Hormones and Neurotransmitters of the Endocrine and Digestive Systems, Exams of Pathophysiology

Download Hormones and Neurotransmitters of the Endocrine and Digestive Systems and more Exams Pathophysiology in PDF only on Docsity! Advanced pathophysiology NR 507 final exam (320 Questions and Answers) Fat Soluble Hormones - Correct answer Steroids Water Soluble Hormones - Correct answer Need 2nd Messenger to transport across phospholipid membranes Pituitary Hormones - Correct answer TSH, GH, ACTH, FSH, LH, Oxytocin, ADH, Melanocyte Stimulating Hormone Anterior Pituitary - Correct answer Acct for 75% of total weight of pituitary gland. Three regions, pars distalis, parts tuberalis, and pars intermedia. Pars distalis is major component of Anterior Pituitary and source of Anterior Pituitary Hormones. Posterior Pituitary (neurohypophysis) - Correct answer Arises from 3rd ventricle of brain, consists of three parts, median eminence, pituitary stalk, and infundibular process (pars nervosa or neural tube). Median eminence is composed mainly of nerve endings of axons that arise primarily from ventral hypothalamus. Hypothalamic releasing Hormones in Posterior pituitary's median eminence. - Correct answer Includes 10 hypothalamic releasing hormones and neurotransmitters such as dopamine, norepinephrine, serotonin, acetylcholine, and histamine. Pituitary stalk - Correct answer contains axons of neurons that originate in the supraoptic and paraventricular nuclei of the hypothalamus. Hormones of posterior pituitary - Correct answer ADH, and Oxytocin (Peptide Hormones) ADH (antidiuretic Hormone) - Correct answer Major homeostatic function of posterior pituitary is control of plasma osmolality, as regulated by ADH Hypothalamic hormones and target tissues (Hypophysiotropic hormones) - Correct answer HORMONES: Thyrotropin Releasing Hormone (TRH), Gonadotropoin-releasing hormone (GnRH), Somatostatin, Growth hormone-releasing hormone (GHRH), corticotropin-releasing hormone (CRH), Substance P, Dopamine, Prolactin-releasing factor. TARGET Tissue: Anterior Pituitary Somatostatin - Correct answer Inhibits release of growth hormone and TSH Gonadotropoin-releasing hormone - Correct answer Stimulates release of FSH and LH Dopamine - Correct answer Inhibits synthesis and secretion of prolactin Prolactin-releasing factor (PRF) - Correct answer Stimulate secretion of prolactin Tropic Hormones of Anterior Pituitary and their function - Correct answer ACTH, Melanocyte-stimulating Hormone (MSH, Somatotropic hormones, GH, prolactin, LH, TSH, FSH, glycoprotein hormones Adrenocorticotropic hormone (ACTH) - Correct answer SECRETORY CELL TYPE: Corticotropic TARGET ORGANS: Adrenal Gland (cortex) FUNCTIONS: Increased steroidogenesis (cortisol, and androgenic hormones Regulation of anterior pituitary is achieved by: - Correct answer feedback from hypothalamic releasing-inhibitory hormones and factors, and feedback from target gland hormones (cortisol, estrogen). Growth Hormone secretion is controlled by 2 hormones from the __________________, ______________________and ________________ - Correct answer hypothalamus, Growth Hormone-releasing hormone (GHRH) which releases, and somatostatin which inhibits GH. GH is released by the? - Correct answer GH is released from the pituitary in a pulsatile fashion, and overall secretion peaks during adolescence. GH is essential for what? - Correct answer Growth, effects of aging, sleep, nutritional status, stress, and reproductive hormones Anabolic functions of GH are mediated by? - Correct answer partially by insulin-like growth factors (IGF's) or also called somatomedins. IGF (insulin-like growth factors) - Correct answer IGF-1, and IGF-2, IGF-1 most biologically active. IGF-2 causes a negative effect on tissue thus balancing IGF-1 Pineal Gland - Correct answer Located in the brain and composed of photoreceptive cells that secrete melatonin. Melatonin - Correct answer In Pineal Gland. Its' release is stimulated by darkness, and inhibited by light exposure. It is synthesized from tryptophan which is first converted to serotonin than to melatonin. Thyroid hormone (TH) is regulated by: - Correct answer through a negative feedback loop involving hypothalamus Thyrotropin-releasing hormone (TRH) - Correct answer synthesized and stored within the hypothalamus initiates negative feedback loop TRH levels increase with exposure to what? - Correct answer Cold or stress and decreased levels of T4. TSH is a glycoprotein synthesized and stored where? - Correct answer Anterior pituitary When TSH is secreted by the anterior pituitary it circulates