X
|
STUDENT DIGITAL NEWSLETTER ALAGAPPA INSTITUTIONS |
|
Robert D. Smink, Jr. MD, FACS
Villous adenomas are soft juvenile diabetes diet management discount acarbose 50 mg overnight delivery, spongy diabetes insipidus heart rate 50 mg acarbose overnight delivery, sessile lesions which arise from the bowel wall and have an even higher likelihood of becoming malignant diabetic diet plan quality acarbose 50mg. Familial polyposis diabetes insipidus review nejm buy acarbose 25mg mastercard, a hereditary polypoid disease diabetes prevention games acarbose 50 mg fast delivery, has a marked tendency to undergo malignant change blood sugar over 400 symptoms purchase acarbose 50mg line. You may be required to include some of these diagnoses in your registry, or, at least, record these conditions if they are mentioned in the history of a patient with malignant disease of the colon. Cecum Ascending colon Transverse colon Descending colon Sigmoid colon 226 Take Test Table of Contents Manuals Q43 the ileocolic nodes are regional nodes for which one of the following sites Right colic Inferior hemorrhoidal Left colic Inferior mesenteric 227 Table of Contents Manuals Answer: Q43 3. Answer: Q44 a c,d d b,d 1) Ascending colon 2) Descending colon 3) Sigmoid colon 4) Rectum Right colic Left colic, inferior mesenteric Inferior mesenteric Inferior hemorrhoidal, inferior mesenteric 228 Table of Contents Manuals Liver the liver is the largest internal organ of the body, weighing three to four pounds (1. Its visceral surface is molded over the stomach, duodenum, gallbladder, hepatic flexure of the colon, right kidney, and right suprarenal gland. The right lobe has three parts called the right lobe proper, the caudate lobe, and the quadrate lobe. The small bile ducts within the liver (intrahepatic ducts) join to form two larger ducts which emerge from the under surface of the liver at the porta hepatis as the right and left hepatic ducts. The liver is one of the most vital organs in the body and plays a crucial role in the digestion and absorption of food. It breaks down protein, stores glycogen, iron, and vitamins, maintains the composition of the blood, and secretes products of detoxification. It continuously produces bile which is important in the digestion of fat and protein. The liver assists in keeping the amount of glucose (sugar) in the blood at a normal level. The urea then enters the blood stream and is carried to the kidneys where it is concentrated in urine and eliminated from the body. These substances pass through the bile ducts and may be stored in the gallbladder. With the stimulation of eating, these chemicals then pass through the cystic duct and the common bile duct to enter the duodenum at the ampulla of Vater. All of these ducts and the gallbladder are referred to as the "extra-hepatic biliary system. Malignant and Benign Tumors Malignant tumors of the liver are of glandular origin, i. Benign liver tumors are of current interest because of a suggested association with oral contraceptive use. It is the predominant type of primary malignant liver tumor and is associated with pre-existing cirrhosis of the liver. Consequently, you may find cholangiocarcinomas of the liver as well as of the extrahepatic bile ducts. Hemangioma is a benign tumor which arises in the blood vessels of the liver; it is the most common benign liver tumor. Section E, the Cardiovascular System, describes the transport of blood to the liver more fully. The right and left hepatic ducts emerging from the liver immediately join to form one common hepatic duct. The common hepatic duct merges with the cystic duct from the gallbladder to form the common bile duct. The 231 Table of Contents Manuals Answer: Q45 the most common primary tumor of the liver is hepatocarcinoma or hepatoma. The most 232 Table of Contents Manuals Gallbladder the gallbladder is a pear-shaped sac 7 to 10 cm. The wall of the gallbladder is composed of three layers: a mucosa, a muscular layer, and an outer covering of peritoneum called the serosa which coats the gallbladder except where it is in immediate contact with the liver. The mucous lining is arranged in folds called rugae which are similar in structure and function to those of the stomach. The cystic duct from the gallbladder unites with the hepatic duct to form the common bile duct. During the digestive process the gallbladder ejects concentrated bile into the duodenum by way of the common bile duct. Lymph nodes for the gallbladder and extrahepatic bile ducts accompany the cystic and hepatic arteries to the celiac axis region. Nodes are located in relation to the common bile duct (pericholedochal), hilus of liver (hilar), the duodenum (periduodenal), liver (periportal), pancreas (peripancreatic), and cystic duct. A node of the anterior border of the foramen of Winslow may be identified specifically. Answer: Q47 the histologic type of malignant tumors of bile duct origin, whether intrahepatic or extrahepatic, is called cholangiocarcinoma. It is located behind the stomach with its head situated in the C-shaped curve of the duodenum, its body extending horizontally across the posterior abdominal wall and its tail touching the spleen. Its exocrine functions are in manufacturing and secreting pancreatic juice which empties into the duodenum via the main pancreatic duct (duct of Wirsung). For example, it contains lipase which helps in the digestion of fats, and it makes amylase which helps in the digestion of sugars and starches. Its endocrine functions involve certain cells (beta) of the islets of Langerhans scattered all over the gland, which secrete insulin, a hormone that plays a major role in carbohydrate metabolism. When these cells begin to lose their ability to produce insulin, the disease known as diabetes mellitus results. Other cells (alpha) of the pancreas secrete glucagon, another hormone involved in carbohydrate metabolism. The blood supply is derived from the splenic, superior mesenteric, and hepatic arteries. The veins accompany the arteries and drain into the portal vein by way of the splenic and superior mesenteric tributaries. Peripancreatic lymph nodes may be located superior, inferior, anterior or posterior to the organ, and the drainage will differ depending on whether it is from the head or body and tail of the pancreas. The lymph nodes for the pancreas are the: Splenic: pancreaticolienal (body and tail) Hepatic: infrapyloric/subpyloric (head) pancreaticoduodenal Superior mesenteric Celiac axis (head) Lateral aortic/retroperitoneal Malignant and Benign Tumors Adenocarcinomas make up the majority of all malignant tumors of the pancreas. Usually these