Manual Physiology PDF 2018

Session No. 6 Pulse Rate & Arterial blood pressure Measurement The pulse gives an idea about the condition of the vessel walls and amount of variation of pressure of the contained blood, therefore state of the heart and circulation may be obtained. Your pulse is the rate at which your heart beats. A...

Session No. 6 Pulse Rate & Arterial blood pressure Measurement The pulse gives an idea about the condition of the vessel walls and amount of variation of pressure of the contained blood, therefore state of the heart and circulation may be obtained. Your pulse is the rate at which your heart beats. As your heart pumps blood through your body, you can feel a pulsing in some of the blood vessels close to the skin's surface. Examination of pulse: Arterial pulse may be examined in the radial, brachial, femoral, posterior tibial and dorsalis pedis. Examination of radial pulse is more commonly practiced, figure (1 a, b). Feel the pulse (palpate) by placing two or three fingers on the radial artery. Do not use the thumb. Forearm is pronated and the wrist slightly flexed. Pulse Rate: count beats for not less than 1/2 minute. The rate is accelerated (tachycardia), by emotion, exercise, fever, and atrial fibrillation. The rate is slowed (bradycardia) in heart block. The typical pulse of healthy adult man should be at rate of 72/min. Figure (1, a) 22  Figure (1, b) Part Two: Arterial blood pressure Blood pressure is defined as the pressure exerted against any unit area of the blood vessel walls and is generally measured in arteries. Because the heart contracts and relaxes, the resulting rhythmic flow of blood into the arteries causes the blood pressure to rise and fall during each beat. There are two types of blood pressure (recorded in millimeters Mercury (mm Hg)) Figure (2) 23 : 1. The systolic pressure: is the pressure in the arteries at the peak of ventricular ejection. When your heart beats, it squeezes and pushes blood through your arteries to the rest of your body. This force creates pressure on those blood vessels, and that's your systolic blood pressure. The diastolic pressure: it reflects the pressure during the ventricular relaxation. 2. The diastolic reading, or the bottom number, is the pressure in the arteries when the heart rests between beats. This is the time when the heart fills with blood and gets oxygen. For example, if the systolic blood pressure is 120 and the systolic blood pressure is 80, the blood pressure is expressed as 120/ 80 (120 over 80). Figure (2) Abnormal blood pressure values: 1. Hypertension: if the systolic pressure > 140 mm Hg or the diastolic pressure > 90 mm Hg. 2. Hypotension: if the systolic pressure < 90 mm Hg or the diastolic pressure < 60 mm Hg. Materials: 1. Stethoscope. 2. Sphygmomanometer (mercury, inflatable cuff, pulb). Procedure: The blood pressure is estimated mainly by a sphygmomanometer and stethoscope (auscultatory method). 1. Clean the earpieces of the stethoscope with alcohol swab, and check the cuff for the presence of trapped by compressing it against the laboratory table. 24 2. The subject should sit in a comfortable position with one arm resting on the laboratory table (approximately at the heart level if possible). 3. Wrap the cuff around the subjects’ elevated arm, just above the elbow, with the inflatable area on the medial arm surface (over the brachial artery) (figure 3). Secure the cuff by tucking the distal end under the wrapped portion or by bringing the Velcro areas into position. 4. Palpate the brachial pulse and lightly mark its position with a felt pen. Place stethoscope diaphragm over the pulse point. The cuff should not inflate for more than one minute. 5. Inflate the cuff to approximately 160-mm Hg pressure, and slowly release the pressure valve. Watch the pressure gauge as you listen carefully for the first soft thudding sounds of the blood spurting through the partially occluded artery. Note this pressure (systolic pressure), and continue to release the cuff pressure. You will notice first an increase, then a muffling, of the sound. Note: Make two blood pressure determinations, and record your result below. Effect of various factors on blood pressure: Many factors—age, weight, time of day, exercise, body position, emotional state, and various drugs for example alter blood pressure Figure (3): Sphygmomanometer 25 Session No. 7 Conduction system of the heart and Electrocardiography Introduction: Heart contraction results from a series of electrical potentials changes (depolarization waves) that travel through the heart preliminary to each beat. The conduction of impulses through the heart generates electrical currents that eventually spread throughout the body. These impulses can be detected on the body’s surface and recorded with an instrument called an electrocardiogram (ECG) machine. The graphic recording of the electrical changes (depolarization and repolarization) occurring during the cardiac cycle is called an Electrocardiograph. Figure(1): Normal Electrocardiogram. - The typical ECG consists of a series of three recognizable waves. 