By P. Tempeck. University of Tulsa. 2018.
Finally purchase 10 mg arava with mastercard, the hip joint tends to deteriorate with age 20 mg arava with mastercard, so that muscle originates from this fossa discount 20mg arava with mastercard. The iliac tuberosity, for the at- many elderly people suffer from degenerative arthritis (osteoarthrosis). Three roughened ridges are present on the gluteal surface of the posterior aspect of the ilium. These ridges, which Sex-Related Differences in the Pelvis serve to attach the gluteal muscles, are the inferior, anterior, Structural differences between the pelvis of an adult male and and posterior gluteal lines (see fig. In a vaginal delivery, a Ischium baby must pass through its mother’s lesser pelvis. Diameters may be deter- the ischium is the projection immediately posterior and inferior mined by vaginal palpation or by sonographic images. The ischial tuberosity is the bony projection that supports the weight of the body in the Thigh sitting position. Skeletal System: The © The McGraw−Hill Anatomy, Sixth Edition Appendicular Skeleton Companies, 2001 184 Unit 4 Support and Movement Head of femur Greater trochanter Greater trochanter Fovea capitis femoris Intertrochanteric crest Intertrochanteric line Neck of femur Gluteal tuberosity Lesser trochanter Linea aspera Body of femur Lateral epicondyle Lateral epicondyle Medial epicondyle Intercondylar fossa Patellar surface Medial condyle Lateral condyle (a) (b) FIGURE 7. Femur The body of the femur has a slight medial curve to bring the knee joint in line with the body’s plane of gravity. The body of the femur has several distinguishing features femur articulates with the acetabulum of the os coxae. On the proximolateral side of the body is roughened shallow pit, the fovea capitis femoris, is present in the greater trochanter, and on the medial side is the lesser the lower center of the head of the femur. It Lateral also articulates both proximally and distally with the fibula. Two epicondyle of femur slightly concave surfaces on the proximal end of the tibia, the medial and lateral condyles (fig. The condyles are separated by a slight up- Patella ward projection called the intercondylar eminence, which pro- vides attachment for the cruciate ligaments of the knee joint (see Head of figs. The tibial tuberosity, for attachment of the tibia patellar ligament, is located on the proximoanterior part of the Tibia body of the tibia. The anterior crest, commonly called the “shin,” is a sharp ridge along the anterior surface of the body. A fibu- lar notch, for articulation with the fibula, is located on the disto- FIGURE 7. In that the tibia is the weight-bearing bone of the leg, it is much larger than the fibula. The patellar surface is located between the condyles on fibula articulates with the proximolateral end of the tibia. Above the condyles on the lateral and medial distal end has a prominent knob called the lateral malleolus. Both processes can be seen as prominent surface features and are easily palpated. Fractures to the fibula above the lateral malleolus are common in Patella skiers. Articular facets on the articular surface of the patella ar- The foot contains 26 bones, grouped into the tarsus, metatarsus, ticulate with the medial and lateral condyles of the femur. Although similar to the bones of the The functions of the patella are to protect the knee joint hand, the bones of the foot have distinct structural differences in and to strengthen the patellar tendon. It also increases the lever- order to support the weight of the body and provide leverage and age of the quadriceps femoris muscle as it extends (straightens) mobility during walking. It usually does Tarsus not fragment, however, because it is confined within the patel- lar tendon. Dislocations of the patella may result from injury or from There are seven tarsal bones. The most superior in position is the underdevelopment of the lateral condyle of the femur. Leg It has a large posterior extension, called the tuberosity of the Technically speaking, leg refers only to that portion of the lower limb between the knee and foot. Skeletal System: The © The McGraw−Hill Anatomy, Sixth Edition Appendicular Skeleton Companies, 2001 186 Unit 4 Support and Movement Base of patella Articular surface Anterior surface Medial Apex of patella condyle Intercondylar eminence Intercondylar eminence Lateral condyle Articular surface of fibular head Head of fibula Tibial tuberosity Fibular articular Neck of fibula surface Anterior border Body of Body of tibia fibula Patella Tibia Fibula Medial malleolus Lateral malleolus Lateral malleolus (a) (b) FIGURE 7. Anterior to differ in shape, however, because of their load-bearing role.
