of the thighs and the muscular spindles embedded in them are stretched. The impulses from the spindle receptors are increased, the alpha-motoerones of the quadriceps muscle are excited, there is a reflex to stretching, which immediately stops the beginning flexion in the knees and restores the original length of the extensor muscles.
20. When the head is thrown back, the tonus of the extensors of the forelimbs and flexors of the hind limbs increases.
21. When the head is thrown forward, the tonus of the flexors of the anterior and extensor muscles of the hind limbs increases.

 

Physiology of higher nervous activity

 

1. The last two. There is also cortical inhibition of differentiation and the type of "conditioned inhibition".
2. The cerebral cortex, nonspecific nuclei of the thalamus.
3. A conditional reflex will not manifest itself, since for a dog the word "bell" is not a signal of a real bell, but is merely a sound stimulus made up of a certain combination of sounds.

 

Physiology of sensory systems

 

1. Pelma, back, forearm, forehead, nose, lips, fingertips.
2. The refractive indices of water, cornea and eye media are approximately the same, and the eye is adapted for the passage of rays in the air-cornea system. Therefore, an air chamber placed in front of the eyes improves vision under water.
3. You can. With pain stimulation, a reflex dilatation of the pupils is observed.

 

Blood physiology

 

1. CP = 140x3 / 550 = 0.76. The indicator is below the norm, normally it is 0.85-1.05.
2. Large squares contain 80 small ones, the volume of each of them is 1/4000 mm3. Blood for counting erythrocytes diluted 100 times (PT 0.5). Therefore, in one cubic mm blood contained (4000 x 580 x 200): 80 = 5880000 erythrocytes and in one liter blood - 5.88 x 1012.
3. The person moved to the mountains. Since the rise for every 1000 m above sea level causes an increase in the number of erythrocytes on 700,000 in mm cube, the person climbed 2.5 km.
4. The leukocyte formula of this blood: eosinophils 1.25%, basophils 0.25%, neutrophils 75%, lymphocytes 18.7%, monocytes 4.8%. There is a relative and absolute neutrophilia, lymphopenia.
5. The volume of one small square is 1/4000 mm3. In 25 large squares, it contains 400. Blood for counting leukocytes was diluted 20 times. Consequently, in this case, 1 mm3 of blood contains (100 * 4000 * 20): 400 = 20,000 leukocytes. This is a evident leukocytosis.
6. Under the action of strong oxidants (KMnO4, Berthollet salt).
7. Erythrocytes having a color index of 0.8-1.
8. The method of spectral analysis.
9. The osmotic pressure is directly proportional to the concentration of the solution. Freezing point, too. It is known that a temperature of 0.56 ° C corresponds to an osmotic pressure of 7.6 atm. (0.9% NaCl). If the freezing point is -0.4 ° C, then the osmotic pressure of such a blood will be 5.5 atm. (0.65% NaCl).
10. The osmotic pressure rises, as the norm of Na + concentration is 140-160 mmol / l.
11. The concentration of salts is less than 0.9%, but more than 0.5%. The presence of erythrocytes is observed.
12. Some increase in the amount of fibrinogen (normal 2-4 g / l) and total protein (normal 60-80 g / l) at a normal concentration of mineral salts, can be considered associates with inflammatory processes in the body.
13. Before the blood loss in the human body a blood amount was 7% of 80 kg, i.e. 5.60 l; 1.6 liters will be 28.5% of this value - this is the level of blood loss.
14. The patient has blood AB (IV) group, since it contains both agglutinogen-A and B.
15. There is no danger. If the rhesus antigen of the mother gets into the fetal blood, immunization will not occur, since the fetus has immunocompetent organs that not yet developed.
16. It should be thought that the cause of death could be a transfusion of Rh-positive blood to a person who had already had such blood transfused and who has Rh-antibody in the plasma. The doctor's mistake lies in the fact that he apparently forgot to ask the patient about previous transfusions and did not determine the resuscitation of blood from the donor and the recipient.

 

 

Physiology of the cardiovascular system

 