to bind with what? - Correct answer TSH receptor sites located on plasma membrane of thyroid follicular cells What are the effects of TSH on the thyroid? - Correct answer increase in release of stored thyroid hormone, increase in iodide uptake and oxidation, and increase in thyroid hormone synthesis, increase in the synthesis and secretion of prostaglandins by the thyroid. Thyroid hormones have a ____________feedback effect. - Correct answer Negative Thyroid hormone inhibit what hormones? - Correct answer TRH and TSH which decreased TH synthesis and secretion. T3 and T4 thyroid hormones regulate many functions in body. - Correct answer Calcitonin - Correct answer Elevated serum calcium (major stimulant for calcitonin), regulates gastrin, pregnancy, lowered serum calcium, (suppresses calcitonin release). Calcitonin lowers serum calcium by opposing bone resorbing effects of PTH, prostaglandins, and calciferols by inhibiting osteoclastic activity. Thyroid hormones affect many body tissues and influence the genetic expression of specific proteins. They affect cell metabolism by altering what? - Correct answer protein, fat and glucose metabolism, and as a result heat production and oxygen consumption are increased. Calcitonin are used to treat what? - Correct answer Osteoporosis, osteoarthritis, Paget bone disease, hypercalcemia, osteogensesis imperfecta, and metastatic cancer of bone. Precursor molecule to calcitonin is what? - Correct answer procalcitonin (stress hormone) which is elevated in infection and inflammation and can aid in diagnosing disease. Parathyroid glands. - Correct answer 2 pairs but may range from 2-6. Located behind the upper pole and lower pole of the thryoid gland. Parathyroid gland produce what? - Correct answer PTH PTH works with Vitamin ? - Correct answer Vitamin D to increase serum calcium concentration and decrease serum phosphate level. What other 2 things affect PTH levels? - Correct answer Magnesium and phosphate What is the function of PTH? - Correct answer The overall effect of PTH secretion is to increase serum calcium concentration and decrease serum phosphate level. What do the pancreatic hormones regulate? - Correct answer Carbs, fats and proteins Beta cells secrete? - Correct answer Insulin Alpha cells secrete - Correct answer Glucagon Nerves from both the______________and ____________________divisions of the ______________________innervate the pancreatic islets. - Correct answer sympathetic and parasympathetic of the ANS. What part of the pancreas are alpha, beta and delta cells most numerous? - Correct answer Anterior lobe of pancreas Proinsulin - Correct answer A precursor to synthesis of insulin by beta cells Proinsulin is composed of what peptides? - Correct answer A peptide, B peptide and C peptide and two disulfide bonds. Which two peptides become insulin? - Correct answer A and B peptides which become bonded. Insulin is not bound to a _________________. - Correct answer Carrier in plasma Secretion of Insulin is regulated by? - Correct answer Chemical, hormonal, and neural control. High levels of insulin and sympathetic stimulation of the alpha cells in islets diminishes insulin secretion using the ___________________feedback system. - Correct answer Negative Insulin is secreted when glucose, amino acids, GI hormones (glucoagon, gastrin, cholecystokinin, secretin) increase or decrease? - Correct answer Increase Parasympathetic stimulation of Beta cells causes a release of? - Correct answer Insulin Insulin facilitates rate of glucose uptake into many cells within the body. Insulin binds with with enzyme-linked plasma membrane receptor that contains what? - Correct answer tyrosine kinase on the cytosolic surface Insulin receptor binding sends a cascade of signals to activate what? - Correct answer Glucose transporters for entry of glucose into the cell. What is GLUT4? - Correct answer Stored in cellular vesicles until it is needed to facilitate glucose diffusion into cells. Glucose uptake is increased in ______________cells,_______________cells, and___________cells? - Correct answer Liver, muscle and adipose Glycogenesis is increased in both ___________cells and____________cells. - Correct answer Liver and muscle cells Glycogenolysis is decreased in which two types of cells? - Correct answer Liver and muscle Glycolysis is increased in which three cell types? - Correct answer Liver, muscle and adipose cells Insulin is a __________________hormone. - Correct answer Anabolic Insulin promotes the synthesis of what? - Correct answer Proteins, carbs, lipids, and nucleic acids. It also promotes