Physics All Questions PDF

THERMO - DYNAMICS 1. What is a System? List which Types of Systems you now and describe each of them. System - is a collection of material objects, enclosed from the surrounding area. Isolated System - The system which does not exchange matter or energy w...

THERMO - DYNAMICS 1. What is a System? List which Types of Systems you now and describe each of them. System - is a collection of material objects, enclosed from the surrounding area. Isolated System - The system which does not exchange matter or energy with the surroundings Closed System - The system which shares only energy with the surroundings Open System - The system which shares matter and energy with the surroundings 2. What is Energy? List the Types of Energy and describe each of them. Energy - is the measure of matter movement while its transforming from one form to another Mechanical Energy - The form energy describing the movement of macro body and its ability to perform work during movement (Kinetic and Potential energy) Thermal Energy - The sum of energies of thermal chaotic movements of atoms and molecules of a substance Chemical Energy - The energy of interaction of atoms and molecules Electrical Energy - The energy of interaction of electrically charged particles, which causes their motion in electric field 3. What is Work? List the Types of Work and describe each of them. Work – is the measure of energy conversion from one form to another Mechanical Work - The work performed during the displacement of body components and organs against mechanical forces. Chemical Work - Work performed during the synthesis of various kinds of high molecular substances and various types of chemical reactions Osmotic Work - The work done by transferring various substances through membranes from the area of low concentration into the area of high concentration. Electrical Work - The work done by transferring of charged particles through electric field in points with different potential and during the production of electric power 4. Formulate the First Law of Thermodynamics and write the Mathematical Formulation of the First Law of Thermodynamics. First Law of Thermodynamics - states that total energy of material system remains constant despite the changes developed in this system The change of system energy is available only in case of energy exchange with surrounding medium 5. Explain the process of generating primary and secondary heat and provide relevant examples of each process. Primary Heat is produced during the dissipation of energy during metabolism. (The energy used by the heart for blood circulation is consumed to overcome the friction in blood vessels and released in the form of heat) Secondary Heat- Electrical energy is consumed to overcome electrical resistance of tissues while electric current is flowing through them and is converted into heat (During contraction activities of muscles) 7. Formulate the Second Law of Thermodynamics and write the mathematical formulation of the 1st law of thermodynamics. Second Law of Thermodynamics - all processes of energy conversion are accompanied by energy dissipation in the form of heat and energy dissipated is not able to be converted to other forms of energy. 8. Explain the Reversible and Irreversible processes. Reversible process - Thermodynamic process is reversible if the transition of the system into the initial state does not require external energy from outside. (Reversible processes doesn’t convert system energy into heat) Irreversible process - Thermodynamic process is irreversible if the transition of the system into the initial state does not o require external energy from outside (characterized by energy dissipation in the form of heat) 9. Explain the drop in entropy and explain the entropy alterations in reversible and irreversible processes. Entropy - is the ratio of heat amount Q, which is produced during the isothermal process to value of absolute temperature T, where the process is finished. yo 10. Explain Thermodynamic Equilibrium and Steady State. Explain the Similarities between them two. Thermodynamic Equilibrium - the condition of the system where free energy equals zero, while entropy is maximum. Steady State - the state of the system where the parameters of the system does not change, but the exchange of matter and energy between the system and surrounding medium is constant. The Similarity lies in the constancy of its parameters at any time. Constant Direction and Speed at any time. 11. Explain the concept of Coefficient of Effectiveness and explain how its value changes in reversible and irreversible processes. Coefficient of Effectiveness - the system performs work at the expense of free energy. In irreversible process the part of the free energy is dissipated in the form of heat and performed work is less than the amount of free energy which is consumed to perform this work. The coefficient of efficiency of reversible processes is equal to 1 And in irreversible processes it is less than 1 12. Formulate the Prigozhin Theorem and explain what is the peculiarity of the Auto-Regulation of the body? Prigozhin’s Theorem: - is speed of entropy increases which is caused by irreversible processes in steady state has positive and minimum values out of all possible values. 13. Describe alterations of entropy and free energy in living system (at life and death conditions) 14. Describe alterations of entropy and free energy in living system (at steady state and stationary conditions) Internal Energy – equals to the sum of Free Energy and Bound Energy. (U = F + T S) Free Energy - is a part of internal energy, which can be used in order to perform work. Bound Energy - is the part of internal energy which cannot be used to do work, it’s uselessly dissipated as heat. -------------------------------------------------------------------------------------------------------------------------------------------- BIO - MECHANICS 1. Types of Deformations and Relative Deformation. Types of Deformation - Tension, Movement, Pressure Relative Deformation - The extent of deformation, which is proportional to the force and disproportional to cross sectional body surface. 2. What is a Young's Modulus? Its Unit. Young’s Modulus or the modulus of elasticity in tension, is a mechanical property that measures the tensile stiffness of a solid material & equals to the strain that changes the body’s length by the factor of two. Unit - Pascals or Nm-2 3. Describe Hookean and Non-Hookean Materials. How do you determine the Potential Energy of the deformed body? Hooke’s Law - the displacement or size of the deformation is directly proportional to the deforming force or load. Under these conditions the object returns to its original shape and size upon removal of the load Hookean Materials - Materials that are subjected to Hooke’s law and are Linearly Elastic. Potential Energy of elasticity of Hookean materials determined by the formula U = 0,5kL2 Non-Hookean Materials - Materials that are not subjected to Hooke’s law are called non-Hookean materials. E.g. - RUBBER Potential Energy of Non-Deformed Material in equilibrium is 0. Deformed material tends to decrease its potential energy and return to its initial non-deformed condition. 4. Describe dependence of the Mechanical Strain on Deformation (graphical dependence). In case of a small deformation, the Mechanical Strain is Proportional to the Relative Deformation. 5. Describe Viscose-Elastic properties of Materials from the view of Free and Bonding (Entropy) Energies. Viscose Resistance - materials elasticity is determined by the rate of thermal energy which is utilized during deformation-relaxation cycle (with viscose resistance inside the material) and this is conditioned. That is material’s elasticity expressed by dissipation function of deformation-relaxation and determines the measure of non-ideal quality of the system 6. Which Components (Compositions) of Muscle determine its Deformation? Plasticity - Deformation maintaining ability after the termination of the influence of outer force is determined by its residual deformation (if the residual deformation is high, muscle plasticity is less) Elasticity - the ability of the muscle to increase in size (Stretching). Elasticity of material measured of thermal energy which is excreted in deformation cycle and is determined by viscose resistance Viscosity / Viscose Property- Muscle ability to maintain its form (Plasticity). Viscosity is characterized for dynamic processes and occurred only at deformation. Solidity Margin / Tension Bound - This is the characteristic of the flexibility of the muscle system. 