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The neighborhood day-care center won’t third and fifth lumbar vertebrae order betoptic 5 ml line. A renal stone (calculus) discount betoptic 5ml overnight delivery, would most You’ve tried to toilet train your likely cause stagnation of urine in which 5. In a male, trace the path of urine from the site of filtration at the renal corpuscle to 15-month-old boy, but you haven’t made portion of the urinary system? List in order all the structures through which the urine your efforts, or would it be better to wait? What functions of a real kidney does an (d) the renal pelvis artificial kidney (dialysis machine) fail to (e) the urethra types of nephrons found in a kidney. Describe the urinary bladder with regard (d) the transitional epithelium. Male Reproductive © The McGraw−Hill Anatomy, Sixth Edition Development System Companies, 2001 Male Reproductive System 20 Introduction to the Male Reproductive System 698 Perineum and Scrotum 700 Testes 702 Spermatic Ducts, Accessory Reproductive Glands, and the Urethra 707 Penis 710 Mechanisms of Erection, Emission, and Ejaculation 712 CLINICAL CONSIDERATIONS 714 Developmental Exposition: The Reproductive System 716 Clinical Case Study Answer 722 Chapter Summary 723 Review Activities 723 Clinical Case Study During a routine physical exam, a 27-year-old man mentioned to his family doctor that he and his wife had been unable to conceive a child after nearly 2 years of trying. He added that his wife had taken the initiative of having a thorough gynecological evaluation in an attempt to find out what was causing the problem. Her test findings revealed no physical conditions that could be linked to infertility. Upon palpating the patient’s testes, the doctor found nothing un- usual. When he examined the scrotal sac above the testes, however, the doctor appeared per- plexed. He informed his patient that two tubular structures, one for each testis, appeared to be absent, and that they probably had been missing since birth. During a follow-up visit, the doc- tor told the patient that examination of his ejaculate revealed azoospermia (no viable sperm). Explain how the result of the semenalysis relates to the patient’s physical exam findings. Does it seem peculiar that the patient is capable of producing an ejaculate? FIGURE: Fertility specialists have made remarkable advancements during the past decade in treating couples with fertility problems. A semenalysis reveals the relative number of sperm (sperm count), sperm vitality, and chemical nature of the fluid medium in a sample ejaculate. Male Reproductive © The McGraw−Hill Anatomy, Sixth Edition Development System Companies, 2001 698 Unit 7 Reproduction and Development (the blastocyst), pregnancy, and delivery of a baby. The more INTRODUCTION TO THE MALE complex reproductive system of the female also provides a means REPRODUCTIVE SYSTEM for nourishing the baby through the secretion of milk from the mammary glands. In addition, like in the male, another function The organs of the male and female reproductive systems are is to produce and secrete sex hormones, which maintain the fe- adapted to produce and allow the union of gametes that contain male sex organs and contribute to the female libido. A random combination of the genes during sexual In this chapter we will consider the anatomy of the male reproduction results in the propagation of individuals with genetic reproductive system; the female reproductive system is the focus differences. Objective 1 Explain why sexual reproduction is biologically advantageous. Objective 2 List the functions of the male reproductive Categories of Reproductive Structures system and compare them with those of the female. The structures of the male reproductive system can be catego- Objective 3 Distinguish between primary and secondary rized on a functional basis as follows: sex organs. The primary sex organs are called go- nads; specifically, the testes in the male. Gonads produce Unlike other body systems, the reproductive system is not essen- the gametes, or spermatozoa, and produce and secrete sex tial for the survival of the individual; it is, however, required for hormones. The secretion of male sex hormones, called an- the survival of the species. It is through reproduction that addi- drogens, at the appropriate times and in sufficient quanti- tional individuals of a species population are produced and the ties causes the development of secondary sex organs and genetic code passed from one generation to the next. Secondary sex organs are those ual reproduction, in which genes from two individuals are com- structures that are essential in caring for and transporting bined in random ways with each new generation, offers the spermatozoa.

