Exam 4 Review Questions
What are the effects of caffeine and alcohol consumption on the urinary system and urine output? Why?
Primarily, there is concern that both substances cause diuresis resulting in increased urine output and subsequent dehydration. Alcohol consumption may lead to impaired judgment and the inability to adopt cooling behaviors.
If the urinary excretion rate of a drug such as penicillin is greater than the rate at which it is filtered at the glomerulus, how else is it getting into the urine?
tubular secretion
Why are nucleic acids seldom catabolized for energy?
Nucleic acids are a type of macromolecules that make up the genetic material. This is their main function. Unlike the other three macromolecules (carbohydrates, lipids, and proteins), nucleic acids are not used for energy production; therefore, the results stated in this question don't seem valid.
Describe the vessels through which blood passes from its entrance into the kidney to its exit from the kidney.
Oxygenated blood comes to the kidneys from the right and left renal arteries off the abdominal aorta. Deoxygenated blood leaves the kidneys via the right and left renal veins that run into to the inferior vena cava.
What is a fluid shift?
Rapid shifts between ECF and ICF (response to osmotic gradient). If ECF osmotic concentration increases, fluid becomes hypertonic to ICF and water moves from cells to ECF. If osmotic pressure in ECF decreases fluid becomes hypotonic to ICF moves water from ECF to cells ICF volume is greater than ECF volumes. ICF acts as a water reseve, prevents large osmotic changes in ECF.
What effect would drinking a pitcher of distilled water have on your level of ADH?
Secretion of ADH increases. Secretion of ADH decreases. Increased ADH secretion prompts secretion of renin in the kidney.
Differentiate between sensible and insensible perspiration.
Sensible is produced by merocrine or eccrine sweat glands. It is clear and basically it is sweat. Insensible perspiration is not from glands.
What happens when the temperature at the preoptic nucleus of the hypothalamus exceeds its thermostat setting?
When the temperature of the preoptic area of the hypothalamus exceeds its thermostat setting, a. peripheral vasoconstriction occurs.
How would increased urinary loss of sodium affect the ECF volume?
when the ECF volume is excessive, the body increases urinary sodium excretion and hopes that the individual will not eat incredible amounts of salt. In this way, the body can exert control of the total amont of sodium in the ECF by modulating urinary sodium excretion.
How do angiotensin II, aldosterone, atrial natriuretic peptide, and antidiuretic hormone regulate the volume and osmolarity of body fluids?
- Angiotensin II+ stimulates secretion of aldosterone= reduces loss of water in urine- Aldosterone+ by promoting urinary reabsorption of Na and Cl, increases water reabsorption via osmosis= reduces loss of water in urine- Atrial natriuretic peptide (ANP)+ promotes natriuresis, elevated urinary excretion of Na and Cl accompanied by H20= increases loss of water in urine- Antidiuretic hormone (ADH), also known as vasopressin+ promotes insertion of water-channel proteins (aquaporin 2) into apical membranes of principal cells in collecting ducts of kidneys. As a result water permeability of these cells increases and more H20 is reabsorbed= reduces loss of water in urine
Why do cells perform anabolic reactions? (four reasons)
Anabolic reactions, or biosynthetic reactions, synthesize larger molecules from smaller constituent parts, using ATP as the energy source for these reactions. Anabolic reactions build bone, muscle mass, and new proteins, fats, and nucleic acids.
Differentiate between catabolism and anabolism.
Catabolism the breakdown of complex molecules in living organisms to form simpler ones, together with the release of energy; destructive metabolism. Anabolism the synthesis of complex molecules in living organisms from simpler ones together with the storage of energy; constructive metabolism.
LasixTM is a diuretic that acts by decreasing the amounts of sodium and chloride ions actively transported by the ascending limb of the loop of Henle. Why would this medication be given to someone with high blood pressure?
Loop diuretics block the Na+-K+-2Cl− cotransporter in the thick ascending limb of Henle loop, where 25% of the NaCl filtered load is usually reabsorbed. They are consequently highly effective because only a small proportion of the filtered Na+ that escapes reabsorption in the loop can be reabsorbed downstream
Define thermoregulation. Why is it so important?