1- The P wave: Indicates the depolarization of the atria immediately before atrial contraction. 2- The large QRS complex: Resulting from ventricular depolarization has a complicated shape (primarily because of the variability in size of the ventricles and the time differences required for these chambers to depolarize). It precedes ventricular contraction. The repolarization of the atria, which occurs during QRS interval, is generally obscured by the large QRS complex. 26 3-The Twave: Results from currents propagated during ventricular repolarization. *Standards leads are used to record an ECG for diagnostic purposes: 1- Three bipolar standard limb leads: Lead I, II, III A- Lead I: Detects potential difference between the left arm and right arm ( LA-RA). B- Lead II; Detects potential difference between the right arm and left leg (RA-LL). C-Lead III: Detects the potential difference between the left arm and left leg (LA-LL). 3- Six unipolar chest leads: They called V1 – V6 (V: Stand for vector) or C1 – C6 (C: Stands for chest) 1- V 1: At the right margin of the sternum in the fourth intercostals space. 2- V 2: At the left margin of the sternum in the fourth intercostals space. 3- V 3: Midway between position 2 and 4. 4- V4: At the left midclavicular line in the fifth intercostals space. 5- V5: At the left anterior axillary line and at the same level as position 4. 6- V6: At the left midaxillay line and at the same level as position 4. Note: the right leg is used as ground or earth. Measuring heart rate from ECG 1. The paper speed is 25 mm/sec, each mm (1 small square) speed = 1/ 25= 0.04 sec. 2. Measure the duration of one cardiac cycle represented by the length of R-R interval (number of small squares between two successive R waves (in mm). 3. Multiply R-R length by 0.04 sec (the time of each cardiac cycle). 60 sec 4. Heart rate/ min  (R - R)  0.04 sec 27 Abnormal Heart Rate Values: Tachycardia; A heart rate over 100 beat/min. Bradycardia : A heart rate below 60 beat/min. Example R-R interval length = 18 mm So cardiac cycle duration = 18 x 0.04 =0.72 sec Heart Rate = 60/ 0.72 = 83 beat/ min. Materials: 1- ECG recording apparatus. 2- ECG gel. 3- Alcohol swabs cot. Procedure: 1- Clean the skin with a cotton moistened with alcohol to remove died cells and oil. 2- Apply the ECG gel on the cleaned skin sites (limb, chest) for good conduction. 2- Attach the electrodes to the cleaned skin sites. Take care not to let the electrodes come in contact with each other, then connect the electrodes with the machine through leads, see figure (2). 3- Attach the electrodes to the cleaned skin sites. Take care not to let the electrodes come in contact with each other, then connect the electrodes with the machine through leads, see figure (2). 28 Figure (2): Attaching the electrodes. 29 Session 8 Pulmonary Function Tests (Lung Volumes and Capacities) Introduction: The volume of air a person inhaled (inspires) and exhales (expires) can be measured with a Spirometer (Spiro=breath, meter = to measure). is an apparatus for measuring the volume of air inspired and expired by the lungs.. The resultant record of volume changes versus time is called a spirogram. Lung volumes 1- Tidal volume: It is the volume of air expired or inspired per breaths during normal quite breathing. The tidal volume of 70g adult man is about 500ml per inspiratory breath; this can be increased dramatically during exercise. 2- Inspiratory reserve volume: Volume of air inhaled maximal (deepest) inspiration (started after normal tidal inspiration). This volume is about 3000ml. 3- Expiratory reserved volume: Volume of air expelled during maximal active contraction of expiratory muscles starts at the end of normal tidal expiration. This about 1500ml. 4- Residual volume: Volume of air remaining in lungs after a maximal forced expired, which is about 1000ml. Lungs Capacities: 1- Vital capacity: It is a useful clinical measurement; it’s the maximal volume of air that can be expelled after maximal inspiration. It is about 5000ml. It is also equal to the sum of tidal volume and inspiratory and expiratory reserved volumes 2- 2- Functional residual capacity: Volume of air remaining in lungs at the end of normal tidal expiration. It is about 2500ml [Sum of residual volume and expiratory reserved volume (1000+1500=2500)].  