7. How will free energy change during Reversible / Irreversible Deformation? Free Energy is a part of Internal Energy which can be used to perform work. Free Energy (decreases) During Muscle contraction, chemical energy is transformed into mechanical energy (without intermediate transformation into thermal or electric energy) That is a Chemo-Mechanical System. 8. How will Bound Energy of the system change during Reversible / Irreversible deformation? Bound energy is a part of Internal Energy which cannot be used to do work, but it is dissipated in the form of heat.  All the living processes naturally undergo irreversibly due to energy being dissipated in form of heat. But the ability of the object to increase size during stretching and return to initial during relaxation is reversible. During contraction, muscle fibers slide over one another and due to friction forces, viscosity is present so due to friction, heat is dissipated, Entropy is high since a large amount of energy being used. Bound Energy (Increases) 9. How does Entropy Change in Living and Non-Living Systems? In a Non-Living System, the entropy is Maximum or reach the Equilibrium. So, Free Energy is equal to 0. The System will not spontaneously require input of energy 10. What is the Inductor (from Thermodynamical view) of Involuntary to Tremble? Sweating? During intense exercise, body temperature is sharply increased due to muscle contraction. This is accompanied by Sweating, the energy consumed for water evaporation contributes to decrease body temperature. Feverish body is often characterized by Tremor, developed in order to increase body temperature by heat released during the process of muscle contraction. 11. What are the Types of Contractions Characterize Muscles (Isometric and Isotonic)? I Iso-metric Muscles - are Static muscles. During their contraction, the part of the material is Immobile. Iso-tonic Muscles – are Dynamic muscles, during contraction, part of the material is moving (Eccentric & Concentric). Eccentric shortens during tension & Concentric is lengthened during tension. 12. Write Hill's equation and explain what its physical nature is. (F + a) (v + b) = Constant Relationship between the speed of a muscle contraction (v) and the force (F) generated by it is determined. So, when Muscle Contraction Speed Increases, Force generated Decreases. 13. Describe Muscles as a Thermo-dynamic System. According to 1st Law of Thermo-dynamics, the change in muscle Internal Energy ^U is equal to the sum of released heat and consumed energy. (-Delta U = Q + K^L) Hence, muscle contraction efficiency is increased along with increase in Loading within a certain range. -------------------------------------------------------------------------------------------------------------------------------------------- OSCILLATIONS & MECHANICAL WAVES What are Internal Forces? Internal Forces - oscillating bodies are not isolated from the environment, they are the integral part of the mechanical system, and consequently, other subjects of the system influence the oscillating body with certain forces. What is an Oscillation? Oscillation - The periodical change in magnitude of a physical parameter. They depend on Nature of the Magnitude, Mechanical, Electromagnetic, Heat of the Environment and the Oscillating Object, What is an Amplitude? Amplitude - the maximum extent of a vibration or oscillation, measured from the position of equilibrium. 1. Explain Periodic Processes. The Universality of Periodic Processes in Living and Non-Living nature; Periodic Processes - are processes that are repeated after a given interval of time. Periodic processes in Non-Living Nature – swinging of a pendulum, changing of seasons (Autumn, winter, spring, summer), shifting between day and night. Periodic process in Living Nature – heart- beat, breathing, periodical replication of microbes, hibernation of animals. 2. Explain the Mechanical Oscillations and the Characteristic Parameters of Mechanical Oscillations. Mechanical Wave - When we generate any particle oscillation in flexible medium, due to particles interaction, this motion is propagated along the neighbor particles, generating the movement of neighboring particle and so on. Every wave no matter its nature, including Mechanical Waves have properties of – Interference, Diffraction, Reflection and Refraction. Diffraction: - is a deviation in the direction of a wave at the edge of an obstacle in its path. Diffraction of sounds wave occurs in our everyday life, when we hear voice that is coming from the source behind any large item. Wave Reflection: - occurs, when the wave while propagating, reflected from the surface dividing mediums, and coming back. Entirely reflected wave propagation speed and energy remains constant. Wave Refraction: - occurs, when wave propagates from one medium to another. During the refraction wave frequency is not changed, only wave length is changed (due to changes in wave propagation velocity while passing from one medium to another). 3. Explain Free and Forced Oscillations. Explain Harmonic Oscillation and write the Harmonic oscillation equation. Free Oscillations - The oscillations caused only by internal forces. Forced Oscillations - When the oscillating body is additionally influenced by the external forces. Harmonic Oscillation - When alternation of oscillation value is described by sine or cosine function. X = A sin (𝝎0t +𝝋) = A cos (𝝎0t +𝜷) 4. Explain Free and Force Oscillations. How the Amplitude of the Free Oscillation changes during the Damped and Non-Damped Oscillations. Free Oscillations are always Damped, due to the friction forces in the air. Eventually their Amplitude equals to 0. Resistance Forces - During Damping, Amplitude decreases over time, but the Frequency stays the same influencing oscillation system. 5. Explain the Decrement of Damping. Decrement of Damping - the ratio of the amplitude of any two successive peaks or ratio of one given amplitude at a given time over a following amplitude after a period. 6. What is a Resonance? Explain the Impact of Resonance on Living and Non-Living Systems. Resonance - is a phenomenon in which a vibrating system or external force drives another system to oscillate with greater amplitude at a specific frequency 7. Explain difference between Auto-Oscillation and Forced Oscillation. Give examples Auto - Oscillations - the oscillations that occur in their own frequency Example is clock and heart rhythm Forced Oscillations - the oscillation which is performed by influence of external periodically variable force. Difference- Auto-Oscillations differ from Forced Oscillations by the fact that the moment of external influence is induced by the oscillation system itself. 8. Which Parameter changes during Resonance? Which one remains the same? Amplitude changes Frequency remains same (Resonance frequency) 9. What means Damped Oscillation? Which Parameter changes during Damped Oscillation and which remains constant? Damped Oscillation - Each oscillating system is exposed to resistance force as well as electric force. A part of system energy is used to overcome this force. Therefore, oscillation amplitude gradually reduces and after some interval of time the oscillation becomes damped. 