By N. Folleck. University of Chicago. 2018.
Describe the locations of the peripheral chemoreceptors chemoreceptors control breathing indirectly via sensory neurons and identify the two paired cranial nerves that carry sen- to the medulla oblongata discount voltaren 100 mg with visa. The aortic bodies send sensory infor- sory impulses from these sites to the respiratory centers mation to the medulla oblongata in the vagus nerves; the carotid within the brain stem order voltaren 100mg line. Respiratory System © The McGraw−Hill Anatomy, Sixth Edition Body Companies, 2001 Developmental Exposition ing the seventh week, and a single large oronasal cavity forms. The Respiratory System Shortly thereafter, tissue plates of mesoderm begin to grow hori- zontally across the cavity. At approximately the same time, a ver- tical plate develops inferiorly from the roof of the nasal cavity. EXPLANATION These plates have completed their formation by 3 months of de- The development of the respiratory system is initiated early in velopment. The vertical plate forms the nasal septum, and the embryonic development and involves both ectoderm and en- horizontal plates form the hard palate. Although all of the structures of the respiratory sys- tem develop simultaneously, we will consider the upper and A cleft palate forms when the horizontal plates fail to meet in the midline. This condition can be corrected surgically lower systems separately because of the different germ layers (see fig. In humans, pouching, from the ventral surface of endoderm along the cephalization is apparent early in development. This diverticulum, which tial events is the formation of the nasal cavity at 3 1/2 to 4 forms during the fourth week of development, is referred to as weeks of embryonic life. The placode invaginates to portion bifurcates (splits) into a right and left principal form the olfactory pit, which extends posteriorly to connect bronchus. The foregut, derived of endoderm, later devel- The buds continue to elongate and split until the entire ops into the pharynx. As the terminal portion forms air sacs, called pul- nasal cavity, and for a short time there is a thin oronasal mem- monary alveoli, at about 8 weeks of development, the sup- brane separating the two cavities. The complete structure of the lungs, however, is not fully developed until about 26 weeks of fetal development. Premature infants born prior to this time therefore require special artificial respiratory equip- cephalization: Gk. Respiratory System © The McGraw−Hill Anatomy, Sixth Edition Body Companies, 2001 EXHIBIT I The development of the upper respiratory system.
Integumentary System © The McGraw−Hill Anatomy discount voltaren 100 mg on line, Sixth Edition Companies voltaren 50mg with mastercard, 2001 112 Unit 4 Support and Movement 6. FUNCTIONS OF THE SKIN The skin not only protects the body from pathogens and external injury, it is a highly dynamic organ that plays a key role in main- taining body homeostasis. Objective 5 Discuss the role of the skin in the protection of the body from disease and external injury, the regulation of body fluids and temperature, absorption, synthesis, sensory reception, and communication. Physical Protection The skin is a barrier to microorganisms, water, and excessive sun- FIGURE 5. Bedsores are most common on skin overlying a bony pro- form an acidic protective film (pH 4. The protein ker- atin in the epidermis also waterproofs the skin, and the cornified outer layer (stratum corneum) resists scraping and keeps out mi- Hypodermis croorganisms. As mentioned previously, exposure to UV light The hypodermis, or subcutaneous tissue, is not actually a part of stimulates the melanocytes in the stratum basale to synthesize the skin, but it binds the dermis to underlying organs. In addition, sur- dermis is composed primarily of loose connective tissue and adi- face friction causes the epidermis to thicken by increasing the pose cells interlaced with blood vessels (see fig. Collagenous rate of mitosis in the cells of the stratum basale and stratum spin- and elastic fibers reinforce the hypodermis—particularly on the osum, resulting in the formation of a protective callus. The amount of adipose tissue in the hypodermis varies Regardless of skin pigmentation, everyone is susceptible to skin cancer if his or her exposure to sunlight is sufficiently intense. Females generally have about an 8% United States, and approximately 9,300 of these are diagnosed as the thicker hypodermis than males. Sunscreens are advised for people The hypodermis is the site for subcutaneous injections. Subcutaneous devices to administer slow-release, low-dosage medications are now available. For exam- Hydroregulation ple, insulin may be administered in this way to treat some forms of di- The thickened, keratinized, and cornified epidermis of the skin is abetes.
