By Q. Kippler. Ohio Northern University.

History of Anatomy © The McGraw−Hill Anatomy buy 500 mg glycomet amex diabetes type 2 online test, Sixth Edition Companies discount glycomet 500mg on-line managing diabetes holistically, 2001 Chapter 1 History of Anatomy 15 FIGURE 1. Tulp, a famous Rembrandt painting completed in 1632, depicts one of the public anatomies that were popular during this period. Nicholas Tulp was a famous Dutch anatomist who described the congenital defect in the spinal column known as spinal bifida aperta. Two of the most important contributions were the explana- name Vesanus (madman). Vesalius became so unnerved by the tion of blood flow and the development of the microscope. Harvey Although Vesalius was the greatest anatomist of his epoch, In 1628, the English physician William Harvey (1578–1657) others made significant contributions and to an extent paved published his pioneering work On the Motion of the Heart and the way for Vesalius. Not only did this brilliant research establish supplied with corpses by the friar of a local monastery. Mondino de’ Luzzi and the surgeon Jacopo Berengario of Carpi also corrected proof of the continuous circulation of blood within contained many of Galen’s errors. Fallopius (1523–62) and Eustachius vessels, it also provided a classic example of the scientific (1524–74) completed detailed dissections of specific body regions. Like Vesalius, Harvey was severely criticized for his departure from Galenic philosophy. The controversy over circulation of the blood raged for 20 years, Seventeenth and Eighteenth Centuries until other anatomists finally repeated Harvey’s experiments and During the seventeenth and eighteenth centuries, the science of concurred with his findings. In some of its as- pects, it also took on a somewhat theatrical quality. Elaborate Leeuwenhoek amphitheaters were established in various parts of Europe for Antoni van Leeuwenhoek (la′ven-hook) (1632–1723) was a public demonstrations of human dissections (fig. Exorbi- Dutch optician and lens grinder who improved the microscope tantly priced tickets of admission were sold to the wealthy, and to the extent that he achieved a magnification of 270 times. His the dissections were performed by elegantly robed anatomists many contributions included developing techniques for examin- who were also splendid orators. The subjects were usually exe- ing tissues and describing blood cells, skeletal muscle, and cuted prisoners, and the performances were scheduled during the lens of the eye. Although he was the first to accurately de- cold weather because of the perishable nature of the cadavers. History of Anatomy © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 16 Unit 1 Historical Perspective salivary glands and lymph nodes within the neck and facial re- gions. In 1664, Thomas Willis published a summary of what was then known about the nervous system. A number of anatomical structures throughout the body are named in honor of the early anatomists. Thus we have graafian follicles, Stensen’s and Wharton’s ducts, fallopian tubes, Bartholin’s glands, the circle of Willis, and many others. Because these terms have no descriptive basis, they are not particularly useful to a student of anatomy. Nineteenth Century The major scientific contribution of the nineteenth century was the formulation of the cell theory. It could be argued that this theory was the most important breakthrough in the history of bi- ology and medicine because all of the body’s functions were eventually interpreted as the effects of cellular function. The term cell was coined in 1665 by an English physician, Robert Hooke, as he examined the structure of cork under his mi- croscope in an attempt to explain its buoyancy. What Hooke actu- ally observed were the rigid walls that surrounded the empty cavities of the dead cells. The significance of cellular structure did not be- come apparent until approximately 150 years after Hooke’s work. Rather, he thought that a spermatozoan contained a teen years later, René H.

