Chapter 23 A&P
name the heat conservation mechanism that conducts heat from deep arteries to adjacent deep in the limbs
countercurrent exchange is the heat conservation mechanism that results in the conduction of heat from deep arteries to adjacent deep veins of the limbs.
compare glycogenesis and glycogenolysis
glycogenesis is the formation of glycogen from glucose. glycogeneolysis is the breakdown of glycogen to glucose
distinguish between a complete protein and an incomplete protein
a complete protein meets the body's amino acid requirements; an incomplete protein is deficient in one or more of the essential amino acids
whys is digestion important
digestion is important because cells throughout the body rely on the organic molecules from the food we eat, produce energy and to replenish the intracellular nutrient pool
identify the fates of fatty acids
fatty acids may become a source of energy or a component of triglycerides, glycolipids, phospholipids, prostaglandins, cholesterol and steroids
describe the source of intestinal gas
intestinal gas, or flatus is generated by bacterial activities in the colon when indigestible carbohydrates stimulate bacterial gas production
when and how do ketone bodies form
ketone bodies form during the post absorptive state, when lipids and amino acids are broken down in the liver. the increase concentration of acetyl-CoA that results from their breakdown forms ketone bodies. ketone bodies are not catabolized by liver cells and they diffuse into the circulation.
how might a lack of neuropeptide Y in the hypothalamus affects the control of appetite.
lack of neuropeptide Y a hypothalamic neurotransmitter would probably decrease appetite because it normally stimulates the feeding center
describe leptin and its effect on appetite
leptin is a peptide hormone produced by adipose tissue during the synthesis of triglycerides. it stimulates the satiety center and suppressed appetite
explain the process of metabolic turnover
metabolic turnover is the process in which cells continuously replace their cellular components
most of the absorbed nutrients enter into which blood vessel
most nutrients enter into a branch of the hepatic portal vein and are transported to the liver
describe the role of nonshivering thermogenesis in regulation body temperature
nonshivering thermogenesis involves the release of hormones that increase the metabolic activity of all tissues resulting in an increase in body temperature
compare oxidation and reduction
oxidation is a gain of oxygen or loss of hydrogen or electrons form an atom or molecule. reduction is the loss of oxygen or gain of hydrogen or electrons to an atom or molecule
define oxidative phosphorylation
oxidative phosphorylation is the generation of ATP as the result of the transfer of electrons from coenzyme NADH and FADH2 to oxygen by a sequence of electron carries within mitochondria
briefly describe phenylketonuria (PKU)
phenylketonuria is an inherited metabolic disorder resulting from an inability to convert phenylalanine to tyrosine
define protein deficiency disease and cite an example
protein deficiency disease are nutritional disorders resulting from a lack of one or more essential amino acids. Kwashiorkor is an example of a protein deficiency disease.
what heat transfer process accounts for about 1/2 of a persons heat loss when indoors
radiation accounts for about 1/2 of a persons heat loss indoors
in amino acid metabolism, identify the processes by which the amino acid group is removed
the amino group is removed by deamination or transamination
what happens to the ammonium ions that are removed from amino acids during deamination
the ammonium ion combine with carbon dioxide to form urea which is ultimately excreted in the urine
list the products of glycolysis
2 molecules each of pyruvate, ATP and NADH
describe the roles of LDL's and HDL's
LDL's deliver cholesterol to body tissue. HDL absorb unused cholesterol form body tissues returning it to the liver, where it may be packed into new LDL or excreted with bole salts in bile.
what two coenzymes transfer hydrogen atoms to the electron transport chain
NAd and FAD transfer hydrogen atoms to the electron transport chain
define a balanced diet
a balanced diet contains all the ingredients needed to maintain homeostasis and prevent malnutrition
what is basal metabolic rate
basal metabolic rate is the minimum resting energy expenditure of an awake, alter person
define beta-oxidation
beta-oxidation is a fatty acid catabolism that produces molecules of acetyl-CoA
explain why carbohydrates are preferred over proteins and lipids as an energy source
carbohydrates are the preferred energy source because proteins and lipids are more important as structural components of cells and tissues
compare catabolism and anabolism
catabolism is the breakdown of large molecules into smaller ones, whereas anabolism converts small molecules into larger ones
when do cells make new compounds
cells make a new compound to maintain and repair structures to support growth, and to build up nutrient reserves
how do the absorptive and postabsorptive states maintain normal blood glucose levels.