3- Total lung capacity: Volume of air in lungs after a maximal inspiration. It consists of all four lung volumes: Residual volume (1000ml) +Tidal volume (500ml)+Inspiratory residual volume(3000ml)+Expiratory reserved volume(1500ml). It is about 6000ml. 4- Inspiratory capacity: Volume of air inhaled during maximal inspiratory begins after end of normal tidal expiration. It is tidal volume+ inspiratory volume, it is about 3500ml Figure (1): Lung volume and capacities spirogram. Chronic pulmonary diseases are classified into two physiological categories: 1. Obstructive pulmonary disorders, such as emphysema and bronchial asthma. In chronic obstructive pulmonary disease (COPD) such as bronchial asthma, excessive mucus secretion partially blocks airways, increasing airways resistance and thus making breathing more difficult. The asthmatic may take longer to inspire and expire, but pulmonary volumes may be normal or near normal. 2. Restrictive pulmonary disorders such as pulmonary fibrosis and other chronic diseases of the lung interstitial. In a restrictive pulmonary disease, the ability to change lung volume is - 31 -  decreased. As a result, lung capacities and volumes are generally reduced (e.g., decreased vital capacity Notes: 1- Body size: Size of lungs depends on subject height and weight or body surface area. All volumes are larger in larger people. 2- Age: Size of lungs depends on age, volumes are smaller in children, and alternation in elasticity and compliance of lung in old age affect lung volumes and capacities 3- Sex: All volumes are slightly smaller in females due to difference in body size 4- Exercise: This increase lung volumes 5- Posture: Vital capacity is larger in sitting than in recumbent position because during sitting the viscera drop down by gravity, helping free decent of the diaphragm. Therefore, lung volume and capacities depend on mechanics of the lung and chest wall (elasticity and airway resistance) and the activity of inspiratory and expiratory muscles. Materials: 1-Spirometer 2-Clamp 3-Steril mouth piece 4-Alcohol 70% Procedure: 1. Close the nose by a clamp 2. Let the subject while sitting to breathe through the mouth piece into the spirometer without looking at the record. 3. After few normal respiratory movement, the subject is asked to perform Vital capacity (VC), Forced vital capacity (FVC) and the maximum voluntary ventilation (MVV). 1. To determine the (VC): Inspire slowly (fully), then expire slowly (fully). 2. To determine the (FVC): Inspire slowly (fully), then expire rapidly (fully). 3. To determine the (MVV): Breath rapidly for 12 – 15 seconds. RESULTS: __________ % Vital capacity (VC) __________ % Forced vital capacity (FVC) __________ % maximum voluntary ventilation (MVV) - 32 - Session 9: Human Reflex Physiology Introduction Reflexes are rapid, predictable, involuntary motor responses to stimuli; they are mediated over neural pathways called reflex arcs. There are five essential components of reflex arc Figure 1: Receptor, sensory neuron, integration center, motor neuron, and effectors. Reflex testing is an important diagnostic tool to assess the condition of the nervous system. Exaggerated, distorted,, or absent reflex may indicate degeneration or pathology or portions of the nervous system, such conditions includes damage to intervertebral discs, tumors, polyneuritis, and apoplexy. Figure 1 Reflexes can be categorized into one of two large groups: 1. Autonomic reflexes are mediated through the autonomic nervous system and are not subject to conscious control. These reflexes result in the activation of smooth muscles, cardiac muscle, and the glands of the body; they include the regulation of such body functions such as digestion, elimination, blood pressure, salivation and sweating. 2. Somatic (spinal) include all these reflexes that involve the stimulation of skeletal muscles by the somatic division of the nervous system.. An example of such reflex is the rapid withdrawal of a hand from a hot object. Clinically, Somatic reflexes are categorized as being either deep or superficial: 1- Deep tendon reflex = Stretch reflexes - 33 -  These type of reflexes provide information on the integrity of the central nervous system and peripheral nervous system. And they can be used to detect the presence of a neuromuscular disease. 2- superficial reflex = cutaneous reflexes A reflex elicited by stimulation of the skin. Materials Reflex hammer. Method: A. Deep reflexes: Reflexes of the upper limb A. Biceps reflexes: This reflex causes flexion of the arm. It is elicited by holding the subject`s elbow with the thumb pressed over the tendon of the biceps brachii, as shown in figure 2- A. To produce desired response, strike a sharp blow to the first digit of the thumb with the reflex hammer. B. The brachioradialis reflex In normal individuals this reflex will cause flexion of the forearm at the elbow joint and halfway between pronation and supination.To demonstrate this reflex, direct the subject to rest the hand on the thigh in the position shown in illustration (figure 2- b). Identify the brachioradialis tendon at the wrist. It inserts at the base of the styloid process of the radius, usually about 1 cm lateral to the radial artery then strike the tendon with