the uptake of glucose Glucagon - Correct answer Produced by alpha cells and cells lining the GI tract. What body parts do not need insulin for glucose transport? - Correct answer Brain, RBC's, kidney, and eye lens. High glucose levels cause inhibition of ______________ release. - Correct answer glucagon Low glucose levels and sympathetic stimulation cause_________________release - Correct answer glucagon What also stimulates glucagon release? - Correct answer Amino acids such as alanine, glycine, and asparagine. Also a protein- rich meal. What is incretin? - Correct answer Hormones secreted from endocrine cells in the GI tract in the presence of carbs, proteins and fats. Glucagon-like peptides (GLP-1) - Correct answer is a major incretin hormone Incretins enhance beta-cell mass and replenish intracellular stores of what? - Correct answer Insulin. Amylin, what is it? - Correct answer (Islet amyloid polypeptide) is a peptide hormone co-secreted with insulin by beta cells in response to nutrient stimuli. adipose cells and lymphatic cells. - Correct answer Gluconeogenesis in the liver. Glucose Glucocorticoids stimulate protein____________and inhibit amino acid uptake and protein synthesis. - Correct answer catabolism (The ultimate affect on the body) A major immune suppressant effect is a glucocorticoid-mediated decrease in the proliferation of T lymphocytes, primarily ____________________lymphocytes. - Correct answer T- Helper Lymphocytes. Glucocorticoids decrease immune and inflammatory response by decreasing ________________cell activity and suppressing synthesis, secretion, and actions of chemical mediators involved in inflammatory and immune responses. - Correct answer Natural killer cell activity Glucocorticoids inhibit bone______, ADH_________, and stimulation of _____________acid secretion. - Correct answer Formation, ADH secretion, and gastric High levels of glucocorticoids increase circulating______________leading to ______________. - Correct answer erythrocytes leading to polycythemia. High levels of glucocorticoids also increase________________ - Correct answer Appetite and promote fat deposition in face and cervical area. Cortisol is the most ________________of the naturally occurring glucocorticoids. - Correct answer Potent What is the main secretory product of the adrenal cortex? - Correct answer Cortisol What does cortisol do in the body? - Correct answer Protects from stress What organ deactivates cortisol? - Correct answer The liver Secretion of cortisol is regulated by? - Correct answer Hypothalamus and anterior pituitary ACTH peaks 3-5 hours after what? - Correct answer sleep begins ACTH declines throughout the? - Correct answer day Stress increases_____________secretion. - Correct answer ACTH Effects of ACTH. - Correct answer Maintenance of gland size, depletion of ascorbic acid, activation of adenylyl cyclase, conversion of cholesterol to pregnenolone, accumulation of cholesterol and secretion of cortisol and adrenal androgens. Mineralocorticoids (Aldosterone) steroids directly affect what? - Correct answer ion transport by epithelial cells, causing sodium retention and potassium and hydrogen loss Aldosterone is the most potent of all the _____________________. - Correct answer mineralocorticoids Aldosterone acts to conserve___________ by increasing the activity of the sodium pump of the epithelial cells in the nephron. - Correct answer sodium Initial stages of aldosterone synthesis occur in the zone______and zona______. - Correct answer fasciculate and reticularis Aldosterone synthesis and secretion are regulated by the renin___________________. - Correct answer renin- angiotensin-aldosterone system. Two of the most important endocrine changes associated with aging effect the _________________gland and the ____________. - Correct answer Thyroid gland and pancreas Age related changes in Thyroid function include what? - Correct answer Decrease in TSH secretion, responsiveness to levels of TSH concentration to TRH administration is reduced, especially in men Approximately 40-50% of individuals have impaired ____________tolerance in the pancreas. - Correct answer glucose Certain organs are at risk when insulin resistance is evident which organs or systems are at greater risk? - Correct answer cardiovascular The decrease in the metabolic clearance of ______________in the adrenal glands is age-related - Correct answer glucocorticoids BEGIN CHAPTER 22 - ALTERATIONS OF HORMONAL REGULATION - Correct answer GOOD LUCK TO YOU!! INAPPROPRIATE AMOUNTS of hormone delivered to target cells results in alterations of hormone