By J. Fraser. Central Bible College.
Calculi (stones) are the most common cause buy discount maxalt 10 mg on-line, but blockage failure is stabilized, the nephrons have an excellent capacity can also come from trauma, strictures, tumors or cysts, spasms or to regenerate. If not corrected, an A person with chronic renal failure cannot sustain life obstruction causes urine to collect behind the blockage and gen- independently. Chronic renal failure is the end result of kid- erate pressure that may cause permanent functional and ney disease in which the kidney tissue is progressively de- anatomic damage to one or both kidneys. As renal tissue continues to deteriorate, the options buildup in a ureter, a distended ureter, or hydroureter, develops. Urinary stones (calculi) are generally the result of infec- Hemodialysis equipment is designed to filter the wastes tions or metabolic disorders that cause the excretion of large from the blood of a patient who has chronic renal failure. As patient’s blood is pumped through a tube from the radial artery the urine becomes concentrated, these substances may crystalize and passes through a machine, where it is cleansed and then re- and form granules in the renal calyces. The cleaning as cores for further precipitation and development of larger cal- process involves pumping the blood past a semipermeable cello- culi. This becomes dangerous when a calculus grows large phane membrane that separates the blood from an isotonic solu- enough to cause an obstruction. The calculus also causes intense tion containing molecules needed by the body (such as glucose). Waste products diffuse out of the blood through the membrane, while glucose and other molecules needed by the body remain in Renal Failure and Hemodialysis the blood. Renal output of 50 to 60 cc of urine per hour is considered More recent hemodialysis techniques include the use of the normal. If the output drops to less than 30 cc per hour, it may patient’s own peritoneal membranes for filtering. Dialysis fluid is indicate renal failure—the loss of the kidney’s ability to introduced into the peritoneal cavity, and then, after a period of maintain fluid and electrolyte balance and to excrete waste time, discarded after wastes have accumulated. Acute called continuous ambulatory peritoneal dialysis (CAPD), can be renal failure is the sudden loss of kidney function caused by performed several times a day by the patients themselves on an shock and hemorrhage, thrombosis, or other physical trauma outpatient basis. Urinary System © The McGraw−Hill Anatomy, Sixth Edition Body Companies, 2001 694 Unit 6 Maintenance of the Body Urinary Incontinence The inability to voluntarily retain urine in the urinary bladder is Clinical Case Study Answer known as urinary incontinence.
A 73-year-old man is brought to the emergency department after (D) S1–S2 being found in his garage in a state of confusion buy cheap maxalt 10mg on line. CT shows an in- (E) T12–L1 farct involving much of the superior frontal gyrus. An MRA (A) Angular artery (Magnetic Resonance Angiography) shows an aneurysm in the in- (B) Callosomarginal artery terpeduncular fossa (and cistern) arising from the basilar tip. The MRI of a 49-year-old woman shows a tumor located immedi- (C) Optic (II) ately superior to the corpus callosum. This lesion is most likely lo- (D) Trigeminal, V1 (V) cated in which of the following lobes? As this lesion expands, due (D) Parietal to edema, and impinges on the immediately adjacent cortical ar- (E) Temporal eas, which of the following deﬁcits would most likely be seen? The examination reveals that the woman has a non- (D) Weakness of facial muscles ﬂuent (Broca) aphasia. A sagittal MRI shows a lesion in which of (E) Weakness of the upper extremity the following gyri? A 47-year-old woman presents with seizures and ill-deﬁned neu- (B) Inferior frontal rologic complaints. The examination reveals a bruit on the lateral (C) Lateral one-third of the precentral aspect of the head immediately rostral and superior to the ear. A (D) Middle frontal CT shows a large arteriovenous malformation in the area of the lat- (E) Supramarginal eral sulcus. Which of the following Brodmann areas represents the primary (A) Inferior sagittal sinus somatosensory cortex? The collection of posterior and anterior roots that occupy the lum- bar cistern are collectively known as which of the following? A 64-year-old man awakens with a profound weakness of his right (A) Cauda equina hand. The man is transported by ambulance to a major medical (B) Conus medullaris center, a distance of 240 miles and taking several hours. Which of the following gyri represents the most likely lo- (E) Filum terminale internum cation of this lesion?
Epilepsy may be secondary to focal lesions such as congenital malformations quality maxalt 10 mg, infarcts, tumours, cysts or inflections but fortunately many patients with these problems do not develop epilepsy. Brain damage such as neuronal loss and glial proliferation may in fact be seen in epileptics but these changes may be secondary to, rather than the cause of, epilepsy. They probably reflect the consequences of intense neuronal activation since in patients dying in status epilepticus they appear to be of recent origin and can be induced in animals by systemic or locally administered convulsant (see Meldrum and Corsellis 1984). Everyone is capable of having a convulsion, indeed their induction has been a common treatment for depression. The convulsive threshold of an epileptic, or more precisely that of some of their neurons, is just lower than normal. There is no known genetic basis for most of the common epilepsies apart from juvenile myoclonic epilepsy and childhood absence epilepsy which are dependent on inheritance of two or more susceptible genes, although genetic factors might more generally determine predisposition. Single distinct mutant genes have been established, however, in three rare forms of epilepsy (less than 1% of total), namely generalised epilepsy with febrile seizures, benign familial neonatal convulsions and autosomal dominant epilepsy (see McNamara 1999). These each encode a part of some voltage- gated ion channel which are believed to be respectively the b subunit of a Na channel (SCNIB), novel K channels and the a subunit of cholinergic nicotinic receptors (CHRNA4). All could lead to increased neuronal excitability and in fact co-expression in oocytes of the Na channel a subunit with the b subunit found in febrile convulsions produces a channel that inactivates more slowly than when it is expressed with normal b subunits. DEVELOPMENT OF AN EPILEPTIC SEIZURE A seizure is accompanied by a burst of spikes in the EEG. Between these so-called ictal phases are solitary EEG interictal spikes. Each of them represents the field potential associated with a burst of action potentials in a group of neurons within the epileptic focus (Fig. Focal neurons when activated show an abnormal excitatory postsynaptic potential (EPSP) called the paroxysmal depolarising shift (PDS) (Fig.