By S. Zakosh. University of the Pacific.
Psychological Issues Disorders of the blood and immune sys- Transfusion tem have a variety of psychological impli- cations discount precose 25mg overnight delivery diabetic diet 50 carbs. The speciﬁc implications for a Part of the treatment for a number of particular individual are dependent on the blood disorders may be the transfusion of condition generic 25mg precose with amex diabetes test empty stomach. Some conditions may be con- whole blood or a blood component, such as trolled relatively easily, whereas others re- packed red blood cells, plasma, or plate- quire constant vigilance. Because blood is living tissue, trans- conditions may be treated and, in some in- fusion can be thought of as a form of stances, cured, others require lifelong treat- transplantation, carrying the same risks of ment and carry a more ominous prognosis. For this reason, the exact the blood and immune system generally matching of a number of factors in the have no visible reminders of their disabil- blood between the donor and the re- ity. Without external adaptive devices, cipient is crucial to prevent serious aller- such as wheelchairs, crutches, or canes, or gic reactions, which could be fatal. In any other signs of disability, individuals addition to the risk of such a reaction, may react by denying the seriousness of there is a risk that a blood transfusion will their condition and resist medical direc- transmit a disease, such as hepatitis or tives. For example, individuals with hemo- HIV, although careful screening by philia may engage in risk-taking behaviors, blood banks has signiﬁcantly reduced even though injury and subsequent bleed- this risk. Individuals with sickle Psychosocial Issues in Conditions Affecting the Blood or Immune System 253 cell anemia may engage in a ﬂurry of ac- variety of ways, ranging from the adop- tivity, even though the associated stress tion of a philosophical view toward life to and fatigue may precipitate a sickle cell passivity and withdrawal. Individuals with HIV infection may The way in which individuals cope with withhold their diagnosis from others with a condition they have had since child- whom they engage in sexual activity, even hood depends on a wide variety of factors, though their behavior could put those some of which relate to the coping mech- others at risk. Individuals’ Some disorders occur later in life, neces- reaction as an adult to their condition is sitating adjustment at the time the disabil- dependent to some extent on how well ity occurs. Disorders such as sickle cell their psychological adjustment was man- anemia and hemophilia are lifelong disor- aged throughout development. Consequently, individuals who were encouraged to live as normal a with these disorders have had to cope life as possible, despite their condition, with their condition in one way or anoth- may exhibit a greater sense of self-esteem er from childhood into adulthood, and and autonomy as adults than do those most of them have experienced frequent who were kept in a dependent, overpro- illness and medical care throughout their tected state. Although these experiences can build conﬁdence in Lifestyle Issues the ability to cope with adversity, they can also have a negative impact on develop- Different conditions affecting the blood ment. Individuals may carry the coping or immune system affect activities of dai- behaviors and attitudes learned in child- ly living in varying degrees, depending on hood into the adult years, where they con- the associated symptoms. Symptoms of tinue to affect their perception of them- fatigue or difﬁculty in breathing with exer- selves, their condition, and their abilities. Although hemophilia can everyone; however, because of the in- be controlled to some degree, there is creased susceptibility to infection that is always the fear that an accident or trau- part of many conditions affecting the matic event may occur in which bleeding blood or immune system (especially HIV may not be controlled. Individuals with infection), individuals must take extra care sickle cell anemia are aware of the possi- to have well-balanced diets and well-bal- bility that sudden death will occur as a anced regimens of rest and activity. Exer- result of a sickle cell crisis or complica- cise is especially important to individuals tions. Regular, moderate exer- know that their progression to AIDS will cise can build the muscles that protect probably result in death. Individuals may joints and decrease the incidence of cope with the threat of early death in a bleeding into the joints. However, activi- 254 CHAPTER 8 CONDITIONS OF THE BLOOD AND IMMUNE SYSTEM ties that carry a higher probability of in- continuing medical care. Because these jury, such as contact sports, should be individuals do not appear to be legitimate- avoided. For the Conditions that are hereditary and those most part, individuals with hemophilia that occur in childhood can impair the need not interrupt their daily schedules. Recurrent hospitalizations may greatly reduced their incapacity by provid- affect children’s school performance and, ing prompt and early treatment of spon- consequently, their sense of industry and taneous bleeding. In addition, frequent school Although neither hemophilia nor sick- absences, hospitalizations, or the inabili- le cell anemia alters sexual function, both ty to engage in some activities may affect are inherited disorders, and individuals children’s interactions and relationships may wish to consider genetic counseling with peers, which, in turn, could affect before deciding to have children. The parents of a child with an inher- partners about their diagnosis prior to sex- ited disorder, such as hemophilia or sick- ual contact and should engage only in safe le cell anemia, may experience guilt, react sexual practices. When women with HIV with overprotectiveness, or foster a sense infection become pregnant, the child of dependency in the child. They may also excuse the child from the normal responsibilities The social effects of conditions affecting or the limits established for the child’s sib- the blood or immune system vary with lings. Such parental reactions can impede the condition, the individual, and the par- the child’s ability to function adequately ticular circumstances.