tumors spread to adjacent organs or have metastasized by the time the diagnosis is made. Islet cell tumors may arise from the cells of the islets of Langerhans, and may be further subdivided as insulinomas, glucagonomas, or gastrinomas on the basis of their hormonal activity. Q49 the three anatomic, and Q50 the into the duct and the duct carry digestive juices to the intestine emptying by way of the subdivisions of the pancreas are the because it secretes 239 Table of Contents Manuals Answer: Q48. The pancreas plays an important role in digestion because it secretes digestive enzymes found in pancreatic juices. Beta cells produce insulin (hormone), and alpha cells produce glucagon (hormone) into the blood stream. Both are involved in carbohydrate metabolism and assist in controlling glucose levels. Answer: Q49 the three anatomic subdivisions of the pancreas are the head, body, and tail. Answer: Q50 the hepatic duct and the cystic duct carry digestive juices to the intestine emptying into the duodenum by way of the common bile duct. It is part of the excretory system of the body which also includes the respiratory, integumentary, and digestive systems. Kidney Each kidney is located lateral to the spinal column in the lumbar region behind the abdominal cavity. The renal pelvis represents extensions of the ureter and the kidney parenchyma 1 at the hilus which is located on the inner, or medial side of each kidney. The outer connective tissue layer is called the cortex; the inner structure is called the medulla. The medulla consists of renal (medullary) pyramids which are separated from one another by extensions of the cortex into the medulla called renal columns. The renal pelvis and calyces2 collect the urine which is then transported by the ureters from the kidney to the urinary bladder for storage. Once tumor has broken through the basement membrane into the lamina propria, it can spread by way of the lymphatics and blood vessels to the other parts of the body. Answer: Q2 the kidneys are located in back of the peritoneal cavity or retroperitoneally, specifically, lateral to the spinal column in the lumbar region behind the abdominal cavity. Answer: Q3 the glandular (working) part of the kidney is called the parenchyma, while the part of the kidney that collects the urine which is then transported by way of the ureter to the urinary bladder is called the renal pelvis. The proximal and the distal convoluted tubules are located in the cortex of the kidney; the loop of Henle is located in the medulla. The distal tubules of several nephrons empty into a common collecting tubule that transports urine back into the renal pyramids of the medulla and then into a minor calyx of the renal pelvis. Here in the kidneys the waste products of metabolism and toxic substances are eliminated. Blood enters the glomerulus through the afferent arteriole which divides into capillaries. These will later unite to form the efferent arteriole that drains blood from the glomerulus. The contents of the distal portion of the tubule pass to branches of the collecting tubule which empties into the calyces of the renal pelvis. These contents are then transported through the ureters from the renal pelvis to the bladder. Certain substances required to maintain fluid and electrolyte balance are reabsorbed by the peritubular capillaries 3. Secretions produced in the distal and collecting tubules cause other substances to be added to the tubular filtrate from the blood. Most of the water is reabsorbed as are other essential substances unless their concentration in the body happens to be too high. Xelectrolytes-mainly, ions such as sodium, potassium, ammonium phosphate, and sulfate. Table of Contents Manuals 250 Take Test Q4 Why is blood circulated through the kidneys Q7 Give the names of the major structures involved in the urinary process from the point at which blood enters the capillaries in the cortex of the kidney until it enters the calyces of the renal pelvis. Answer: Q7 the major structures involved in the urinary process from the point at which blood enters the capillaries in the cortex of the kidney until it enters the calyces of the renal pelvis are: 1. It is a mixed tumor histologically made up of embryonal tissue, probably of nephrogenic origin. Squamous cell carcinoma cell carcinoma Q10 What is the major kidney tumor occurring in childhood Para-aortic or retroperitoneal lymph nodes the regional lymph node drainage for the renal pelvis is to: 1. These muscular tubes are about 26 to 28 cm in length, beginning at the renal pelvis. The microscopic structure of the ureter is similar to that of the renal pelvis consisting of a mucosa of epithelium and lamina propria, a submucosa, a muscularis propria, and an outer adventitia of fibroelastic connective tissue. Regional Lymph Nodes the regional lymph node drainage for the ureters is to the: Periureteral Renal hilar Common iliac Internal iliac (hypogastric) External iliac Paracaval Malignant Tumors Primary cancer of the ureter is rare. When cancer does occur, it is usually transitional cell carcinoma, resembling cancer of the renal pelvis; it often presents as an ureteral obstruction. Q13 What are the tissue layers of the renal pelvis excluding the basement membrane Adventitia } Mucosa } 260 Table of Contents Manuals Urinary Bladder the urinary bladder is a hollow muscular organ which serves as a reservoir for urine. Three openings mark off a triangular area called the trigone at the base of the bladder. The trigone is smooth even when the bladder is empty; the remainder of the bladder wall is in folds allowing for expansion when the bladder is full. The superior surface of the bladder may be referred to as the dome; other subsites are the lateral, anterior, and posterior walls. In the female, the bladder is located in front of and below the uterus being separated from the anterior part of the uterus by a fold of peritoneum called the uterovesical pouch. Posteriorly, it is connected to the cervix and upper vagina by a thick layer of connective tissue. In the male, the inferior surface of the bladder which is not covered by peritoneum is in proximity to the upper rectum and is separated from it by the rectovesical fascia which contains the seminal vesicles and vas deferens. The prostate lies just below the bladder and surrounds the proximal part of the urethra as it emerges from the urinary bladder. The superior and posterior aspects of the bladder have a serosal covering (peritoneum) which is not found interiorly. Most bladder tumors are papillary in appearance and will often occur and recur in multiple sites within the bladder.
