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NERVE AND MUSCLE PHYSIOLOGY UNIT № 1 Topic: General properties of the excitable tissues; electrical potentials of nerve and muscle cells. The purpose of the unit: to understand the nature of bioelectrical phenomena in the excitable tissues. Questions for Self-preparation 1. Organization of the cell. Membrane structures of the cell. 2. Passive and active transport. Protein ion channels, “gating” of ion channels. Sodiumpotassium pump. 3. Resting membrane potential, ion mechanism. Methodic to measure membrane potential. 4. Nerve action potential. Action potential curve, stages of the action potential, ion mechanism. 5. The laws of stimulation for excitable tissues. Initiation of the action potential. Threshold for excitation, “acute local potentials”. All-or-nothing principle. Practice 1. Reproduction of Galvani’s Experiments. The first experiment of Galvani (the experiment with metals): Make the neuromuscular preparation consisting of two frog back paws. Hang it up on copper hook of stand. Touch the preparation with the plate made from the other metal (the zinc). Observe the muscle contraction. Try to explain its nature. The second experiment of Galvani (the contraction without metal): Make the neuromuscular preparation of the frog back paw. Isolate the sciatic nerve carefully. Cross the muscles in the lower part of the hip, quickly throw the sciatic nerve simultaneously upon damaged and undamaged areas of the hip muscles. Observe contraction of the leg muscles. Try to explain its nature. 2. Secondary Muscle Contraction (Matteucci’s Experiment). Make two neuromuscular preparations of the frog back paws. Isolate their sciatic nerves. The nerve of the first preparation place on electrodes united with facilitator and then connect muscles of these preparations with the sciatic nerve. Switch on the facilitator and observe the muscle contractions on both paws. Try to explain its reason. Literature: Guyton A.C., Hall J.E.: Textbook of Medical Physiology. 11/e, 2006.P. 4-22, 26-28. UNIT № 2 Topic: Initiation and propagation of the action potential. Neuromuscular junction. The purpose of the unit: to understand laws of stimulation and propagation of potentials along the nervous fibers and from nerves to muscles. Questions for Self-preparation 1. Propagation of the action potential. Direction of propagation. Inhibition of excitability, local anesthetics. 2. Velocity of conduction in different nerve fibers (by Erlanger, Gasser). 3. Physiologic anatomy of the synapse. Chemical synapse characteristics, neuromuscular transmission. Synaptic delay. 4. Presynaptic terminals. Transmitter’s release, role of calcium ions. 5. Postsynaptic membrane: ion channels, receptors in the postsynaptic membrane. Action fate of acetylcholine. Endplate potential. 6. Blockage of neuromuscular transmission. Synaptic fatigue. Practice 1. Both-side Propagation of Impulses along the Nerve. Make the neuromuscular preparation of the frog back paw. Isolate the sciatic nerve. Place it on electrodes united with facilitator. Stimulate the nerve in the middle portion; observe the muscle contraction on the both sides from the place of stimulation. Try to explain this effect. 2. The Law of Physiological Continuity of the Nerve, Effect of Local Anesthetics. Make the neuromuscular preparation of the frog back paw. Isolate the sciatic nerve. Place tampons with 2% solution of lidocain on the middle part of the nerve. Switch on the facilitator; and observe the absence of the muscle contraction. Then take tampons away, and wash properly the nerve with the Ringer solution. Observe the muscle contraction after the nerve stimulation. 3. The Law of the Isolated Propagation along Nerve Fibers. Make the neuromuscular preparation of the frog back paw. Isolate the sciatic nerve and divide it in separate nervous filaments. Stimulate each filament separately. Observe contraction of the different muscular groups. 4. Optimum and Pessimism, Results of Rhythmical Stimulation of Rabbit’s Muscle. Make neuromuscular preparation of the frog back paw. Fix it in miograph and place the electrodes on the muscle. Observe the differences in the muscle contraction after consequent increasing of the 2 stimuli frequency. Mark the optimum frequency. Mark the reduction of the amplitude of the contraction when the frequency becomes pessimist. 5. Synaptic Fatigue in a Neuromuscular Preparation. Fix neuromuscular preparation in miograph. Place electrodes to the nerve and stimulate it with the electrical current of the average frequency. Observe the gradual reduction of the muscular contraction amplitude. Replace the electrodes on muscle directly; observe the amplitude of the muscular contractions during such way of stimulation. Try to explain the observed phenomenon. Literature: Guyton A.C., Hall J.E.: Textbook of Medical Physiology. 