Somato- Decreased Blood Glucose Stimulates statin clearly inhibits both glucagon and insulin secretion the Secretion of Glucagon from the alpha and beta cells of the pancreas buy generic voltaren 50 mg online, respectively buy cheap voltaren 100 mg on line, Similar to insulin, glucagon is first synthesized as part of a when it is given exogenously. Glucagon secretion is regulated by relationships of delta cells to alpha and beta cells further many of the factors that also regulate insulin secretion. In suggest that somatostatin may play a role in regulating both most cases, however, these factors have the opposite effect glucagon and insulin secretion. The initial gene product for glucagon, pre- proglucagon, is a much larger peptide. Like other peptide hormones, the “pre” piece is removed in the ER, and the pro- METABOLIC EFFECTS OF INSULIN hormone is converted into a mature hormone as it is pack- AND GLUCAGON aged and processed in secretory granules (see Chapter 31). The endocrine pancreas secretes hormones that direct the Secretion of Glucagon. The principal factors that influ- storage and use of fuels during times of nutrient abundance ence glucagon secretion are listed in Table 35. Insulin is se- exceptions, this table is nearly a mirror image of Table 35. These two decrease in blood glucose below about 100 mg/dL pro- hormones play an important role in directing the flow of motes glucagon secretion. CHAPTER 35 The Endocrine Pancreas 627 Insulin Affects the Metabolism of Carbohydrates, dient. The carriers shuttle glucose across the membrane Lipids, and Proteins in Liver, Muscle, and faster than would occur by diffusion alone. Considerable Adipose Tissues recent work has revealed not just one transporter, but a family of about seven different glucose transporters The primary targets for insulin are liver, skeletal muscle, and (GLUT), commonly called GLUT 1 to GLUT 7. Insulin has multiple individual actions in transporters are expressed in different tissues and, in some each of these tissues, the net result of which is fuel storage. GLUT 4, the insulin-stimulated glucose transporter, is Mechanism of Insulin Action. Although insulin was one of the primary form of the transporter present in skeletal mus- the first peptide hormones to be identified, isolated, and cle tissue and adipose tissue. It is present in plasma mem- characterized, its exact mechanism of action remains elusive.
The secreted H replaces one of the Na ions accompanying the basic phosphate cheap 50mg voltaren with mastercard. The new HCO3 generated in the cell moves into the blood purchase voltaren 100 mg on-line, to- gether with Na. For each mEq of H excreted in the urine as titratable acid, a mEq of new HCO3 is added to the Peritubular Tubular Tubular blood. This process eliminates H in the urine, replaces blood epithelium urine ECF HCO3 , and restores a normal blood pH. The amount of titratable acid excreted depends on two factors: the pH of the urine and the availability of buffer. If Glutamine Na+ 2 NH + 4 NH + - 4 Cl Peritubular Tubular Tubular α-Ketoglutarate2- NH NH 3 3 blood epithelium urine + NH + Cl- Glucose or H+ 4 CO +H O H+ Na+ 2 2 Na+ + 2 Na HCO - - HPO 2-2Na+ 2H+ 3 HCO3 4 - - + + HCO3 2 HCO3 Na+ (new) H H (filtered) (new) CO2 CO2 + H2O H2CO3 CA - + CO2 2 CO2 +2 H2O 2 H2CO3 H2PO4 Na CA (excreted) FIGURE 25. Ammonium ions are formed A cell model for the formation of titratable from glutamine in the cell and are secreted into the tubular urine FIGURE 25. H from H2CO3 (bottom) is consumed when -ketoglu- 2– tarate is converted into glucose or CO and H O. For each mEq of titratable acid excreted, a mEq of is added to the peritubular capillary blood—1 mEq for each mEq of NH excreted in the urine. Enhanced renal ammonia synthesis and excretion 1) Hydration of CO2 in the cells, forming H2CO3 and is a lifesaving adaptation because it allows the kidneys to yielding H for secretion remove large H excesses and add more new HCO3 to 2) Dehydration of H2CO3 to H2O and CO2 in the the blood. Also, the excreted NH4 can substitute in the proximal tubule lumen, an important step in the reabsorp- urine for Na and K , diminishing the loss of these cations. In the proximal tubule, the two ions Several factors influence the renal excretion of H , includ- are directly linked, both being transported by the Na /H ing intracellular pH, arterial blood PCO , carbonic anhy- exchanger in the luminal plasma membrane. Enhanced Na reabsorp- drase activity, Na reabsorption, plasma [K ], and aldos- terone (Fig. The avid renal reabsorption of Na observed in states of volume depletion is accompanied by a factor influencing the secretion and, therefore, the excretion parallel rise in urinary H excretion.