However diabetic diet 50 carbs order 50mg acarbose with mastercard, barium emissions from diesel engines has been greatly diminished to near zero emissions with the current use of low-sulfur diesel fuels blood glucose before meal purchase 50mg acarbose mastercard, which do not require the addition of barium as a sulfur-scavenging agent (Hildemann et al blood sugar 02 generic acarbose 25mg visa. Tabor and Warren (1958) report urban and suburban air concentrations of barium ranging from <0 diabetes mellitus type 2 behandlung purchase acarbose 25mg online. No distinct pattern related to industrialization appeared in the results reported on 754 samples from 18 cities and four suburban areas in the United States xylitol diabetes type 2 purchase 50 mg acarbose visa. For example diabetes insipidus uti acarbose 50 mg with amex, in Houston, Texas and its suburbs, 76% of the samples contained barium at levels ranging from 0. Another compilation of atmospheric data shows barium concentrations in urban atmospheres of North America ranging from 2x10-4 to 2. In contrast, barium levels in samples from the South Pole and northern Norway were 1. Mean barium concentrations in background air collected between April and October 2002 on the campus of the University of Birmingham, United Kingdom, were 0. Maximum ground-level barium concentrations (as soluble compounds) associated with uncontrolled atmospheric particulate emissions from chemical dryers and calciners at barium-processing plants have been estimated (using dispersion modeling) to range from 1. Barium has been measured in dust samples taken from 49 residences in Ottawa, Canada. Barium has been detected in air samples collected at 24 of the 798 hazardous waste sites where barium has been detected in some environmental medium (HazDat 2006). Barium concentrations in the shallow aquifer below Denver, Colorado, have been reported to range from 18 to 594 g/L with a median value of 104 g/L (Bruce and McMahon 1996). Barium concentrations in most drinking water supplies are <200 g/L with a mean concentration of 28. In California, mean and median values of 302 and 160 g/L, respectively, were measured for barium concentrations in drinking water supplies (Storm 1994). For example, community water supplies from deep rock and drift wells in northeastern Illinois have been found to have barium concentrations ranging from 1,100 to 10,000 g/L (Calabrese 1977). Water samples taken from groundwater wells in Texas that are within 750 m of brine injection, dry, or plugged gas/oil wells contain barium ranging in concentration from 1. A mean concentration of 167 g/L for barium was measured in influent streams of a public waste water treatment plant in Melbourne, Australia (Wilkie et al. The amount of barium in the influent streams could not be accounted for based on the mean concentrations of barium in domestic water supplies (20 g/L) or domestic sewage (38 g/L). Instead, it is likely that the barium unaccounted for in the influent stream is the result of barium carried in effluents from industries that are discharged into the catchment area of the treatment plant. Barium has also been found in sea water at concentrations ranging from 2 to 63 g/L with a mean concentration of 13 g/L (Bowen 1979). Barium has been detected in surface water and groundwater samples collected at 257 and 561 of the 798 hazardous waste sites, respectively, where barium has been detected in some environmental medium (HazDat 2006). In comparison, maximum concentrations of barium in surface water (lakes, streams, ponds, etc. The barium content in cultivated and uncultivated soil samples collected during a number of field studies ranged from 15 to 1,000 ppm (mean concentration of 300 ppm) for B horizon soils (subsurface soils) in the eastern United States and from 70 to 5,000 ppm (mean concentration of 560 ppm) for B horizon soils in the western United States (Bowen 1979; Schroeder 1970; Shacklette and Boerngen 1984). Barium content ranged from 150 to 1,500 ppm for surface horizon soils collected in Colorado (mean concentration of 550 ppm) (Connor and Shacklette 1975). Soil samples were obtained from areas that were not influenced by industrial activity, such as along roads and sidewalks, parks and open lots, and may account for why the mean values for barium concentration were well below a mean value of 420 mg/kg for the United States. Geometric mean concentrations of barium in sediments taken from 16 sampling sites along the southern shore of Lake Ontario and southeastern shore of Lake Erie ranged from 6. However, these concentrations are lower than the mean barium concentration of 482. The barium content in total suspended solids collected from the Mississippi River before it enters Lake Pontchartrain was 599 g/g. Barium concentrations in sediments near offshore drilling platforms are typically higher than unaffected sediments. These values were higher (although not statistically significant) than the values of 869 and 687 mg/kg dry weight measured in surficial and suspended sediments, respectively, collected at a distance of 1,000 meters from the platform and are similar to the predrilling concentrations of barium in these sediments. In other California coastal sediments, for example the Southern California Bight, barium concentrations range from 145 to 1,259 ppm with an average of 720 ppm (Chow et al. Median barium concentration ranges in sediments from the lake system in Chiapas, Mexico were 54. Barium concentrations ranging from 180 to 2,800 g/g dry weight (mean 729 g/g dry weight) were reported in surface sediments (<63 m fraction) collected in April 2002 from eight stations in Izmit Bay, Turkey (Pekey 2006). Barium has been detected in soil and sediment samples collected at 369 and 260 of the 798 hazardous waste sites, respectively, where barium has been detected in some environmental medium (HazDat 2006). Maximum concentrations of barium in soil (topsoil, <3 inches depth) ranged from 1. In comparison, maximum concentrations of barium in soil (topsoil, <3 inches depth) ranged from 3 to 54,700 ppm in 28 offsite samples (HazDat 2006). In comparison, maximum concentrations of barium in sediment (lakes, streams, ponds, etc. In the Canadian Total Diet Study, the concentrations of barium were found to be less than 4 ppm (4,000 ng/g) in a variety of foods (Health Canada 2005). Some plants bioconcentrate barium from the soil (Beliles 1979; Reeves 1979; Schroeder 1970). The barium content in corn samples from Georgia, Missouri, and Wisconsin collected during a number of field studies ranged from 5 to 150 ppm with mean concentrations ranging from 15 to 54 ppm (Connor and Shacklette 1975). Concentrations of Barium in Food Obtained from the Canadian Total Diet Study Between 1993 and 1999 Concentration (ng/g) Averagea Rangeb 71. Values represent the range of average concentrations of the food items covered under the individual food categories. The authors noted that all metals measured in this study were detected at concentrations below toxic levels or physiological limits for daily intake, where such limits have been identified (Grippo et al. Ninety-six fish composites (fillets) were collected, representing 11 species, from 28 