11/e, 2006, P. 22-27, 41-46, 353-355, 360. UNIT № 3 Topic: Contraction of skeletal and smooth muscles. The purpose of the unit: to study general and molecular mechanisms of muscle contraction. Questions for Self-preparation 1. Skeletal and smooth muscle fibers. Actin and myosin filaments. Sarcoplasmic reticulum. 2. General and molecular mechanism of contraction. Excitation-contraction coupling. ATP as a source of energy for contraction. Rigor mortis. 3. Characteristics of whole muscle contraction. Muscle twitches, frequency summation and tetanization. 4. Mechanics of skeletal muscle contraction. Motor units. Recruitment of motor units. 5. Strength of muscle contraction. Multiple fiber summation. Staircase effect. Effect of muscle length on the strength of contraction. 6. Energetic of muscle contraction. Muscle fatigue. Muscle hypertrophy and atrophy. Effects of muscle denervation. 7. Smooth muscles. Effect of nerves and hormones on the smooth muscle. Practice 1. Multiple Muscle Fiber Summation. Make neuromuscular preparation of the frog’s gastrocnemius muscle. Fix it in miograph and place the electrodes to muscle, enlarge the force of stimulation gradually from zero to maximum. Register muscle contractions; define the current value when the minimal contraction 3 appears. Observe increasing of the muscle contraction while stimulation increases. Fix the stimulus level when the maximal muscle contraction occurs. 2. Muscle Twitch and Frequency Summation. Fix neuromuscular preparation in miograph. Switch on the facilitator and stimulate the muscle with the overthreshold stimuli with frequency 1 Hz, register the muscle twitches. Then increase the frequency of stimulation from 1 Hz to 200 Hz. Mark the point when frequency summation is observed. 3. Dynamometery. Stay straight, one hand aside. Press dynamometer in the hand 10 times with 5-10 seconds intervals. Right down each result. Calculate maximum strength of muscles and their working capacity according to the formulae: P = (f1+f2+f3+…..f10) / 10 where: P – the working capacity; f – the strength of each muscle contraction; S = (f1-fmin)/fmax *100% where: S- index of the working capacity Literature: Guyton A.C., Hall J.E.: Textbook of Medical Physiology. 11/e, 2006.P. 29-40, 44-54. Questions for Colloquium 1. Excitation. Definition of excitability. Excitable tissues. Types of stimuli. 2. Transport mechanisms of the cell membrane. Diffusion through protein channels and “gating” of these channels. Selective permeability of protein channels. 3. Factors that affect net rate of diffusion (concentration difference, membrane electrical potential, pressure difference). 4. Sodium-potassium pump. Electrogenic nature of Na-K-pump. 5. Resting membrane potential, ion mechanism. Measuring the membrane potential. 6. Nerve action potential, ion theory. Stages of the action potential. 7. Stimulus strength. Initiation of the action potential. Threshold of excitation. Acute local potentials, their characteristics. All-or-noting principle. 8. Propagation of the action potential. Direction of propagation. Local anesthetics effect. 9. Physiological classification of nerve fibers. 10. Neuromuscular junction. Presynaptic terminals. Transmitter’s release. 11. Neuromuscular junction. Effect of acetylcholine on the postsynaptic membrane. 4 12. Neuromuscular junction. Role of acetycholinesterase in the synaptic cleft. End plate potential. 13. Neuromuscular junction. Chemicals that block transmission in neuromuscular junction. 14. Neuromuscular junction in the smooth muscles. 15. General mechanism of muscle contraction. Excitation-contraction coupling. 16. Molecular mechanisms of muscle contraction. Sliding filament theory. Role of the calcium ions. 17. ATP as a source of energy for muscle contraction. Muscle fatigue. 18. Characteristics of the whole muscle contraction. Isometric versus isotonic contraction. 19. Muscle twitches. Frequency summation and tetanization. 20. Motor unit. Fast versus slow muscle fibers. 21. Strength of muscle contraction. Effect of muscle length. The staircase effect. 22. Contraction of smooth muscle. Effect of nerves and hormones. PHYSIOLOGY OF THE CENTRAL NERVOUS SYSTEM UNIT № 1 Topic: Organization and mechanisms of the central nervous system activity. The purpose of the unit: to understand structure and functions organization of CNS, reflex principle of its activity. Questions for Self-preparation 1. General design and major levels of the central nervous system. Physiological properties and functions of neurons, neuron types. 2. Neuroglia. Types and functions of the cells. 3. Interneuron interactions. Synaptic organization of CNS, neurotransmitter substances. 4. Transmitters effect on the postsynaptic membrane. Chemical substances that act as direct synaptic transmitters. “Second messenger” systems. 