Thermoregulation is a process that allows your body to maintain its core internal temperature. All thermoregulation mechanisms are designed to return your body to homeostasis. This is a state of equilibrium. A healthy internal body temperature falls within a narrow window. Your body uses energy to maintain its core temperature. You take control when you make the effort to stabilize that temperature during your game. Thermoregulation allows you to preserve your optimal body temperature, so you deliver the best performance and stay safe at the same time.
Why are potassium imbalances more dangerous than sodium imbalances?
A deficiency of aldosterone in particular causes the body to excrete large amounts of sodium and retain potassium, leading to low levels of sodium and high levels of potassium in the blood.
What effect would a high-protein diet have on the composition of urine?
A high intake of animal protein has been linked with an increase in urinary excretion of calcium as well as a reduction of both, urinary pH and excretion of citric acid, biochemical changes, that markedly increase the risk of calcium oxalate stone formation
Define acidosis and alkalosis. Distinguish between respiratory and metabolic acidosis and alkalosis.
Acidosis refers to an excess of acid in the blood that causes the pH to fall below 7.35, and alkalosis refers to an excess of base in the blood that causes the pH to rise above 7.45. Respiratory acid-base disorders are commonly due to lung diseases or conditions that affect normal breathing. Disorders that affect metabolism and cause changes in pH due to either increased acid production or decreased base are called metabolic acidosis (low pH) and metabolic alkalosis (high pH).
What is the role of the protein component (Apoprotein) of the lipoprotein?
Apolipoproteins are proteins that bind lipids (oil-soluble substances such as fat and cholesterol) to form lipoproteins. They transport lipids (and fat soluble vitamins) in blood, cerebrospinal fluid and lymph. The lipid components of lipoproteins are insoluble in water.
Differentiate between aerobic and anaerobic metabolism, and give an example of a cellular pathway of each type.
As we touched on, the main difference between aerobic and anaerobic respiration is whether or not oxygen is present. Aerobic respiration needs oxygen to occur, while anaerobic does not. This presence of oxygen determines what products will be created.
How are infants different from adults in terms of thermoregulation?
Babies can't adjust to temperature changes as well as adults. Babies can lose heat rapidly, nearly 4 times faster than an adult. Premature and low-birthweight babies don't have much body fat. Their bodies may not be ready to control their own temperature, even in a warm environment.
Mannitol is a sugar that is filtered but not reabsorbed by the kidneys. What effect would drinking a solution of mannitol have on the volume of urine produced?
Because mannitol is filtered but not reabsorbed, drinking a mannitol solution would lead to an increase in the osmolarity of the filtrate. Less water would be reabsorbed, and an increase volume of urine would be produced
Physicians often ask for urine samples collected over a 24-hour period rather than a single sample. Why?
Because the content of the urine changes throughout the day, a specific component of the urine may not be present in a particular urine collection.
What effect would being in the desert without water for a day have on your plasma osmotic concentration?
Being in the desert without water, you would lose fluid through perspiration, urine formation, and respiration. As a result, the osmotic concentration of your plasma (and other body fluids) would increase.
What is body fluid? What are the approximate percentage distributions of body fluids?
Body fluids are liquids originating from inside the bodies of living humans. They include fluids that are excreted or secreted from the body. Human blood, body fluids, and other body tissues are widely recognised as vehicles for the transmission of human disease. Most of the human body is water, with an average of roughly 60%. The amount of water in the body changes slightly with age, sex, and hydration levels. While the average percentage of water in a person's body is around 60%, the percentage can vary from roughly 45-75%.
Compare the density and composition (types of lipid) of chylomicrons, VLDL, IDL, LDL and HDL.
Chylomicrons are the largest of lipoproteins, formed in the intestinal wall following fat absorption, and they contain mostly triglycerides VLDL-VLDL stands for very-low-density lipoprotein. Your liver makes VLDL and releases it into your bloodstream. The VLDL particles mainly carry triglycerides, another type of fat, to your tissues. IDL-The triglycerides in VLDL are removed in capillaries by the enzyme lipoprotein lipase, and the VLDL returns to the circulation as a smaller particle with a new name, intermediate-density lipoprotein (IDL). LDL- LDL (low-density lipoprotein), sometimes called "bad" cholesterol, makes up most of your body's cholesterol. High levels of LDL cholesterol raise your risk for heart disease and stroke. HDL-HDL stands for high-density lipoproteins. It is sometimes called the "good" cholesterol because it carries cholesterol from other parts of your body back to your liver. Your liver then removes the cholesterol from your body. LDL stands for low-density lipoproteins.