Changes in sleeping patterns in el- Eventually the patient is bedridden arava 20mg generic, and death may occur any- derly people also probably result from neurotransmitter problems discount arava 20mg fast delivery. The slowing of the nervous system with age is most appar- ent in tests of reaction time cheap arava 10 mg with amex. These ways that are not well understood), in most people it functions syringes progressively destroy the cord from the inside out. Brain dysfunction is not a common the spinal cord deteriorates, the patient experiences muscular characteristic of senescence. Degenerative Diseases Tay–Sachs Disease of the Nervous System In Tay–Sachs disease, the myelin sheaths are destroyed by the ex- Degenerative diseases of the CNS are characterized by a progres- cessive accumulation of one of the lipid components of the myelin. The etiologies of these diseases are poorly under- genes carried by the parents in a recessive state. The disease is in- stood, but it is thought that most of them are genetic. It causes blindness, loss Cerebrovascular Accident (CVA) of mental and motor ability, and ultimately death by the age of 3. Potential parents can tell if they are carriers for this condition by Cerebrovascular accident is the most common disease of the ner- the use of a special blood test for the defective enzyme. It is the third most frequent cause of death in the United States, and perhaps the number one cause of disability. The term stroke is frequently used as a synonym for CVA, but actually a stroke refers to the sudden and dramatic appearance of a neurologi- cal defect. Cerebral thrombosis, in which a thrombus, or clot, forms in an artery of the brain, is the most common cause of CVA. Nervous Tissue and the © The McGraw−Hill Anatomy, Sixth Edition Coordination Central Nervous System Companies, 2001 396 Unit 5 Integration and Coordination Diseases Involving Neurotransmitters At least some psychiatric disorders may be produced by dysfunction of neurotransmitters. There is evidence that schizo- Parkinson’s disease, or paralysis agitans, is a major cause of neu- phrenia is associated with hyperactivity of the neurons that use rological disability in people over 60 years of age. Drugs that are effective in the sive degenerative disease of unknown cause. This causes muscle tremors, muscular rigidity, decreased activity of the neurons that use monoamines—norepi- speech defects, and other severe problems. Antidepressant disease can be partially treated by altering the neurotransmitter drugs enhance the action of these neurotransmitters. Patients are given L-dopa to increase the pro- way, barbiturates and benzodiazepine (e. Alzheimer’s disease is the most common cause of demen- tia, often beginning in middle age and producing progressive mental deterioration. The cause of Alzheimer’s disease is unknown, but evidence suggests that it is associated with the Clinical Case Study Answer decreased ability of the brain to produce acetylcholine. Attempts The affected upper motor neurons have cell bodies that reside in the to increase ACh production by increased ingestion of precursor right cerebral hemisphere. They give rise to fibers that, as they course molecules (choline or lecithin) have thus far not been successful. They continue on the left side, eventually synaps- Drugs that block acetylcholinesterase, an enzyme that inactivates ing at the appropriate level with lower motor neurons in the anterior ACh, offer promise but are so far still in the experimental stage. The lower motor neurons then give rise to fibers that travel to the periphery, where they innervate end organs; namely, muscle cells in the left side of the body. Because the patient’s neurologi- cal deficits are all motor as opposed to sensory, the tumor is most likely located in the right frontal lobe. The parietal lobe contains sensory neu- Parkinson’s disease: from James Parkinson, British physician, 1755–1824 rons. The persistent headache is due to the pressure of the tumorous mass on the meninges, which are heavily sensory innervated. Alzheimer’s disease: from Alois Alzheimer, German neurologist, 1864–1915 CLINICAL PRACTICUM 11. Her father says the girl You call for the neurosurgeon and arrange was hit in the side of the head by a baseball. She was knocked unconscious for about 30 seconds, but then she awakened and seemed QUESTIONS: fine except for a big bruise with swelling over her right temporal area and a slight 1.