5. Electrical basis for neuronal excitation and inhibition. 6. Mechanism of inhibition process in СNS. Different forms of inhibition. 7. Neuronal pools. Transmission and processing of signals in these pools. “Excitatory state”. “Facilitation” of neurons. 8. Reflex principle of the CNS activity, reflex arch. Classification of reflexes. Properties of reflexes: one way conduction, summation, occlusion, etc. 5 Practice 1. Reflex Time Depends on the Strength of Stimulation (Turk’s Method). Prepare a spinal frog by removing its brain (decapitation) and leaving its spinal cord intact. Fix the obtained spinal preparation on the rack hook. Note that the experiment can not start immediately, since the activity of the spinal cord is suppressed due to spinal shock. Place one hind leg in 0.25% sulphuric acid solution. Determine the time interval between placing the leg in the solution and the onset of response. Wash the leg with water. Repeat the experiment using 0.5% and 1% sulphuric acid solution. Explain difference in the results. 2. The Reflex Arch Analysis. Make the spinal preparation of a frog and attach it on the rack hook. Impregnate the filer paper with 0.5% sulphuric acid solution and place it to the skin of the leg. Wait for the onset of flexion reflex. Separate the sciatic nerve on the dorsal femoral surface and tie it with a ligature. Place the impregnated filter paper once more. Wait for response. Then remove a skin flap from the other leg, stimulate this leg with acid. Wait for response. Destroy the spinal cord by inserting the probe into the spinal canal. Repeat stimulation of the fore leg. Give you explanation for absence of motor response. Draw down the scheme for somatic reflex arch in the notebook. 3. Sechenov’s Inhibition Experiment. Take the frog and open its skull. Cut the brain above the thalamus. Suspend the thalamic frog on a hook by a lower jaw. In few minutes simulate one of the hind limbs with 0.5% sulphuric acid solution. Take the time of Turk’s reflex. Then put one crystal of sodium chloride on the brain section. Take the time of Turk’s reflex in 5 minutes. Then wash the section of the brain from the salt and take the reflex time in more 5 minutes. Make your conclusion. 4. Irradiation of Excitation in the Central Nervous System (Experiment with Strychnine). Take the frog and inject 0,5 ml 1% strychnine solution in its lymphatic bag. Observe the frog’s behavior for several minutes. Observe its convulsive reaction in response to weak touch. Pay attention on improper position of the animal, on the inability of usual movements. Explain the observed reactions. Bear in your mind that strychnine possesses the ability for temporal block of inhibitor neurons in the central nervous system. Literature: Guyton A.C., Hall J.E.: Textbook of Medical Physiology. 11/e, 2006. P. 341-355, 361-366. 6 UNIT № 2 Topic: Physiology of the brain structures, their role in the control of motor functions. The purpose of the unit: to understand the role of the spinal cord and upper brain structures in mechanisms of muscular tone regulation. Questions for Self-preparation 1. Organisation and reflex activity of the spinal cord. Spinal shock. 2. Muscle stretch reflex. Clinical application of the stretch reflex. Gamma-efferent system. 3. Reflex activity of brain stem. Vitaly important reflexes. Reticular, vestibular and red nuclei systems in supporting the body against gravity. The decerebrate animal. 4. Physiology of cerebellum. Functions of various cerebellum departments. Neuronal circuit of the cerebellum. Functional unit of the cerebellar cortex. Clinical abnormalities. 5. Thalamus as a collector of afferent pathways, its role in the integrative brain activity. Functions of thalamic nuclei. 6. Basal ganglia – their motor functions. Functions of the specific neurotransmitter substances in the basal ganglia system. 7. Organization of the cerebral cortex. Somatosensory cortex. Motor areas. Association areas. 8. Reflexes of posture and locomotion (Table 1). Practice 1. Spinal Shock Phenomenon (Experiment in a Frog). Prepare a spinal frog by removing its brain (decapitation) and leaving its spinal cord intact. Fix the obtained spinal preparation on the rack hook. Try to obtain flexor reflex. Explain absence of any reflex reaction. 2. Deep Reflexes or Tendon Jerks. Biceps reflex. Tap the tendon of the biceps with a percussion hammer. The response is flexion of the elbow. Centre is C5-6 segments. Triceps reflex. Tap the tendon of triceps when the elbow is slightly flexed. The response is extension of the elbow. Centre is C6-7 segments. Ankle jerk (Achilles tendon jerk). Tap the patient’s Achilles tendon with the percussion hammer. The response is flexion and extension of the foot. Centre is S1-2 segments. Knee jerk. Ask the patient to sit down and put one his leg to another. Tap the patellar tendon with a percussion hammer. The response is extension of the knee. Centre is L3-4 segments. 