Why are the renal plasma clearances of glucose, urea, and creatinine different? How does each clearance compare to the GFR?
Creatinine Clearance ( CrCl ) versus Glomerular Filtration Rate ( GFR ) Creatinine clearance ( CrCl ) is an estimate of Glomerular Filtration Rate ( GFR ); however, CrCl is slightly higher than true GFR because creatinine is secreted by the proximal tubule (in addition to being filtered by the glomerulus).
Damage to which part of the nephron would interfere with the control of blood pressure?
Damage to the juxtaglomerular complex of the nephron would interfere with the hormonal control of blood pressure. Identify the three distinct processes of urine formation in the kidney.
What is ketoacidosis, and when does it usually occur?
Diabetic ketoacidosis is a serious complication of diabetes that occurs when your body produces high levels of blood acids called ketones. The condition develops when your body can't produce enough insulin.
In what order do cells normally prefer to break nutrients down for the generation of energy?
Digestion happens in the mouth, stomach, small intestine, and large intestine. Proteins are broken down into amino acids, lipids are broken down into fatty acids, carbohydrates are broken down into sugars, and DNA is broken down into nucleotides.
Which part of the filtration membrane prevents RBCs from entering the capsular space?
Endothelial fenestrations (pores) in glomerular capillaries prevent red blood cells from entering the capsular space because they are too small for red blood cells to pass through.
What are the essential fatty acids? Why are they considered "essential"?
Essential fatty acids, or EFAs, are fatty acids that humans and other animals must ingest because the body requires them for good health but cannot synthesize them. The term "essential fatty acid" refers to fatty acids required for biological processes but does not include the fats that only act as fuel.
Why is reducing dietary intake of cholesterol insufficient in some people to reduce blood cholesterol levels?
Even though dietary cholesterol modestly increases LDL in these individuals, it does not seem to increase their risk of heart disease ( 15 , 16 ). This is because the general increase in LDL particles typically reflects an increase in large LDL particles — not small, dense LDL.
Why are the lipids in chylomicrons considered to be "exogenous"?
Exogenous pathway for lipid metabolism: Dietary cholesterol and fatty acids are absorbed. ... In peripheral tissues, free fatty acids are released from the chylomicrons to be used as energy, converted to triglyceride or stored in adipose. Remnants are used in the formation of HDL.
Differentiate among fluid balance, electrolyte balance and acid-base balance, and explain why each is important to homeostasis.
Fluid balance is a state in which the amount of water gained each day is equal to the amount lost to the environment. It is vital that the water content of the body remain stable, because water is an essential ingredient of cytoplasm and accounts for about 99 percent of ECF volume. Electrolyte balance exists when there is neither a net gain nor a net loss of any ion in body fluids. It is important that the ionic concentrations in body water remain within normal limits; if levels of calcium or potassium become too high, for instance, cardiac arrhythmias can develop. Acid-base balance exists when the production of hydrogen ions precisely offsets their loss.
How does blood pressure promote filtration of blood in the kidneys?
Glomerular blood hydrostatic pressure (GBHP) promotes filtration - it pushes water and solutes in blood plasma through the glomerular filter. GBHP is the blood pressure in glomerular capillaries, which is about 55mm Hg.
Explain the control of the GFR.
Glomerular filtration is occurs due to the pressure gradient in the glomerulus. Increased blood volume and increased blood pressure will increase GFR. Constriction in the afferent arterioles going into the glomerulus and dilation of the efferent arterioles coming out of the glomerulus will decrease GFR.
Define gluconeogenesis, and explain the significance of this pathway.