The lipids are removed upon fixation generic betoptic 5ml visa, and the denatured protein scaffold remains as a gridlike structure (neurokeratin) (D3) buy betoptic 5ml otc. At regular intervals (1–3mm), the myelin sheath is interrupted by deep constrictions, thenodesofRanvier(AB4F). Thesegmentbe- tween two nodes of Ranvier in peripheral nerves, the internode or interannular segment (F), corresponds to the expansion of one sheath cell. The cell nucleus (ADF5) and perinuclear cytoplasm form a slight bulge onthemyelinsheathinthemiddleofthein- ternode. Cytoplasm is also contained in ob- lique indentations, the Schmidt–Lanterman incisures (C, F6) (see also p. The mar- gins of the sheath cells define the node of Ranvier at which axon collaterals (E) may branch off or synapses may occur. Ultrastructure of the Myelin Sheath (G) The electron micrograph shows the axon enclosed by a plasma membrane, the ax- olemma; it is surrounded by a series of regu- larly spaced, concentric dark and light lines (period lines). The width of each lamella from one dark line to the next measures 120Å on average (1Å=0. As seen at higher magnification, the light lines are subdivided by a thin irregular Kahle, Color Atlas of Human Anatomy, Vol. Myelin Sheath 37 5 4 2 1 A Nerve fiber (according to von Möllendorff) 5 2 4 B Node of Ranvier, osmium stain (diagram) C Schmidt–Lanterman incisures 5 3 D Perikaryon of a Schwann cell E Axonal branching 5 4 6 4 1 F Internode (according to Cajal) 1 2 7 G Electron-microscopic views of the myelin sheath Kahle, Color Atlas of Human Anatomy, Vol. The groove deep- nates only one axon, an oligodendrocyte (B9) ens and its margins approach each other intheCNSmyelinatesseveralaxonsandwill and finally meet. In this way, a duplication later remain connected with several inter- of the cell membrane is formed, the mesaxon nodes via cytoplasmic bridges. The extent (A3), which wraps around the axon like a and shape of the cell becomes clear when spiral as the Schwann cell migrates around visualizing the internodes as being unfurled the encircled axon. The external mesaxon The term mesaxon is based on the term forms an external bulge (B10) starting from mesenterium, a thin duplication that is the cytoplasmic bridge. The myelin lamellae formed as a suspension band by the peri- terminate at the paranodal region (B11) toneum and encloses the intestine. As seen in the longitudi- ilar way, the Schwann cell forms a duplica- nal section, the innermost lamella termi- tion and envelops the axon. Like all plasma nates first and the outermost lamella covers membranes, the cell membrane of the the remaining endings, terminating directly Schwann cell consists of an outer and an at the node of Ranvier. At the ends of the inner dense layer of protein and a light lipid lamellae, the dense major period lines layer between them. Upon membrane du- widen into pockets filled with cytoplasm plication, the two outer protein layers come (B12). The axon of the central nerve fiber is into apposition first and fuse to form the in- completely exposed in the area of the node traperiod line (A4). There are no Schmidt–Lanter- membrane duplication becomes the five- man incisures in the CNS. With further encir- cling, the inner protein layers of the cell membrane make contact as well and fuse to form the dense major period line (A5). At the end of the process, the start of the duplica- tion lies inside the myelin sheath, the inter- nal mesaxon (AB6), while the end lies out- side, the external mesaxon (7 in A, B). Development of Unmyelinated Nerve Fibers (A) Unmyelinated nerve fibers (A8) are en- veloped by sheath cells, each of which en- circles several axons. The margins of the grooves may also form a membrane dupli- cation (mesaxon) but without fusion of the membrane layers. Myelin Sheath 39 4 6 7 1 3 5 2 8 A Development of the myelin sheath (according to Hamilton, Boyd and Mossman) 9 10 7 6 12 B Central nerve fiber, electron-microscopic diagram (according to Bunge) 11 C Oligodendrocyte with myelin lamellae (according to Bunge) Kahle, Color Atlas of Human Anatomy, Vol. This mode of conduction is much borders on a basal lamina (AB2), which en- faster and requires less energy than the con- velops the entire peripheral nerve fiber. The Schmidt–Lanterman The peripheral nerve fiber is surrounded by clefts (A4) are depicted in longitudinal sec- longitudinal collagenous connective-tissue tionascytoplasmiccrevicesofthemajorpe- fibrils; together with the basal membrane, riod lines. The struction, they appear as spirals in which nerve fibers are embedded in a loose con- the cytoplasm communicates between the nective tissue, the endoneurium (D8). At the node of Ranvier able number of nerve fibers is collected into (B5), the Schwann cell processes (AB6) slide bundles or fascicles (C10) by the perineurium over the paranodal region and over the axon (CD9) which consists mainly of circular (ABD7). The innermost layer of the per- dense envelope around the node of Ranvier.