7 3. Cerebellar Tests. Romberg pose (static): put foots together, close eyes, extend hands and move fingers apart. Keep this position. “Finger – nose test”: touch your nose by index finger of left and right arms first with the open eyes and then blindly. Revealing of dismetry symptom: blindly in the Romberg pose put one hand down and then lift it up to the level of the other hand. Revealing adiadokhocinesis symptom: move quickly brushes of the extended hands; such movements will be asynchronous in case of cerebellum defeat. 3. Posture Reflexes, Experiment in Guinea -Pig. Take a healthy animal. Observe its normal position. Check the position of paws during moving the head downwards and upwards. Try to put the animal on its side. Try to hold its head in the lateral position. Mark change in the muscular tone at lifting animal upwards and putting it downwards. Switch off one of animal’s labyrinths by dropping some chloroform into its ear and keep the animal in this position for some minutes. Observe any changes in the position of the animal. Observe state of muscle tone, nystagmus and circular movements. Test cervical and labyrinth postural reflexes. Pay attention on the eye movements at violent fixation of the head in normal position. Literature: Guyton A.C., Hall J.E.: Textbook of Medical Physiology. 11/e, 2006.P. 445-455, 463-464, 470-488. Table 1 I. Static Reflexes at a Change of the Position of the Body, Not Connected With Moving Reflexes of a pose Straitening reflexes Appear While changing of the head position in relation While disturbance of the normal pose to the trunk position in space From receptors of From receptors of From From From labyrinths sinews and muscle’s receptors of receptors of receptors of receptors of neck labyrinths skin and mus- retina of eyes cles of neck and trunk Are directed to Preservation of the normal pose at threat of its Restoration of the normal pose in case of its disturbance disturbance Are expressed in Redistribution of a muscular tone of extensors, Consecutive restoration of normal position of a preventing infringement of balance head and a trunk in space 8 II. Stato-Kinetic Reflexes at Strait and Rotary Movement with Acceleration Reflexes at rotation of a body (compass ones) Reflexes at linear vertical movement (lift ones) Appear From receptors of labyrinths, muscle’s From receptors of labyrinths of semi lunar receptors, receptors of retina of eyes channels Are directed to Preservation of the body position in space at Preservation of the body position in space in the rotary movement case of ascent, descent and at landing Are expressed in Change of a tone of muscles of the head and At ascent - in bending and the subsequent eyes (nystagmus), trunk, extremities straitening of head, trunk and extremities; at descent - in return sequence of the same reactions; at a landing - extremities accept the position being capable of holding balance while meeting with the ground UNIT № 3 Topic: Nerve regulation of inner organs functions; methods to study the central nervous system. The purpose of the unit: to understand organization and functions of the autonomic nervous system; to study modern electro-physiological methods of central nervous system research. Questions for Self-preparation 1. General organization of the autonomic (vegetative) nervous system. 2. Physiological anatomy and basic characteristics of the sympathetic nervous system. 3. Physiological anatomy and basic characteristics of the parasympathetic nervous system. 4. Effects of sympathetic and parasympathetic stimulation on different organs. 5. Mass stimulation and localized responses caused by sympathetic and parasympathetic nerves. 6. Higher brain areas control of the autonomic nervous system from. Hypothalamus - the supreme integrative centre of the somatic, autonomic and endocrine functions. 7. Autonomic reflexes. Peculiarities of the autonomic reflex arch. 8. Modern methods of CNS research (electroencephalography, method of the caused potentials, microelectrode technique, stereotaksis technique). Practice 1. The Cool Test. Take person’s pulse rate and blood pressure. Then put his hand in cold water (40С) for 1 minute. Take blood pressure and pulse rate once more and then do it every minute until the parameters turn to initial level (usually in 2-3 minutes). Reaction is estimated as strong sympathetic if blood 9 pressure increases more than 20 mm Hg, as moderately sympathetic - less than 10 mm Hg, as parasympathetic - at pressure decline. Put the results in the table and make conclusion. Blood pressure Parameters Systolic Pulse rate Diastolic Control values After cold application 1 min 2 min 2. Behaviour and Autonomic Reactions of a Rabbit under Electric Stimulation of Brain Structures. 