General Principles of Gastrointestinal Function—Motility, Nervous Control, and Blood Circulation
50 questions available
Questions
Which enzyme is synthesized by tissues such as adipose tissue, skeletal muscle, and heart, and is transported to the surface of capillary endothelial cells to hydrolyze chylomicron triglycerides?
View answer and explanationWhat is the approximate concentration of free fatty acids in the plasma under resting conditions?
View answer and explanationHow quickly is half of the plasma free fatty acid replaced by new fatty acid, indicating its extremely rapid rate of turnover?
View answer and explanationUnder normal physiological conditions, how many molecules of fatty acid typically combine with a single molecule of albumin for transport in the blood?
View answer and explanationWhich type of lipoprotein is derived from the removal of almost all triglycerides from Intermediate-Density Lipoproteins (IDLs), resulting in a high concentration of cholesterol?
View answer and explanationWhat is the primary function of Very Low Density Lipoproteins (VLDLs)?
View answer and explanationIn what form are more than 95 percent of all lipids found in the plasma in the postabsorptive state, after chylomicrons have been cleared?
View answer and explanationWhat process occurs in the mitochondria to degrade fatty acids by progressively releasing two-carbon segments as acetyl-CoA?
View answer and explanationWhat is the net gain of ATP molecules from the complete oxidation of one molecule of stearic acid?
View answer and explanationWhich condition, resulting from the accumulation of acetoacetic acid, β-hydroxybutyric acid, and acetone, occurs as a consequence of starvation or in persons with diabetes mellitus?
View answer and explanationWhat is the primary product of carbohydrate metabolism that is required to bind with acetyl-CoA for it to be processed in the citric acid cycle, a deficiency of which limits the oxidation of ketone bodies?
View answer and explanationWhat percentage of the original energy in glucose is transferred to stored triglycerides during the process of fat synthesis, with the remainder lost as heat?
View answer and explanationWhich hormone's absence severely impairs the synthesis of fats from carbohydrates, primarily because glucose entry into fat and liver cells is unsatisfactory?
View answer and explanationWhich two hormones, released by the adrenal medullae during heavy exercise, directly activate hormone-sensitive triglyceride lipase in fat cells, causing rapid mobilization of fatty acids?
View answer and explanationBy far the most abundant non-membranous use of cholesterol in the body is the formation of what substance in the liver?
View answer and explanationA diet high in which type of fat is described as increasing blood cholesterol concentration by 15 to 25 percent?
View answer and explanationWhat is the primary substance that makes the skin highly resistant to the absorption of water-soluble substances and helps prevent water evaporation?
View answer and explanationWhat is the initial event in the development of atherosclerosis, which increases the expression of adhesion molecules on endothelial cells?
View answer and explanationMacrophage foam cells, which form fatty streaks in atherosclerosis, are created when macrophages ingest and oxidize which type of lipoprotein?
View answer and explanationWhat is the primary function of apolipoprotein-E on the surface of chylomicron remnants?
View answer and explanationWhat is the term for fatty acids that are bound to albumin in the plasma, distinguishing them from fatty acids that exist as esters of glycerol or cholesterol?
View answer and explanationWhat is the primary location for the formation of almost all lipoproteins in the body?
View answer and explanationFat cells (adipocytes) in adipose tissue are modified fibroblasts that can store almost pure triglycerides in quantities as great as what percentage of their entire cell volume?
View answer and explanationWhich of the following is NOT a principal function of the liver in lipid metabolism?
View answer and explanationThe degradation and oxidation of fatty acids, a process that requires carnitine as a carrier for entry, occurs exclusively in which cellular organelle?
View answer and explanationIn the process of beta-oxidation, the beta carbon of the fatty acyl-CoA molecule binds with which molecule to become oxidized?
View answer and explanationAfter beta-oxidation of fatty acids in the liver, two molecules of acetyl-CoA condense to form what substance, which is then transported in the blood to other cells for energy?
View answer and explanationUnder what circumstance does the body adapt to use far more acetoacetic acid than usual, preventing the development of ketosis?
View answer and explanationThe glycerol portion of triglycerides, used in their synthesis, is furnished by what product derived from the glycolytic scheme of glucose degradation?
View answer and explanationWhen excess carbohydrates are available, they are said to have a 'fat-sparing' effect. What is the primary mechanism for this effect?
View answer and explanationWhich of the following is NOT one of the major types of body phospholipids mentioned in the text?
View answer and explanationWhich phospholipid is necessary to initiate the blood clotting process because it is the main component of thromboplastin?
View answer and explanationWhat percentage of the cholesterol circulating in the lipoproteins of the plasma is in the form of cholesterol esters?
View answer and explanationWhat is the effect of a lack of insulin or thyroid hormone on blood cholesterol concentration?
View answer and explanationAccording to the text, which cells are responsible for producing endogenous cholesterol that circulates in the plasma lipoproteins?
View answer and explanationWhat is the general term for thickened and stiffened blood vessels of all sizes?
View answer and explanationWhat is the turnover rate of triglycerides in fat cells, indicating the dynamic state of storage fat?
View answer and explanationWhich substance is required to maintain the glycerol portion of triglycerides, and its insufficiency in fat cells can promote the hydrolysis of triglycerides?
View answer and explanationWhich statement accurately describes Intermediate-density lipoproteins (IDLs)?
View answer and explanationWhat is the principal reason that the liver cells are more capable of desaturating fatty acids than other tissues?
View answer and explanationAfter being transported into an active tissue, what is glycerol immediately converted into to enter the glycolytic pathway?
View answer and explanationWhat is the net reaction in the citric acid cycle for each molecule of acetyl-CoA that is degraded?
View answer and explanationIn a person with severe diabetes mellitus or during starvation, why do large quantities of triglycerides appear in the liver?
View answer and explanationWhat is the term for the fatty lesions that develop on the inside surfaces of arterial walls in atherosclerosis?
View answer and explanationAfter triglycerides are removed from chylomicrons in the circulation, what are the remaining cholesterol-enriched particles called?
View answer and explanationWhat is the total concentration of lipoproteins in the plasma on average?
View answer and explanationWhich hormone has a ketogenic effect similar to, but weaker than, that of ACTH and glucocorticoids?
View answer and explanationAn intrinsic feedback control system for cholesterol synthesis involves the inhibition of which essential enzyme when dietary cholesterol intake increases?
View answer and explanationWhat are the first two steps of the two-step process for synthesizing fatty acids from acetyl-CoA?
View answer and explanationThe final stage of atherosclerosis, referred to as 'hardening of the arteries,' involves the precipitation of what substance with the lipids in the plaques?
View answer and explanation