the wide end of the reflex hammer C. Triceps reflex: This deep reflex causes extension of the arm in normal individuals. To demonstrate this reflex, flex the arm at the elbow holding the wrist as shown in illustration figure 2-c , with the palm facing the body. Strike triceps brachii tendon above the elbow with pointed end of the reflex hammer. Reflexes of the lower limb D. Patellar reflex: It is referred to as the knee reflex, knee jerk, or quadriceps reflex. the quadriceps muscle cause extension of the leg at knee joint. To perform this test, the subject should be seated on the edge of a table with the leg suspended and somewhat flexed over the edge. Figure 2-D.To elicit the typical response, strike the patellar tendon, which is just below the knee cap. E. Achilles reflex: This reflex is also referred to as the ankle jerk. It is characterized by plantar - 34 -  flexion when the Achilles tendon is struck a sharp blow. To perform this reflex the subject must be relaxed then strike the Achilles tendon. Figure 2-E B. Superficial reflexes F. Plantar flexion: This reflex is the one in this series that is of superficial nature. Note in illustration G figure2-F, and figure 3, that the normal reaction to stroking the sole of the foot in an adult is plantar flexion. If dorsiflexion occurs, starting in the great toe and spreading to the other toes (Babiniski's sign), it may be assumed that there is myelin damage to fibers in the pyramidal tracts. Incidentally, dorsiflexion is normal in infants, especially if they are a sleep. Babiniski`s sign disappears in infants once myelinization of nerve fibers is complete (after 6 months of birth). Perform this test on the bottom of the foot of a subject, using a hard object such as key. Follow the pattern shown in the middle illustration. - 35 - Figure (2): Type of Reflexes Figure (3): Plantar flexion - 36 - Session 10: Special Senses (Vision & Hearing) Part One: Vision Introduction: The image of an object is formed by refraction of light rays from it by the cornea and the lens of the eye, and then the rays are focused on the rods and cones at the retina. Rods and cones are photoreceptors contain light-sensitive pigments which are altered when exposed to visible wave length of light, leading to changes in ion flow which generate neural signals. This signal is translated in the occipital cortex as an image. The various tests outlined in this exercise related to the observation of normal conditions, as well as the election of the more common types of abnormalities. By performing these tests you will learn more about the physiology of vision. Materials: 1. Snellen test letter chart. 2. Green’s astigmatic chart. 3. Vision disc. 4. Ishihara color-blindness test booklets. Procedure: 1. Test for Visual Acuity Visual acuity, or sharpness of vision, is generally tested with a Snellen eye chart, which consist of letters of various sizes pointed on a white card. This test is based on the fact that letters of certain size can be seen clearly by eyes with normal vision at a specific distance. The distance at which the normal, or emmetropic, eye can read each line of letters is printed at the end of that line. 1. Have your partner stand 20 feet from the posted Snellen eye chart, with one eye covered by a card or hand. As your partner reads each consecutive line aloud, check for accuracy. (If this individual wears glasses, the test should be taken twice-first with glasses off and then with glasses on). 2. Record the number of the line with the smallest sized letters read. If it is 20/20, the person’s vision for the eye is normal. If it is 20/40 (or any ratio with a value less than one), his or her vision is less than the normal acuity. (Such an individual is myopic). If the visual acuity is 20/15, vision is better than normal, because this person can stand 20 feet from the chart and read letters that are only discernible by the normal eye at 15 feet. 3. Have your partner test and record your visual acuity. If you wear glasses, the test result without - 37 -  glasses should be recorded first. Results: Visual acuity right eye: __________ Visual acuity left eye:__________ Figure (1): Snellen test letter chart. 