3. Study of Basal Autonomic Tone by Kerdo Autonomic Index. Take patiant’s blood pressure and pulse rate in sitting position. Calculate the Kerdo autonomic index (KAI) using parameters of diastolic blood pressure (DBP) and pulse rate (PR): KAI = (1DBP/PR) * 100%. Make a conclusion about autonomic basal tone according to the following classification. Normal tone: KAI +10% till 10%. Sympathetic prevalence in autonomic balance: KAI over + 10%. Parasympathetic prevalence in autonomic balance: KAI lesser than 10%. 4. Electroencephalogrphy. The EEG is recorded either with bipolar arrangement (two recording electrodes placed on the scalp) or with unipolar arrangement (recording electrode is on the scalp and distant reference electrode on the earlobe). The graph is interpreted primarily on the base of frequency, amplitude, shape and pattern of the EEG waves. Use the sample of EEG. Try to analyze the EEG, think about the types of the EEG waves. Compare the data obtained by analysis of EEG in patient’s resting state with closed eyes and under stimulation Literature: Guyton A.C., Hall J.E.: Textbook of Medical Physiology. 11/e, 2006.P. 503-505, 511-512, 517-527. Questions for Colloquium 1. Organization and major levels of CN. Physiological properties and function of neurons. Neuron types. Neuroglia. 10 2. CNS synapses. Classification of synapses. Characteristics of electrical and chemical synapses. Synaptic organisation of CNS. 3. Classification of neurotransmitters. Chemical substances that function as synaptic transmitters. 4. Action of the transmitters on the receptor proteins of postsynaptic membrane. 5. Electrical events during neuronal excitation and inhibition. 6. Different forms of inhibition in the CNS. 7. Transmission and processing of signals in neuronal pools: divergence, convergence, afterdischarge, “dominant” principle. 8. Reflex principle of CNS activity. Classification of reflexes. Sensory, central and motor part of reflex arch. 9. Properties of reflexes: one way conduction, summation, occlusion, recruitment, subliminal fringe, afterdischarge, fatigue. 10. Organisation of the spinal cord for motor functions. Autonomic reflexes of the spinal cord. Spinal cord transaction and spinal shock. 11. Muscle stretch reflex. Receptor functions of the muscle spindle. Clinical application of the stretch reflex. 12. Flexor and crossed extensor reflex. Reciprocal innervations and reciprocal inhibition. 13. Role of the brain stem in the control of motor function. Reflexes of posture and locomotion. 14. Cerebellum and its motor functions. Function of the cerebellum in overall motor control. 15. Thalamus as an afferent pathways collector, its role in the integrative brain activity. Functions of thalami nuclei. 16. Hypothalamus- the supreme centre of vegetative and endocrine control of an organism functions. 17. Motor functions of basal ganglia. Functions of specific neurotransmitter substances in the basal ganglia system. 18. Cerebral cortex, characteristic of specific cortical areas. Somatocensory cortex. 19. Electrical activity in the brain. Brain waves. Electroencephalography. 20. General organization of the autonomic nervous system. Neurons of sympathetic and parasympathetic nervous system. 21. Basic characteristics of sympathetic and parasympathetic function. Sympathetic and parasympathetic “tone”. 22. Excitatory and inhibitory effects of sympathetic and parasympathetic stimulation on different organs. 23. Autonomic reflexes. Control of brain stem autonomic centres by higher areas. 11 PHYSIOLOGY OF ENDOCRINE GLANDS The purpose of the unit is to study mechanism of hormone action, to discuss functions of specific endocrine glands and effects of their hormones. Report Topics 1. Types of chemical messenger systems in organism. Endocrine system. 2. Chemical structure and synthesis of hormones. Stages of hormone “life”. 3. Mechanisms of hormone action. Main features of hormones. 4. Methods to study endocrine functions. 5. Pituitary gland and its relation to the hypothalamus. Posterior pituitary gland. 6. Anterior pituitary gland. Functions of growth hormone. 7. Thyroid metabolic hormones, their physiological functions. 8. Adrenocortical hormones. Functions of mineralocorticoids. Effects of aldosterone. 9. Adrenocortical hormones. Functions of glucocorticoids. 10. Endocrine part of the pancreas. Metabolic effects of insulin. Glucagons and its functions. 11. Calcium and phosphate regulation in the extracellular fluid and plasma. Parathyroid hormone. Calcitonin. 12. Male sex hormones. Functions of testosterone. 13. Female sex hormones, ovarian hormones. Effects of estrogen on specific organs. 14. Hormonal function in pregnancy. 15. Control of male and female sex hormones by hypothalamic pituitary hormones. Literature: Guyton A.C., Hall J.E.: Textbook of Medical Physiology. 