The Digestive and Urinary Systems: The Digestive System, Metabolism and Nutrition, The Urinary System, Fluid, Electrolyte, and Acid-Base Balance (Challenge 3.1-3.4)

Generalize normal dietary guidelines and obesity. What is considered the calorie count that an average adult needs per day to sustain themselves?

1,500-2,000 On average, a person needs 1,500 to 2,000 calories per day to sustain (or carry out) daily activities.

Summarize the characteristics of urine. Which is the normal volume of urine produced in a single day?

1-2 L/day The normal range is one to two liters per day.

Generalize normal dietary guidelines and obesity. A healthy body mass index (BMI) is considered to be which of the following?

18-24.9 kg/m² The normal, or healthy, BMI range is between 18 and 24.9 kg/m².

Summarize anabolic and catabolic reactions. In this reaction A⁰ + B⁰ ---> A⁺ + B⁻, which of the following happens?

A is oxidized and B is reduced A loses an electron, so it is oxidized. B gains an electron, so it is reduced.

Determine the structure and function of the bladder and ureters. Which of the following anchors the ureters between the parietal peritoneum and the posterior abdominal wall?

A loose adventitial layer composed of collagen and fat A loose adventitial layer composed of collagen and fat anchors the ureters between the parietal peritoneum and the posterior abdominal wall.

Determine how hormones regulate water balance. Which hormone controls water reabsorption in the collecting ducts of the kidney?

ADH ADH, also known as vasopressin, is made in the hypothalamus and secreted by the posterior pituitary in response to an increase in blood osmolality.

Describe metabolism of glucose. Which molecule enters the citric acid cycle?

Acetyl-CoA In the presence of oxygen, a carbon is removed from pyruvate and a coenzyme is added to make acetyl-CoA, which enters the citric acid cycle. The carbon that is removed is released as carbon dioxide.

Define the metabolism of lipids. From which basic molecule are fatty acids synthesized?

Acetyl-CoA Lipogenesis begins with acetyl-CoA and advances by the subsequent addition of two carbon atoms from another acetyl-CoA; this process is repeated until fatty acids are the appropriate length.

Define the metabolism of proteins. To which metabolic intermediate are the ketogenic amino acids directly converted?

Acetyl-CoA The ketogenic amino acids, such as phenylalanine, lysine, leucine, tyrosine, isolucine, and tryptophan, get converted to acetyl-CoA.

Indicate the roles and functions of the pharynx and esophagus in digestion. Which layer of the esophagus is made of loose connective tissue?

Adventitia The adventitia is composed of loose connective tissue and is not covered by a fold of visceral peritoneum.

Define the basic parts of nephrons. What structure supplies blood to the nephron?

Afferent arterioles The afferent arterioles are arterioles that supply blood to the nephron and service about 1.3 million nephrons in each kidney.

Define the structure and function of the nephron. Which of the following is a potent vasoconstrictor and stimulates the secretion of aldosterone?

Angiotensin II Angiotensin II is the protein produced by the enzymatic action of ACE on inactive angiotensin I—actively causes vasoconstriction and stimulates aldosterone release by the adrenal cortex.

Characterize the structure and function of the large intestine. What is the 3-inch winding tube containing lymphoid tissue in the large intestine referred to as?

Appendix The appendix (or vermiform appendix) is a winding tube that attaches to the cecum. Although the 7.6-cm (3-in) long appendix contains lymphoid tissue, suggesting an immunologic function, this organ is generally considered vestigial.

Summarize the characteristics of urine. An odor in urine can be caused by which of the following foods?

Asparagus About one in five people detect a distinctive odor in their urine after consuming asparagus; other foods such as onions, garlic, and fish can impart their own aromas. These food-caused odors are harmless.

Define the metabolism of lipids. Which process breaks down fatty acids by 2C fragments at a time and releases them as acetyl-CoA?

Beta-oxidation Fatty acid oxidation, also known as beta (β)-oxidation, is the breakdown of fatty acids into smaller chain fatty acids and acetyl-CoA.