during the absorptive state, insulin prevents a large surge in blood glucose after a meal by stimulating the liver to remove glucose from the circulation. during postabsorptive state, blood glucose begins to decrease triggering the release of glucagon which stimulates the liver to release glucose into the circulation
identify and briefly define two eating disorders
eating disorders are psychological problems that result in inadequate food consumption or excessive food consumption followed by purging
define energetics
energetics is the study of the flow of energy and its change from one form to another
what is the difference between a micelle and chylomicron
micelles are lipids- bile salt complexes (containing fatty acids, glycerol, and monoglycerides) formed in the intestinal lumen. chylomicrons are lipoproteins formed in intestinal epithelial cells and contain newly synthesized triglycerides cholesterol and other lipids surrounded by phospholipids and proteins
Identify when most of the CO2 is released during the complete catabolism of glucose
most (2/3) of the CO2 release is the complete catabolism of glucose occurs during the citric acid cycle
where does most nutrient absorption occur
most nutrient absorption occurs in the small intestine primarily in the jejunum
define nutrition
nutrition is the absorption of nutrients from food
define and describe the absorptive state
the absorptive state, lasting about 4 hours, is the period following a meal when nutrient absorption is underway. during this time insulin stimulates glucose uptake and glycogenesis amino acid uptake and protein synthesis. androgens, estrogens and growth hormone stimulate protein synthesis. glycolysis and aerobic metabolism provide the necessary ATP
list the reactants required and products generated by mitochondria
the reactants required by mitochondria are continuous supply of 2-carbon substrates and O2's the mitochondria products are CO2, H2O and ATP
identify the two classes of vitamins
the two classes of vitamins are fat-soluble vitamins and water soluble vitamins
predict the effect of peripheral vasodilation on a persons body temperature.
the vasodilation of peripheral vessels would increase blood flow to the skin and thus the amount heat the body can lose. as a result, body temperature would decrease
define thermoregulation
thermoregulation is the hemostatic control of body temperature
if vitamins do not provide a source of energy, what is their role in nutrition
vitamins play an important role in metabolic pathways by serving as coenzymes
which molecule is a key reactant in both ATP production from fatty acids and lipogenesis
acetyl-CoA is a reactant molecule in ATP production and in the synthesis of most types of lipids
how is heat loss different between conduction and convection
conduction is the direct transfer of heat through physical contact. convection is heat loss to the cooler air in contact with the skin. the air warmed by the skin rise and it is repeatedly replaced by cooler air until there is no difference in temperature
which hormone inhibits the satiety center and stimulates appetite in the short term
ghrelin, a hormone secreted by the gastric mucosa when the stomach is not full, inhibits the satiety center and stimulates appetite
explain the role of glycogen in cellular metabolism
glycogen is synthesized form excess glucose molecules by liver and muscle cells, and it serves as an intracellular glucose reserve
explain when glycolysis is important in cellular metabolism
glycolysis is important when ATP must be produced anaerobically, for example during peak levels of physical activity, at all times in red blood cells, or when a tissue temporarily deprived of oxygen
describe the role that hydrogen ion channels play in the generation of ATP
hydrogen ion channels are the passageway for the diffusion of hydrogen ions from the inner membrane space of the mitochondria to the matrix. this movement of hydrogen ions power the production of ATP by ATP synthase
define insensible perspiration
insensible perspiration is the evaporation of water from the skin and alveolar surface of the lungs
define the role of CCK release and its effects on proteins
the arrival of acidic chyme in the duodenum triggers the release of CCK which stimulates the production and release of inactive pancreatic proenzymes. enteroipeptides released from the duodenum converts the pancreatic proenzyme trypsinogen into the proteolytic enzyme trypsin. trypsin then converts other proenzymes to yield chymotrypsin, carboxypeptidase and elastase. each of these enzymes attacks peptide bonds that link specific amino acids while ignoring others. as a result they break down proteins into a mixture of dipeptides, tripeptides and amino acids
of these- carbohydrates, lipids or proteins- which releases the greatest amount of energy per gram during catabolism
the catabolism of lipids release the greatest amount of energy per gram
briefly describe the citric acid cycle, and explain its role
the citric acid cycle is the reaction sequence that occurs in the matrix of mitochondria. in the process organic molecules are broken down, carbon dioxide molecules are released, and hydrogen atoms are transferred to coenzymes that deliver them to the electron transport chain
what molecule forms the common substrate for the citric acid cycle
the common substrate for the citric acid cycle in the mitochondria is the 2-carbon acetate ion, CH3COO-, which is attached to coenzyme A to form acetyl-CoA
what does the liver do when the chylomicrons it receives
the liver absorbs chylomicrons, removes the triglycerides, combines the cholesterol from the chylomicron with recycled cholesterol and alters the surface proteins. newly synthesized complexes are released into the bloodstream as low density lipoproteins (LDL) or very low density lipoproteins (VLDL)