11/e, 2006.P. 74, 612-715. PHYSIOLOGY OF ANALYZERS UNIT № 1 Topic: Physiology of sensory systems. Visual analyzer. Chemical senses, taste and smell. Purpose of the unit: to study sensory systems and the basic principles of their function. Questions for Self-preparation 1. Characteristics of sensory receptors: Types of sensory receptors and stimuli. Modality of sensation – the “Labeled line” principle. 12 2. Conversion of sensory stimuli into nerve impulses: local potentials of nerve endings - receptor potentials; mechanisms of receptor potentials. 3. Optics of the eye. Mechanism of refraction. Errors of refraction. 4. Mechanism of "accommodation". 5. Visual acuity. Binocular and monocular vision. 6. Function of the retina. Photochemistry of vision. Rhodopsin-retinal visual cycle and excitation of the rods. 7. Color vision. Photochemistry of color vision. Color blindness. 8. Visual Pathways. Organization and function of the visual cortex. Fields of vision; perimetry. Practice 1. Weber’s Experiment. The Person holds a weight of 100 grams in his hand. Then, Observer adds a weight of 300 mg, 500 mg, etc…on the Person’s hand. The Person has to inform when he feels that the mass in his hand becomes heavier. Repeat this experiment starting with 50 gms weight. Make a conclusion – sensation is related to the stimulus strength. 2. Visual Acuity Test. Patient stays 5 meters far from the table and closes one eye by special dashboard. Observer shows letters (rings) in the different lines of the chart; the Patient repeats letters (or where is the gap in the ring). Visual acuity is calculated by Snellen’s formula: V=d/D, where V - visual acuity, d - a distance from eye to the cart, D - normal distance. 3. Visual Field Test. The Person puts his head on the plane of Forster’s perimeter and closes one eye. The Person looks into the centre of the perimeter, not moving the eye. Observer takes the pointer with color marker and moves it along the perimeter arch to its centre. The Person says, when he observes the marker. Repeat this experiment turning arch of perimeter in 15º, 30º, 60º and 90º. Make a conclusion. 4. Detection of the Retina Blind Spot. Person takes the card with symbols “+” and “O”. The Person closes his left eye and looks at the “+” symbol moving the card slowly. Symbol “O” disappears at the 20-25 cm distance. Repeat this experiment with the other eye. Make a conclusion. Literature: Guyton A.C., Hall J.E.: Textbook of Medical Physiology. 11/e, 2006.P. 356-358, 392-426. 13 UNIT № 2 Topic: Special senses: Hearing, vestibular, taste and smell. The Purpose of the unit: to study the main mechanisms of sound perception, chemical sensation. Questions for Self-preparation: 1. The sense of hearing. Conduction of sound wave from the tympanic membrane to the cochlea. 2. Inner ear. Determination of the sound frequency: the "Place" principle, "Traveling wave". 3. Auditory pathways. Central auditory mechanisms. 4. Vestibular sensations and maintenance of equilibrium. 5. Sense of taste. Primary taste sensation. Threshold for taste. 6. Sense of smell. Primary smell sensation. Threshold for smell. Mechanism of the olfactory cells excitation. Practice 1. Hearing Acuity Test. Person closes one ear and turns sideways to prevent reading from the lips. Observer reads slowly and not loudly the words with the bass sound. If Person can not repeat words he comes closer to Observer. The chart contains 3 groups of words for 5, 12 and 20 m distance to determine hearing acuity. 2. Spatial Sound Localization. Set into both ears of Person a long rubber tube. Observer makes a sound by tapping right side, left side and centre of the tube. Person must detect location of the sound. Then Observer compresses the tube and taps near the place of the compression. Person must detect the place of the sound again. Make a conclusion about the factors making possible proper spatial localization of the sound. 3. Deafness Simulation Test. Person reads the text. Mark the loudness of his reading. Person puts on the earphones and Observer switches on the source of sound. Pay attention that Person begins to read louder. If the Person is deaf he can not do it. 4. Olfactometry. The Person puts olives of olfactometer in both nostrils. Vapors of smelling substance are introduced by means of the syringe into nose until Person can name the Smell (measured in cm3). 5. Taste Threshold. Observer puts on the Patient’s tongue a drop of one of the following solutions: sweet, acid, salty, bitter (the concentrations of the solutions 0,001%, 0,01%, 0,1%, 1%). Experiment starts with 14 the minimal concentration, then concentration is increased till Person is able to define the taste of the proposed solution. Literature: Guyton A.C., Hall J.E.: Textbook of Medical Physiology. 