Define the structure and function of the nephron. Which of the following structures has cells with finger-like projections that interdigitate to form a filtration membrane?

Bowman's capsule The visceral layer of Bowman's capsule has cells called podocytes forming finger-like processes that interdigitate to form a filtration membrane.

Define the structure and function of the major components of the mouth. What is the function of lingual lipase?

Break down triglycerides The enzyme lingual lipase plays a minor role in breaking down triglycerides but does not begin working until it is activated in the stomach.

Define the structures and function of the exocrine pancreas. Which of the following pancreatic enzymes breaks down proteins?

Carboxypeptidase Carboxypeptidase and chymotrypsin are active forms of protein digestive enzymes secreted by the pancreas.

Characterize the structure and function of the large intestine. Which part of the large intestine connects to the ileum?

Cecum The first part of the large intestine is the cecum, a sac-like structure that is suspended inferior to the ileocecal valve of the ileum.

Summarize the processes involved in digestion. The digestion of proteins into amino acids is an example of which process?

Chemical digestion In chemical digestion, starting in the mouth, digestive secretions break down complex food molecules into their chemical building blocks (for example, proteins into separate amino acids). These secretions vary in composition but typically contain water, various enzymes, acids, and salts. The process is completed in the small intestine.

Indicate the mechanisms by which the pH of the blood is regulated. Which buffer systems act in order from the fastest to the slowest?

Chemical, Respiratory, Renal It takes only seconds for the chemical buffers in the blood to make adjustments to pH. The respiratory tract can adjust the blood pH upward in minutes by exhaling CO₂ from the body. The renal system can also adjust blood pH through the excretion of hydrogen ions (H⁺) and the conservation of bicarbonate, but this process takes hours to days to have an effect.

Define the structures and function of the exocrine pancreas. Which hormone stimulates the acini to secrete pancreatic enzymes?

Cholecystokinin The presence of proteins and fats in the duodenum stimulates the secretion of cholecystokinin (CCK), which then stimulates the acini to secrete enzyme-rich pancreatic juice and enhances the activity of secretin.

Define the structure and function of the liver and gallbladder. Through which vessel does bile flow into the small intestine?

Common bile duct The common hepatic duct joins with the cystic duct from the gallbladder to form the common bile duct through which bile flows into the small intestine.

Indicate the mechanisms of thermoregulation. Which is the transfer of heat through physical contact?

Conduction Conduction is the transfer of heat through physical contact.

Define the structure and function of the major components of the mouth. Which set of teeth is used to tear food?

Cuspids The four cuspids (or canines) flank the incisors and have a pointed edge (cusp) to tear up food. These fang-like teeth are superb for piercing tough or fleshy foods.

Summarize the processes involved in digestion. Which is the final step of digestion?

Defecation In defecation, the final step in digestion, undigested materials are removed from the body as feces.

Determine the structure and function of the bladder and ureters. Which is composed of irregular crisscrossing bands of smooth muscle?

Detruscor muscle The bladder is a highly distensible organ composed of irregular crisscrossing bands of smooth muscle collectively called the detrusor muscle.

Define the structure and function of the nephron. The cells that form the macula densa belong to which portion of the nephron?

Distal convoluted tubule The macula densa consists of cells found in the part of the distal convoluted tubule forming the juxtaglomerular apparatus; they sense Na+ concentration in the forming urine.

Determine how hormones regulate water balance. Which of the following is under voluntary control?

Drinking Drinking is a voluntary behavior when stimulated by the thirst center of the hypothalamus.

Define the basic parts of nephrons. What structure takes blood from the glomerulus to the capillary beds that are around the convoluted tubules and loop of Henle?

Efferent arterioles The efferent arteriole is the arteriole carrying blood from the glomerulus to the capillary beds around the convoluted tubules and loop of Henle.

Characterize how the large intestine aids in digestion. When bacteria break down, some carbohydrate, hydrogen, carbon dioxide, and methane gases can be discharged. What does this create?