2. Blind Spot: The blind spot of the retina is the optic disc where nerve fibers of the retina converge and exit the eyeball via the optic nerve. There are no cones or rods present in the optic disc; therefore no image can be formed in this area. 1. Hold figure 5 about 18 inches from your eye, and focus your right eye on the X, which should be positioned so that it is directly in line with your right eye. Move the figure slowly toward your face, keeping your right eye focused on the X. When the dot focuses on the blind spot, which lacks photoreceptors, it will disappear. Have your laboratory partner record in metric units the distance at which this occurs. (The dot will reappear as the figure is moved closer). Results: Distance at which the dot disappears: Right eye:__________ Repeat the test for the left eye, this time closing the right eye and focusing the left eye on the dot. - 38 - Record distance at which the X disappears: Left eye:__________ Figure (2): Blind spot test. 3. Test for Near point Accommodation: The elasticity of the lens decreases dramatically with age, resulting in difficulty in focusing for near or close vision. Measuring the near point of accommodation can test lens elasticity. The near point of vision is about 7 cm at age 10, 10 cm at age 20, 14 cm at age 30, 22 cm at age 40, 40 cm at age 50 and 100 cm at age 60. To determine your near point of accommodation, hold a common straight pin at arm’s length in front of one eye. Slowly move the pin toward that eye until the pin images becomes distorted. Have your lab partner measure the distance from your eye to the pin at this point, and record the distance below. Repeat the procedure for the other eye. Near point for right eye:__________ Near point for left eye:__________ 4. Test for color blindness: Ishihara`s color plates are designed to test for deficiencies in the cones, or color photoreceptor cells. Studies suggest that there are three cone types, each contains a photoreceptor pigment. One type primarily absorbs the red wavelengths of the visible light spectrum, another blue wavelength, and a third the green wavelengths, nervous impulses reaching the brain from these different photoreceptor types are then interpreted (seen) as red, blue, and green, respectively. The interpretation of the intermediate colors of the visible light spectrum is a result of overlapping input from more than one cone type. Color blindness is a sex linked hereditary condition that affects 8% of the male population and 0.5% of females. The most common type is - 39 - red-green color blindness, in which either the red or green cones are lacking. If red cones are lacking, a condition called protanopia exists. Individuals that have this condition see blue-green and purplish-tinted reds as gray. A lack green cones is designated as deuteranopia. 1. View the various color plates in bright light or sunlight while holding them about 30 inches away and at right angles to your line of vision. Report to your laboratory partner what you see in each plate. (Take no more than three seconds for your decision). 2. Your partner is to write down your responses and then check your accuracy with the correct answers given at the front of the color plate book. Is there any indication that you have some degree of color blindness? If so what type? Part Two: Hearing and Equilibrium Materials: 1. Ear model. 2. Tuning forks (middle C 256 Hz). Hearing Tests: 1- Weber Test: (to determine conductive and nerve deafness). Strike tuning fork on the heel of your hand or with a mallet and place the handle of the tuning fork medially on your forehead (figure 5). Is the tone equally loud in both ears, or is it louder in one ear? If it is equally loud in both ears, you have equal hearing, or equal loss of hearing, in both ears. If nerve deafness is present in one ear, the tone will be heard in the unaffected ear but not in the ear with nerve deafness. If conduction deafness is present, the sound will be heard more strongly in the ear in which there is a hearing loss. Conduction deafness can be stimulated by plugging one ear with cotton to interfere with the conduction of sound to the inner ear. - 40 -  Figure (1): Weber Test. 2- Rinne Test: (for comparing Bone-and Air-conduction hearing) Procedure: 1. Strike the tuning fork, and place its handle on your partner’s mastoid process (figure 6 (a)). When the sound is no longer audible to your partner, hold the still-vibrating prongs close to his auditory canal (figure 6(b)). If your partner hears the fork again when it is moved to that position (by air conduction), hearing is not impaired and the test result is recorder as positive (+). (Record below). 2. Repeat the test, but this time test air-conduction-hearing test. 3. After the tone is no longer heard by air conduction, hold the handle of tuning fork on the bony mastoid process. If the subject hears the tone again by bone conduction after hearing by air conduction is lost, there is some conductive deafness; and the result is recorded as negative. 4. Repeat the sequence for other ear. Right ear:___________ Left ear:____________ Does the subject hear better by bone or air conduction? - 41 -  Figure (2): Rinne Test Table (1): The comparison between the Rinne test and the Weber’s test Case/ Test name Rinne test Weber’s test Normal Hears vibration of air after Hears equally in the two ears bone conduction is finished Conduction deafness Does not hear vibration of air Hears is louder in defective after bone conduction is ear. finished Nerve deafness Hearing is very Sound is better in normal ear Diminished (almost lost) - 42 -