10. Explain the Mechanical Wave and Write the Formula for Calculating the Wavelength. Mechanical Wave - is the process of propagating of oscillation motion in a flexible medium. Due to particle interaction, this motion is propagated along with their nearby particles generating the movement of neighboring particles. λ = VT 11. Explain Longitudinal and Transverse Waves. Longitudinal Waves - during the wave propagation, if the particles oscillate parallel to the propagation of wave. Transverse Waves - during wave propagation, if the particles oscillate perpendicular to the propagation of wave. 12. What Parameter of the Wave Changes during the Wave Refraction (transition from one area to another)? Speed of the wave changes (dispersion) 13. In which case does the Wave Reflect? Diffracted? Give examples. Reflect - while the wave propagates, when it meets a boundary or a surface dividing medium Diffract - when a wave meets the edge of an obstacle in its path 14. List the Basic Properties of a Mechanical Wave and Explain each of them. Interference - when two or more waves simultaneously propagate in s medium and generate a new wave which is weakened or strengthened. Diffraction - a deviation in the direction of a wave at the edge of an obstacle in its path Reflection - the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Refraction - when a wave propagates from one medium to another, the frequency of the wave is not changed but the wavelength changes. 15. Explain the Wave Front and Wave Surface. Wave Front - a surface containing points affected in the same way by a wave at a given time. Wave Surface - a surface wave is a mechanical wave that propagates along the interface between differing media 16. Describe the Environment in which the Mechanical Wave Propagates Mechanical Wave - the process of propagation of oscillation motion. Longitudinal waves are produced and propagate in Solids, Liquids and Gases. Amplitude is the difference between minimum and maximum pressure and is perceived as loudness. Frequency is the number of peaks that go by a fixed point in one second -------------------------------------------------------------------------------------------------------------------------------------------- SOUND 17. What is Sound Wave? Explain Longitudinal and Transverse Sound Waves. Sound - is a Mechanical Wave that propagates in discrete medium and it is not able to propagate in vacuum. The simplest kind of Sound wave is Sinusoid Wave. Longitudinal Sound Waves – fluctuation of alternating pressure around equilibrium condition that is determined by local compression and extension and travel parallel to the wave propagation. Transverse Sound Waves (in solid material) - waves, determined by alternating deformation of solid material (layers sliding) in direction perpendicular of waves propagation. 18. Explain the Acoustic Specter of Sound Waves. Explain Simple Tones and Complex Tones. Acoustic Specter / (Harmonic Specter) - The sum of frequencies, participating in Superposition of a Complex Sound. Simple Tone - When the Acoustic Specter of musical sound includes only one frequency. Complex Tone / (Musical Sound) - When acoustic specter is intermittent, i.e., includes only certain discrete values of frequencies. 19. Explain the Amplitude of a Sound Wave, the Frequency of a Sound Wave, and the Pressure of a Sound Wave. Amplitude is the difference between minimum and maximum pressure and is perceived as loudness. Frequency is the number of peaks that go by a fixed point in one second. Sound Wave Pressure is directly proportional to the density of the medium and the pressure of the wave and is a measure of the energy of sound waves. P= density * a * v 20. On what parameters does the Speed of Sound Wave propagation depend? Propagation medium Pressure Temperature Under conditions of constant pressure and temperature, speed depends on elasticity and density of the medium. 21. What Parameters determine the Energy of a Sound Wave? Amplitude Intensity and Frequency Sound Pressure - is propagated through an elastic medium through mechanical compressions and extensions, due these fluctuations of pressure occur in the medium as a result of the particle oscillation movements. This developed pressure in the medium. 23. Explain the Acoustic Impedance. What is the Intensity of the Sound Wave? Acoustic Impedance (or sound impedance) Z is a physical characteristic of a medium, where sound wave is propagated; acoustic impedance depends on density of a medium and its elastic properties. Impedance is not dependent on wave frequency. Intensity / Energy Stream Density :- The stream of energy that propagates in a plane surface perpendicular to the direction of wave propagation. [I] = Watt/m2 24. What does the Speed of Sound Propagation depend on? Velocity of Sound - wave propagation depends on the properties of its propagation medium (solid, gas, liquid), its pressure and temperature. Physical Characteristics of Sound Waves - frequency, wave length, period, amplitude, intensity, propagation velocity and direction, acoustic impedance 25. What is a Noise? Noise - A sound, acoustic specter of which includes continuous sequence of frequencies. 26. What’s an Energy Stream? Energy Stream - The ratio of energy transferred during unit of time. 27. What are Compressive Waves? Compressive Waves - Sound is propagated in gas, plasmas and liquids as longitudinal waves. 28. What are the subjective and objective characteristics of Sound Waves? Objective Characteristics of Sound waves are the Physical Characteristics of Sound Wave - Acoustic Specter, Frequency, Amplitude, Intensity, Period which are evaluated by physical methods. Subjective Characteristics of sound (Acoustic) waves are Sound Loudness, Volume and Timbre. -------------------------------------------------------------------------------------------------------------------------------------------- HEARING MECHANISMS OF SOUND 29. Describe the Mechanism of Hearing. The three parts are separated by membrane window, eardrum (between outer and middle ear), and oval window (between middle ear and inner ear). The cochlea is separated by the basilar membrane. Pinna acts as a sound collector, directing sound waves across outer ear (auditory) canal. Auditory channels increase intensity of sound waves by the decrease in its section area. On most occasions, human’s audio system for signal transmission uses only sound pressure and not particle displacement. Sound passes down the air-filled outer ear canal; vibrates the ear drum and the vibration is conveyed to across air-filled middle ear by three bones called the ossicles. The ossicles vibrate the oval window, a membrane which seals the opening to the cochlea. Oscillating movement of ossicles through the lever system increases oscillation amplitude of drum membrane transmits increased wave and causes oscillation of oval window membrane of cochlea. Finally, vibrations reach the fluid filled inner ear where, inside a coiled shaped cochlea, neurons and transmitted by action potentials. 30. 3 types of Sound Waves? Infra sound : - sometimes referred to as low-frequency sound, describes sound waves with a frequency below the lower limit of human audibility (generally 20 Hz) Ultra Sound : - waves propagated in the elastic medium, with the frequency that varies in the diapason between 2×104 and 2×109 (this a frequency greater than the upper limit of human hearing). Acoustic Impedance : - is a physical characteristic of a medium, where sound wave is propagated; acoustic impedance depends on density of a medium and its elastic properties. Impedance is not dependent on wave frequency. 31. What is Audio-Meter? Audio-Meter - is a machine used for Evaluating Hearing Acuity. They usually consist of an embedded hardware unit connected to a pair of headphones and a test subject feedback button. 13. What is the Role of the Outer Ear in the Hearing Aid? Outer Ear- (Pinna) acts as a sound collector and directs it across the ear (auditory) canal towards the ear drum. 14. What is the Role of the Inner Ear in the Hearing Mechanism? Inner ear - consists of a spiral snail-like fluid filled tube called cochlea and the internal organ of cochlea. Fluid oscillations are produced that cause movement of the basilar membrane and thus the hair cells supported by the membrane (within the organ of cochlea) K ion channels on the hair cells open and influx of K ions occur and thus nerve impulses are generated towards the brain 15. What is the Role of the Middle Ear in the Hearing Mechanism? Middle Ear - consists of 3 small bones – ossicles and these transmit vibrations towards the oval window. The ossicles help to amplify the sound The ossicles help to produce energized oscillations and concentrate or focus them towards the oval window which has a much smaller area (compared to ear drum). So, a much higher intensity is produced along with a greater pressure that helps to push against the high resistance (acoustic impedance) of the fluid in the cochlea and produce fluid oscillations. 