Flatus Flatus is gas in the intestines that can be created from bacteria breaking down carbohydrates.

Summarize the filtration rates in the nephron. Which of the following describes filtration fraction?

Fraction of RPF filtered across the glomerulus Filtration fraction (FF) is the fraction of renal plasma flow (RPF) filtered across the glomerulus. The equation is GFR divided by RPF. A typical value of FF is about 20%.

Summarize the filtration rates in the nephron. Which is the volume of filtrate formed by both kidneys per minute?

GFR Glomerular filtration rate (GFR) is the volume of filtrate formed by both kidneys per minute.

Determine how the stomach facilitates digestion. Which process contributes to chemical digestion?

Gastric secretion Gastric juices, which are produced by gastric secretion, contribute to chemical digestion processes.

Define mechanical and chemical digestion in the small intestine. What increases the force of ileal segmentation?

Gastroileal reflex Digestive activity in the stomach provokes the gastroileal reflex, which increases the force of ileal segmentation.

Define the basic parts of nephrons. Which blood vessels filter the blood based on particle size?

Glomerulus The glomerulus is a tuft of high-pressure capillaries about 200 µm in diameter that lies within the renal corpuscle and filters the blood based on particle size.

Summarize anabolic and catabolic reactions. Which is an example of an anabolic reaction?

Gluconeogenesis Gluconeogenesis is an anabolic process where glucose is made from broken down fats and proteins.

Indicate how carbohydrates, fats, and proteins are broken down in the digestive system. Which of the following carbohydrates is readily absorbed?

Glucose Glucose, galactose, and fructose are the three monosaccharides that are commonly consumed and readily absorbed.

Indicate how carbohydrates, fats, and proteins are broken down in the digestive system. At the cellular level, which of the following molecules is absorbed via a co-transport with sodium ions?

Glucose The monosaccharides glucose and galactose are transported into the epithelial cells by common protein carriers via secondary active transport (that is, co-transport with sodium ions).

Summarize the metabolic states. In the post absorptive state, which of the following does your body initially rely upon to maintain blood glucose levels?

Glycogen During the postabsorptive state, the body must rely initially on stored glycogen. Glucose levels in the blood begin to drop as it is absorbed and used by the cells. In response to a drop in blood glucose concentration, the hormone glucagon is released from the alpha cells of the pancreas. Glucagon acts upon the liver cells, where it inhibits the synthesis of glycogen and stimulates the breakdown of stored glycogen back into glucose. This glucose is released from the liver to be used by the peripheral tissues and the brain. As a result, blood glucose levels begin to rise.

Describe metabolism of glucose. In which of the following is pyruvate produced?

Glycolysis phase 3 Glycolysis phase 3 is when pyruvate is produced. Pyruvate is an end product of glycolysis.

Generalize normal dietary guidelines and obesity. According to the "My Plate" diagram, which food groups are the largest portion of a meal?

Grains and vegetables According to My Plate, grains and vegetables constitute about 60% of a meal.

Define the structures and function of the exocrine pancreas. Which of the following describes acini?

Grape-like clusters of exocrine cells The exocrine part of the pancreas arises as little grape-like cell clusters, each called an acinus (plural = acini), located at the terminal ends of pancreatic ducts. These acinar cells secrete enzyme-rich pancreatic juice

Define the macroscopic structures and function of the kidney. What is the function of the renal capsules?

Helps kidneys hold their shape and protects them The renal capsule is a fibrous capsule composed of dense, irregular connective tissue that covers the kidney, helps to hold its shape, and protects it.

Indicate the mechanisms by which the pH of the blood is regulated. Which of the following is the main pH buffer within red blood cells?

Hemoglobin Hemoglobin is the principal protein inside red blood cells and accounts for one-third of the mass of the cell. During the conversion of CO₂ into bicarbonate, hydrogen ions liberated in the reaction are buffered by hemoglobin, which is reduced by the dissociation of oxygen. This buffering helps maintain normal pH.