On the diffusion-weighted SSFP sequence buy cheap voltaren 50mg on-line, the benign frac- tures exhibited isointense or low signal intensity as com- Fig discount 50 mg voltaren mastercard. Bone marrow ede- pared to surrounding normal bone marrow, whereas ma of the medial condylus metastatic vertebral compression fractures showe a high due to insufficiency fracture signal intensity. This probably reflects a higher diffusion and overload (PDw fatsat of water protons in acute benign fractures with bone mar- image) row edema in comparison to vertebral bodies filled with tumor cells. Differentiation of transient bone marrow edema-syndrome and avascular necrosis a b Areas of subchondral epiphyseal bone marrow edema adjacent to weight bearing joints have to be differenti- ated in transient bone marrow edema syndrome, sub- chondral farcture and avascular bone necrosis (AVN) (Figs. An AVN lesion is typically a well-demar- cated epiphyseal area of variable signal intensity, often associated with a double-line signal intensity pattern. A transient bone marrow edema lesion is ill-delimited with low-signal-intensity in the epiphyseal area on T1- weighted images with high-signal-intensity on water sensitive images. Contrast-enhanced MR images may increase diagnostic confidence by showing homoge- neous hypervascularization in bone marrow edema le- sions and by depicting hypovascular marrow areas in Fig. T1w image (a) and PDw fatsat image (b) Bone Marrow Disorders 81 Suggested Readings Fletcher BD, Wall JE, Hanna SL (1993) Effect of hematopoietic growth factors on MR images of bone marrow in children un- Allison JW, James CA, Arnold GL, Stine KC, Becton DL, Bell JM dergoing chemotherapy. Radiology 189:745-751 (1998) Reconversion of bone marrow in Gaucher disease treat- Ghanem N, Kelly T, Altehoefer C, Winterer J, Schafer O, Bley TA, ed with enzyme therapy documented by MR. Radiologe 44:864-873 Barkhausen J, Dahmen G, Bockisch A, Debatin JF, Ruehm SG Hundt W, Petsch R, Helmberger T, Reiser M (2000) Effect of su- (2003) Whole-body dual-modality PET/CT and whole-body perparamagnetic iron oxide on bone marrow. JAMA 290:3199-3206 10:1495-1500 Avrahami E, Tadmor R, Dally O, Hadar H (1989) Early MR Kattapuram SV, Khurana JS, Scott JA, el-Khoury GY (1990) demonstration of spinal metastases in patients with normal ra- Negative scintigraphy with positive magnetic resonance imag- diographs and CT and radionuclide bone scans. Skeletal Radiol 19:113-116 Assist Tomogr 13:598-602 Kyle RA (1983) Long-term survival in multiple myeloma. New Baker LL, Goodman SB, Perkash I, Lane B, Enzmann DR (1990) Engl J Med 308:314-316 Benign versus pathologic compression fractures of vertebral Kyle RA (1975) Multiple myeloma review of 869 cases. Mayo Clin bodies: Assessment with conventional spin-echo, chemical Proc 50:29-39 shift, and STIR MR imaging. Radiology 174:495-502 Lauenstein TC, Freudenberg LS, Goehde SC, Ruehm SG, Goyen Bartl R, Frisch B, Diem H et al (1991) Histologic, biochemical, M, Bosk S, Debatin JF, Barkhausen J (2002) Whole-body MRI and clinical parameters for monitoring multiple myeloma. Eur Radiol 12:2091-2099 Baur A, Bartl R, Pellengahr C, Baltin V, Reiser M (2004) Latour LL, Svoboda K, Mitra PP, Sotak CH (1994) Time-depen- Neovascularization of bone marrow in patients with diffuse dent diffusion of water in a biological model system.