Results of the test are pitch in each ear is plotted on the audio- then plotted on the audiogram purchase arava 20 mg without a prescription. A pure-tone audio- ing level scale is constructed so that gram is a graph on which an individual’s average normal hearing equals 0 decibel; 154 CHAPTER 5 HEARING LOSS AND DEAFNESS normal hearing sensitivity ranges from Tests of speech reception threshold help –10 to +25 decibels cheap arava 20mg visa. The higher the num- identify the lowest intensity trusted 10mg arava, or softest ber on the decibel scale, the greater the sound level (decibels), at which an individ- degree of hearing loss. Words from a tests speech frequencies that range from standardized list with two syllables, such 250 to 8,000 Hertz. The inability to dis- as baseball, ice cream, or cowboy, are pre- criminate frequencies within this range sented to the individual through the ear- may interfere with everyday communi- phones. The speech reception threshold should corre- Bone Conduction Audiometry spond closely to average pure-tone air con- duction thresholds and provides a check When audiometric testing reveals a for the accuracy of the pure-tone measure- hearing loss, the audiologist conducts fur- ments. The higher the decibel level re- ther testing to determine whether hearing quired for either threshold, the greater the loss is sensorineural, conductive, or mixed. A speech reception threshold Tests used for this purpose include bone or average pure-tone threshold of 25 deci- conduction tests. The procedure for bone bels (dBHL) (HL = hearing level), for in- conduction audiometry consists of placing stance, is considered borderline normal a vibrator on the individual’s mastoid hearing for adults. A tones from the vibrator go directly into threshold of 26 to 40 decibels is considered the inner ear, bypassing the external and a mild hearing loss. The individual’s In addition to measuring how loud responses to the thresholds are plotted on speech has to be to be heard, testing also the audiogram and contrasted with the air determines how well individuals under- conduction test results. Speech discrimination tests (sometimes thresholds for air and bone conduction are called word recognition tests) help to pro- compared. During the test, between the two thresholds, hearing loss words from standardized lists of phon- is classiﬁed as sensorineural, conductive, or etically balanced one-syllable words are mixed. Words are Speech Audiometry presented at a suprathreshold level, and the individual must identify and repeat Whereas pure-tone audiometry is used to words back to the examiner. The test is determine individuals’ ability to hear scored as the percentage of correctly speciﬁc tones, speech audiometry may indi- repeated words. The lower the percentage, cate individuals’ ability to understand the greater the problem in understanding. Two meas- Individuals with speech discrimination ures are speech reception threshold and hearing loss may be able to recognize speech discrimination threshold. The individuals wear headphones and listen to speech discrimination score provides a words being transmitted through the measure of the ability to understand words headphones without any visual cues. It assesses the Diagnostic Procedures 155 ability to judge acoustic information and Acoustic immittance testing requires no to distinguish between similar speech voluntary responses from the individual. Acoustic immittance measurement in- Electrocochleography cludes a battery of tests that evaluate mid- dle ear status. Tympanometry is a test of Electrocochleography is a procedure in acoustic immittance in which the mobility which stimulus-related electrical activity or ﬂexibility of the tympanic membrane generated in the cochlea and auditory is assessed by measuring how much sound nerve is recorded. For the test, the individ- energy is admitted into the ear as air pres- ual reclines with electrodes placed in the sure is varied in the external auditory external auditory canal. The by altering the air pressure in the ear canal test is useful in evaluating inner ear ﬂuid and measuring the response of the ear- disorders such as Meniere’s syndrome. Auditory Brain Stem Response As sound energy strikes the eardrum, some (ABR) Testing is transmitted to the middle and inner ear, but some is reﬂected back into the ear The ABR records electrical activity gen- canal. If the tympanic membrane is stiff, erated as sound travels from the auditory much of the sound energy is reﬂected back nerve through the auditory brain stem into the external ear canal. The individual reclines with pedance, the more sound energy is admit- electrodes placed on the mastoid or on the ted to the middle and inner ear. A stimulus is then presented increased level of resistance is diagnostic through earphones, and electroencephalo- of middle ear pathology. The results are gram activity is evaluated and the audito- plotted on a graph called a tympanogram. The ABR The ear’s response is plotted on the verti- is useful in ruling out auditory diseases cal dimension of the graph, and air pres- such as diseases of the cochlea; degener- sures are plotted on the horizontal ative or demyelinating diseases of the dimension.