Define the structure and function of the liver and gallbladder. Which is formed by fenestrated capillaries from hepatic portal veins and hepatic arteries?

Hepatic sinusoid Hepatic sinusoids are blood capillaries between rows of hepatocytes that receive blood from the hepatic portal vein and the branches of the hepatic artery.

Characterize the structure and functions of the digestive system. Which is the function of the peritoneum?

Hold the digestive organs in place The peritoneum is a broad serous membranous sac made up of squamous epithelial tissue surrounded by connective tissue that holds the digestive organs in place.

Determine the regulation of sodium and potassium in the blood. Which term refers to an increased sodium concentration in the blood?

Hypernatremia Hypernatremia is abnormal increase in blood sodium levels.

Determine how hormones regulate water balance. Where are receptors that sense osmolality located?

Hypothalamus The hypothalamus contains the osmoreceptors that monitor the blood osmolality.

Define the roles of the kidney in regulating other body functions. What is the kidney's association with vitamin D?

In converts an inactive form of vitamin D to an active form. When stimulated by PTH, the kidney converts the inactive form of vitamin D, calcidiol, to the active form calcitriol (also called 1,25-dihydroxycholecalciferol) by adding a hydroxyl (-OH) group to calcidiol

Indicate the mechanisms that control the flow through the kidney. Which is a consequence of vasoconstriction of the efferent arteriole, while there is no change in the afferent arteriole?

Increased GFR and decreased RPF Vasoconstriction of the efferent arteriole in the absence of a change in the afferent arteriole will increase its resistance, thereby increasing GFR and decreasing RPF.

Summarize anabolic and catabolic reactions. Which hormone stimulates glucose uptake and glycogenesis?

Insulin Insulin is an anabolic hormone that promotes the uptake of glucose into body cells; causes cells in muscle, adipose tissue, and liver to take up glucose from the blood and store it in the liver and muscle as glycogen (glycogenesis).

Determine the structure of the urethra and associated parts of the urinary system. What structure is regulated by the autonomic nervous system, consists of smooth muscle, and regulates urination?

Internal urinary sphincter The internal urinary sphincter is the structure that regulates urination, is regulated by the autonomic nervous system, and consists of smooth muscle.

Summarize the movement of body fluids between compartments. Which fluid compartment has the highest water content?

Intracellular fluid compartment The intracellular fluid compartment contains about 60% of the body's water content.

Summarize the movement of body fluids between compartments. Which compartment has a high potassium concentration and a low sodium concentration?

Intracellular fluid compartment The intracellular fluid compartment has a high potassium and a low sodium concentration due to the activity of the sodium-potassium pump.

Determine the structure and function of the stomach. Which substance secreted by the stomach is necessary for the absorption of vitamin B12 by the small intestine?

Intrinsic factor Secreted by parietal cells, the intrinsic factor is a glycoprotein necessary for the absorption of vitamin B12 in the small intestine.

Categorize the roles of various vitamins and minerals. Which trace mineral found in fish and shellfish is important for normal thyroid function and its lack can cause hypothyroidism?

Iodine Iodine is found in fish and shellfish and is important for thyroid function, specifically the production of thyroid hormones. A lack of iodine will lead to hypothyroidism.

Describe metabolism of glucose. What is the importance of adding a phosphate group to glucose to make glucose-6-phosphate?

It traps glucose in the cell and prevents it from diffusing out. Once glucose enters the cell, a phosphate gets attached to it by an enzyme called hexokinase to make glucose 6-phosphate. This step traps the non-polar glucose molecule and prevents it from diffusing out of the cell by making it a polar molecule.

Define the metabolism of lipids. When glucose is limited, which molecule can serve as a fuel source for the brain?

Ketone bodies Organs that have classically been thought to be dependent solely on glucose, such as the brain, can actually use ketones as an alternative energy source. This keeps the brain functioning when glucose is limited.

Summarize the metabolic states. When glucose is unavailable, what fuel source can the brain use?

Ketone bodies The brain can only use glucose and ketone bodies for energy.