16. Explain the Mechanism of Distinguishing Sounds according to their Loudness during the Hearing Process Louder Sound - causes more hair cells to oscillate therefore more generation on of nerve impulses occurs. Whereas, quiet sounds cause less hairs to oscillate. 17. Explain the Mechanism of Distinguishing Sounds according to Frequency The Basilar Membrane is narrower and stiffer at the region closer to the oval window, whereas, it is wider and flexible at the apex on the other side. A High Frequency Sound causes movement of the stiffer part of the membrane closer to the oval window and thus stimulates the nerve fibers at that region A Low Frequency Sound causes the flexible region at the apex to oscillate and stimulates the nerve fibers at that part. 18. What is the Significance of the Impedance difference between the Middle and Inner Ear areas? The fluid filled inner ear has much higher Acoustic Impedance than the Air-filled Middle ear. The high acoustic impedance of the inner ear damps sound waves so it needs to be amplified to be able to perceive the sound. 19. Name some of the Causes and Mechanisms of Hearing Loss Loud Sounds - extremely loud sounds such as explosions, gunfire can rupture the eardrum, break the ossicles or rupture the basilar membrane. Whereas usual loud sounds like loud music can cause significant damage to hair cells and even the hair filaments that open ion channels. Infections - Middle inner infections can rupture the eardrum (rare) and inner ear infections can damage hair cells. Toxic drugs – toxins and antibiotics can enter hair cells through openings and poison or kill hair cells. Old age – Some parts of our acoustic organ can wear out with me. In old age, blockage of blood supple can kill cells. 20. Explain the Intensity of Sound. Explain the limits of Hearing and Pain. Intensity / Energy Stream Density: - The stream of energy that propagates in a plane surface perpendicular to the direction of wave propagation. [I] = Watt/m2 The human acoustic organ can perceive sound waves within rather large intervals. The human acoustic organ is most sensitive to a range of 2500-3000Hz frequency. This is equal to 10 -12 - 10 w/m2. The lower limit of intensity I0 = 10-12 w/m2 → called Acoustic threshold. We cannot perceive any sound at this intensity The upper limit of intensity I = 10 w/m2 → called Pain limit/ threshold. We can only perceive pain and not sound. 21. What is the psychophysical law of Weber-Fechner? Law of Weber – Fechner - if the loudness of sound is increasing by geometrical progression, the sensation/perception of sound is only increasing by arithmetical progression E.g., If the intensity of sound is increases 1000-fold, we perceive the sound only 3 times stronger (lg 1000 = 22. How are Acoustic Sounds used in Medicine? Stethoscope – standard medical instrument used to amplify and analyze characteristic body sounds like heart beat and blood flow. Phonocardiography – a method used to record sounds produced by heart valves, visualize them on a personal computer and to analyze with a computer algorithm (to discover heart valve dysfunction) 9. Describe the Frequency Scale of Sound Waves. Acoustic Waves = 20 – 20000Hz Infra-sound → < 20Hz Ultra-sound → > 20000Hz -------------------------------------------------------------------------------------------------------------------------------------------- INFRA-SOUND & ULTRA-SOUND 67. Explain Ultra-sound. Ultra-sound generators. Ultra-sound - waves propagated in the elastic medium, with the frequency that varies in the diapason between 4 9 2×10 and 2×10 (this a frequency greater than the upper limit of human hearing). 68. Establish Methods of Electrostriction and Magnetostriction. Electro-striction - by multiple researches that some piezoelectric crystals (e.g. quartz, barium, titanate, tourmaline, topaz, cane sugar, Rochelle salt (sodium potassium tartrate tetrahydrate), certain ceramics, and bone ability to generate an electric field or electric potential in response to applied mechanical stress (when contracted mechanically charge redistribution/relocation takes place – one surface is charged positively and the other will be charged negatively) and we have the opposite result during expanding. This effect is called the Direct Piezo-Electric Effect 69. Explain the Interaction of Ultra-sounds with Living Tissues (Mechanisms). Mechanism of Ultra-sound with Living Tissues - sound wave consists of cycles of compression and expansion that exert alternating positive and negative pressure. Periodic alteration of pressure exerted by sound wave causes its mechanical effect on the environment. The effect depends on the amplitude of change in pressure (it corresponds to intensity of sound wave). For example, damaging effect of high intensity acoustic wave on an organ of hearing and its components (eardrum, ear bones, and basal membrane) or damaging effect of ultrasound on cellular membrane 70. What is Cavitation. Explain Stable and Un-stable Cavitation. Cavitation - is the formation of micro bubbles in liquids (e.g., Water) due to pressure distribution asymmetry by ultrasound propagation impact. Un-stable Cavitation - might be dangerous for living cells and tissues because relatively big bubbles are formed and inside of them temperature rises to a few thousand-degree Celsius mark. Afterwards those bubbles are collapsed and huge energy is released into surrounding medium which is accompanied by noise and destructive effects upon cells. This released energy is called Shockwave. Stable Cavitation – ultra-sound energy is not enough for bubble collapse and bubbles are changing their shape due to pressure distribution asymmetry created by ultrasound propagation in liquid. Hence, those pulsing bubbles cause resonate energy release which can be beneficial to cells and utilized in physical therapy to stimulate cells and tissues. 71. What are the Mechanical, Thermal and Chemical Effects of ultra-sound? Ultrasound wave, same as any other mechanical waves when propagates in the discrete medium, is reflected by the medium, Absorbed, Scattered, Refracted or the Doppler shift takes place. Reflection: ultrasound waves can reflect from external and internal surfaces. Measuring the reflected energy forms the basis of ultrasound imaging. Scattering: ultrasound waves can scatter due to inhomogeneities within different tissues. Transmission: ultrasound passes through tissue as a mechanical pressure wave. Absorption: acoustic energy is absorbed by frictional and viscous forces, and produces heat in the tissue. Refraction: ultrasound waves can change direction especially when they pass between two different media. Doppler Shift: ultrasound waves change frequency (and wavelength) when they encounter moving surfaces. Acoustic Impedance – physical characteristic of a medium related to the density and elastic properties. Acoustic impedance is independent of sound wave frequency: 72. Ultrasound and Animals Animals - such as Dogs, Cats, Dolphins, Bats, and Mice - have an Upper Frequency Limit that is greater than that of the human ear, therefore it can hear Ultra-sounds. Bats use Ultra-sounds to move in the darkness (Echo-Location). Echolocation - is the biological sonar used by several kinds of animals. Echolocating animals emit ultrasounds out to the environment and listen to the echoes of those ultrasounds that return from various objects near them. 73. How are Ultra-sounds used in Medicine? Diagnostics – ultra-sonography (finding structural changes of tissues and organs). By reflected ultrasound wave traveled distance we can learn about the nature of pathology in terms of its location. By intensity of reflected ultra-sound wave, we can learn about Acoustic Density of tissues. By reflected ultra-sound wave frequency change, we can learn about the speed of moving objects in the organism (like red blood cells). Physical Therapy - thermal effects, cavitation (mostly stable cavitation) – for drug penetration in tissues (ionophoresis, phonophoresis in dentistry), transportation of big molecules into cells (sono-poration), kidney stones breakage (lithotripsy), dental