Gluconeogenesis is the metabolic process by which organisms produce sugars (namely glucose) for catabolic reactions from non-carbohydrate precursors. Glucose is the only energy source used by the brain (with the exception of ketone bodies during times of fasting), testes, erythrocytes, and kidney medulla. Gluconeogenesis is a pathway used by the body to create glucose from other molecules and an important pathway that allows the body to store needed energy for the brain in the form of glucose. It is essentially glycolysis, which is the process of converting glucose into energy, in reverse.
What is glycogen, and what is its significance in metabolism?
Glycogen a substance deposited in bodily tissues as a store of carbohydrates. It is a polysaccharide which forms glucose on hydrolysis. Glycogen's role in maintaining blood-glucose levels is especially important because glucose is virtually the only fuel used by the brain, except during prolonged starvation. Moreover, the glucose from glycogen is readily mobilized and is therefore a good source of energy for sudden, strenuous activity.
What is glycolysis (general terms only), and what is its significance in metabolism? How much ATP is generated in this pathway? Where does it take place?
Glycolysis the breakdown of glucose by enzymes, releasing energy and pyruvate acid. Search Results Featured snippet from the web The essential metabolic pathway of glycolysis involves the oxidative breakdown of one glucose into two pyruvate with the capture of some energy as ATP and NADH. Glycolysis is important in the cell because glucose is the main source of fuel for tissues in the body. 2 ATP and it takes place in the cytoplasm
What factors control the movement of water between interstitial fluid and intracellular fluid?
Hydrostatic pressure, the force exerted by a fluid against a wall, causes movement of fluid between compartments. The hydrostatic pressure of blood is the pressure exerted by blood against the walls of the blood vessels by the pumping action of the heart.
Which has more of an effect on cells - a shortage of glucose or oxygen? Why?
If oxygen is present, then glucose can be broken all the way down into carbon dioxide and water. This process is called aerobic respiration because it requires air (oxygen). In the absence of oxygen, the cell uses a process called anaerobic fermentation. or simply fermentation.
How does urea recycling contribute to the production of concentrated urine?
In the inner medullary collecting ducts it increases both water and urea permeability, which allows urea to flow passively down its concentration gradient into the interstitial fluid. This adds to the osmotic gradient and helps drive water reabsorption.
What effect would increased amounts of aldosterone have on the K+ concentration of urine?
Increased amounts of aldosterone, which promotes Na+ retention and K+ secretion at the kidneys, would elevate the K+ concentration of urine.
Why are the lipids in the other lipoproteins considered to be "endogenous"?
It is divided into two pathways, exogenous and endogenous, depending in large part on whether the lipoprotein particles in question are composed chiefly of dietary (exogenous) lipids or whether they originated in the liver (endogenous), through de novo synthesis of triacylglycerols
Why is LDL cholesterol considered to be "bad" cholesterol, and HDL considered to be "good"?
It is sometimes called the "bad" cholesterol because a high LDL level leads to a buildup of cholesterol in your arteries. HDL stands for high-density lipoproteins. It is sometimes called the "good" cholesterol because it carries cholesterol from other parts of your body back to your liver.
How would eating a meal high in salt affect the amount of fluid in the ICF?
It would cause a reduction of fluid in the ICF; the ingested salt would temporarily increase the osmolarity of the ECF, so water would shift from the ICF to the ECF
What conditions cause the production of ketones? What is their purpose? Name the three ketones.
Ketones and ketoacids are alternative fuels for the body that are made when glucose is in short supply. They are made in the liver from the breakdown of fats. Ketones are formed when there is not enough sugar or glucose to supply the body's fuel needs. This occurs overnight, and during dieting or fasting. There are three endogenous ketone bodies: acetone, acetoacetic acid, and (R)-3-hydroxybutyric acid; others may be produced as a result of the metabolism of synthetic triglycerides.
What are the physiological functions of Magnesium?
Magnesium is a cofactor in >300 enzymatic reactions and thus it is essential for many crucial physiological functions, such as heart rhythm, vascular tone, nerve function and muscle contraction and relaxation. Magnesium is also needed for bone formation and can also be referred to as a natural 'calcium antagonist'.
Which solutes are the main contributors to the high osmolarity of interstitial fluid in the renal medulla?