lakes and reservoirs across Wyoming. In this study, barium concentrations were at or below the method detection limit of 0. Barium is also found in anaerobic sewage sludge at concentrations ranging from 100 to 9,000 ppm (mean concentration of 800 ppm) and in aerobic sewage sludge at concentrations ranging from 100 to 300 ppm (mean concentration of 200 ppm) (Sommers 1977). The highest levels are in tilemsi phosphate rock (669 g/g), austenite (408 g/g), milorganite (165 g/g), manure (153 g/g), and compost (131 g/g). There is some concern that continued use of fertilizers and soil amendments, which contain high amounts of barium and other metals, may result in an accumulation of barium in agricultural soils. The accumulation of barium in soils that is due to the continued use of fertilizers and soil amendments and the potential for increased content of barium in agricultural products and potential harm to the environment have not yet been assessed (Raven and Loeppert 1997). Assuming an average adult drinking water consumption rate of 2 L/day and that barium is present at concentrations of 30 g/L, the average adult daily intake of barium through the consumption of drinking water would be 60 g/day (0. Since average ground level concentrations of an emission vary with the distance from the emission point, the population around a source site will be exposed to differing emission levels. No other correlations have been established between barium concentrations in air and geographical areas or land-use types. The day-to-day intake of barium is likely to vary with the quantity and types of food ingested since the barium content in foods varies widely (Schroeder 1970). Based on consumption of food and beverages in long-term balance studies of four individuals, daily barium intake was estimated to range from 650 to 1,770 g/day, or from 9. Thus, food is typically the primary source of barium exposure for the general population. For individuals older than 4 years, the average barium intake decreased for both males and females with increasing age to values of 9. Mean daily balances (excluding loss via hair and sweat) determined from long-term balance studies of four adult subjects ranged from a negative balance of 800 g to a positive balance of 890 g (Tipton et al. Using these latter estimates of barium intake and loss, a negative barium balance of 25 g would occur. Barium content in the human population has been determined in urine and major organs and tissues in more current studies. The geometric mean (95% confidence interval) for the creatinine-adjusted levels of barium in urines for all ages was 1. Within age groups, the geometric means for the barium concentration in urine decreased as a function of age, from 2. As a function of ethnicity, non-Hispanic whites had the highest geometric mean barium concentrations (1. Occupational exposure to barium primarily occurs in workers and miners who inhale barium sulfate (or the ore, barite) and barium carbonate dust during the mining of barite and the manufacturing and processing. The data for barium and barium compounds included in the survey are summarized in Table 6-6. This is a survey that provides only estimates of the number of workers potentially exposed to chemicals in the workplace. Differences from adults in susceptibility to hazardous substances are discussed in Section 3. The main exposures of children to barium are expected to occur mainly from the diet or by dermal contact with barium-containing dust, with minor exposures through barium in air. Data on the daily intake of barium in the total diet of children in the United States were not located in the available literature. For older children (>4 years), there is a continual decrease in the average daily barium intake, with values of 18. It is expected that the data obtained from the Canadian Total Diet Study will reasonably approximate the daily barium intake for children living in the United States. It is estimated that for children in the United States, the barium intake through drinking water will range between 36 and 60 g/day. This estimate is based on an average concentration of 30 g barium/L in drinking water within the United States (Thomas et al. A factor to be taken into account is that fractional intestinal absorption of metals in young children, as in young mammals, may be higher than in adults (Foulkes and Bergman 1993). Dermal contact with barium in household dust is not expected to result in uptake of barium through the skin. Oral intake of barium through hand-to-mouth exposures to barium-containing dust is likely to occur. However, it is not known how much barium is taken in through this route of exposure. There is also the potential of oral intake of barium through the licking or ingestion of crayons or water colors, but it is not known how much barium is ingested or how much is bioavailable (Rastogi and Pritzl 1996). The average barium intake from the consumption of breast milk only was determined to be 4 g/day. Barium intake increases with exclusive consumption of bottled milk (39 g/day), evaporated milk (42 g/day), formula (44 g/day), and dried milk (59 g/day). The highest average intake of barium occurred with exclusive consumption of soya milk (91 g/day). High levels of barium have been reported in groundwater from deep rock and drift wells in several communities in northeastern Illinois (Brenniman et al. Other populations that might receive increased exposure to barium are consumers of crops grown on soils that have been used for the land farming of waste oil-well drilling muds (Bates 1988). Individuals who work at or live near barium mining, manufacturing, or processing plants might inhale higher ambient air concentrations or increased amounts of fugitive dust containing barium particulates. No information was found regarding the sizes of these populations or their intake levels of barium. This definition should not be interpreted to mean that all data needs discussed in this section must be filled. Physical and chemical properties of organic compounds of barium have not been comprehensively examined probably due to the limited extent of formation of these compounds. However, further study of the properties of these compounds would help in understanding their role in the environmental fate and transport of barium, particularly at hazardous waste sites where high levels of organic contaminants might be present. According to the Emergency Planning and Community Right-to-Know Act of 1986, 42 U. Because barium compounds occur naturally and are widely used in oil well drilling muds, in steel, rubber and plastic products, glass and ceramics, chemical, and pyrotechnics industries, in insecticides, and as a smoke suppressant in diesel fuels (Bodek et al. Recent data on production volumes and import and export of barite and some barium compounds. Additional information on production, import, export, and disposal would be useful in assessing the potential for the release of, and exposure to , barium compounds. The partitioning of barium in environmental media is influenced by the specific form of the compound and such site-specific conditions as pH and cation exchange capacity (Bates 1988; Bodek et al.