11/e, 2006.P. 427-444, 464-468. UNIT № 3 Topic: The sense of pain. Somatic sensation, thermal sensation The Purpose of the unit: to study of the basic mechanisms of skin sensations, get acquainted with manifestation and mechanisms of pain. Questions for Self-preparation: 1. Somatic sensations: general organization. Classification of somatic senses. Tactile receptors. Two point touch threshold. Adaptation of receptors. 2. Thermal sensations. Thermal receptors and mechanism of their excitation. 3. Pain. Types of pain: fast pain and slow pain, referred pain. Pain receptors and their stimulation. 4. Dual pathways for transmission of pain signals into the central nervous system. 5. Pain suppression ("Analgetic") system in the brain and spinal cord. 6. Physiological base for anesthesia/ Practice .1. Aristotle’s Experiment. Person closes eyes, turns his middle finger over the second finger. Observer puts the small boll between Person’s fingers. Person describes what he feels. Make a conclusion explaning role of the cortex in sensation. 2. Two-Point Touch Threshold in the Different Skin Areas. Person closes his eyes. The Observer touches different areas of the skin by the Veber’s compass with restricted drumstick (finger-tips, palm, forearm, shoulder, back), with both the drumsticks simultaneously. Touch with a minimum distance of 1 mm each time until the Person feels double touch. 3. Thermoesteziometria. Put the ice into thermoesteziometer glass and find cold receptors in 1 sm2 areas of skin (the finger, palm, forearm, shoulder, neck, back, face). Put hot water into thermoestesiometer glass and find heat receptors the same way. 15 4. Types of Pain Sensations. Prick yourself with the needle. Pull your hair initially in a short time period and then after long time gap. Compare your sensations when you squeeze: 1) the skin between two fingers or 2) the tendon. Make a conclusion about types of pain. 5. Pain Receptors Topography. Draw a 1 sm2 square on dorsal surface of your hand. Prick each point of square with the needle. Distinguish two sensations: touch feeling (the tactile receptor) or unpleasant feeling with a sense of burning (the pain receptor). Make a scheme of pain receptors. Literature: Guyton A.C., Hall J.E.: Textbook of Medical Physiology. 11/e, 2006.P. 359-360, 367-369, 371-373, 379-386, 388-390. Questions for Colloquium 1. Sensory receptors: classification of sensory receptors. Modality of senses. 2. Convertion of sensory stimuli into nerve impulses. Mechanisms of receptor potentials. Adaptation of receptors. 3. Somatic sensations: general organization. Classification of somatic senses. Detection and transmission of tactile sensation. Two point touch threshold. 4. Thermal sensations. 5. Sense of taste. 6. Sense of smell. 7. Pain. Pain receptors and their stimulation. Transmission of pain signals into the central nervous system. 8. Pain suppression ("Analgesia"). 9. Referred pain. Visceral pain. 10. The sense of hearing. Transmission of sound. 11. Transmission of sound waves in the cochlea -"Traveling Wave". Determination of sound frequency-the "Place" principle. 12. Determination of loudness. Central auditory mechanisms. 13. Vestibular sensations and maintenance of equilibrium. 14. Organization and function of the visual analyzer. Intraocular fluid. Intraocular pressure. 15. Mechanism of refraction. Errors of refraction. 16. Mechanism of "Accommodation". 16 17. Visual acuity. Determination of distance of an object from the eye. Binocular and monocular vision. 18. Function of the structural elements of the retina. Fields of vision. 19. Photochemistry of vision. Dark and light adaptation. 20. Color vision. Photochemistry of color vision. Color blindness. INTEGRATIVE AND INTELLECTUAL FUNCTIONS OF THE BRAIN UNIT № 1 Topic: Physiological basis of conditioned reflexes and learning. The purpose of the unit: to study mechanisms and characteristics of conditioned reflex. Questions for Self-preparation 1. Learning. Classification of conditioned and unconditioned reflexes by Pavlov. 2. Characteristics and functions of conditioned reflexes, their importance. 3. Working out conditioned reflex, procedure. 4. Conditioning, temporary connection in the cortex is the base for conditioned reflex. 5. Inhibition during learning, different types of inhibition. 