Mechanism of urine concentration in long-loop juxtamedullary nephrons: Which solutes are the main contributors to the high osmolarity of interstitial fluid in the renal medulla? Na+, Cl-, and urea.
Differentiate between sensible and insensible water loss, and give examples of each.
Sensible" loss is loss that can be perceived by the senses and can be measured. If you've lost it, you know you've lost it! "Insensible" losses can neither be perceived nor measured directly. You've lost it, but you don't know that you've lost it (and, of course, you do not know how much you have lost
What is the mechanism in the distal convoluted tubule and collecting duct for reabsorption of Na+?
Sodium and potassium levels are controlled by secreting K+ and absorbing Na+. Sodium absorption by the distal tubule is mediated by the hormone aldosterone. Aldosterone increases sodium reabsorption. Sodium and chloride (salt) reabsorption is also mediated by a group of kinases called WNK kinases.
Would the level of ADH in the blood be higher or lower than normal in a person who has just completed a 5 km run without drinking any water?
The blood level of ADH would be higher than normal after a 5km run, due to loss of body water in sweat, since ADH is anti-diuretic and the person is trying to conserve as much water as possible.
Why should cholesterol not be eliminated from the diet completely?
The bottom line. High blood cholesterol levels are a risk factor for heart disease. However, dietary cholesterol has little to no effect on blood cholesterol levels in most people. More importantly, there is no significant link between the cholesterol you eat and your risk of heart disease.
When will cells break down proteins for energy generation? Why?
The breakdown processes must act on food taken in from outside, but not on the macromolecules inside our own cells.
Explain how each of the following buffer systems helps to maintain the pH of body fluids: proteins, carbonic acid-bicarbonate and phosphates.
The buffer systems functioning in blood plasma include plasma proteins, phosphate, and bicarbonate and carbonic acid buffers. The kidneys help control acid-base balance by excreting hydrogen ions and generating bicarbonate that helps maintain blood plasma pH within a normal range
What is the countercurrent mechanism? Why is it important?
The counter-current multiplier or the countercurrent mechanism is used to concentrate urine in the kidneys by the nephrons of the human excretory system. The nephrons involved in the formation of concentrated urine extend all the way from the cortex of the kidney to the medulla and are accompanied by vasa recta.
What is the electron transport system (general terms only), and what is its significance in metabolism? How much ATP is generated in this pathway? Where does it take place?
The electron transport chain (Figure 1) is the last component of aerobic respiration and is the only part of glucose metabolism that uses atmospheric oxygen. Oxygen continuously diffuses into plants; in animals, it enters the body through the respiratory system. 32 ATP and takes place in the mitochondrial membrane
What occurs when the plasma concentration of a substance exceeds its tubular maximum? What does this have to do with the concept of renal threshold?
The excess is not reabsorbed, so it is excreted in the urine.
What is obligatory water reabsorption, and in which parts of the nephron does it occur?
The first part of the nephron that is responsible for water reabsorption is the proximal convoluted tubule. Filtered fluid enters the proximal tubule from Bowman's capsule. Many substances that the body needs, which may have been filtered out of the blood at the glomerulus, are reabsorbed into the body in this segment.
Which force draws water out of the loop of Henle and into the interstitial fluid or the renal medulla?
The first part of the nephron that is responsible for water reabsorption is the proximal convoluted tubule. Filtered fluid enters the proximal tubule from Bowman's capsule. Many substances that the body needs, which may have been filtered out of the blood at the glomerulus, are reabsorbed into the body in this segment.
Why does the intake of other lipids (like triacylglycerides) also have to be reduced in order to decrease blood cholesterol levels?
The first ways to reduce your lipid levels are (1) eat less fat, (2) exercise regularly and (3) lose weight if you weigh too much. If you smoke, stop smoking. If these steps don't lower your LDL level enough, your doctor may have you take medicine to take the fat out of your blood.
What are the major parts of the nephron, and what are their general functions?
The glomerulus is the site in the nephron where fluid and solutes are filtered out of the blood to form a glomerular filtrate. The proximal and distal tubules, the loop of Henle, and the collecting ducts are sites for the reabsorption of water and ions.