Cheap 50 mg acarbose with amex. What is Type 2 diabetes? | Diabetes UK.
The cerebrum is divided into lobes designated as frontal diabetes of the brain cheap acarbose 50 mg line, temporal diabetes symptoms patient.co.uk acarbose 25mg visa, parietal and occipital (see Figure 71) definition von diabetes mellitus discount 25mg acarbose with mastercard. The thalamus is an important relay center for sensory fibers on their way to the cerebral cortex; crude sensation and pain may be registered here diabetes quiz questions acarbose 50 mg fast delivery. The hypothalamus contains the centers for the autonomic nervous system controlling sleep diabetes medications new buy 25mg acarbose otc, water balance diabetes signs in mouth generic acarbose 50 mg without prescription, temperature regulation, and secretions from the pituitary gland. Hindbrain (rhombencephalon) consists of the pons, the cerebellum, and the medulla oblongata. It contains nerve fibers which link the cerebral cortex with the medulla oblongata and the spinal cord. The function of the cerebellum is coordinating groups of muscles to work together smoothly. Spinal Cord the spinal cord lies in the vertebral canal of the spinal column and extends from the medulla oblongata to the lumbar vertebrae. In certain areas of the spinal cord the anterior rami (branches) of the spinal nerves combine to form networks of nerve fibers called plexuses. These are the cervical (first 4 cervical spinal nerves) branchial (last 4 cervical and first thoracic spinal nerve), lumbar (first 4 lumbar nerves), sacral (fourth and fifth lumbar and first sacral nerve), pudendal (third and fourth sacral nerves), and coccygeal (fifth sacral and coccygeal nerve) plexuses. Meninges the meninges are comprised of three membranes which surround the brain and spinal cord. The arachnoid mater lies between the two; it is a thin covering and contains the blood vessels. Peripheral nerves are connected to the spinal cord by two roots: the anterior, ventral, or motor root and the posterior, dorsal, or sensory root. Peripheral nervous system innervates all voluntary muscles and transmits the sensory impulses from the whole body. Thus, injury or disease of peripheral nerves usually results in both sensory and motor loss. Because of the regenerative ability of the neurilemma, however, eventual recovery is possible if the nerve is largely intact or the ends of the divided nerve are placed close together. Autonomic Nervous System the autonomic nervous system is a subdivision of the peripheral nervous system and carries impulses from the brain and spinal cord to body organs. It controls and regulates largely by involuntary action of the glands, heart, and smooth muscle tissues. The autonomic nerves arising from the spinal cord comprise the sympathetic (thoracolumbar) and parasympathetic (craniosacral) nervous system. Spinal Nerves There are 31 pairs of spinal nerves: 9 pairs of cervical nerves, 12 pairs of thoracic nerves, 5 pairs of lumbar nerves, 5 pairs of sacral nerves, and 1 pair of coccygeal nerves. All spinal nerves carry impulses between the spinal cord and the abdomen, chest, and extremities. Glial cells (neuroglia), which may be either protoplasmic or fibrous, provide the connective tissue which binds together the neurons of the central nervous system. This tumor generally occurs in the cerebrum of adults and the cerebellum of children and is the most common type of glioma. It is the most malignant of all brain tumors and occurs most frequently in adults arising in the cerebral hemispheres. Oligodendroglioma arises from glial cells known as oligo- (small, few) dendro(branching) glia. These supporting cells are located as satellites about the nerve cells, between nerve fibers, and along blood vessels. It is one of the most frequent gliomas of childhood and tends to occur at the midline of the cerebellum; in young adults it is found more often in the lateral lobes of the cerebellum. Ependymoma arises from the ependymal cells which line the ventricles of the brain and the central canal of the spinal cord. It is found most often in the fourth ventricle occurring in children and young adults. Neurofibrosarcoma is composed of interlacing bundles of anaplastic spindle-shaped which resemble those of nerve sheaths. Neoplasms Neuroblastoma is derived from embryonic nerve tissue (neuroblasts) arising primarily in the autonomic nervous system and adrenal medulla, but not in the brain or spinal cord. Meningiomas arise in the meninges, the membranes that envelop the brain and spinal cord: the dura mater, pia mater, and arachnoid. These tumors are, thereby, potentially lethal, although they do allow for more prolonged survival than do malignant brain tumors. Consequently, cancer registries generally collect information on benign brain tumors as well as malignant brain tumors. The most common the most malignant Non-nervous Tumor of malignant brain tumor of all brain tumors the nerve cells common in the tissue which supports the brain of children. Cranial nerves 407 Table of Contents Manuals Answer: Q6 Match each term on the left with one of the descriptions on the right. Astrocytoma Neuroglia Medulloblastoma the most common malignant brain tumor Non-nervous tissue which supports the nerve cells Tumor of the brain which is most common in the cerebellum of children. Tumor of the membranes surrounding the brain and spinal cord the most malignant of all brain tumors a 4. Glioblastoma Answer: Q7 the sympathetic nerves are nerves of the autonomic nervous system. The body, however, has literally millions of sensory organs (or receptors), each associated with one or more nerves whose function is to convert the energy of a stimulus into a sensation or reflex. Receptors detect changes in our external and internal environment and initiate the responses necessary for adjusting the body to these changes. It is the dendrite portion of the sensory neuron which serves as the receptor of a sense organ. Table of Contents Manuals Q2 Match the receptors on the left with a location on the right. Location Located in the walls of blood vessels in the stomach, intestines, and other organs 2. Located in the skin, mucosa, eye, and ear Located in the muscles, tendons, joints, and the internal ear 413 Table of Contents Manuals Answer: Q1 the five major senses of the body are: 1. Proprioceptors Visceroceptors Located in the muscles, tendons, joints, and the internal ear Located in the walls of blood vessels in the stomach, intestines, and other organs 414 Table of Contents Manuals the Sense of Vision (Eye) the eye is set in a bony socket, the orbit. It contains a large interior cavity that is divided into two parts, the anterior and posterior cavities. The anterior cavity, in turn, has two subdivisions known as the anterior chamber and the posterior chamber. Most of the eyeball (Figure 76) is recessed in the orbit, protected by the walls of this bony cavity. The wall of the eyeball is composed of three layers; from the outside to the inside, they are the sclera, the choroid, and the retina. The sclera, composed of tough fibrous tissue, is the protective and supportive layer of the eye. The anterior portion of the sclera, called the cornea, lies over the colored part of the eye (iris) and the pupil. The middle or choroid layer (the pigmented vascular coat) of the eye contains a great many blood vessels. The iris, the colored muscular ring, controls the size of the pupil and the amount of light entering the eye. The anterior portion is modified to form the ciliary body, the main part of which is ciliary muscle. Its function is the adjustment of the lens of the eye for vision at different distances. The crystalline lens is suspended from the inner surface of the ciliary body by circular ligaments called the suspensory ligaments. The function of the lens is to bend light rays in order to focus an image on the retina. It is composed of two sections: the outer is pigmented and attached to the choroid layer, and the inner is composed of nervous tissue. The eyelid is lined with mucous membrane (called conjunctiva) which continues over the surface of the eyeball. The corner where the upper and lower eyelids join is called the canthus, the medial canthus being on the innerside, the internal (temporal) canthus being on the outer side. The lacrimal apparatus consists of four structures: the lacrimal glands, lacrimal ducts, lacrimal sac, and nasolacrimal duct. These structures perform the functions of secreting and draining tears on the surface of the eyeball (Figures 76 and 77). It is divided into two large Table of Contents Manuals Q6 the corner where the upper and lower eyelids meet is called the Q7 the apparatus performs the function of secreting tears. Answer: Q6 the corner where the upper and lower eyelids meet is called the canthus. The conjunctiva and the eyelid are drained by the submandibular, preauricular and infraauricular (parotid) and cervical lymph nodes. Retinoblastoma, a tumor arising from the retinal germ cells, is the most common intraocular neoplasm in children. Cornea, sclera, and lens: Eyelid:, and Table of Contents Manuals Q9 the most common malignancy of the eye is Q10 the most common eye malignancy in children is 425 Table of Contents Manuals Answer: Q8 Name the lymph nodes which drain each of the following areas of the eye: 1. Cornea, sclera, and lens: no true lymphatics Eyelid: submandibular, preauricular (parotid), and cervical. There are separate taste buds for sweet, sour, bitter, and salt substances (see Figure 80). All other qualities of experienced taste are a result of the fusion of two or more of the four primary tastes and as a result of the stimulation of the olfactory receptors. Therefore, the numerous tastes recognized are not taste alone but taste plus odors. The four kinds of taste buds or corpuscles are not evenly distributed over the tongue. Most of those sensitive to bitter are located at the back of the tongue, those sensitive to sweet at the tip, and those sensitive to salt and sour along the sides and tip. Malignant Tumors Malignant lesions are more common on the anterior two-thirds than on the posterior one-third of the tongue. Squamous cell carcinomas constitute 90 percent of all malignant tumors of the tongue. The other 10 percent are made up primarily of lymphoepitheliomas and lymphosarcomas. Lymphosarcomas will arise in the lymphoid tissue (lingual tonsil) found at the base of the tongue. Answer: Q12 Separate receptors sense the taste of sweet, sour, bitter, and salt, but all other qualities of taste are a result of a fusion of two or more primary tastes and the stimulation of the olfactory receptors. Their location explains the necessity for sniffing or draining air forcibly into the nose in order to smell delicate odors. The olfactory sensory organs consist of hair cells which are extremely sensitive to stimulation by even very slight odors. This explains why odors that are at first very noticeable are not sensed at all after a short time. This chamber is divided A lower or respiratory An upper or olfactory portion of the nasal fossa. Lymph Nodes Regional the regional lymph nodes are the submental, (upper and lower deep cervical) nodes: retropharyngeal. Table of Contents Manuals portion and an upper or Q14 the receptors for the sense of smell lie in the mucosa of the the cavity. Answer: Q15 the most common type of tumor in the nasal cavities is squamous cell carcinoma. It collects the sound which is transmitted through the external auditory canal, leading to the tympanic membrane (or eardrum). The middle ear lies in a cavity in the temporal bone and is separated from the external ear by the tympanic membrane which transmits sounds to the internal ear. The inner ear is comprised of membranous tissue contained within a bony structure. The bony labyrinth has three divisions: the vestibule and two extensions of the vestibule called the cochlea and the semicircular canals. The cochlea is a spiral canal containing a receptor for hearing called th Organ of Corti. Lymphatics from both parts of the ear go directly or indirectly to the internal jugular (upper and lower deep cervical) nodes. Benign Tumors Acoustic neuroma, a benign tumor of the auditory nerve, is the most common tumor of the ear. Contains the receptors for hearing Made up of the auricle and the auditory canal 3. Contains the opening from the Eustachian tube Table of Contents Manuals 437 Table of Contents Manuals Answer: Q16 b c a 1. Because of the rarity of subacute leukemias and aleukemias, they have been excluded from this table.