Characterize the structure and functions of the digestive system. Which of the following organs is an alimentary canal organ?

Large intestine The alimentary canal is a one-way tube that begins at the mouth and terminates at the anus. Between those two points, the canal is modified as the pharynx, esophagus, stomach, and small and large intestines to fit the functional needs of the body.

Summarize the characteristics of urine. Which of the following's presence in urine can indicate a urinary tract infection?

Leukocytes Cells are not normally found in the urine. The presence of leukocytes may indicate a urinary tract infection.

Summarize the metabolic states. Upon ingestion of food after a prolonged fast, which organ that normally absorbs and processes glucose, will not do so?

Liver The liver, which normally absorbs and processes glucose, will not do so after a prolonged fast. The gluconeogenesis that has been ongoing in the liver will continue after fasting to replace the glycogen stores that were depleted in the liver. After these stores have been replenished, excess glucose that is absorbed from the intestine by the liver will be converted into triglycerides and fatty acids for long-term storage.

Indicate the roles and functions of the pharynx and esophagus in digestion. Which action allows the bolus to move from the esophagus into the stomach and prevents chyme from entering the esophagus?

Lower esophageal sphincter relaxation Lower esophageal sphincter relaxation allows the bolus to move from the esophagus into the stomach and contracts to prevent chyme from entering the esophagus after the bolus has passed through

Summarize the filtration rates in the nephron. What can you substitute for GBHP in calculating NFP?

MAP GBHP is difficult to measure in a clinical setting. So, mean arterial pressure (MAP) can be used. If you use mean arterial pressure for the GBHP in the formula for calculating NFP, you can determine that as long as mean arterial pressure is above approximately 60 mm Hg, the pressure will be adequate to maintain glomerular filtration.

Characterize how the large intestine aids in digestion. What part of mechanical digestion refers to strong waves that quickly force the contents from the colon toward the rectum?

Mass movements Mass movements are strong waves that start midway through the transverse colon and quickly force the contents toward the rectum. These typically occur during or just after eating.

Summarize the processes involved in digestion. Which digestive processes produce chyme?

Mechanical digestion, chemical digestion, and propulsion Production of chyme involves mechanical digestion, chemical digestion, and propulsion. The mechanical churning of food in the stomach serves to further break it apart and expose more of its surface area to digestive juices (chemical digestion), creating an acidic "soup" called chyme. Peristalis is a propusive action that allow the stomach to churn the food.

Define mechanical and chemical digestion in the small intestine. What initiates peristalsis in the small intestine?

Motilin When most of the chyme has been absorbed, the small intestinal wall becomes less distended. At this point, the localized segmentation process is replaced by transport movements. The duodenal mucosa secretes the hormone motilin, which initiates peristalsis in the form of a migrating motility complex.

Define the structure and function of the major components of the mouth. Which muscle is responsible for the tongue being raised?

Mylohyoid The mylohyoid muscle is responsible for raising the tongue.

Indicate the mechanisms that control the flow through the kidney. Which mechanism regulating blood flow within the kidney depends upon a characteristic shared by most smooth muscle cells of the body?

Myogenic mechanism The myogenic mechanism regulating blood flow within the kidney depends upon a characteristic shared by most smooth muscle cells of the body. When you stretch a smooth muscle cell, it contracts; when you stop, it relaxes, restoring its resting length. This mechanism works in the afferent arteriole that supplies the glomerulus. When blood pressure increases, smooth muscle cells in the wall of the arteriole are stretched and respond by contracting to resist the pressure, resulting in little change in flow. When blood pressure drops, the same smooth muscle cells relax to lower resistance, allowing a continued even flow of blood.

Indicate the mechanisms that control the flow through the kidney. Which paracrine substance acts secondarily as a "fine-tuning" effect on tubuloglomerular feedback?

NO NO has the opposite effect, relaxing the afferent arteriole at the same time ATP and adenosine are stimulating it to contract or contracting the afferent arteriole when ATP and adenosine are causing it to relax. Thus, NO fine-tunes the effects of adenosine and ATP on GFR.