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If K were not reabsorbed generic glycomet 500mg visa diabetes type 1 ketones, its concentration would increase as much as that of inulin buy generic glycomet 500 mg on-line diabetes symptoms bloating. The luminal (apical) cell membrane in The fact that the concentration ratio for K remains about this nephron segment has a large surface area for transport be- 1 in this nephron segment indicates that 70% of filtered K is reabsorbed along with 70% of the filtered water. Glucose, amino acids, phosphate, and numerous other substances are transported by separate carriers. This nephron seg- ment and the proximal straight tubule are responsible for complete reabsorption of these substances. Separate, specific rounding the tubules, and filtered Na salts and water are mechanisms reabsorb glucose and various amino acids. The concentration ratio for urea rises along the proximal At the luminal cell membrane (brush border) of the tubule, but not as much as the inulin concentration ratio be- proximal tubule cell, Na enters the cell down combined cause about 50% of the filtered urea is reabsorbed. The inside of concentration ratio for PAH in proximal tubular fluid in- the cell is about 70 mV compared to tubular fluid, and in- creases more steeply than the inulin concentration ratio be- tracellular [Na ] is about 30 to 40 mEq/L compared with a cause of PAH secretion. Na entry In summary, though the osmolality (total solute concen- into the cell occurs via several cotransporter and antiport tration) does not detectably change along the proximal mechanisms. Na is reabsorbed together with glucose, convoluted tubule, it is clear that the concentrations of in- amino acids, phosphate, and other solutes by way of sepa- dividual solutes vary widely. The downhill (energetically substances fall (glucose, amino acids, HCO3 ), others rise speaking) movement of Na into the cell drives the uphill (inulin, urea, Cl , PAH), and still others do not change transport of these solutes. By the end of the proximal convoluted tubule, acids, phosphate, and so on are reabsorbed by secondary only about one-third of the filtered Na , water, and K re- active transport. Na is also reabsorbed across the luminal main; almost all of the filtered glucose, amino acids, and cell membrane in exchange for H. The Na /H ex- HCO3 have been reabsorbed, and several solutes destined changer, an antiporter, is also a secondary active transport for excretion (PAH, inulin, urea) have been concentrated in mechanism; the downhill movement of Na into the cell the tubular fluid. This mechanism is important in the acidification of urine (see Na Reabsorption Is the Major Driving Force Chapter 25). Cl may enter the cells by way of a luminal cell membrane Cl -base (formate or oxalate) exchanger. This membrane ATPase pumps three Na out ters the cell from the lumen across the apical cell mem- of the cell and two K into the cell and splits one ATP mol- brane and is pumped out across the basolateral cell mem- ecule for each cycle of the pump. K pumped into the cell diffuses out the basolateral cell membrane mostly through brane by Na /K -ATPase. The Na and accompanying anions and water are then taken up by the blood sur- a K channel. Glucose, amino acids, and phosphate, accu- CHAPTER 23 Kidney Function 393 mulated in the cell because of active transport across the ies was previously filtered in the glomeruli. Because a pro- luminal cell membrane, exit across the basolateral cell tein-free filtrate was filtered out of the glomeruli, the [pro- membrane by way of separate, Na -independent facilitated tein] (hence, colloid osmotic pressure) of blood in the per- diffusion mechanisms. HCO3 exits together with Na by itubular capillaries is high, providing an important driving an electrogenic mechanism; the carrier transports three force for the uptake of reabsorbed fluid. Cl may leave the cell by way of an pressure in the peritubular capillaries (a pressure that op- electrically neutral K-Cl cotransporter. The bal- tablishes an osmotic gradient across the proximal tubule ance of pressures acting across peritubular capillaries favors epithelium that is the driving force for water reabsorption. Some experimental evidence indi- The Proximal Tubule Secretes Organic Ions cates that proximal tubular fluid is slightly hypoosmotic to The proximal tubule, both convoluted and straight por- plasma; since the osmolality difference is so small, it is still tions, secretes a large variety of organic anions and organic proper to consider the fluid as essentially isosmotic to cations (Table 23. Water crosses the proximal tubule epithelium nous compounds, drugs, or toxins. The organic anions are through the cells via water channels (aquaporin-1) in the mainly carboxylates and sulfonates (carboxylic and sulfonic cell membranes and between the cells (tight junctions and acids in their protonated forms). Examples of organic anions actively secreted water is uptake by the peritubular capillaries. Organic nism involves the usual Starling forces that operate across anion transport becomes saturated at high plasma organic capillary walls. Recall that blood in the peritubular capillar- anion concentrations (see Fig. Upward pointing arrows indicate transport metabolism against an electrochemical gradient (energetically uphill trans- aThis list includes only a few of the large variety of organic anions and port) and downward pointing arrows indicate downhill transport.