The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation diabete 64 effective 50mg acarbose. These deficits can accumulate to levels of impairment equivalent to those observed after 1 or even 2 nights of total sleep deprivation diabetes type 1 feet problems acarbose 50 mg amex. A diabetes prevention diabetes basics buy acarbose 25 mg with mastercard, Cumulative sleep loss relative to habitual sleep duration-that is diabetes symptoms undiagnosed order 50mg acarbose overnight delivery, all hours of sleep habitually obtained (as measured at home during the 5 days prior to the experiment) but not received in the experiment because of sleep restriction diabetes symptoms numbness buy acarbose 50mg without prescription. B diabetic diet list of foods generic acarbose 50 mg without a prescription, Cumulative wake extension relative to habitual wake duration-that is, all consecutive hours of wakefulness in excess of the habitual duration of a wakefulness period. Daily means are shown for subjects in the 8-hour (diamond), 6-hour (light blue square), 4-hour (circle), and 0-hour (green square) sleep period conditions. A also shows the range (orange band) of cumulative sleep loss (relative to habitual sleep duration) after 3 days in the 0-hour sleep condition, which was 23. This was significantly less than the cumulative sleep loss after 14 days in the 4-hour sleep period condition (t20 = 10. The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral func, tions and sleep physiology from chronic sleep restriction and total sleep deprivation. It has been found that after 1 night of restricted sleep (5 hours), a decrease in performance on a driving simulator, with a concurrent increase in subjectively reported sleepiness, was found. This suggests that individuals frequently underestimate the actual cognitive impact of sleep restriction and believe themselves fit to perform. Experiments using driving simulators have found similar results, with drivers unable to accurately perceive their level of fatigue and cognitive impairment. For example, not everyone was affected to the same degree when sleep duration was limited to less than 7 hours per day in the studies described earlier. It has been postulated that these individual differences are a result of state (basal level of sleepiness/alertness and basal differences in circadian phase) and trait differences (optimal circadian phase for sleep/wakefulness, sensitivity/responsiveness of sleep homeostat, and compensatory mechanisms),52 but these factors have not been widely researched. For studies of the possible genetic contributors to differential vulnerability to sleep loss, it is significant that the neurobehavioral responses to sleep deprivation have been found to be stable and consistent within subjects,23 suggesting they are traitlike. Alterations in other physiologic parameters, such as endocrine (see Chapter 125) and immune function (see Chapters 25 and 26), have been recognized and have implications for health status and risk. Several anecdotal and longitudinal studies have reported an increased incidence and risk of medical disorders and health dysfunction related to shift work schedules, which have been attributed to both circadian disruption and sleep disturbance. Further links between sleep disturbance and health effects have been reported in studies examining insomniac patients and patients with other sleep disorders and medical disorders that disturb sleep. In addition, an increased risk of coronary events in women obtaining 7 hours of sleep or less per night was observed. A meta-analysis study found a consistent, increased risk of obesity among short sleepers-both children (sleeping less than 10 hours per night) and adults (sleeping less than 5 hours per night)-but, as the authors pointed out, causal inference was difficult because of the lack of control of confounders and inconsistency in the methodologies used. One study reported that antibody titers were decreased by more than 50% after 10 days in subjects who were vaccinated for influenza immediately after 6 nights of sleep restricted to 4 hours per night, compared with those who were vaccinated after habitual sleep duration. Cardiovascular Effects Increased cardiovascular events and cardiovascular morbidity have been reported with reduced sleep durations. Shift workers who typically experience chronic reductions in sleep time as well as circadian disruption have been found to have reduced cardiovascular health. Regardless of its cause, chronic sleep deprivation results in cumulative adverse effects in daytime awake functions, including sleep propensity, cognitive performance, driving safety, mood, and physiologic conditions. Changes in total amount of stage 4 sleep as a function of partial sleep deprivation. The three-process model of alertness and its extension to performance, sleep latency, and sleep length. Paradoxical timing of the circadian-rhythm of sleep propensity serves to consolidate sleep and wakefulness in humans. Comparison of mathematical model predictions to experimental data of fatigue and performance. Maintenance of wakefulness test-a polysomnographic technique for evaluating treatment efficacy in patients with excessive somnolence. Preliminary observations on the effects of sleep time in a sleep restriction paradigm. Evaluation of techniques for ocular measurement as an index of fatigue and the basis for alertness management. Sustained attention performance during sleep deprivation: evidence of state instability. Lapsing during sleep deprivation is associated with distributed changes in brain activation. Performance deficits following shortterm partial sleep-deprivation and subsequent recovery oversleeping. Response surface mapping of neurobehavioral performance: testing the feasibility of split sleep schedules for space operations. Neurobehavioural functioning during chronic sleep restriction at an adverse circadian phase. Low levels of alcohol impair driving simulator performance and reduce perception of crash risk in partially sleep deprived subjects. Partial night sleep deprivation reduces natural killer and cellular immune responses in humans. Effects of sleep and sleep deprivation on interleukin-6, growth hormone, cortisol, and melatonin levels in humans. Overtime work, insufficient sleep, and risk of non-fatal acute myocardial infarction in Japanese men. Patients with severe obstructive sleep apnea syndrome and elevated high-sensitivity C-reactive protein need priority treatment. Similarly, arousal and waking are facilitated by several chemically distinct neuronal groups localized in the midbrain, the posterior and lateral hypothalamus, and the basal forebrain. These include histaminergic, orexinergic, serotonergic, cholinergic, dopaminergic, and noradrenergic neurons. These arousal systems share the property of having long axons and extensive projections to widespread brain regions, including the diencephalon, limbic system, and neocortex. Signals from the circadian clock originating in the hypothalamic suprachiasmatic nucleus regulate the circadian timing of sleep through connections in this brain region. We take it for granted that the brain controls sleep and waking, and