regulation. Inadequate hormone synthesis leads to inadequate quantity of hormone Tumors associated with SIADH - Correct answer small cell carcinoma of lung, duodenum, stomach, pancrease. Bladder cancer, prostate, endometrium, and lymphomas and sarcomas Pulmonary disorders associated with SIADH include> - Correct answer pneumonia, TB, asthma, CF, rest fail. requiring ventilation. Central nervous system disorders associated with SIADH? - Correct answer encephalitis, meningitis, intracranial hemorrhage, tumors and trauma In regards to the kidneys, what mutations cause SIADH? - Correct answer Mutations in arginine vasopressin (AVP) genes lead to chronic activation of tubular V2 receptor and results in excessive free water reabsorption. Any surgery can result in post-op fluid volume shifts and transient _______________for as long as 5-7 days post op. - Correct answer SIADH What factors cause post-op transient SIADH during surgery? - Correct answer Fluid and volume changes, IV fluids (amount and tyupe), and narcotic analgesics. Decreased hypothalamic function/anterior pituitary SEE diagram - Correct answer Transient SIADH is especially common after what type of surgery? - Correct answer pituitary What other medication can cause SIADH, especially in older adults? - Correct answer antidepressants, antipsychotics, narcotics, anesthetics, chemo agents, NSAIDs, quinolone antibiotics, and synthetic ADH analogs. Pathophysiologic affects of SIADH. - Correct answer Result in enhanced renal water retention. Water retention results from the action of ADH on renal collecting ducts where permeability to water is increased, increasing water reabsorption by the kidneys. Symptoms of SIADH - Correct answer Hypotonic (dilution) hyponatremia and hypervolemia and weight gain. Thirst, impaired taste, anorexia, dyspnea, fatigue and NA that decreased from 140 to 130 rapidly. Hypoosmolarity. Urine is ________________in SIADH - Correct answer concentrated Diagnosis of SIADH includes what? - Correct answer Serum hypoosmolality <280mOsm/kg, and hyponatremia <135 mEq/L In SIADH osmolality is higher in urine than in plasma, that is why urine is ___________________. - Correct answer concentrated What solution (IV) corrects low sodium? - Correct answer Hypertonic saline, and fluid restriction Diabetes Insipidus is an insufficiency of what? - Correct answer ADH, leading to polyuria, and polydipsia (frequent urination and frequent drinking) What are the three types of Diabetes Insipidus? - Correct answer Neurogenic (hypothalamic), nephrogenic (renal), and polydipsic (polydipsia-polyuria syndrome) What causes neurogenic DI? - Correct answer Brain tumors (primary or secondary), aneurysms, thrombosis, infection and immunologic disorders Nephrogenic DI is caused by? - Correct answer Insensitivity of the renal collecting tubules to ADH. Diseases of the Anterior Pituitary include? - Correct answer Hypopituitarism, Hyperpituitarism (primary adenoma), Acromegaly (Hypersecretion of GH), hypersecretion of prolactin. Most common of the hormonally active pituitary tumors are called what? - Correct answer prolactinomas (hormones that secrete prolactin) they are either microprolactinomas (<1cm) or macroprolactinomas (>1cm). Which of the two types of pituitary tumors (prolactinomas), micro or macro, are most invasive? - Correct answer Macroprolactinomas commonly expand into the optic chasm and invade local structures. What are the physiological actions of prolactin? - Correct answer breast development during pregnancy, postpartum milk production, and suppression of ovarian function in nursing women. Describe Acromegaly. - Correct answer Excessive levels of GH and concomitant elevation of IGF-1. Giantism? - Correct answer In children and adolescent whose epiphyseal plates have not yet closed, the effets of increased GH level on long bone growth is termed giantism. Hypopituitarism? - Correct answer failure or absence of all pituitary hormone function. What is DiGeorge syndrome? - Correct answer A genetic syndrome associated with hypoparathyroidism. Hypoparathyroidism results in a decrease in serum________levels and increased serum _________levels. - Correct answer serum calcium levels and increased serum phosphate levels. Hypomagnesemia can cause a decrease in _________secretion and function. - Correct answer PTH Diabetes Mellitus is a dysfunction of what endocrine organ? - Correct answer Pancreas Type I is a absolute______________deficiency resulting from ____________cell destruction. - Correct answer Insulin, beta cell Type II is ______________resistance. - Correct answer