stones removal and so on. microcurrents 74. Which range of ultra-sound Frequencies (HIGH / LOW) is used for In-depth ultra-sound examinations? LOW – E.g., Sonography use ultrasound for viewing in depth of tissues etc. 75. Which range of ultra-sound frequencies (HIGH / LOW) is used for Superficial ultrasound examinations? HIGH 77. Name the Sources of Infra-red. Infra-sound - sometimes referred to as low-frequency sound, describes sound waves with a frequency below the lower limit of human audibility (generally 20 Hz) Infra-sound can also be generated by man-made processes such as sonic booms and explosions, by machinery such as diesel engines and older designs of down tower wind turbines and by specially designed mechanical transducers (industrial vibration tables) and large-scale subwoofer loudspeakers. Infra-red - Since the primary source of radiation is heat or thermal radiation, any object which has a temperature radiates in the infrared. Even objects that we think of as being very cold, such as an ice cube, emit infrared 78. Explain the Biological Effects of Infra-red Infra-sound and low-frequency noise produced by some wind turbines is believed to cause certain breathing and digestive problems in humans and other animals in close proximity to the turbines. Infrasound sometimes results naturally from severe weather, surf, lee waves, avalanches, earthquakes, volcanoes, and bolides, waterfalls, calving of icebergs, aurora, lightning and upper atmospheric lightning. Whales, elephants, hippopotamuses, rhinoceros, giraffes and alligators are known to use infrasound to communicate over distances. calls may be used to coordinate the movement of herds and allow male elephants to find mates. 79. Explain Infra-red. How are Infra-reds used in Medicine? Medical Application of Infra-sound - lately infra-sound is used for therapeutic purposes on an increasing extent: infrasonic pneumo-massage (of 4 Hz frequency) helps prevent farther aggravation of progressive myopia in school age children; thermo-vibratory massage (of 10 Hz frequency) proved to be sufficiently effective to fight chronic cholecystitis; infrasonic phonophoresis of antibacterial medicines is successfully used in patients with bacterial keratitis. 80. Describe the Resonance during Infra-red Exposure. What is its Biological Significance? 81. What is Doppler’s Effect? Doppler’s Effect – is the apparent change in frequency (and wavelength) of a wave that is perceived by an observer moving relative to the source of the waves. 82. Establish the Doppler Effect Medico-Biological Use. Medico-Biological use of Doppler Effect we are able to measure the velocity of travelling objects in medium. For instance, erythrocytes velocity in blood, walls motion, oscillation velocity of intestines wall having a big importance for medicine. Acoustic Attenuation – absorption of energy of ultrasound wave during the propagation of ultrasound wave in the medium. Attenuation is loss of acoustic energy as ultrasound wave passes through tissue. 1. Explain Fluid Pressure and Hydrostatic Pressure Pressure - is the force per unit area applied in a direction perpendicular to the surface of an object. Fluid / Liquid Pressure - is the force per unit area of hard substance surface from the fluid layer. Fluid Hydrostatic Pressure - is the pressure of Non-Moving (Static) Fluid. It is determined by exertion of gravitational forces on fluid (fluid mass). 4. Establish Archimedes' Law. Give Examples of Living Systems of Archimedes' Law. Archimedes Law - An object is immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object. Example - The brain positioned in the Human Cerebral fluid due to the effect of the Archimedes Principle. It is floating in the cerebral fluid 2. Establish Pascal's Law. Give Examples of Living Systems of Pascal's Law. Pascal's Law - the Principle of Transmission of Fluid Pressure states “that pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid” Two Principles of Pascal’s law - The pressure ratio (initial difference) remains the same in all points of a horizontal plane. Despite the shape of a container, pressure on a given horizonal plane is the same since height (h) is the same. (E.g.) - The excessive pressure in the fluid areas of the organism can cause various pathological processes such as, a tight clothes or mechanical trauma on the surface of the body can affect embryo through amniotic fluid. If we apply pressure to the eye or cause any kind of blunt trauma excessive pressure transmitted may cause damage to retina or optic nerve. 3. What is the principle of U-Pipe Principle? The Medical Use of the Principle U- Pipe Principle - When a U-tube is filled with two different fluids with different densities as ρ1 and ρ2, according to the Pascal’s law mostly mercury due to its density. If the densities of the two liquids are equal, then the levels of the liquids in the tubes are equal, Therefore, the homogenous fluids in the U-tube are in the same level. P1 = P2 ρ1gh1 = ρ2 gh2 Medical Uses - Manometers work according to the U-pipe principle. They consist of a fluid (mercury, water, alcohol, oil) Containing U-pipe. Heavy fluids (water, mercury) are used in case of measurement of high values of pressure. Q4. Explain Resistance. What Components determine the Resistance of the Circulatory System? R = 8Ln/𝝅𝝅 𝝅 RESISTANACE Resistance – an essential parameter of blood circulatory system that determines permeability of vessels in conditions of given pressure difference and the intensity of blood flow decreases. Physical Characteristics of the Blood (Viscosity, Protein, Blood cells concentration), laminar /turbulent flow. Extra vascular and endovascular mechanical forces. Vessel length, form and diameter. Properties of vessel walls. Q5. Establish the Physical Characteristics of the Blood (Non Nutuoneal) – viscosity, what factors determine the importance of blood viscosity? Viscosity is one out of factors that determines vascular resistance (impedance). Whole blood viscosity depends on its components content and their physical-chemical characteristics Influence of changes in proteins content on blood viscosity Blood viscosity is dependent on plasma viscosity. Plasma viscosity, in its turn, is dependent on proteins concentration. Fibrinogen, due to its properties, high density and lack of charge, maximally influences blood viscosity index: increases erythrocytes aggregation, causes deceleration of blood flow (stasis) and leucocytes migration at vessels walls. Q6. The Role of Temperature in the Regulation of Blood Viscosity? Temperature Influence on Blood Viscosity- the influence of change in temperature on blood viscosity is determined by the existence of specific Thermo-Proteins, which are physically changed when temperature is changed. Cryoglobulin below 37°C is a subject to reversible and/or irreversible transformation of gel into crystal condition. Pyroglobulin is subject to transformation at high temperature. That means, that at high temperature conditions, blood viscosity is sharply changed. At 0°C blood viscosity 3-fold decreased than norm. This factor along with other factors determines blood circulation decrease in cold condition and sometimes it is a cause of fingers pain in humans. 1.) How is Gas transported in the Respiratory System? (List the Stages and Characterize the Mechanisms). Ventilation - the mechanical movement of gas in the lungs and outside the lungs. This is performed by convection mechanism. Convection is molecules movement in fluids and gases. Gas exchange between lungs and blood Oxygen and carbon dioxide transport in the blood Tissue Respiration - the exchange of gases between tissues and blood 5. Explain Surface Tension. Characterize Wetting and Non-Wetting Fluids and its Role in Medicine. Surface Tension - is a property of the surface liquid, which can cause the surface portion of liquid to be attracted to another surface. It is the force of contraction acting across a line of unit length on the surface. Wetting Fluids - If the interaction between molecules of fluids and solid materials is stronger than the interaction of fluid molecules, they are wetting fluids. Their meniscus is concaved. (θ < 90O) Medical Uses - To Clean Wounds Non - Wetting Fluids - If the interactions between fluid molecules and solid material is weaker than the interaction between fluid molecules, they are non-wetting fluids. Meniscus in convex. (θ < 900 ). Medical Uses - Mercury is used in thermometers as to measure the body temperature, because mercury has the ability to expand with temperature and it doesn’t wet glass, we can get a clear reading. 