Answers to work sheet free essay sample

Utilizing knowledge from your learning and assigned readings, respond to the following questions: 1. The maintenance of normal volume and composition of extracellular and intracellular fluids is vital to life. List and briefly describe the kinds of homeostasis involved. 2. Why does maintaining fluid balance in older people require a higher water intake than in a normal, healthy adult under age 40? 3. Why does potassium concentration rise in patients with acidosis? What is this called? What effects does it have? 4. Saline solution is used to reverse hypotonic hydration. Are body cell membranes permeable to saline? Explain your response. 5. Explain the renin-angiotensin mechanism. 6. Explain how ADH compensates for blood that contains too many solutes. Answers 1. Three types of homeostasis are involved: fluid balance, electrolyte balance, and acid-base balance. Fluid balance means that the total quantity of body water remains almost constant and that the distribution between the ICF and ECF are normal. Electrolyte balance implies the same thing for ions. We will write a custom essay sample on Answers to work sheet or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Acid-base balance means that the pH of the ECF is maintained in the range of 7. 35 to 7. 45, and that gains or losses of hydrogen ion as a consequence of metabolism are followed by equivalent losses or gains so as to maintain constant buffer reserves. 2. Maintaining adequate fluid balance is an essential component of health across the life span; older adults are more vulnerable to shifts in water balance, both over hydration and dehydration, because of age-related changes and increased likelihood that an older individual has several medical conditions. Dehydration is the more frequently occurring problem. 3. When pH is low, hydrogen ion levels in the blood are high and also in the interstitial and peritubular fluid. Hydrogen ion competes with potassium ion for the sodium countercurrent exchanger in the tubules. As hydrogen ion secretion rises (which compensates for the acidosis), potassium is retained and hyperkalemia develops. If severe enough, muscle cramps and cardiac arrhythmias result. 4. Water molecules can easily diffuse into or out of a cell passing through the cell membrane. This process is known as osmosis. A semipermeable membrane is a membrane that allows certain types of molecules to pass through but blocks others; which helps to control what substances can and cannot pass into the cells. By serving as a barrier between the interior and the exterior of the cell, it protects the cell from foreign bodies that could be harmful. 5. The RAAS plays a significant role in the blood vol. and BP. You have angiotensinogen which is an enzyme made by the liver it ciriculates and when there is a change to BV or BP the receptors in the Afferent arteriole pick it up and sense the change. Angiotensinogen is then converted to angiotensin I then it goes to the kidney where angio I is converted to angio II via ACE, and angio II stimulates aldosterone to retain Na and H2O thus increasing blood vol and bp. 6. Osmoreceptors in the hypothalamus react to changes in blood composition, such as less water and too many solutes. The posterior pituitary is alerted to releaseantidiuretic hormone (ADH) which travels through the blood to its target organ, the kidney. In the kidney, the collecting ducts respond to ADH by reabsorbing more water. As a result, more water returns to the blood while small amounts of concentrated urine are formed. ADH is released and additional water is reabsorbed from the filtrate until blood solute concentration returns to normal.