6. Function of the brain in speech and communication. Sensory and motor aspects of communication. Practice 1. Working out Conditioned Blinking Reflex in Students. The conditioned blinking reflex is based on defensive unconditioned reflex in response to air flow to the cornea. First observe the unconditioned blinking reflex: blow air to the eye by means of rubber pear (choose the force of air flow which causes blinking). Use light of a red lamp as indifferent stimulus and combine it with air flow to the eye (light first and air flow in 1-5 seconds). You may work out conditioned blinking reflex after 5 or 6 light/air combinations. Observe the conditioned reaction fast blinking or in closing the eyes in absence of the air flow. Make the scheme of the reflex arch in your copy-book. 2. Working out Conditioned Word-based Reflex. Conditioned word-based reflex has its central part in nerve centers of the second signal system. The base of the reflex is the accurate verbal instruction: "Press the rubber pear as soon as red lamp is 17 switched on, do not compress the pear if lamp is green". In this case green light of the lamp is a neutral signal. You may work out the conditioned word-based reflex after several combinations (78) of the light and verbal instruction. The conditioned reaction manifests in pressing the rubber pear after switching on the red light without verbal instruction. Compare the reflex time of blinking and word-based conditioned reflexes, txplain the difference. 3. The Corrective Test. This experiment is carried out by all the students. Student has special chart with letters for four tasks, 3 minutes for each task. Wright down all 4 results. Task 1. Count a certain letter in all lines of the chart. If student counts the letter correctly (possible mistake is + 2 units) it means balance of his excitation and inhibition processes; if the result is wrong - the process of inhibition prevails; if the task is done correctly and promptly (less then 2,5 minutes) - the process of excitation prevails. Task 2. Count the same letter in the situation of external inhibition (loud reading). If the task is done correctly - the process of excitation prevails; if the result is wrong – the process of inhibition prevails; if the result is better than in Task 1 (more exactly or faster) - balance of excitation and inhibition is observed. Task 3. Count the definite set of letters. The exact result (+ 5%) indicates proper discriminative ability. Task 4. Repeat Task 1 and compare results. More number of mistakes or more taken time point on the fatigue process in the brain. Batter result means increased working capacity. Literature: Guyton A.C., Hall J.E.: Textbook of Medical Physiology. 11/e, 2006.P. 488-493. UNIT № 2 Topic: Neurophysiology of memory. Behavioral functions of the brain and emotions. Theories of sleep. The purpose of the unit: to study mechanisms of emotions, memory and sleep. Questions for Self-preparation 1. Types of the higher nervous activity (by Hippocratus, by Pavlov). 2. Memory. Classification of memory. Mechanisms of short-term and long-term memory. Role of the brain in the memory process. 18 3. Sleep. Types of sleep. Basic theories of sleep. Sleep and wakefulness cycle. 4. Brain waves, EEG characteristics of different stages of sleep. 5. Behavioral and motivational mechanisms of the brain, role of limbic system and the hypothalamus. Practice 1. Level of Short-Term Memory. The Observer reads slowly a set of any 10 words. Students reproduce the set in the same order in copy-books. The experiment is repeated three times with different sets of words. Define percentage of memorized words first for each set: K1 = a / 10 х 100, where a- amount of remembered words. Then calculate the average volume of the short-term memory: K = (K1+K2+K3) / 3. The result is excellent if K = 91-100; very good - K = 71-90; good - K = 51-70; satisfactory - K = 31-50; bad - K = 11-30 and very bad - K = 0-10. 2. Eysenk’s test. Answer all the questions of Trait 1 and Trait 2 and then analyze the result according to the key. Literature: Guyton A.C., Hall J.E.: Textbook of Medical Physiology. 11/e, 2006.P.343, 493-513. Questions for Colloquium 1. Learning. Classification of conditioned and unconditioned reflexes by Pavlov. 2. Characteristics and functions of conditioned reflexes, their importance. 3. Working out conditioned reflex, procedure. 4. Conditioning, temporary connection in the cortex is the base for conditioned reflex. 5. Inhibition during learning, different types of inhibition. 6. Function of the brain in speech and communication. Language input, sensory aspects of communication. 7. Function of the brain in speech and communication. Language output, motor aspects of communication. 8. Memory. Classification of memory. 9. Synaptic facilitation and synaptic inhibition, role in memory storage. 10. Short-term memory, neuron base. 19 11. Intermediate long-term memory, molecular mechanism. 12. Long term memory, consolidation of memory. 13. Activating-driving system of the brain. 14. The limbic system of the brain. 15. Vegetative and endocrine control functions of the hypothalamus. 16. Behavioral functions of the hypothalamus. 17. Reward and punishment centers, importance in behavior. 18. Types of the higher nervous activity (by Hippocratus, by Pavlov). 19. Sleep, two types of sleep. 20. Basic theories of sleep. 20