By A. Hogar. Coastal Carolina University. 2017.
It is positioned immediately be- LIVER ponstel 250mg online, GALLBLADDER order ponstel 250mg on-line, neath the diaphragm in the epigastric and right hypochondriac regions (see fig. The liver, consisting of four lobes, processes nutrients and se- The liver has four lobes and two supporting ligaments. An- cretes bile, which is stored and concentrated in the gallbladder teriorly, the right lobe is separated from the smaller left lobe by prior to discharge into the duodenum. Inferiorly, the caudate endocrine (islet) cells and exocrine (acini) cells, secretes impor- tant hormones into the blood and essential digestive enzymes into the duodenum. Digestive System © The McGraw−Hill Anatomy, Sixth Edition Body Companies, 2001 Chapter 18 Digestive System 661 Gallbladder Quadrate lobe Inferior vena cava Right lobe Coronary ligament Ligamentum teres Left lobe Cystic duct Hepatic duct Hepatic Right lobe artery Left lobe Hepatic portal Falciform Ligamentum teres vein ligament Caudate lobe Inferior vena cava Common bile duct Gallbladder Quadrate lobe Falciform ligament Hepatic artery Left lobe Right lobe Common bile duct Left triangular ligament Inferior vena Hepatic portal Ligamentum cava vein Caudate lobe venosum (c) FIGURE 18. The falciform liga- tercellular gaps between adjacent Kupffer cells make these sinu- ment attaches the liver to the anterior abdominal wall and the soids more highly permeable than other capillaries. The ligamentum teres (round ligament) extends structure of the liver and the high permeability of the sinusoids from the falciform ligament to the umbilicus. This ligament is allow each hepatocyte to be in direct contact with the blood. The hepatic plates are arranged to form functional units Although the liver is the largest internal organ, it is, in a called liver lobules (fig. This is because the liver cells, central vein, and at the periphery of each lobule are branches of or hepatocytes, form hepatic plates that are one to two cells the hepatic portal vein and of the hepatic artery, which open thick and separated from each other by large capillary spaces into the spaces between hepatic plates. The sinusoids are containing molecules absorbed in the GI tract, thus mixes with Kupffer cells: from Karl Wilhelm von Kupffer, Bavarian anatomist and hepatic: Gk. Digestive System © The McGraw−Hill Anatomy, Sixth Edition Body Companies, 2001 662 Unit 6 Maintenance of the Body Branch of hepatic portal vein Biliary ductule Hepatic triad Branch of hepatic artery Hepatic plate Creek Central vein Hepatic plate Liver (hepatic) sinusoid Intralobular biliary ductule Liver (hepatic) sinusoids (a) Branch of hepatic portal vein Branch of hepatic artery Biliary ductule Biliary canaliculi Liver (hepatic) sinusoid Connective tissue sheath (c) (b) FIGURE 18. Blood enters a liver lobule through the vessels in a hepatic triad, passes through hepatic sinusoids, and leaves the lobule through a central vein. The central veins converge to form hepatic veins that transport venous blood from the liver. The central veins of different liver lobules converge to form the hepatic vein, The gallbladder is a saclike organ attached to the inferior surface which carries blood from the liver to the inferior vena cava. This organ stores and concen- The liver lobules have numerous functions, including syn- trates bile.
Both factors could be improved by targeting NMDA receptor subtypes but it may be that AMPA and kainate receptors also have key roles in excitotoxicity buy ponstel 500mg with amex. Another issue is that even when NMDA receptors are blocked the influx of calcium through voltage-gated calcium channels may induce neuronal damage ponstel 250mg amex. However,a combination of motoneuron disease,dementia and a Parkinson-like syndrome was possibly triggered by a constituent of the cyclad seed,used in Guam in times of famine for which the most likely candidate appears to be an excitatory amino- acid agonist. Certainly,there is evidence for a defect in mitochondrial energy metabolism in PD which may lead to neuronal depolarisation and an easier removal of the voltage-dependent Mg2 block of the NMDA receptor. The resulting excessive neuronal excitation may contribute to nigrostriatal cell death. Whatever the case,once PD is established,the corticostriatal and subthalamofugal pathways,that use glutamate, are overactive. In MPTP-treated monkeys both NMDA and non-NMDA antagonists have efficacy. Finally,AIDS dementia has parallels with cerebral ischemia or stroke and again the key mechanism appears to involve overactivation of glutamate receptors,in particular the NMDA receptor,followed by excessive influx of calcium and the generation of free radicals. Clearly there is much therapeutic potential for drugs acting on glutamate systems but much more progress is needed. DEVELOPMENT Glutamate receptor expression is developmentally regulated and glutamate-mediated neurotransmission is generally enhanced in the immature brain at ages when certain glutamate receptors are transiently overexpressed. Glutamate receptors play a critical role in neuronal plasticity and activity-mediated growth during brain development and yet the immature brain is more vulnerable than the adult to excitotoxic neuronal injury, suggesting that the functional state of glutamate receptors modifies the response of the brain to injury. In view of the general role of glutamate in the development and plasticity of connections in the immature CNS it is perhaps surprising that as yet we know little of its function apart from a pivotal role in the organisation of sensory pathways. In the CNS,NMDA receptor binding is much more restricted in the adult than in young animals although in broad terms,affinity appears the same as in the adult. In the immature hippocampus,NMDA EPSPs are much greater in amplitude and significantly less sensitive to Mg2 although glycine modulation appears the same as in the adult.