Most of the Na consumed in ing the uptake of reabsorbed fluid and diminishing Na FIGURE 24 generic arava 20mg with mastercard. CHAPTER 24 The Regulation of Fluid and Electrolyte Balance 417 When kidney perfusion is threatened purchase arava 20mg on line, the kidneys re- The distribution of K across plasma membranes—that tain salt and water arava 20 mg lowest price, a response that tends to improve their is, the ratio of intracellular to extracellular K concentra- perfusion. Low plasma [K ] leads to mem- widespread accumulation of salt and water in the interstitial brane hyperpolarization and reduced excitability; muscle spaces of the body. Excessive plasma K levels ident until a person has accumulated more than 2. Expansion of the interstitial High plasma K levels cause cardiac arrhythmias and, even- space has two components: (1) an altered balance of Star- tually, ventricular fibrillation, usually a lethal event. K is needed for Patients with congestive heart failure may accumulate tissue growth and repair. Tissue breakdown or increased many liters of edema fluid, which is easily detected as protein catabolism result in a loss of K from cells. Because of the effect of gravity, the ankles become swollen and pitting Most of the Body’s K Is in Cells edema develops. As a result of heart failure, venous pressure is elevated, causing fluid to leak out of the capillaries be- Total body content of K in a healthy, young adult, 70-kg cause of their elevated hydrostatic pressure. About 2% of this, about 60 mEq, pumping of blood by the heart leads to a decrease in EABV, is in the functional ECF (blood plasma, interstitial fluid, and so the kidneys retain salt and water. Alterations in many of lymph); this number was calculated by multiplying the the factors discussed above—decreased GFR, increased plasma [K ] of 4 mEq/L times the ECF volume (20% of RAAS activity, changes in intrarenal physical forces, and body weight or 14 L). About 8% of the body’s K is in increased sympathetic nervous system activity—contribute bone, dense connective tissue, and cartilage, and another to the renal salt and water retention. Ninety percent of the body’s cumulation of edema fluid, patients are often placed on a K is in the cell compartment. By definition, Hypertension may often be a result of a disturbance in plasma [K ] below 3. The [K ] in skele- adequate renal excretion of salt tends to increase intravas- tal muscle cells is about 150 mEq/L cell water. Skeletal mus- cular volume; this change translates into an increase in cle cells constitute the largest fraction of the cell mass in blood pressure. A reduced salt intake, ACE inhibitors, di- the human body and contain about two thirds of the body’s uretic drugs, or drugs that more directly affect the cardio- 2 K. One can easily appreciate that abnormal leakage of K vascular system (e. A variety of factors influence the distribution of K be- tween cells and ECF (Fig. If this enzyme is inhibited—as a result of in- adequate tissue oxygen supply or digitalis overdose, for ex- Potassium (K ) is the most abundant ion in the ICF com- ample—hyperkalemia may result. It has many important effects in the body, and its 2) A decrease in ECF pH (an increase in ECF [H ]) tends plasma concentration is closely regulated. When a mineral acid such as HCl is added to the ECF, a fall in blood pH of 0. When an organic acid (which can penetrate plasma membranes) is Acid-Base Balance, and Metabolism added, the rise in plasma K for a given fall in blood pH is As the major osmotically active solute in cells, the amount considerably less. The fact that blood pH influences plasma of cellular K is the major determinant of the amount of [K ] is sometimes used in the emergency treatment of hy- water in (and, therefore, the volume of) the ICF compart- perkalemia; intravenous infusion of a NaHCO3 solution ment, in the same way that extracellular Na is a major de- (which makes the blood more alkaline) will cause H to terminant of ECF volume. When cells lose K (and accom- move out of cells and K , in exchange, to move into cells. This effect appears to be a result of stim- 418 PART VI RENAL PHYSIOLOGY AND BODY FLUIDS Shift K+ to Shift K+ + Ingested K outside of cells into cells 100 mEq/day Body cell Input ECF pH, ECF pH, digitalis, K+ insulin, O2 lack, epinephrine Bone, dense ATP hyperosmolality, connective tissue, hemolysis, cartilage K+ ADP + Pi Extracellular Intracellular infection, 300 mEq fluid K+ + + fluid K ischemia, Na 60 mEq 3,300 mEq trauma Transcellular fluid K+ K+ H+ + HCO - CO + H O 40 mEq 3 2 2 H+ K+ Output + Urinary K K+ in feces excretion 10 mEq/day FIGURE 24. In- sulin (administered with glucose) is also used in the emer- gency treatment of hyperkalemia. In chronic renal failure, hyperkalemia usually does shrink and raises intracellular [K ], which then favors out- not develop until GFR falls below 15 to 20 mL/min because ward diffusion of K into the ECF. The major cause of renal K wasting is iatro- pseudohyperkalemia, results if blood has been mishandled genic, an unwanted side effect of diuretic drug therapy. In un- The plasma [K ] is sometimes taken as an approximate controlled diabetes mellitus, K loss is increased because of guide to total body K stores. For example, if a condition the osmotic diuresis caused by glucosuria and an elevated is known to produce an excessive loss of K (such as taking rate of fluid flow in the cortical collecting ducts. Several a diuretic drug), a decrease in plasma [K ] of 1 mEq/L may rare inherited defects in tubular transport, including Bart- correspond to a loss of 200 to 300 mEq K. Clearly, how- ter, Gitelman, and Liddle syndromes also lead to excessive ever, many factors affect the distribution of K between renal K excretion and hypokalemia (see Table 23.