This leads to a Equilibrium and steady state are sometimes confused further reduction in cardiac pumping ability cheap precose 50mg fast delivery blood sugar vs blood glucose, even less with each other buy generic precose 50 mg on line diabetes type 2 pancreas. A steady state is simply a condition that coronary blood flow, and further deterioration of cardiac does not change with time. The physician’s task is sometimes to interrupt or concentration of a substance in a compartment is constant. In a steady state, there is no net gain or net loss of a sub- stance in a compartment. Steady state and equilibrium both suggest stable conditions, but a steady state does not nec- Steady State and Equilibrium Are Separate Ideas essarily indicate an equilibrium condition, and energy ex- Physiology often involves the study of exchanges of matter penditure may be required to maintain a steady state. For or energy between different defined spaces or compart- example, in most body cells, there is a steady state for Na ments, separated by some type of limiting structure or ions; the amounts of Na entering and leaving cells per unit membrane. But intracellular and extracellular Na ion compartments: extracellular fluid and intracellular fluid. Extracellular These two compartments are separated by cell plasma mem- [Na ] is much higher than intracellular [Na ], and Na branes. The extracellular fluid consists of all the body fluids tends to move into cells down concentration and electrical outside of cells and includes the interstitial fluid, lymph, gradients. The cell continuously uses metabolic energy to blood plasma, and specialized fluids, such as cerebrospinal pump Na out of the cell to maintain the cell in a steady fluid. In living systems, conditions Ordinary extracellular fluid is subdivided into interstitial are often displaced from equilibrium by the constant ex- fluid—lymph and plasma; these fluid compartments are sep- penditure of metabolic energy. If we were to increase the rate of in- flow (open the tap), the fluid level would rise, and with time, a new steady state might be established at a higher level. Note that the term steady state can Autocrine Paracrine apply to a single or several compartments; the term equi- Receptor librium describes the relation between at least two adjacent compartments that can exchange matter or energy with each other. Coordinated Body Activity Requires Integration of Many Systems Nervous Target cell Body functions can be analyzed in terms of several sys- tems, such as the nervous, muscular, cardiovascular, res- piratory, renal, gastrointestinal, and endocrine systems. Neuron Synapse These divisions are rather arbitrary, however, and all systems interact and depend on each other. The nerv- ous system coordinates the movements of the limbs and Endocrine body, stimulates the muscles to contract, and senses Endocrine cell Target cell muscle tension and limb position. The cardiovascular system supplies blood to the muscles, providing for Blood- stream nourishment and the removal of metabolic wastes and heat. The gastrointestinal system Neuroendocrine Target cell supplies energy-yielding metabolites. The endocrine system helps adjust blood flow and the supply of various metabolic substrates to the working muscles. Coordi- Blood- nated body activity demands the integration of many stream systems. Recent research demonstrates that many diseases can be explained on the basis of abnormal function at the molecu- FIGURE 1. This reductionist approach has led to incredible communicate with each other directly via gap advances in our knowledge of both normal and abnormal junctions or chemical messengers. With autocrine and paracrine signaling, a chemical messenger diffuses a short distance through function. Diseases occur within the context of a whole or- the extracellular fluid and binds to a receptor on the same cell or ganism, however, and it is important to understand how all a nearby cell. Nervous signaling involves the rapid transmission of cells, tissues, organs, and organ systems respond to a dis- action potentials, often over long distances, and the release of a turbance (disease process) and interact. Endocrine signaling involves the whole is more than the sum of its parts,” certainly applies to release of a hormone into the bloodstream and the binding of the what happens in living organisms. Neuroendocrine signal- ogy has the unique challenge of trying to make sense of the ing involves the release of a hormone from a nerve cell and the complex interactions that occur in the body. Understand- transport of the hormone by the blood to a distant target cell.
The TF SNGFR can be measured from the single nephron inulin clear- Amino acids ˙ Glucose ance and is equal to TFIN VTF/PIN precose 25 mg with amex diabetes drugs online. From these relations: 0 0 20 40 60 80 100 % of filtered water [1 1/(TFIN/PIN)] 100 (11) % Proximal tubule length Figure 23 order precose 50 mg without prescription metabolic disease zombie. All values start at a ratio of 1, ulin is freely filterable), so the concentration ratio starts at 1. Na+ + This is evidence that Na can be reabsorbed against a con- ATP Na centration gradient and is an active process. The fall in ADP + Pi + Glucose, K proximal tubular fluid [Na ] increases diffusion of Na K+ amino acids, Solute into the tubule lumen and results in reduced net Na and phosphate + + water reabsorption, leading to increased excretion of Na Na H2O and water, an osmotic diuresis. Glucose, Two major anions, Cl and HCO3 , accompany Na + + amino acids, in plasma and glomerular filtrate. HCO3 is preferentially H K phosphate reabsorbed along the proximal convoluted tubule, leading Base- Cl- to a fall in tubular fluid [HCO3 ], mainly because of H Na+ secretion (see Chapter 25). The Cl lags behind; as water - Cl- 3HCO is reabsorbed, [Cl ] rises (see Fig. The result is a tu- 3 bular fluid-to-plasma concentration gradient that favors H2O H2O Cl diffusion out of the tubule lumen. Outward movement of Cl in the late proximal convoluted tubule creates a Apical small (1–2 mV), lumen-positive transepithelial potential cell Tight Lateral difference that favors the passive reabsorption of Na. If K were not reabsorbed, its concentration would increase as much as that of inulin. 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.