Indicate the mechanisms of thermoregulation. Non-shivering thermogenesis occurs in which of the following?

Newborns Non-shivering thermogenesis occurs in newborns who have large deposits of brown fat in their chest, shoulders, and back.

Summarize tubular reabsorption and secretion in the nephron. In which part of the nephron is most of the Na⁺, K⁺, and H₂O reabsorbed?

PCT Approximately 2/3 of Na⁺, K⁺, and H₂O are reabsorbed in the PCT.

Define mechanical and chemical digestion in the small intestine. Which of the following contributes to the chemical digestion of fats?

Pancreatic lipase Pancreatic lipase is an enzyme that helps digest lipids, or fats, alongside bile.

Determine how the stomach facilitates digestion. Which of the following helps break down proteins during chemical digestion in the stomach?

Pepsin Pepsin and hydrochloric acid break down proteins in the stomach.

Indicate how carbohydrates, fats, and proteins are broken down in the digestive system. Which enzyme in the stomach breaks down protein?

Pepsin The digestion of protein starts in the stomach, where HCl and pepsin break proteins into smaller polypeptides.

Indicate the roles and functions of the pharynx and esophagus in digestion. Which action propels the bolus through the esophagus?

Peristalsis Peristalsis propels the bolus through the esophagus.

Summarize tubular reabsorption and secretion in the nephron. Under stimulation by PTH, which of the following occurs?

Phosphate reabsorption in the PCT is inhibited and calcium reabsorption in the DCT is stimulated. PTH acts on bone to release calcium and phosphate. In the kidney, PTH inhibits phosphate reabsorption in the PCT and stimulates calcium reabsorption in the DCT. These actions facilitate increasing calcium levels in the blood and increase urinary excretion of phosphate.

Determine the structure and function of the stomach. Which is the lower funnel-shaped portion of the stomach?

Pylorus The pylorus is the lower, funnel-shaped part of the stomach that is continuous with the duodenum.

Define the macroscopic structures and function of the kidney. Which is the outer part of the kidney where the majority of the nephrons are located?

Renal cortex The renal cortex is the outer part of the kidney containing all of the nephrons; some nephrons have loops of Henle extending into the medulla.

Define the roles of the kidney in regulating other body functions. Which is the kidney's role in the renin- renin-angiotensin-aldosterone system?

Renin secretion When the blood pressure is low, the kidney synthesizes and secretes renin.

Indicate the mechanisms by which the pH of the blood is regulated. Which of the following happens in response to an initial acidosis?

Respiration rate increases, blood carbon dioxide, and carbonic acid decrease, and pH increases In response to acidosis, respiration rate increases, blood carbon dioxide and carbonic acid decrease, and pH increases, thereby returning blood pH to normal.

Characterize the structure and functions of the digestive system. Which is the outermost layer of the alimentary canal wall present in regions within the abdominal cavity?

Serosa The serosa is the outermost layer of the alimentary canal wall present in regions within the abdominal cavity; a layer of visceral peritoneum overlying a layer of loose connective tissue.

Summarize tubular reabsorption and secretion in the nephron. What is the major function of the countercurrent mechanism of the loop of Henle?

Set up an osmotic gradient in the renal medulla. The countercurrent mechanism in the loop of Henle sets up an osmotic gradient in the medulla that will drive the reabsorption of water from the collecting ducts when stimulated by ADH.

Determine the regulation of sodium and potassium in the blood. Which is the major cation of extracellular fluid?

Sodium Sodium is the major cation of the extracellular fluid. It is responsible for one-half of the osmotic pressure gradient that exists between the interior of cells and their surrounding environment.

Determine the regulation of sodium and potassium in the blood. When aldosterone secretion is increased, which of the following happens?

Sodium reabsorption in the kidney increases, while potassium excretion increases. In response to increased aldosterone secretion, sodium reabsorption in the kidney is increased, while potassium excretion is increased.

Define the structure and function of the liver and gallbladder. What gives stool its brown color?