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The wall of the GI tract is composed of chewed food called bolus (deglutition) four tunics purchase glycomet 500 mg mastercard diabetes test equipment reviews. Pharynx Receives bolus from oral cavity; autonomically continues deglutition of bolus to esophagus Objective 4 Describe the arrangement of the serous Esophagus Transports bolus to stomach by peristalsis; lower membranes within the abdominal cavity glycomet 500 mg low cost bulldog diabetes signs. These organs are supported and covered by down chyme; absorbs nutrients; transports wastes serous membranes that line the cavities of the trunk and cover through peristalsis to large intestine; prohibits the organs within these cavities. Serous membranes are com- backflow of intestinal wastes from large intestine posed of simple squamous epithelium, portions of which are rein- Large intestine Receives undigested wastes from small intestine; absorbs forced with connective tissue. Serous membranes secrete a water and electrolytes; forms, stores, and expels feces when activated by a defecation reflex lubricating serous fluid that continuously moistens the associ- ated organs. The parietal portion of the serous membrane lines the body wall, and a visceral portion covers the internal organs. As de- scribed in the previous chapter, the serous membranes associated with the lungs are called pleurae (see fig. The serous It usually takes about 24 to 48 hours for food to travel the membranes of the abdominal cavity are called peritoneal mem- length of the GI tract. Along the posterior abdominal cavity, the pari- specific functions in preparing food for utilization (table 18. The mesentery so many people are malnourished that eating patterns have supports the GI tract, at the same time allowing the small intes- become a critical public health concern. Grossly overweight people are at greater risk for cardiovas- ture for the passage of intestinal nerves and vessels. People with good nutritional habits are better able to withstand mesocolon is a specific portion of the mesentery that supports trauma, are less likely to get sick, and are usually less seriously ill the large intestine (fig. The peritoneal covering continues around the intestinal viscera as the visceral peritoneum. The peritoneal cavity is the Knowledge Check space between the parietal and visceral portions of the peri- toneum. Which functional activities of the digestive system break peritoneum, and are therefore said to be retroperitoneal. Which functional activities move the food Retroperitoneal organs include most of the pancreas, the kid- through the GI tract? List in order the regions of the GI tract through which in- and the abdominal aorta. Digestive System © The McGraw−Hill Anatomy, Sixth Edition Body Companies, 2001 Chapter 18 Digestive System 637 In a female, however, it is not isolated from the outside, which pre- Notochord sents the potential for contamination through the entry of microorgan- Neural tube isms. A fairly common gynecological condition is pelvic inflammatory Aorta disease (PID), which results from the entry of pathogens into the peri- toneal cavity at the sites of the open-ended uterine (fallopian) tubes. Mesentery Parietal peritoneum Gut Peritoneal cavity Layers of the Gastrointestinal Tract Liver Visceral peritoneum The GI tract from the esophagus to the anal canal is composed of four layers, or tunics. Each tunic contains a dominant tissue type Body wall that performs specific functions in the digestive process. The four tunics of the GI tract, from the inside out, are the mucosa, sub- mucosa, muscularis, and serosa (fig. Umbilical cord Mucosa The mucosa, which lines the lumen of the GI tract, is both an absorptive and a secretory layer. External to the lamina propria are thin layers of smooth muscle called the muscularis mucosae, which provide limited involuntary churning movements. Specialized goblet cells in the mucosa throughout most of the GI tract se- Peritonitis is a bacterial inflammation of the peritoneum. Treatment usually involves the injection Submucosa of massive doses of antibiotics, and perhaps peritoneal intubation (insertion of a tube) to permit drainage. The relatively thick submucosa is a highly vascular layer of con- nective tissue serving the mucosa. Absorbed molecules that pass Extensions of the parietal peritoneum serve to suspend or through the columnar epithelial cells of the mucosa enter into anchor numerous organs within the peritoneal cavity (fig. In addition to The falciform (fal'sı˘-form) ligament, a serous membrane rein- blood vessels, the submucosa contains glands and nerve plexuses. Functions of the greater omentum include storing fat, cushioning visceral organs, sup- The tunica muscularis is responsible for segmental contractions porting lymph nodes, and protecting against the spread of infec- and peristaltic movement through the GI tract. In cases of localized inflammation, such as appendicitis, inner circular and an outer longitudinal layer of smooth muscle. It includes neurons and ganglia from both the sympathetic and parasympathetic divisions of the ANS.