Baltimore: Williams ing predict some abnormality of coronary artery function? Why was a 45-minute delay before going for medical inter- vention after intense pain started inappropriate for the CASE STUDY FOR CHAPTER 18 man’s health? How does the lower than normal arterial pressure buy 10 mg arava free shipping, smaller than normal arterial pulse pressure order arava 10 mg mastercard, and decreased blood During a routine health assessment 20 mg arava fast delivery, a 52-year-old man flow to the hands and feet indicate impairment of the con- was found to have a blood pressure of 180/95 mm Hg. How did the streptokinase improve performance of the blood pressure has always been a little high. How is aspirin useful to protect the coronary vasculature the heart, eyes (including the blood vessels of the from occlusions by blood clots? How might lowering the low-density lipoproteins and rais- resting heart rate is 87 beats/min. Explain how drugs might lower the blood pressure by af- oxygen for the heart cells. Partially occluded arteries did not fecting 1-adrenergic receptors, 1-adrenergic receptors, in- provide sufficient blood flow to provide the needed oxygen travascular fluid volume, the renin-angiotensin-aldosterone and hypoxia resulted. Coronary artery problems leading to system, and intracellular calcium ion levels. Anything that increases cardiac output or SVR can cause an the pain extends into the left arm and hand, as well as neck increase in arterial blood pressure. Chronic hypertension can damage many organs and tis- mal electrical activity in the heart. The results can range sues, some of which may be detected by physical exami- from mild disturbances of conduction to rapidly lethal ven- nation. In addition, the longer cardiac cells are phy as a result of increased afterload. The blood vessels without adequate blood flow, the more damage is done to of the eye can become thickened and sclerotic. The sooner oxygenation is restored, the less repair hypertension can contribute to atherosclerosis, the pe- is needed in the heart tissue. When the contractile ability of the heart is compromised, such as the kidneys, may also be damaged by hyperten- the typical result is a reduced stroke volume, which would sion, but these abnormalities require specific laboratory explain the decreased pulse pressure. If cardiac output de- testing to evaluate and usually cannot be assessed by creases, in spite of an increased heart rate, then arterial physical examination. Streptokinase is a bacterial product that activates plasmino- lower SVR. Drugs that reduce intravascular fluid volume (di- gen, which leads to clot dissolution. Blood flow and oxygen uretics such furosemide or hydrochlorothiazide) reduce pre- supply to the downstream muscle will then be restored. If load and, thereby, lower cardiac output and arterial pres- the muscle cells are not seriously injured, they will show sure. With sure by preventing the vasoconstriction and sodium reten- aspirin present, platelets are far less likely to be activated, tion that would otherwise occur when the RAAS is acti- 308 PART IV BLOOD AND CARDIOVASCULAR PHYSIOLOGY vated. Calcium blockers diminish cardiac contractility (a de- References terminant of cardiac output) and vascular smooth muscle Izzo JL, Black HR, eds. In: Young JR, Olin JW, Bartholomew blocking either its entry or its release into the cytosol of car- JR, eds. CHAPTER Pulmonary Circulation and the Ventilation- Perfusion Ratio 2020 Rodney A. CHAPTER OUTLINEFUNCTIONAL ORGANIZATION OF THE PULMONARYBLOOD FLOW DISTRIBUTION IN THE LUNGS CIRCULATIONSHUNTS AND VENOUS ADMIXTUREPULMONARY VASCULAR RESISTANCETHE BRONCHIAL CIRCULATIONFLUID EXCHANGE IN PULMONARY CAPILLARIES KEY CONCEPTS 1. Gravity causes lung perfusion to be better at the base than and low-pressure system. A mismatch of ventilation and blood flow occurs at both pulmonary vascular resistance to fall with increased car- the base and the apex of the lungs. High pulmonary capillary hydrostatic pressure leads to pul- lation-perfusion ratio in the lungs. The bronchial circulation is part of the systemic circulation and does not participate in gas exchange. FUNCTIONAL ORGANIZATION OF THE mately equal to the stroke volume of the right ventricle PULMONARY CIRCULATION (about 80 mL) under most physiological conditions. The heart drives two separate and distinct circulatory sys- tems in the body: the pulmonary circulation and the sys- The Pulmonary Circulation Functions in Gas temic circulation.
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