6. Establish the Laplace’s Law. The Manifestation of Laplace's Law in Living Systems. Laplace’s Law - Any non-flat surface creates additional pressure in the fluid that depends on the surface curvature (E.g., formation of bubbles on the surface of water during rain, soap bubble and etc.). At any point of surface, additional pressure is dependent on surface mean curvature (K) at this point and is determined by Laplace’s Law. Example for Living Systems - Contracting heart, where the force is generated in the wall and rise of pressure occur due to the result of contracting muscles. Q10. What is the effect of the Fareus – Lindkvis? Its Importance for Blood Circulation FAREUS LINDQVYS EFFECT - is an effect where the viscosity of a fluid, in this case blood, changes with the diameter of the tube it travels through, if diameter is small. Fahraeus– Lindqvist effect erythrocytes move over the center of the vessel, Fahraeus-Lindqvis effect causes distribution of various type blood cells in blood vessels by size. Fahraeus-Lindqvis effect is responsible that in large blood vessels erythrocytes concentrate in central part of the vessel (in area of minimal resistance force). Q7. Explain Hematocrit and explain how Blood Viscosity depends on Hematocrit; Give examples of Genetic Mutations in Anemia, Polycythemia, and Hemoglobin. Hematocrit - Blood cells percentage content in blood. Hematocrit = 𝝅𝝅/𝝅𝝅 % where: V1 is blood cells volume, V2 is whole blood volume. Anemia - blood viscosity is twice decreased. This causes decrease in resistance of peripheral vessels towards blood flow, intensification of venous flow, cardiac output, and increase in cardiac muscle work Polycythemia - is a condition, when percentage content of forming cells (hematocrit) is increased per blood volume unit. This could be caused by the increase in packed red blood cells or decrease in plasma volume. Along with an increase in hematocrit, blood viscosity is increased as well as oxygen saturation. 3.) What is Airway Resistance? At What Point is the Resistance Maximum, Minimum? Airway Resistance - Airway resistance refers to degree of resistance to the flow of air through the respiratory tract during inspiration and expiration. The degree of resistance depends on many things, particularly the diameter of the airway and whether flow is laminar or turbulent Resistance of Respiratory ways is determined by: - Internal friction force between gas molecules. - Friction forces between molecules and walls of Respiratory Ways. - Character of air flow in respiratory ways (can be Laminar or Turbulent and Transitional) Respiratory Ways perform the functions of Filtration, Cleaning and Distribution An individual small airway has much greater resistance than a large airway. Where air is flowing in a laminar manner it has less resistance than when it is flowing in a turbulent manner. If flow becomes turbulent, ant the pressure difference is increased to maintain flow, this response itself increases resistance. Larger airways are more prone to turbulent flow than smaller airways. 9. Explain Ideal and Real Fluid. Give Examples Ideal Fluid - Fluid that is not characterized by viscosity and constriction forces is called an Ideal Fluid. Ideal fluids are imaginary and doesn’t exist. Real Fluid - Fluids that are characterized by viscosity and constriction forces are called Real Fluids. (Ex: Petrol, Air) 10. What is the Equation for the Stability of a Liquid Jet (Flow). Its Manifestation in Livin g Sms. ysteS1v1 =S2v2=S3v3 =Snvn SV = const 11. What is Bernoulli Equation? Its Practical Significance Etotal = PV + mgh + 𝝅𝝅𝝅 =const Bernoulli Equation - is the main equation in Hydrodynamics. We also use the Bernoulli’s equation in vascular and respiratory patho-physiology in order to measure pressure (for example at stenosis). Pulse Pressure - the difference between systolic and diastolic blood pressure. Unit - mm/Hg Systolic Pressure - is the force that heart exerts on the walls of the arteries each time it beats Diastolic Pressure - is the measure of force that the heart exerts on the walls of arteries in between heart beats 14. Explain mean Blood Pressure, Central Venous Pressure, and Pulse Pressure; Blood Pressure - is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. BP values are generally stated in mmHg, but can be converted to an SI-unit, in Pascal’s. Central Venous Pressure reflects the amount of blood returning to the heart and the ability of the heart to pump the blood into the arterial system. 13. Describe Newtonian and Non-Newtonian fluids. Give Examples. Newton's Equation. Newton established that velocity gradient value is dependent on fluid properties. Newtonian Fluids - are the fluids that the viscosity coefficient of which η is dependent only on fluid properties and temperature and does not depend on dynamic indices (E.g.: - water, melted metals and their salts) Non - Newtonian Fluids - are the Fluids viscosity coefficient of which depends not only on fluids properties and temperature, but also on the fluids pressure and velocity gradient as well. (E.g.- suspensions, emulsions, high molecular organic compounds like blood ) η = 𝝅𝝅/Sv = 𝝅 (52) 𝝅𝝅 𝝅𝝅 15. What is the Formula of Poiseuille’s, its practical significance? Describe the Laminar Flow of Viscous Fluid in a Cylindrical Tube. Laminar Flow in Viscous Fluid - If viscous fluid equally flows in a tube, distribution of fluid particles velocities along the radius will be the same at any segment at points that are equally far from the center. Along the central axis of the tube has the greatest flow velocity, while layer which is attached to tube surface is static. POISEUILLE’S EQUATION: - Current Curve - curve in fluid flow where the tangent drawn at each point of it has a direction of fluid particle velocity at this point. 7. What is Capillary Effect Capillary Effect - Capillary action is the process of a liquid flowing in narrow spaces without assistance or even in opposition to external forces like gravity. Capillarity action is employed in estimation of blood clotting time. In this method blood from pricked finger is filled in a free glass tube capillary by capillary action. Absorbent cotton or gauze used in surgical dressing also works on the principal capillarity. In addition, capillarity action is imploding for a surgical drain. 5.) Explain the Role of Surface Tension in Respiratory Bio-Mechanics. Laplace's law. Surface Tension - force has the significant role in breathing, in particular in constriction and extension of alveoli in breathing. Air, that reaches the lungs through respiratory ways, is saturated with water vapour. In alveoli water molecules are condensed and cover their inner surface and are characterised with high surface tension. The surface tension of liquid membrane on the inner surface of alveoli in expiration (when the air pressure inside alveoli is reduced) provides the reduction of surface area of alveolar bubble, consequently the reduction of bubbles’ radius. The pressure, defining the decrease in surface area of alveolar bubble, is expressed by the Laplace formula (for sphere surface): P=4σ/R where: σ – coefficient of surface tension; R – inner radius of alveoli. The Role of Surfactant in the Respiratory Process Surfactants - are compounds that lower the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Alveoli walls are covered with a thin layer of water and in this layer surfactant amphipathic molecules are embedded. Because of surfactants, different size alveoli have different surface tension – smaller ones have less radius and less surface tension; bigger ones have more radius and more surface tension. 