PHYSIOLOGY HELP PLEASE! 2. what would you expect when a subject drinks fluids th
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Question
PHYSIOLOGY HELP PLEASE!
2. what would you expect when a subject drinks fluids that are hypotonic, isotonic, and hypertonic? Explain
3. the loss of water during sweating on a hot day causes the blood volume to decrease and the osmolarity of body fluids to increase. Outline the mechanisms operating to restore homeostasis via the release of antidiuretic hormone ADH in this situation.
4. two symptoms present in a person with diabetes mellitus are hyperglycemia (elevated blood glucose) and diuresis (increased urine production). What causes this increase in urine output?
5. Transport of materials across membrances occurs by several processes, listed below. Where do we see these processes operating in the kidney? give one example of each transport process.
a) active transport
b) osmosis
c) filtration
d) diffusion
5. briefly describe the importance of the following to renal physiology and homeostasis:
a) juxtaglomerular apparatus
b) angiotensin II
c) atrial natriuretic hormone
Part 2:
1. Why would prolonged elevations of blood aldosterone produce hypertension?
2. Give two reasons why a person urinates more after a night a bar-hopping and drinking many beers.
3. During dialysis, the flow of blood and the flow of a hypotonic dialysis fluid move in opposite directions and are separated by a semipermeable membrane. Explain the following:
a) Why are the flows in opposite directions?
b) Why is the dialysis fluid hypotonic?
c) Why is a semipermeable membrane used to separate the blood and the dialysis fluid?
4. Some diuretics (drugs that increase the volume of urine produced) act by inhibiting the reabsorption of sodium in various parts of the nephron and thus reduce blood pressure. Using knowledge of diffusion and osmosis, as well as how urine is produced by the nephron, to explain how these diuretics work.
Explanation / Answer
2. Consumption of hypotonic drink quickly replaces the fluids lost by sweating. Consumption of isotonic drink also helps in replacement of fluids lost by sweat also replinishes the carbohydrate levels. Hypertonic drinks are consumed after strenuous exercise like longruns to replinish the energy by consuming carbohydrates and also to replace lost fluids. But, the hypertonic drinks are consumed in conjunction with isotonic drinks.
3. The loss of water during sweating on a hot day causes the blood volume to decrease and the osmolarity of body fluids to increase. The antidiuretic hormone (ADH) increases the reabsorption of sodium ions and water to restore the normal condition.
4. Osmotic diuresis is a condition of the increase of urination rate caused by certain substances in the small tubes of the kidneys (mostly glucose and ions). The substances such as glucose entering the kidney tubules cannot be reabsorbed. The substances increase the osmotic pressure within the renal tubules, resulting in retention of water within the lumen, and thereby reduce the water reabsorption increasing urine output, a condition known as diuresis. Substances in the circulation increase the amount of circulating fluid by increasing the osmolarity of the blood. This results in pulling water from the interstitial space by making more water available in the blood and causing the kidney to compensate through urination. This causes increase in blood pressure and the kidney removes the excess fluid as urine. The ions such as Sodium, chloride, potassium are excreted in Osmotic diuresis, caused by Diabetes Mellitus. Osmotic diuresis results in dehydration from polyuria or frequent urination and the polydipsia or excessive thirst.
5. Active transport in kidneys is observed in nephrons (proximal convoluted tube) PCT to reabsorb the substances like glucose, amino acids water and sodium etc. Osmosis or passive transport of solutes and ions is observed in glomerulus of kidney.
Filtration is the process of removal of waste materials retaining the organic and inorganic solutes and nutrients. Kidneys are the filtration organs that retain the ions, proteins and solutes removing all the waste. The filtration process occurs at various subparts in the kidney. The plasma filtration occurs at renal corpuscle where the proteins are retained. The remaining solution is said to be a filtrate..
Diffusion of ions is observed along the nephrons in both the proximal and distal convoluted tubules.
5 a. The juxta glomerular complex contains specialized cells for the secretion of renin that causes the decrease in the blood pressure in the glomerulus. The juxta gromerular complex is involved in the coordinating the responses to decrease the glomerular filtration rate (GFR). When the GFR is under the central regulation, integrated endocrine and neural mechanisms are stimulated. The endocrine response triggers the increased production of renin by juxta glomerular complex.
5b. Renin - angiotensin system regulates the hormone and bllod pressure systems. The reduction in the renal blood flow stimulate juxtaglomerular cells in the kidneys to convert the prorenin into renin and secrete it directly into the circulation. Plasma renin converts angiotensinogen released by the liver to angiotensin I. Angiotensin I is converted to angiotensin II by the enzyme angiotensin-converting enzyme . Angiotensin II is a peptide that causes constriction of blood vessels thereby increasing blood pressure. Angiotensin II stimulates the production of the aldosterone hormone from the adrenal cortex. Aldosterone enhances reabsorption of sodium and water by kidney tubules into the blood, and excretes potassium maintaining electrochemical balance. This causes increase in the volume of extracellular fluid in the body, which also increases blood pressure.
5c. Atrial natriuretic hormone is a vasodilator peptide hormone produced in the heart muscle. It causes decrease in the blood pressure by increasing the blood volume and reduces the water, sodium on the circulatory system, thereby acting opposite to the aldosterone hormone produced in the kidneys. The aldosterone encourages the retention of sodium levels where as, Atrial natriuretic hormone promotes sodium loss.
Part 2
1. Prolonged aldosterone levels cause retention of sodium by kidneys causing the increase in the blood pressure.
2. Alcohol content of the beer consumed decreases the reabsorption the water levels by kidneys due to reduced production of vasopressin that controls the signalling of urination to urethra. The loss of signalling fills the bladder frequently and causes urination.
3a. The flow of blood would be enriched with solutes and ions and is hypertonic. The hypotonic dialysis fluid does not contain that much of solutes and ions as blood. The difference in solute concentration make them move in opposite directions across the semi permeable membrane.
3b. Dialysis fluid is hypotonic because it is used for the removal of concentrated solutes from the kidney which contains high concentrations of solutes.
3c. A semipermeable membrane selectively and specifically allows the movement of ions between blood and dialysis fluid across the concentration gradiant.
4. The diuretics work by reabsroption of sodium from proximal and ditstal converted tubules of nephrons and decrease the water retention causing decrease in the blood pressure. The movement of solutes in counter current multiplication between the proximal and distal tubules increase the urine volume and cause excess urination.
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