Insulin Type II is strongly associated with? - Correct answer Genetics, hypertension and dyslipidemia What is MODY? - Correct answer Maturity onset diabetes of Youth MODY includes 6 specific what? - Correct answer Autosomal dominant mutations including genes for hepatocyte nuclear factor- 1a Other genetic factors associated with DM? - Correct answer Down, Klinefelter, Turner, Wolfram syndromes HgbAIC is greater than or equal to what? - Correct answer 6.5% in DM FPG of ________indicates Diabetes - Correct answer >126 Random plasma glucose of________is hyperglycemic. - Correct answer >200mg/dl Diabetes Type I is the loss of __________in the __________. - Correct answer beta cells, in the pancreatic islets Enteroviruses can cause_____________ - Correct answer Type I Diabetes Type I DM is a slowly progressive ______________ - Correct answer Autoimmune T cell-mediated disease that occurs in genetically susceptible individuals. The ratio of __________ to glucagon in the portal vein controls hepatic glucose and fat metabolism in Type I DM. - Correct answer insulin There is an environmental-genetic interaction responsible for type________diabetes, what are the risk factors? - Correct answer Type II, age, weight, lifestyle, activity, and family history.. Metabolic syndrome is what? - Correct answer Combination of central obesity, dyslipidemia, prehypertension, and elevated FBS. Polycystic ovarian syndrome also plays a role in developing______________ - Correct answer diabetes, and insulin resistance A group of insulin-sensitizing drugs, call the thiazolidinediones that modulate PPARy activity have been used in the treatment of_____________ - Correct answer Type II diabetes Glucagon is a hormone produced by______________ of the_____________and acts primarily in the ______________to increase blood glucose levels by stimulating glycogenolysis and glucogenesis. - Correct answer Alpha cells, pancreas, liver Glucagon acts as an____________to insulin. - Correct answer antagonist Another Beta-cell hormone is what? - Correct answer Amylin Amylin is _____________in both typeI and type II DM. - Correct answer decreased. What is the function of Amylin? - Correct answer Increases satiety, and suppresses glucagon release from the alpha cells. it also contributes to islet cell destruction through the deposition of abnormal amyloid polypeptide in the pancreas. DKA results when there is an absolute or relative deficiency of________________and an increase in the levels of insulin counterregulatory________________. - Correct answer Insulin, hormones What are the insulin counter regulatory hormones? - Correct answer catecholamines, cortisol, glucagon, and GH. Most common causes of DKA? - Correct answer infection, trauma, surgery, or MI Glycation? - Correct answer normal non-enzymatic process that involves the reversible attachement of glucose to proteins, lipids, and nucleic acids without the action of enzymes. diabetic retinopathy is the leading cause of what? - Correct answer Blindness in adults older than 60 with DM. (ptyalin), an enzyme that initiates carbohydrate digestion in the mouth and stomach. The pharynx and upper third of the esophagus contain - Correct answer striated muscle innervated by skeletal motor neurons. Swallowing occurs in two phases: - Correct answer the oropharyngeal (voluntary) phase and the esophageal (involuntary) phase. During the oral and pharyngeal phases of swallowing, food is segmented into a bolus by the tongue and forced posteriorly toward the pharynx as the tongue pushes upward against the hard palate. pyloric sphincter, - Correct answer relaxes as food is propelled into the duodenum. Functional areas of the stomach are the - Correct answer the fundus (upper portion), body (middle portion), and antrum (lower portion). Blood is supplied to the stomach by branches of the - Correct answer celiac artery The vagus nerve - Correct answer provides parasympathetic innervation and branches of the celiac plexus innervate the stomach sympathetically. Other neurons are intrinsic; that is, they originate within the stomach and respond to local stimuli and are components of the enteric nervous system. Extrinsic sympathetic fibers reach the stomach through the - Correct answer celiac plexus (solar plexus), whereas extrinsic parasympathetic fibers enter through the gastric branch of the vagus nerve. The stomach mucosa is impermeable - Correct answer to water, but the stomach can absorb alcohol and aspirin and other nonsteroidal anti-inflammatory agents. Swallowing causes the fundus to relax (receptive relaxation) to receive a bolus of food