Stercobilin Stercobilin is a brown pigment that gives your stool its characteristic color. It is produced when bacteria in the large intestine break down bilirubin.

Summarize the movement of body fluids between compartments. Which of the following organs has the least water content?

Teeth Teeth have the lowest water content at 8-10%.

Define the roles of the kidney in regulating other body functions. When moving to a high altitude, such as Denver, how does your body compensate for the decreased oxygen partial pressure?

The decreased oxygen partial pressure stimulates the kidneys to secrete EPO, which acts on the bone marrow to make more red blood cells. The decreased oxygen partial pressure stimulates the kidneys to secrete EPO, which acts on the bone marrow to make more red blood cells. This increases the the hematocrit and the oxygen carrying capacity of the blood.

Indicate the mechanisms of thermoregulation. When you are outside in the cold, which explains why your hands and feet feel cold and numb?

The superficial blood vessels in the limbs vasoconstrict, thereby reducing blood flow and decreasing heat loss. When it is cold, superficial blood vessels in the limbs vasoconstrict, thereby reducing blood flow to the limbs, reducing heat loss, and preserving the core body temperature. This reduction in blood flow makes the hands and feet feel cold and numb.

Determine how the stomach facilitates digestion. What of the following stimulates stomach secretory activity during the cephalic phase?

Thinking of foods you enjoy eating Secretion can be stimulated during the cephalic phase when you see or think of food.

Characterize the structure and function of the large intestine. Which of the following describes the teniae coli accurately?

Three bands of smooth muscle that make up the longitudinal muscle layer of the muscularis of the large intestine The teniae coli are three bands of smooth muscle that make up the longitudinal muscle layer of the muscularis of the large intestine, except at its terminal end.

Define the metabolism of proteins. Which is the first step in breaking down amino acids?

Transferring the amine group or ammonium ion from the amino acid to another molecule The first step involves transamination in the liver. In these reactions, an amine group, or ammonium ion, from the amino acid is exchanged with a keto group on another molecule.

Define the metabolism of proteins. Which enzyme directly converts chymotrypsinogen into chymotrypsin?

Trypsin Trypsin binds to chymotrypsinogen to convert it into the active chymotrypsin. Trypsin and chymotrypsin break down large proteins into smaller peptides, a process called proteolysis.

Determine the structure and function of the bladder and ureters. What structure transports urine from the kidney to the bladder?

Ureter The ureters are ducts that transport urine from the kidney to the bladder.

Identify the structures of the mouth. Which is a fleshy bead of tissue that drops down from the center of the posterior edge of the soft palate?

Uvula A fleshy bead of tissue called the uvula drops down from the center of the posterior edge of the soft palate. When you swallow, the soft palate and uvula move upward, helping to keep foods and liquid from entering the nasal cavity.

Characterize how the large intestine aids in digestion. What is the voluntary procedure through which feces are eliminated from the body?

Valsalva maneuver The Valsalva maneuver voluntarily facilitates defecation by contracting the diaphragm and abdominal wall muscles and closing of the glottis, which increases intra-abdominal pressure.

Identify the regions of the small intestine. Lacteals are found in which of the following structures of the small intestine?

Villi Each villus contains a capillary bed composed of one arteriole and one venule, as well as a lymphatic capillary called a lacteal. The breakdown products of carbohydrates and proteins (sugars and amino acids) can enter the bloodstream directly, but lipid breakdown products are absorbed by the lacteals and transported to the bloodstream via the lymphatic system.

Categorize the roles of various vitamins and minerals. Which of the following vitamins is a water-soluble vitamin?

Vitamin C Vitamin C is a water-soluble vitamin.

Categorize the roles of various vitamins and minerals. The lack of which of the following vitamin can lead to gingivitis and scurvy?

Vitamin C Vitamin C, which is found in citrus fruits and green vegetables is necessary to produce collagen for formation of connective tissue and teeth. A lack of vitamin C can lead to gingivitis, bleeding gums, and scurvy.