Where is the juxtaglomerular apparatus located, and what are its functions?
The juxtaglomerular apparatus is a specialized structure formed by the distal convoluted tubule and the glomerular afferent arteriole. It is located near the vascular pole of the glomerulus and its main function is to regulate blood pressure and the filtration rate of the glomerulus.
Discuss the factors that regulate calcium concentration in the ECF.
The kidney has been known as the central organ for calcium homeostasis through fine regulation of renal calcium excretion. Extracellular calcium ion concentration is tightly regulated through the actions of parathyroid hormone (PTH) on kidney and bone. The intact peptide is secreted from the parathyroid glands at a rate that is appropriate to, and dependent upon the prevailing extracellular calcium ion concentration.
How are the waste products urea, ammonia and creatinine removed from the blood? In which part of the nephron does this occur?
The kidneys remove urea from the blood through tiny filtering units called nephrons. Each nephron consists of a ball formed of small blood capillaries (glomerulus) and a small tube called a renal tubule.
Which organs constitute the urinary system?
The kidneys, ureters, urinary bladder, and urethra are the components of the urinary system.
Why can't lipid stores provide large amounts of ATP in a short period of time? When is the catabolism of lipids optimal?
The main type of fat we consume, triglycerides are especially suited for energy storage because they pack more than twice as much energy as carbohydrates or proteins. Regulation of lipid metabolism by leptin, insulin and adiponectin. Insulin and leptin are secreted in direct proportion, and adiponectin in negative proportion, to the size of the adipose mass. These three hormones are key molecules in the regulation of lipid metabolism.
What are the two fluid compartments? Which compartment is monitored and adjusted in order to maintain homeostasis?
The major body-fluid compartments includ: intracellular fluid and extracellular fluid (plasma, interstitial fluid, and transcellular fluid). The best known homeostatic mechanisms in humans and other mammals are regulators that keep the composition of the extracellular fluid (or the "internal environment") constant, especially with regard to the temperature, pH, osmolality, and the concentrations of sodium, potassium, glucose, carbon dioxide, and oxygen.
What are the basic differences between cortical and juxtamedullary nephrons?
The major difference between cortical nephrons and juxtamedullary nephrons are the length of the loops of Henle. In cortical nephrons, the glomeruli, proximal and distal convoluting ducts, and loops of Henle stay limited to the cortex. In juxtamedullary nephrons, they extend into the medulla.
How is Na+ reabsorbed in the proximal convoluted tubule? Which other solutes are reabsorbed or secreted with Na+ in each mechanism?
The majority (70%) of sodium is reabsorbed in the proximal tubule. It is reabsorbed into the cytosol of the epithelial cells either alone by diffusion through ion channels followed by water and chloride or together with another product such as glucose or AA using a co-transporter by secondary active co-transport.
In which part of the nephron does the most reabsorption of water occur? Which part of the nephron is unable to reabsorb water?
The majority of water reabsorption that occurs in the nephron is facilitated by the AQPs. Most of the fluid that is filtered at the glomerulus is then reabsorbed in the proximal tubule and the descending limb of the loop of Henle.
Why does the tubular fluid become more dilute as it travels through the loop of Henle?
The medullary ascending limb is largely impermeable to water. Sodium (Na+), potassium (K+) and chloride (Cl−) ions are reabsorbed by active transport. ... This drives more paracellular reabsorption of Na+, as well as other cations such as magnesium (Mg2+) and importantly calcium Ca2+ due to charge repulsion.
What is the functional unit of renal anatomy?
The nephron is the functional unit of the kidney. The glomerulus and convoluted tubules of the nephron are located in the cortex of the kidney, while the collecting ducts are located in the pyramids of the kidney's medulla.
Suppose a tumor is pressing on and obstructing the right ureter. What effect might this have on capsular hydrostatic pressure and thus on net filtration pressure in the right kidney? Would the left kidney also be affected?
The net filtration pressure is determined by the balance of the Starling forces (the hydrostatic pressure and the oncotic pressure within the glomerular capillaries and Bowman's capsule).
What happens when the temperature at the preoptic nucleus of the hypothalamus drops below acceptable levels?