14. Describe the Laminar and Turbulent Flow or Reynolds Number. What type of Flow is seen in the Blood Vessels? Laminar Flow / Reynolds Number - When a fluid flow has relatively low velocities than critical velocity, fluid particles move parallel to the tube walls and without mixing with each other. They may not remove from one layer to another. Fluid velocity is constant at any point of fluid and is not changed by time. Turbulent Flow - When the fluid flow has high velocities than the critical velocity, fluid motion cannot be considered as sorted layers, these layers mix with each other. At this time fluid particles trajectories are not parallel to tube walls. At a certain point of the fluid, the velocity is not constant, it changes chaotically without any order. Blood Flow is Lamina 1. What is the formula of Poiseuille’s, its practical significance? Describe the laminar flow of viscous fluid in a cylindrical tube; In laminar flow all elements of the fluid move in streamlines that are parallel to the axis of the tube. Velocity of fluid layers adjacent to the tube walls is minimal, while the velocity of fluid layer in the center of the tube is maximal The equation states that flow rate is proportional to the radius to the fourth power, meaning that a small increase in the internal diameter of the cannula yields a significant increase in flow rate of IV fluids. 3. Establish physical circulatory mechanisms. List the factors that help maintain blood flow direction Blood circulation in circulatory system is promoted also by the contractile activity of skeleton muscles. When skeleton muscles are contracting, they press the veins and thus promote blood circulation to heart. To move in opposite side is prevented by vein valves. – Muscle (heart, vessels, limbs) constriction (contraction); – Breathing (negative pleural pressure); – Existence of one-port valves. 4. Explain resistance; What components determine the resistance of the circulatory system? Resistance is a force that opposes the flow of a fluid. In blood vessels, most of the resistance is due to vessel diameter 1. Physical characteristics of the blood (viscosity, protein, blood cells concentration), laminar /turbulent flow. 2. Extra vascular and endovascular mechanical forces. 3. Vessel length, form and diameter. 4. Properties of vessel walls. 5. Establish the physical characteristics of the blood - viscosity; What factors determine the importance of blood viscosity? Blood is a suspension of blood cells (erythrocytes, leucocytes, platelets) in plasma. Plasma is a solution of water dissolved salts and hydrated molecules. Blood viscosity at 37°C temperature varies within approximately 3.5 Pa sec, which is determined by protein high concentration in blood and existence of suspended blood cells. Blood viscosity is dependent on plasma viscosity. Plasma viscosity, in its turn, is dependent on proteins concentration. Temperature and hematocrit. 6. The role of temperature in the regulation of blood viscosity The influence of change in temperature on blood viscosity is determined by the existence of specific thermoproteins, which are physically changed when temperature is changed (deviation from 37°C level). That means, that at high temperature conditions (40°C and above) blood viscosity is sharply changed. At 0°C blood viscosity 3 fold decreased than norm. This factor along with other factors determines blood circulation decrease in cold condition and sometimes it is a cause of fingers pain in humans. 7. Explain hematocrit and explain how blood viscosity depends on hematocrit; Give examples of genetic mutations in anemia, polycythemia, and hemoglobin Blood cells percentage. v1/v2%. V1 is blood cells volume, V2 is whole blood volume. When hematocrit is high, resistance force value is increased towards blood flows, consequently, blood viscosity is significantly increased (10 fold), and that is, at the increase in hematocrit by 60 – 70%, increase in blood viscosity causes increase in resistance of peripheral vessels and development of hypertension, while it contributes to the decrease in venous flow. At severe anemia blood viscosity is twice decreased. Polycythemia is a condition, when percentage content of forming cells (hematocrit) is increased per blood volume unit. At anemia, which is caused by abnormal hemoglobin, (Thalassemia - lack of globin chains), erythrocytes are light, small (Fig. 92a), consequently blood viscosity is decreased 8. Blood flow laminar / turbulence. In laminar flow all elements of the fluid move in streamlines that are parallel to the axis of the tube. Velocity of fluid layers adjacent to the tube walls is minimal, while the velocity of fluid layer in the center of the tube is maximal. In turbulent flow all element of the fluid moves confusedly, towards various directions (in parallel, perpendicular to axis of the tube or boundary), at various speed (Fig. 97), fluid layers are mixed with each other. 9. What is the peculiarity of blood circulation in small blood vessels? Properties of erythrocytes (deformity). Blood flow velocity) Erythrocytes deformability is decreased owing to structural changes of their membranes or structural defect, decrease in membrane fluidity due to changes in its lipid spectre, deposition of excess cholesterol, as well as in case of hemoglobin defects. 10. What is the effect of the fareus-Lindkvis; Its importance for blood circulation The Fahraeus–Lindqvist effect is an effect where the viscosity of a fluid, in this case blood, changes with the diameter of the tube it travels through (only if the vessel diameter is between 10 and 300 micrometers). According Fahraeus–Lindqvist effect erythrocytes move over the center of the vessel. Fahraeus-Lindqvis effect causes distribution of various type blood cells in blood vessels by size. Fahraeus-Lindqvis effect is responsible that in large blood vessels erythrocytes concentrate in central part of the vessel 11. Establish the effect of vascular length, shape, and diameter on blood flow; Give examples diameter: When blood flows through vessel system, the same volume of blood should pass through vessel cross-sectional area per time unit. Consequently, if vessel cross-sectional area is changed, fluid flow will be changed as well (Puieasuille equation). Thus, the conductance of the vessel increases in proportion to the fourth power of the diameter length: That is along with increase in vessel length (distance from the heart) blood pressure is decreased. Shape: 12. Vascular elasticity; Its role in the significance of pulse pressure In the arterial system, where the protein is most abundant, elastin forms an elastic mortar between the arrays of cells that line the arteries. There, the protein provides the stability that allows the vessels to expand and contract continuously as blood pulses along. elasticity is essential for vessel wall development and cardiovascular function in vertebrates. Without elastic vessels to provide an elastic reservoir, high blood pressure and stiff, stenotic arteries cause impaired LV function 13. Explain what factors affect the importance of blood pressure. Explain systolic, diastolic, pulse pressure It measures the force your heart exerts on the walls of arteries. Systolic pressure is the pressure of the blood in the arteries when the heart pumps. Diastolic pressure, the force exerted when the heart is at rest (bw the beats) pulse pressure is the difference between systolic and diastolic pressures. 14. Explain mean blood pressure, central venous pressure MAP, or mean arterial pressure, is defined as the average pressure in a patient's arteries during one cardiac cycle. It is considered a better indicator of perfusion to vital organs than systolic blood pressure (SBP). Central venous pressure (CVP) is the blood pressure in the venae cavae, near the right atrium of the heart. CVP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood back into the arterial system. 15. Learn the methods of measuring blood pressure. practice, pressure is usually measured at the arm at heart level. The increased hydrostatic pressure in the veins of the legs upon standing pushes outward upon the veins wall, causing marked distension with polling of blood. Manually using a cuff and a stethoscope. oscillometric method Using an electronic blood pressure monitor. 