1. The cardiac shock volume (CSV) is equal to the minute volume of blood flow divided by the heart rate. Minute volume of blood flow is determined by Fick's method as the ratio of the amount of oxygen absorbed per minute in ml to the arteriovenous oxygen difference in ml. In this case, the minute volume of blood flow is 7L, the CSV is 93.5 ml.
2. The same.
3. In the large circle, the resistance is much larger, so the left ventricle performs more work than the right
4. With unexpected painful irritation, a reflex change in heart rate may occur.
5. The frequency of contractions decreases, since in this case the level of the membrane potential of the peymekker is removed from the critical level of depolarization and the time of slow diastolic depolarization is prolonged.
6. With the shortening of the absolute refractory period, the heart can contract tetanically, which is not compatible with its pumping function and can lead to death.
7. The pathological focus is, in all probability, in the ventricular myocardium, since a long compensatory pause is observed.
8. On non-simultaneous excitation of the ventricles in the case of conduction disturbance along one of the bundle branch.
9. Such ratios of ECG teeth occur with left ventricular hypertrophy (left-handed curve).
10. Such a ratio of wave on the ECG occurs with hypertrophy of the right ventricle (lawgram).
11. The frequency of palpitations will increase, since atropine blocks the cholinergic receptors and the inhibitory effect of the vagus does not appear under these conditions.
12. It is necessary to put on the nerve a strong irritation. The irritation of the peripheral end of the vagus causes a slowdown in the rhythm of the heart, central does not give effect.
13. The frequency of contractions of the denervated heart increases, since in these conditions the inhibitory effect of vagus nerves is excluded, the center of which is normally in a constant tone.
14. With an unexpected painful irritation, a reflex change in the heart rate may occur.
15. Vasodilators: acetylcholine, histamine, bradykinin, nicotinic acid, noradrenaline (when interacting with beta-adrenergic receptors). Vasoconstrictors: adrenaline, noradrenaline (in interaction with alpha-adrenoceptors, renin, vasopressin, cortisone.
16. Redness of the skin under the mustard plaster is the result of vasodilation, which is based on the axon-reflex.
17. The snake dies due to the fact that the blood because of its gravity stagnates in the lower part of the body and does not reach the head and heart.
18. If the lumen of the capillaries is 1000 times larger than the artery lumen, then the linear speed of the blood in them is less in the same rate (in fact, the volumetric speed is the same). Consequently, in this case the blood moves at a rate of 0.25 mm / sec.
19. Accumulation of CO2 and a decrease in oxygen in inhaled air causes hypoxia and hypercapnia in the blood. The consequence is irritation of chemoreceptors of blood vessels and tissues, as a result of which the heart rate increases and blood pressure rises. The blood flow increases.
20. With arterial hypertension, the flow of impulse from the reflexogenic zones to the center of the vagus decreases, its tone falls and the heart intensifies its work. The blood pressure is restored to normal.
21. It is necessary to put on the nerve a strong irritation. The irritation of the peripheral end of the vagus causes a slowdown in the rhythm of the heart, central does not give effect.
22. The increased inflow of blood into the atrium leads to an increased discharge into the aorta, which in turn will cause an increase in blood pressure. Increased urine reduces the amount of fluid in the circulatory system and leads to a drop in blood pressure.

 

Physiology of breathing

 

1. Mucous airways.
2. When cutting vagus nerves, breathing will be deeper and more rare. B. When the central end of the vagus is stimulated, respiratory retention will occur on exhalation, as the sensory fibers from the lung stretch receptors pass through this nerve. C. When stimulating the peripheral end of the vagus, the breathing will not change.
3. PVCL of the woman = Н (21,78 - 0,101 А), where Н - growth in sm, And A is age in years (formula of Baldwin). In this case, the PVCL is 3620 ml.
4. The partial gas pressure is 106 mm Hg.
5. Breathing stops, because in this case the respiratory centers are isolated from the respiratory muscles.
6. As a result of the hold of breath, carbon dioxide accumulates in the blood, which irritates the chemoreceptors of the reflexogenic zones and causes an increase and deepening of the respiration.

 

Physiology of the digestive and metabolic system

 

1. They are digested with proteolytic enzymes of intestinal juice.
2. Atropine blocks transmission in the cholinergic synapses. Vagus strengthens the motility of the small intestine, so the blockade of its synapses will weaken the motor function of the intestine.
3. The pituitary gland - secretes hormones that control the work of other endocrine glands. Likewise, the duodenum secrete numerous gastrointestinal hormones that affect the functioning of the digestive system.
4. They are cleaved by proteolytic enzymes of intestinal juice.
5. For a respiratory coefficient equal to 1, the caloric equivalent of oxygen is 5.047 kcal. For an hour, the amount of oxygen absorbed is 18 liters. During this time, the energy expenditure is 91 kcal.
6. One gram of nitrogen corresponds to 6.25 g of protein. In this case, the body destroyed 75 g of protein.
7. An increase in the amount of renin contributes to an increase in urine production, as this increases the blood pressure in the glomeruli, which leads to an increase in the filtration pressure.
8. Filter: bicarbonate, urea, uric acid, urobilin, phosphate, glucose, ammonia, potassium and sodium ions, albumin, creatinine. As a result of tubular secretion, urine is excreted: urea, penicillin, ammonia, hippuric acid.
9. At night the blood pressure decreases, which leads to a drop in the filtration pressure.
10. Ways of heat recovery by the body - convection, radiation, evaporation, conductivity. At a temperature of 38 ° C, the main role is played by evaporation. Consequently, the third one will be most effectively cooled.

 

Physiology of thermoregulation, secretion and endocrine system

 

1. Filter: bicarbonate, urea, uric acid, urobilin, phosphate, glucose, ammonia, potassium and sodium ions, albumin, creatinine. As a result of tubular secretion, urine is excreted: urea, penicillin, ammonia, hippuric acid.
2. At night the blood pressure decreases, which leads to a drop in the filtration pressure.
3. Ways of heat recovery by the body - convection, radiation, evaporation, conductivity. At a temperature of 38 ° C, the main role is played by evaporation. Consequently, the third one will be most effectively cooled.
4. An increase in the amount of renin contributes to an increase in urine production, as this increases the blood pressure in the glomeruli, which leads to an increase in the filtration pressure.