California’s experience over the preceding quarter century stands as firm testimony to these data order betoptic 5 ml overnight delivery. In 2002 discount betoptic 5ml without a prescription, the nonpartisan Congressional Budget Office estimated that the MICRA-based reforms contained in House Resolution 4600 (which failed to pass the Senate) would have lowered malpractice insurance premiums by 25 to 30% (40). Milliman USA analyzed medical malpractice claims in the 15 largest states from 1990 to 2001 and concluded that caps on noneconomic damages reduced medical malpractice loss costs for physicians (41). In this study, reform states like California and Colorado saw loss costs reduced 48 and 31%, respectively. In contrast, New York’s loss cost per physician stood at 300% compared to California, and Pennsylvania’s stood at 328%. In an earlier study, Milliman had estimated that a $250,000 cap on noneconomic damages in New York would reduce premium levels by 29% (32). Perhaps the most comprehensive study of this issue ever undertaken was that delivered by the Governor’s Select Task Force on Healthcare Professional Liability Insurance in Florida in 2002 (22). Testimony ran to 13 volumes and included physicians, lawyers, insurance industry representatives, regulators, legal scholars, professional organizations, and concerned citizens. The final report exceeds 300 pages and contains more than 1300 citations. The report takes note of Florida’s past history of unsuccessful reform and concludes that: “A cap on non-economic damages of $250,000 per incident limited only to healthcare professional liability cases is the only available remedy that can produce a necessary level of predictability... The authors noted that Florida’s unsuccessful previous attempts at reforms that did not include such a cap “are nothing more than a failed litany of alternatives” (22). Chapter 15 / The Case for Legal Reform 217 The National Association of Insurance Commissioners (NAIC) stud- ied the market for medical malpractice insurance to evaluate the current crisis in 2003 (28). Its conclusions, made independently and with access to the considerable state statutory data and experience, are in accord with those detailed previously. It found rising premium rates to be pri- marily a function of increasing claims costs. In addition, they found these problems were impeding public access to essential health care. They made six recommendations for states to consider when addressing these issues, including a $250,000 cap on noneconomic damages, a periodic payments provision, and collateral source reform. In addition, they recommended consideration of reforms to limit nonmeritorious claims, “bad faith” claims (ex post facto litigation alleging failure to make a timely settlement), and exploration of mechanisms that would add more predictability to insurers’ loss costs (28). There is ample evidence that the MICRA reforms have had a substan- tial impact on the availability and cost of malpractice insurance. In assessing the cost of the current crisis, we should also review the impact of defensive medicine and reduced access to care. Defensive Medicine In addition to its obvious direct impact, the tidal wave of malpractice litigation extracts a severe indirect toll on practicing physicians (42,43), forcing many doctors to regard patients as potential adversaries and leading to the practice of defensive medicine. By definition, defensive medicine is unnecessary and consists of interventions that do not benefit the patient but are meant to protect the physician from litigation. The facile argument that perhaps a degree of defensive medicine would be salutary for our health care system is thus clearly invalid. Unfortunately, one can argue that virtually all medicine in the United States is to some degree defensive (43). Medical standards of care have been replaced by medical-legal standards, physician judgment has been devalued, and the value of medical chart documentation set above the actual benefit to the patient. The standard of care in the community is not necessarily the most ratio- nal or the one with best supporting evidence but rather the one that keeps physicians out of court. Two examples of this phenomenon nationally are the high rate of Cesarean sections (C-sections) and high percentage of mammograms interpreted as suspicious for breast cancer (43). The United States has a much higher C-section rate than any other developed country, with no improvement in birth outcomes. Similarly, the rate of false-positive 218 Anderson mammograms in the United States is twice that in other developed coun- tries, again without improving the cancer detection rate. In another example of litigation-biased decision making, cardiac surgeons have been accused of gaming risk selection of patients to improve outcome data, limiting surgical access for the highest risk patients (44).