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The capillaries in the brain buy 500mg glycomet otc diabetes mellitus gestasional, it forms a closed wall without exhibit a nonfenestrated closed endothelium fenestration order glycomet 500mg on-line rimadyl and diabetes in dogs. There are no of many other organs (liver, kidney [E8]) ex- lymph vessels in the CNS. The bar- and widen into perivascular glial feet rier effect has been demonstrated for (AB1). In electron micrographs, capillaries numerous substances in studies using iso- are completely covered by perivascular feet. The barrier may result in a complete The capillary wall consists of endothelialcells blockade or in a delay of penetration. The capillary is enclosed by the basallamina (BE3) and the astrocyte covering (BE4). The sealing of the brain tissue from the rest of the body manifests itself in the blood– brain barrier, a selective barrier for numer- ous substances that are prevented from penetrating from the bloodstream through the capillary wall into the brain tissue. If the dye is injected intravenously into experi- mental animals (Goldmann’s first experiment) (C), almost all organs stain blue, but the brain and spinal cord remain unstained. Minor blue staining is only found in the gray tubercle (C5), the postremal area, and the spinal ganglia. The choroid plexus (C6) and the dura (C7) show a distinct blue staining. The same pattern is observed in cases of jaundice in humans; the bile pigment stains all organs yellow, only the CNS remains un- stained. If the dye is injected into the space Kahle, Color Atlas of Human Anatomy, Vol. Perivascular Glial Feet, Blood–Brain Barrier, Blood–CSF Barrier 45 1 5 6 5 7 A Blood vessel surrounded by astrocytes, silver impregnation 4 2 3 C Goldmann’s first experiment 1 7 B Blood vessel with perivascular glial feet (diagram according to Wolff) 3 2 8 4 D Goldmann’s second experiment E Brain capillary (left) and kidney capillary C–D Blood-brain barrier in the rab- (right), diagram based on electron- bit (according to Spatz) microscopic findings Kahle, Color Atlas of Human Anatomy, Vol. Spinal Cord and Spinal Nerves Overview 48 The Spinal Cord 50 Peripheral Nerves 70 Cervical Plexus 72 Posterior Branches 72 Brachial Plexus 74 Nerves of the Trunk 84 Lumbosacral Plexus 86 Sacral Plexus 90 Kahle, Color Atlas of Human Anatomy, Vol. It has two spindle- emerges from the foramen lying at its own shaped swellings: one in the neck region, level. During development, however, the the cervical enlargement (C1), and one in the vertebral column increases much more in lumbar region, the lumbar enlargement (C2). As a result, At the lower end, the spinal cord tapers into the lower end of the spinal cord moves the medullary cone (BC3) and ends as a thin further up in relation to the surrounding thread, the terminal filament (C4). In the newborn, the lower end of riormedianfissure at the ventral side and the the spinal cord lies at the level of the third posterior median sulcus (BC5) at the dorsal lumbar vertebra, and in the adult, at the side mark the boundaries between the two level of the first lumbar or twelfth thoracic symmetrical halves of the spinal cord. Thus, the spinal nerves no longer fibers enter dorsolaterally and emerge ven- emerge at their levels of origin; instead, trolaterally at both sides of the spinal cord their roots run down a certain distance and unite to form the dorsal roots, posterior within the vertebral canal to their foramen roots, and the ventral roots, anteriorroots. The more caudally the roots join to form short nerve trunks of 1cm roots originate from the spinal cord, the in length, the spinal nerves. Only the are therefore no longer identical with the posterior roots of the first cervical spinal corresponding levels of the spinal cord. From the medullary cone (BC3) onward, the vertebral canal contains only a dense mass Inhumans,thereare31pairsofspinalnerves of descending spinal roots, known as the which emerge through the intervertebral cauda equina (tail of a horse) (B7). The impression of segmentation is created by the bundling of nerve fibers emerging from the foramina (p. The spinal nerves are subdivided into cervi- calnerves, thoracicnerves, lumbarnerves, sacral nerves, and coccygeal nerves (A). Spinal Cord and Spinal Nerves 49 1 2 C 1 C 2 3 4 1 5 6 C 7 7 C 8 T 1 T 1 8 1 2 5 6 3 4 5 6 7 8 9 10 5 11 2 12 T 12 1 L 1 L 1 3 2 3 4 4 7 L 5 C Spinal cord S 1 S 1 5 1 Coccyx 2 Sacral 3 nerves 4 5 Coccygeal nerves A Lateral view of the spinal nerves B Dorsal view of the spinal ganglia Kahle, Color Atlas of Human Anatomy, Vol. The relay may also take place in the medulla ob- Structure (A, B) longata. However, the afferent fibers may also run to the anterior horn cells and trans- The gray matter, substantia grisea (nerve mit the signal directly to these cells. The re- cells), appears in transverse section of the sulting muscle reaction is called reflex, the spinal cord as a butterfly configuration sur- underlying neuronal circuit is called reflex rounded by the white matter, substantia alba arc (D). Wedistinguishoneithersidea run directly to the motor neuron (mono- dorsal horn (posterior horn) (AB1) and a ven- synaptic reflex arc) but via interneurons that tral horn (anterior horn) (AB2). Between them lies the cen- reflex)and the multisynaptic extrinsic reflex tral intermediate substance (A3) with the (withdrawal reflex) are of clinical impor- obliterated central canal (A4). In the stretch reflex (F), the muscle is thoracicspinalcord,thelateralhorn(AB5)is briefly stretched by a tap on its tendon.

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