The posterior hypothalamic nucleus and mammillary nuclei are its main nuclei. The posterior hypothalamic nucleus helps regulate body temperature by causing shivering and blocking sweat production. The role of the mammillary nuclei is less clear.
What factors regulate the movement of fluid between the vasculature (plasma) and the tissues (interstitial fluid)?
The primary force driving fluid transport between the capillaries and tissues is hydrostatic pressure, which can be defined as the pressure of any fluid enclosed in a space. Blood hydrostatic pressure is the force exerted by the blood confined within blood vessels or heart chambers.
How does filtered glucose enter and leave a proximal convoluted tubule cell?
The proximal convoluted tubule avidly reabsorbs filtered glucose into the peritubular capillaries so that it is all reabsorbed by the end of the proximal tubule. ... Mannitol is freely filtered by the kidney but neither secreted nor reabsorbed.
How is IDL converted into LDL?
The remaining lipid portion is called IDL. IDL is then converted to LDL by enzymatic action of hepatic lipase or is taken up by the liver via the LDL receptor. LDL particles carry the majority of the cholesterol in the blood, supplying cholesterol to the cells.
How do respiratory and renal mechanisms support the buffer systems?
The respiratory tract can adjust the blood pH upward in minutes by exhaling CO2 from the body. The kidneys help control acid-base balance by excreting hydrogen ions and generating bicarbonate that helps maintain blood plasma pH within a normal range. Protein buffer systems work predominantly inside cells.
A water molecule has just entered the Bowman's capsule. Which parts of the nephron will it travel through in order to reach the renal pelvis in a drop of urine?
The secreted ions combine with the remaining filtrate and become urine. The urine flows out of the nephron tubule into a collecting duct. It passes out of the kidney through the renal pelvis, into the ureter, and down to the bladder.
How does ADH stimulate water reabsorption by the collecting system? Is this process obligatory or facultative?
The water withdrawn from the plasma filtrate as a regulated negative feedback control of hydration status under the influence of ADH = antidiuretic hormone; this water reabsorption occurs primarily in the loops of the nephrons, particularly the juxtamedullary nephrons
What is a lipoprotein, and why are they necessary?
These lipoproteins play a key role in the absorption and transport of dietary lipids by the small intestine, in the transport of lipids from the liver to peripheral tissues, and the transport of lipids from peripheral tissues to the liver and intestine (reverse cholesterol transport).
What is lipoprotein lipase, and what is its purpose?
This enzyme is found primarily on the surface of cells that line tiny blood vessels (capillaries) within muscles and in fatty (adipose) tissue. Lipoprotein lipase plays a critical role in breaking down fat in the form of triglycerides, which are carried from various organs to the blood by molecules called lipoproteins.
How may kidney function be evaluated? GFR
This test is a measure of how well the kidneys are removing wastes and excess fluid from the blood. It may be calculated from the serum creatinine level using your age, weight, gender and body size. Normal GFR can vary according to age (as you get older it can decrease). The normal value for GFR is 90 or above. A GFR below 60 is a sign that the kidneys are not working properly. A GFR below 15 indicates that a treatment for kidney failure, such as dialysis or a kidney transplant, will be needed.
What are the characteristics of normal urine?
Transparent yellow, and aromatic odor.
What is the TCA cycle (general terms only), and what is its significance in metabolism? How much ATP is generated in this pathway? Where does it take place?
Tricarboxylic acid cycle, (TCA cycle), also called Krebs cycle and citric acid cycle, the second stage of cellular respiration, the three-stage process by which living cells break down organic fuel molecules in the presence of oxygen to harvest the energy they need to grow and divide. The citric acid cycle is a key metabolic pathway that connects carbohydrate, fat, and protein metabolism. The reactions of the cycle are carried out by eight enzymes that completely oxidize acetate (a two carbon molecule), in the form of acetyl-CoA, into two molecules each of carbon dioxide and water. 36 ATP and takes place in the mitochondria
Describe the general ways in which substances are absorbed across the tubular cells.
Tubular reabsorption is the process by which solutes and water are removed from the tubular fluid and transported into the blood.May
What is uric acid, and where does it come from (metabolically)? What problems are associated with the over production of uric acid? When is this likely to happen?