from the esophagus. Relaxation is coordinated by efferent, nonadrenergic, noncholinergic vagal fibers and is facilitated by - Correct answer gastrin and cholecystokinin, two polypeptide hormones secreted by the gastrointestinal mucosa. SELECTED HORMONES AND NEUROTRANSMITTERS OF THE DIGESTIVE SYSTEM∗ - Correct answer Gastrin Histamine, somatostatin, acetylcholine, bombesin(Gastric releasing peptide), acetylcholine, Secretin, Cholecystokinin Products of fat digestion, which are formed in the duodenum by the action of bile from the liver and enzymes from the pancreas, stimulate the secretion of - Correct answer cholecystokinin Intrinsic factor is necessary for the intestinal absorption of - Correct answer vitamin B12 and gastroferrin facilitates small intestinal absorption of iron. The parietal cells (oxyntic cells) within the glands secrete - Correct answer hydrochloric acid, intrinsic factor, and gastroferrin. Solids, fats, and nonisotonic solutions delay gastric - Correct answer emptying. The chief cells within the glands - Correct answer secrete pepsinogen, an enzyme precursor that is readily converted to pepsin (a proteolytic enzyme) in the gastric fluid. The major functions of gastric hydrochloric acid are to dissolve - Correct answer food fibers, act as a bactericide against swallowed organisms, and convert pepsinogen to pepsin. The vagus nerve releases ACh and stimulates the secretion of histamine and gastrin-releasing peptide (GRP), which stimulates release of - Correct answer gastrin Pepsin - Correct answer Acetylcholine, through vagal stimulation during the cephalic and gastric phases, is the strongest stimulation for pepsin secretion. Prostaglandins and nitric oxide protect the mucosal barrier by stimulating the secretion of - Correct answer mucus and bicarbonate and by inhibiting the secretion of acid. Intrinsic factor (IF), a mucoprotein produced by parietal cells, combines with vitamin B12 in the stomach.It is required for the absorption of vitamin - Correct answer B12 by the ileum. Atrophic gastritis and failure to absorb vitamin B12 result in - Correct answer pernicious anemia The phases of gastric secretion are the - Correct answer cephalic phase, gastric phase, and intestinal phase The small intestine is about 5 to 6 m long and is functionally divided into three segments: - Correct answer the duodenum, jejunum, and ileum SOURCES OF DIGESTIVE ENZYMES - Correct answer Salivary Glands: Amylase Lingual lipase Stomach: Pepsin, Gastric Lipase Pancreas: Amylase, Trypsin, Lipase-colipase etc In the liver, unconjugated bilirubin moves from plasma in the sinusoids into the hepatocyte. Within hepatocytes it joins with glucuronic acid to form - Correct answer conjugated bilirubin, which is water soluble Ingested fat absorbed by lacteals in the intestinal villi enters the liver through the lymphatics, primarily as - Correct answer triglycerides In the liver the triglycerides can be hydrolyzed to glycerol and free fatty acids and used to produce - Correct answer metabolic energy (ATP), or they can be released into the bloodstream bound to proteins (lipoproteins). Protein synthesis requires the presence of all the essential amino acids (obtained only from food), as well as - Correct answer nonessential amino acids deamination - Correct answer Within hepatocytes, amino acids are converted to carbohydrates by the removal of ammonia (NH3), a process known as deamination Aspartate aminotransferase (AST) - Correct answer AST transfers an α-amino group between aspartate and glutamate. Alanine aminotransferase (ALT) - Correct answer ALT transfers an amino group from alanine to α-ketoglutarate to form pyruvate and glutamate. Lactate dehydrogenase (LDH) - Correct answer catalyzes the conversion of lactate to pyruvate; LDH is widely distributed throughout the body and different isoenzymes are found in different tissues The liver contributes to the stability of blood glucose levels by releasing glucose during states of - Correct answer hypoglycemia (low blood glucose levels) and taking up glucose during states of hyperglycemia (high blood glucose levels) and storing it as glycogen (glyconeogenesis) or converting it to fat The liver alters exogenous and endogenous chemicals (e.g., drugs), foreign molecules, and hormones to make them less toxic or less biologically active. This process, called - Correct answer metabolic detoxification (biotransformation), diminishes intestinal or renal tubular reabsorption of potentially toxic substances and facilitates their intestinal and renal excretion. Chapter 41 Alterations of Digestive Function -