In anterior cruciate ligament discount 5ml betoptic with mastercard, which is snapped over the lat- flexion generic 5 ml betoptic, full motion of the knee ranges from valgus-ex- eral femoral condyle. There is no longer passive restraint ternal rotation to varus-internal rotation. Within this to anterior translocation, so the entire tibia can shift for- range, the joint can be actively exercised without danger ward, pulled by the extensor mechanism and quadriceps of injury. Before the joint can reduce itself, continued valgus force acts on the knee that already is in extreme valgus force and axial load cause impaction across the valgus-external rotation, or when an additional varus lateral compartment, with fracture or contusion involving force acts on the knee that is in extreme varus-internal ro- the lateral femoral condyle and the posterior rim of tibial tation. Medial combined injuries are 10-20 times more fre- Patterns of Osseous Injury on Magnetic quent than lateral combined injuries. In the medial triad Resonance Images (O’Donaghue’s triad), excessive valgus stress in the ex- ternally rotated knee injures the tibial collateral ligament, Osseous injury is an expected finding following knee anterior cruciate ligament and medial meniscus (menis- trauma. In the era of arthroscopy and MRI, tures that are not visible on plain radiographs, as well lateral meniscal tear is now recognized as a common as- as trabecular contusions. Therefore, the medial triad is sometimes abnormalities and their patterns of bone-marrow edema an even unhappier medial tetrad. In the lateral triad, ex- provide additional clues about the traumatic mecha- cessive varus stress in the internally rotated knee injures nism. Impaction is most closely associated with Biomechanical principles can be applied to more than depressed fracture or osseous contusion, although crush- just image interpretation. Picture yourself playing bas- related meniscal or cartilage tear may also occur. Due to the function of paired running for a touchdown, but getting tackled from the cruciate and collateral ligaments, compressive load on side as you plant your foot to sidestep your opponent; cir- one side of the knee occurs simultaneously with con- cling the goal in a lacrosse game, then turning quickly to- tralateral tensile stress. During anteromedial impaction of wards the net to split the defense while pushing forceful- the knee, for example, kissing contusions of the femoral ly but awkwardly off your foot; enjoying the scenery condyle and tibial plateau are associated with lateral col- along a ski trail, but catching your ski tip on a protruding lateral sprain or avulsion fracture of the fibular head. As you are On MR images, impaction and distraction fractures falling to the ground in the agony of medial triad injury, show differences that can be explained by their biome- it is possible to recognize and construct mentally the se- chanical etiologies. Since impaction injury results from quence of traumatic events occurring in your knee. The frac- is valgus-external rotation with some flexion and abduc- ture line represents compacted trabecular bone or, in the tion. Valgus stress tightens the medial collateral ligament, subacute setting, intramedullary callus formation. Although fat- that first gives way depends on complex factors, such as suppressed T2-weighted images are more sensitive in the the degree of knee flexion and abduction. Excessive val- detection of marrow edema or hemorrhage, T1-weighted gus force may first tear the deep fibers of the medial col- images better demonstrate the fracture line. Trabecular lateral ligament, followed by the stronger superficial contusion, or microfracture, is diagnosed if no discrete fibers. As the medial compartment begins to distract, ax- fracture line is visible on T1-weighted images. At the same that is transmitted to cortical bone by the tendon, liga- time, traction on the posterior oblique ligament avulses ment or joint capsule. Whereas an impaction fracture the periphery of medial meniscus or tears the menisco- fragment shows depression and prominent surrounding capsular junction. Since the posteromedial corner is now bone-marrow edema on MR images, a distraction frac- destabilized, the anterior cruciate ligament becomes the ture fragment shows diastasis from its donor site and 36 D. Decreased or ab- produce predictable patterns of knee injury, a biome- sent osseous edema reflects the direction of mechanical chanical approach has several advantages in the interpre- force away from bone. Locations of meniscal tear, capsu- ed in trabecular bone, there is no contusion. By understanding plain radiographs may be difficult or impossible to visu- traumatic patterns, the identification of one abnormality alize on MR images. Poor visualization reflects both the may lead to a directed search for subtle abnormalities in- absence of marrow fat within the distracted fragment as volving anatomically or functionally related structures, well as the absence of sentinel bone-marrow edema sur- thus improving diagnostic confidence. Larger avulsed fragments con- tain trabecular bone and marrow fat, which have high signal intensity on T1-weighted images and are conspic- References uous against the surrounding lower signal intensity of 1. Lee JH, Weissman BN, Nikpoor N et al (1989) Lipohe- soft-tissue edema and hemorrhage.