The skeletal system serves the circulatory system by producing blood cells in pro- tected sites cheap 500 mg ponstel amex. Directly or indirectly cheap 500 mg ponstel fast delivery, the skeletal system supports and protects all of the systems of the body. Discuss two ways in which the skeletal system serves the Periosteum circulatory system in the production of blood. Medullary cavity Yellow bone marrow BONE STRUCTURE Each bone has a characteristic shape and diagnostic surface fea- Compact bone tures that indicate its functional relationship to other bones, mus- cles, and to the body structure as a whole. Objective 3 Classify bones according to their shapes and give an example of each type. Objective 5 Describe the gross features of a typical long minerals which account for approximately two-thirds of the bone and list the functions of each surface feature. About 95% of the calcium and 90% of the phosphorus within the The shape and surface features of each bone indicate its func- body are deposited in the bones and teeth. Bones that are long, for concentration of these inorganic salts within the blood is example, provide body support and function as levers during kept within narrow limits, both are essential for other body body movement. Calcium is necessary for muscle contraction, blood have large articular surfaces and processes for muscle attachment. Phosphorus is required for the activities of the ligaments, tendons, or muscles. A flattened surface provides an nucleic acids DNA and RNA, as well as for ATP utilization. If mineral salts are not present in the diet in sufficient Grooves around an articular end of a bone indicate where a ten- amounts, they may be withdrawn from the bones until they don or nerve passes, and openings through a bone permit the are replenished through proper nutrition. Shapes of Bones Vitamin D assists in the absorption of calcium and phospho- rus from the small intestine into the blood. As bones develop The bones of the skeleton are grouped on the basis of shape into in a child, it is extremely important that the child’s diet contain an adequate amount of these two minerals and vitamin D. If the diet is four principal categories: long bones, short bones, flat bones, and ir- deficient in these essentials, the blood level falls below that neces- regular bones (fig. Rickets is characterized by soft bones that may re- sult in bowlegs and malformation of the head, chest, and pelvic and function as levers. Skeletal System: © The McGraw−Hill Anatomy, Sixth Edition Introduction and the Axial Companies, 2001 Skeleton 136 Unit 4 Support and Movement TABLE 6. Irregular bones have varied shapes and process Any marked bony prominence (the mastoid many surface features for muscle attachment or articulation process of the temporal bone) (e.
Parkinson’s disease may walk with small generic 500 mg ponstel free shipping, Tremor of a limb buy discount ponstel 250mg online, usually most notice- shufﬂing steps and may have difﬁculty ris- able in one hand, is the most frequent ear- ing from a chair or bed. The difﬁcult to initiate or to stop voluntary tremor intensiﬁes when the hand rests in movements. While walking, for example, the lap (resting tremor) and diminishes they may experience gait hesitation and with voluntary movement. The tremor is suddenly “freeze,” taking seconds to re- not present during sleep, however. The impairment arms fail to swing with their stride when experienced with bradykinesia can inter- they are walking. The loss of postural re- fere with activities such as shaving, but- ﬂexes makes it difﬁcult for these individ- toning clothes, or cutting food, all of uals to maintain an upright position if they which take longer and become more difﬁ- are suddenly bumped, increasing the risk cult to perform as the disease progresses. To keep from falling, they may Because Parkinson’s disease affects both inadvertently quicken their steps as if to the central and autonomic nervous sys- “catch up” with their own center of grav- tems, some individuals may also experi- ity. They may blink less engage in voluntary movement, fatigue is frequently and may develop a masklike, also increased. They may develop dif- Mental and behavioral changes do not ﬁculty swallowing (dysphagia), which always occur as a result of Parkinson’s dis- results in saliva accumulation and drool- ease, but cognitive changes, as well as ing. Because the individual is unable to changes in emotions and behavior, can be swallow quickly, the rate of swallowing part of the symptoms. Dementia can also decreases and eating becomes slower and occur in some individuals later in the 96 CHAPTER 3 CONDITIONS OF THE NERVOUS SYSTEM: PART II course of the condition. Apathy, passivi- of a medication called levodopa (L-dopa) ty, depression, and loss of initiative may frequently decreases its symptoms. Some studies indicate that dopa works by helping to increase the lev- depression is present in a large number of el of the neurotransmitter dopamine in the individuals with Parkinson’s disease and brain. At ﬁrst, small amounts are usually can have more impact on quality of life prescribed, and the dosage is then gradu- than the symptoms of the condition or ally increased. As the individual becomes aware have serious side effects and limited long- of his or her decreasing cognitive abilities, term efﬁcacy (Jankovic, 1999; Janson, depression related to losses may result. Some individuals The degree to which depression reﬂects may experience side effects such as nau- physiologic changes rather than a reac- sea or abnormal involuntary movements tion to the disease itself is not known. Treatment, usually in causes mental confusion or decreases the form of medication, physical therapy, alertness.