16. Explain the effect of gravitational force on blood in the vascular system. gravity acts on the vascular volume causing blood to accumulate in the lower extremities. Because most veins must move blood against the pull of gravity, blood is prevented from flowing backward in the veins by one-way valves  -------------------------------------------------------------------------------------------------------------------------------------------- AERODYNAMICS 1.) How is Gas transported in the Respiratory System? (List the Stages and Characterize the Mechanisms). Ventilation - the mechanical movement of gas in the lungs and outside the lungs. This is performed by convection mechanism. Convection is molecules movement in fluids and gases. Gas exchange between lungs and blood Oxygen and carbon dioxide transport in the blood Tissue Respiration - the exchange of gases between tissues and blood 2.) What is the Relationship between Lung Volume and Pressure? Which Law describes this Attitude? Law of Boil – Marriot - that is, when the Internal Volume of the lung is increased (Inhalation), the pressure is reduced by the same value and atmospheric air gets into the lung, until pressures are equal (like atmospheric air inflates lungs). PV = CONSTANT. Respiratory Process - In relaxed state, Pressure in the lungs is equal to Atmospheric Pressure. Lungs because of their elasticity are drawn to decrease their volume and they contract slightly (elastic contraction), this decreases pressure in pleural cavity. (Because pleural cavity does not have a connection with air medium, and it does not get refilled with air), so pleural cavity pressure in lungs relaxed state is negative and is balanced by lungs elasticity. 3.) What is Airway Resistance? At What Point is the Resistance Maximum, Minimum? Airway Resistance - Airway resistance refers to degree of resistance to the flow of air through the respiratory trac t during inspiration and expiration. The degree of resistance depends on many things, particularly the diameter of the airway and whether flow is laminar or turbulent Resistance of Respiratory ways is determined by: - Internal friction force between gas molecules. - Friction forces between molecules and walls of Respiratory Ways. - Character of air flow in respiratory ways (can be Laminar or Turbulent and Transitional) Respiratory Ways perform the functions of Filtration, Cleaning and Distribution An individual small airway has much greater resistance than a large airway. Where air is flowing in a laminar manner it has less resistance than when it is flowing in a turbulent manner. If flow becomes turbulent, ant the pressure difference is increased to maintain flow, this response itself increases resistance. Larger airways are more prone to turbulent flow than smaller airways. 4.) List the Factors / Diseases that cause Changes in Airway Elasticity. How does the Gas Flow change in this case? Diagnostic significance of Flow Change Airway Elasticity - the size of elasticity of the respiratory system is Tensility. Tensility - is determined as the ability of respiratory system (lungs–chest) to change the volume by the influence of the pressure The total tensility of the respiratory system is determined by the tensility (Elasticity) of lungs, wall of chest and alveoli. The tensility of lungs depends on morphological-physiological characteristics of the connective tissue, which is its component. Lungs’ tensility is reduced with age increase, as well as with fibrosis of lungs (due to decrease in elastin content, increase in volume of collagen fibers), or is increased when emphysema (pathological extension of distal bronchioles with destructive-alveolar changes in alveolar walls – chronic non-specific disease of lungs which occurs due to genetic disorders, smoking etc.) occurs. During various pathologies along with changes in lungs’ elasticity air flow intensity is also changed. 5.) Explain the Role of Surface Tension in Respiratory Bio-Mechanics. Laplace's law. Surface Tension - force has the significant role in breathing, in particular in constriction and extension of alveoli in breathing. Air, that reaches the lungs through respiratory ways, is saturated with water vapour. In alveoli water molecules are condensed and cover their inner surface and are characterised with high surface tension. The surface tension of liquid membrane on the inner surface of alveoli in expiration (when the air pressure inside alveoli is reduced) provides the reduction of surface area of alveolar bubble, consequently the reduction of bubbles’ radius. The pressure, defining the decrease in surface area of alveolar bubble, is expressed by the Laplace formula (for sphere surface): P=4σ/R where: σ – coefficient of surface tension; R – inner radius of alveoli. The Role of Surfactant in the Respiratory Process Surfactants - are compounds that lower the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Alveoli walls are covered with a thin layer of water and in this layer surfactant amphipathic molecules are embedded. Because of surfactants, different size alveoli have different surface tension – smaller ones have less radius and less surface tension; bigger ones have more radius and more surface tension. 6.) How Gas Exchange takes place in the Alveoli Gas Exchange in Alveoli - The wall of alveoli and capillaries is so thin that oxygen/carbon dioxide molecules can freely diffuse from alveoli into capillary system and then forms a chemical bond with erythrocytes’ haemoglobin. Oxygen and carbon dioxide molecules move across the surface of air-water boundary. Partial pressure of oxygen and carbon dioxide are essential for proper gas exchange between alveolar spaces and blood. If gas partial pressure in air phase (alveolus) is greater than its partial pressure in fluid (blood) gas diffuses in blood, if it is less, gas will move towards partial pressure gradient. In inspiration, air flow is directed towards alveoli; oxygen molecules diffuse from alveoli towards partial pressure gradient in blood, while carbon dioxide moves in the opposite direction. 7.) What Causes Hysteresis? Hysteresis - is the phenomenon in which the value of a physical property lags behind changes in the effect causing it. At first it is hard to inflate alveoli during inhale because epithelial wall resists pressure. After some time, alveoli are inflated and more pressure exerted translates into more expansion like in case of a balloon (high compliance). When exhale process begins, air leaves alveoli, pressure is decreased, but alveoli deflation will not follow it. After some time, alveoli deflation value becomes extremely high (like balloon is deflated very fast during the terminal stage of a deflation process). By the way, expiration takes longer than inspiration because of hysteresis. Describe the Ventilation Process of Inhalation and Exhalation Ventilation Processes of Inhalation and Exhalation - are regulated by changes of pressure / volume of lungs. Chest (ribs and diaphragm) plays a role of the pump. At breathing in muscles provide active extension of the chest and consequently pressure reduction in pleural cavity (comparing with atmospheric). Convection - is molecules movement in fluids and gases 9.) What is the Function of the Respiratory System? Function of Respiratory System - is to supply the circulatory system with oxygen and elimination of waste product of oxidative metabolism - carbon dioxide from blood. 10.) Describe the Process of Pneumo-thorax. Negative Pressure & Pneumo-Thorax - inside pleural cavity pressure is Sub-atmospheric because lung and chest walls are pulled in different directions due to elastic recoil and making pressure in pleural cavity less than atmospheric. When there is disruption of pleural cavity isolation from environment, due to pressure gradient air flows from environment into pleural cavity and pressure inside pleural cavity becomes atmospheric. This is condition when lung is collapsed, it can’t expand due to increased pressure in pleural cavity and patient can’t breathe. Transpulmonary Pressure becomes zero – zero difference between alveolar and pleural pressures. For an open pneumothorax, treatment requires sealing the open wound with an occlusive dressing. This is often taught by using Vaseline gauze and securing the gauze to the patient's chest with tape 11.) What is Emphysema and Fibrosis? a region around a magnetic material or a moving electric charge within which the force of magnetism acts