Uric acid is a heterocyclic compound of carbon, nitrogen, oxygen, and hydrogen with the formula C₅H₄N₄O₃. It forms ions and salts known as urates and acid urates, such as ammonium acid urate. Uric acid is a product of the metabolic breakdown of purine nucleotides, and it is a normal component of urine. Excess uric acid can be released from the blood and build up under the skin and cause gouty arthritis (arthritis caused by an accumulation of uric acid in the joints). Uric acid accumulation can also cause kidney and bladder stones.
What are the structures through which urine drains in it exit from the nephron to the urinary bladder?
Urine drains from the renal pelvis of each kidney into the ureters. The ureters are long, thin tubes made of smooth muscle. Contractions of the smooth muscle push urine down through the ureters and into the bladder.
What chemical substances normally are present in urine?
Urine is an aqueous solution of greater than 95% water. Other constituents include urea, chloride, sodium, potassium, creatinine and other dissolved ions, and inorganic and organic compounds. Urea is a non-toxic molecule made of toxic ammonia and carbon dioxide.
What is water intoxication? Why is it dangerous?
Water intoxication, also known as water poisoning, hyperhydration, overhydration, or water toxemia, is a potentially fatal disturbance in brain functions that results when the normal balance of electrolytes in the body is pushed outside safe limits by excessive water intake.
Which hormones stimulate and which inhibit water reabsorption?
Water levels in the body are controlled by antidiuretic hormone (ADH), which is produced in the hypothalamus and triggers the reabsorption of water by the kidneys.
What is the major chemical difference between blood plasma and glomerular filtrate?
What is the major chemical difference between blood plasma and glomerular filtrate? blood plasma: contains blood cells, platelets, most plasma proteins and nutrients. glomerular filtrate: contains nutrients but no formed elements and very few, if any, of the plasma proteins.
Explain the statement "water follows salt".
When salt is absorbed, water must also be absorbed to maintain osmotic pressure from which comes the familiar statement "water follows salt".
Which produces more energy when catabolized, carbohydrate or lipid? Why?
Whereas carbohydrates provide a readily available source of energy, lipids function primarily as an energy reserve. The amount of lipids stored as an energy reserve far exceeds the energy stored as glycogen since the human body is simply not capable of storing as much glycogen compared to lipids.
Name three important extracellular electrolytes and three important intracellular electrolytes and indicate how each is regulated.
Within the extracellular fluid, the major cation is sodium and the major anion is chloride. The major cation in the intracellular fluid is potassium. These electrolytes play an important role in maintaining homeostasis.Electrolyte levels are measured in blood tests, and their levels must stay within a fairly small range, or serious problems may arise.
Define the following terms: a. Calorie b. Basal Metabolic Rate (BMR) c. Leptin
a. calorie- the energy needed to raise the temperature of 1 kilogram of water through 1 °C, equal to one thousand small calories and often used to measure the energy value of foods b. basal metabolic rate- Basal metabolic rate is the rate of energy expenditure per unit time by endothermic animals at rest. It is reported in energy units per unit time ranging from watt to ml O₂/min or joule per hour per kg body mass J/. c.leptin- Leptin is a hormone predominantly made by adipose cells and enterocytes in the small intestine that helps to regulate energy balance by inhibiting hunger, which in turn diminishes fat storage in adipocytes.
Why is there much greater filtration through glomerular capillaries than through capillaries elsewhere in the body?
glomerular capillaries present a large surface area for filtration, are about 50 times leakier than capillaries in most other tissues due to their large fenestrations, and glomerular capillary blood pressure is high.
What is the difference between lipolysis and beta oxidation?
lipolysis the breakdown of fats and other lipids by hydrolysis to release fatty acids. Beta oxidation is the catabolic process by which fatty acid molecules are broken down in the cytosol in prokaryotes and in the mitochondria in eukaryotes to generate acetyl-CoA, which enters the citric acid cycle, and NADH and FADH2, which are co-enzymes used in the electron transport chain
What are the four mechanisms of heat transfer?
radiation, conduction, convection, evaporation