this has been confirmed. These studies argue that neuronal groups localized between the midpons and upper midbrain are important for generating a waking-like state. Neuropathologic findings reveal initial severe cell loss and gliosis in the anterior medial thalamus, including the dorsomedial nucleus. In the first sleeplike state, cats lay down in a random position, pupils exhibited reduced but variable miosis, and eyes exhibited slow and nonconjugate movements, and they could be aroused by auditory or other stimuli. Additional studies support the hypothesis that the lower brainstem contains sleep-facilitating processes. These discrete neuronal groups are identified and differentiated by their expression of molecular machinery that synthesizes and releases specific neurotransmitters and neuromodulators. These include neuronal groups that synthesize serotonin, noradrenalin, histamine, acetylcholine, and orexin/hypocretin (herein called orexin). Each of these systems has been studied extensively in the context of the control of specific aspects of waking behaviors. Here we will give only a brief overview of each, focusing on their contribution to generalized brain arousal or activation. Before proceeding, we point out certain general properties of these neuronal systems. Thus, it is intriguing that most arousal systems share one critical property: the neurons give rise to long, projecting axons with extensive terminal fields that impinge on multiple regions of the brainstem and forebrain. These diffuse projections enable the systems to have multiple actions, as might be expected of arousal systems. In this review, we emphasize the ascending projections-that is, projections from the brainstem and hypothalamus to the diencephalon, limbic system, and neocortex, as these are particularly germane to the generation of cortical arousal. The release of neurotransmitters and neuromodulators at nerve terminals is initiated by the propagation of action potentials to the terminals. The upper brainstem, posterior and lateral hypothalamus, and basal forebrain contain several clusters of neuronal phenotypes, with arousal-inducing properties. B, Sagittal view of brainstem and diencephalon showing localization of orexin-containing neurons and their projections to both forebrain and brainstem. Arousal systems also facilitate motor-behavioral arousal through descending pathways. Pharmacologic actions are usually mediated by actions on specific receptor types or transporters (see examples later). Electrophysiologic studies show that the arousal systems are normally activated and deactivated within seconds or minutes. Thus, effects of acute experimental manipulations of particular arousal-related neurotransmitters, as with administration of a drug, may better mimic the normal physiologic pattern and be more informative as to their function. Most arousal systems have been studied by recording the discharge patterns of neurons in "freely moving" animals, in relationship to spontaneously occurring wake and sleep states. Increased discharge during arousal or wake compared with sleep constitutes part of the evidence for an arousal system. The actions of a neurotransmitter on a target system are determined primarily by the properties of the receptors in the target. The neurotransmitters and neuromodulators underlying arousal systems each act on several distinct receptor types, with diverse actions. These neurons project to virtually all regions of the diencephalon, limbic system, and neocortex. Although it was initially hypothesized that serotonin might be a sleeppromoting substance,10 much evidence shows that the immediate effect of release of serotonin is arousal (reviewed in reference 11). Because of the great diversity of serotonin receptors (there are at least 14 types), the effects of serotonin on target neurons are complex. Direct application of alpha-1 and beta agonists in preoptic area and adjacent basal forebrain sites induces increased wakefulness (reviewed in reference 16). Administration of an antagonist of this receptor causes disinhibition and increased waking. The effects are dosage dependent: low dosages produce arousal, and high dosages produce sedation. To von Economo, this suggested the concept of opposing hypothalamic sleeppromoting and wake-promoting systems. Larger bilateral lesions (3 to 5 mm in diameter) that extend into the adjacent basal forebrain yield more severe insomnia (reviewed in reference 38). Examples of c-Fos immunostaining and the correlations between c-Fos counts and sleep amounts are shown in Figure 7-2. After sleep, increased staining was seen in the midline (A) or around the top of the third ventricle (B) compared with the wake samples (C and D). Lower: Regression functions and correlations relating c-Fos counts and sleep amounts before sacrifice among individual animals. In all sites, high correlations were found between sleep amounts and c-Fos counts at a normal ambient temperature. Sleep-related c-Fos expression in the preoptic hypothalamus: effects of ambient warming. The presence of sleep-active neurons provides one critical piece of evidence for the importance of a brain region in the facilitation of sleep. These mutually inhibitory processes are hypothesized to underlie a sleep-wake switch or "flip-flop" model (see Fig 7-4). On the other hand, activation of sleep-promoting neurons would inhibit arousal-related neurons, removing inhibition from sleeppromoting neurons and reinforcing consolidated sleep episodes. This model provides a mechanism for the stabilization of both sleep and waking states. Abnormalities in one or more of the components of this "flipflop" system could result in less stable sleep and wake states, a possible explanation for the fragmentation of sleep in sleep disorders in which insomnia is an element, and the fragmentation of waking in narcolepsy. The arousal-related neuronal groups also have widespread additional ascending and descending projections that control state-related functions throughout the brain. Activity of either sleep-promoting or wake-promoting neurons inhibits the neurons generating the opposing state. These two modes of action potential generation reflect the expression of intrinsic properties of thalamocortical neurons, and a specialized, voltage-sensitive Ca2+ current plays a critical role. Thus, when depolarizing input is delivered to a relay neuron that is resting at this level of membrane polarization, the cell responds with tonic single-spike firing. When relay neurons are hyperpolarized (membrane potential more negative than -65 mV), It becomes activated, and depolarizing input evokes a slow Ca2+-mediated depolarization (100 to 200 msec in duration) that is crowned by a burst of three to eight fast Na+ action potentials. Tonic versus burst firing reflects intrinsic, voltage-dependent properties of thalamic neurons, and it can be recorded in neurons from isolated slices of thalamus. C and D, In vitro intracellular recordings of a relay neuron from guinea pig thalamus. A depolarizing current step (1) delivered at resting potential (> -65 mV) evokes a tonic depolarizing response in the neuron (3) that is subthreshold for action potential generation.