Physiology II Exam 5

what are the 4 pathways of activation of hormones in the GI tract?

1. paracrine (works on neighbor cells) 2. endocrine (travels through blood stream) 3. neurocrine (travels through nerves) 4. neuroendocrine (through nerve and into the blood stream)

Unique Aspects of Intestinal Motility • Duodenal Refluxes - Occur _____ - _____ times per hour - Duodenal/ileal motility reverses and returns ingesta into the muscular stomach - Mixing of distal ___________________ and ___________ content with proximal and stomach content - Serves to allow more complete digestion of food with a shorter gut • Colon (rectum): near continuous ___________________________ except during defecation

2 - 4; duodenal and ileal; antiperistalsis

Crop: Variation ‐ Hoatzin • Diet: ______% leaves • Crop Fermentation • Rough equivalent of rumination • Aka "_____________ Bird"

80%; Manure

What's Unique About the "Avian " GIT? • Calling it "The Avian GIT" > _____________ species! • Variations in anatomy for exploitation of feeding niches • Multiple manifestations of selection pressure over the millenia

9000

Summary: Clinical Aspects • Many clinical presentations - ___________________ - Traumatic (Beaks; Crops) - Infectious Diseases (Parasitic; Yeasts; Bacteria) - ____________________ causes of stasis - Surgical removal of foreign bodies - _______________ removal of foreign bodies (heavy metals) - Cloacal issues: ____________________, __________________

Anorexias; Iatrogenic; Gavage; Prolapses, Uroliths

Intestinal Anatomy • Duodenum - ___________________ Loop - ____________________ loop - ___________________ and ______________ ducts enter at distal end of descending loop • Ileum • _________________ _______________________- Attachment point of embryonic yolk stalk (umbilicus); Nominal point of differentiation between jejunum and ileum

Ascending; Descending; Pancreatic and biliary; Meckel's diverticulum

III. Regulation of Splanchnic Blood Flow Local Vascular Properties: • _________________________ ‐ is the ability of a local circulation to maintain a fairly steady blood flow in the face of fluctuating ________________ pressures. Autoregulation is mediated by release of ___________________ substances like histamine, and takes place primarily in the _________________ and __________. Autoregulation has a protective value because continued functioning of an organ depends on a steady flow of blood. • Escape ‐ The escape phenomenon is similar to autoregulation insofar as local _______________ _________________________ keep blood flow steady in the face of forces trying to decrease flow. Reductions in blood flow mediated by activation of _____________________ nerves are followed by restoration in blood flow to normal levels. • Re‐distribution ‐ _____________________ nervous stimulation can evoke a re‐distribution of blood flow within the wall of the gut that ________________ perfusion diminishes and _________________ blood flow increases about equally. • Oxygen Counter‐Current Exchange ‐ Counter‐current exchange of oxygen takes place in the _________ of the intestine. At the base of each villus the inflow and outflow vessels are within ______ to ______ _______ of one another, and some oxygen escapes from the arterialized blood to enter the _____________ without passing to the ____________________ at the villus tip.

Autoregulation; arterial; vasoactive; intestine and liver; vascular compensations; sympathetic; Sympathetic; mucosal; muscular; villi; 10 to 20 um; venule; capillaries

Egestion (aka Casting) • Gastrointestinal function unique to birds. • Ingested ___________, ________, or __________________ are compacted and orally egested. • Physiologically distinct from ruminating, regurgitating or vomiting • Sequence of Events - starts in the stomach - ____________________ contraction increased in frequency and amplitude about ______ minutes before egestion. - This process compacts the materials into a pellet and moves it into the lower esophagus. - _____ to ______ seconds prior to egestion, the pellet is moved orally by esophageal __________________________.

Bone, fur or feathers; Ventricular; 12; 8 to 10; antiperistalsis

ENTERIC NEUROPEPTIDES E. Gastrin ─ __________ Family - As an enteric neuropeptide, CCK stimulates __________ contraction and relaxation of the sphincter of ___________.

CCK; ileal; Oddi (sphincter that controls rate of bile and pancreatic fluid release into the intestines (duodenum?))

Hormonal Components of the Fight or Flight Response: • hypothalamus --(_________)--> anterior pituitary --(____________)--> adrenal cortex --> cortisol • Autonomic regulation is crucial for homeostasis in animals. ____________________ activity and __________________ activity in vertebrates change in opposite phases during sympathetic stimulation. The stage where circulatory activity is high and digestive activity is low is termed the "__________ or ____________" stage, while the stage where circulatory activity is low and digestive activity is high is termed the "_________ and ____________" stage. The autonomic nervous system originated in early vertebrate phyla and developed to its greatest extent in mammals.

CRF; ACTH; Circulatory; digestive; fight or flight; rest and digest

III. Regulation of Splanchnic Blood Flow Neurohumoral substances: • Adrenal medulla ‐ __________________________ (epinephrine, norepinephrine, dopamine) ‐ ________________ blood flow • Kidney ‐ ____________________ ____ ‐ stimulated by renin released from the kidney ‐ _________________ blood flow • Posterior Pituitary ‐ ____________________ ‐ constricts blood flow • Gastrointestinal Hormones ‐ ___________________ and _________ ‐ ________________ pancreatic and intestinal blood flow • Gastrointestinal Hormones ‐ _____________ ‐ __________________ blood flow to gastric mucosa

Catecholamines; constrict; Angiotensin II; constricts; Vasopressin; Glucagon and CCK; increase; Gastrin; increases

Features of the avian mouth • Beak • Palate - "cleft" - ________________ __________ (has fimbria along the borders) • Salivary glands and taste buds - Sub‐lingual salivary glands present in _______________________ birds • Tongue • Glottis (no __________________) • Pharynx • no digestion in upper G. I. despite ________________ in some

Choanal Slit (on the roof of the mouth); gramnivorous; epiglottis (there are muscles to seal the glottis but they don't do as good of a job); amylase

Intestinal Pathology • _________________ Infections • ______________ viruses: Corona spp • ___________________ infections

Coccidial; Enteric; Salmonella

Cloacal Anatomy - Several Components • Structural Components: - _____________________ (cranial part, receives material from GI tract) - __________________ (middle part, receives material from urinary tract) - _____________________ (caudal part) - Vent - Bursa of ___________________ (lymphoid) • Functions: intestinal, reproductive, and urinary products (& immune function) - Receiving - _________________ - Retention - Expulsion

Coprodeum; Urodeum; Proctodeum; Fabricious; Refluxing

IV. Clinical Signs of Liver Disease • _____________________/_____________________ - Hypoglycemia, hepatoencephalopathy (NH3, fatty acids, mercaptans, alkalosis) • _________________/______________ loss - Inflammation, infection, protein-calorie malnutrition, vomiting, diarrhea, disturbances in intermediary metabolism • ___________ - Autoimmunity, infection, inflammation, neoplasia • _________________ - Central mechanisms (hepatotoxins), inflammation, hypergastrinemia, ketosis • _________________ - Bile salt deficiency, concurrent intestinal disease, portal hypertension • _______________ feces - Biliary obstruction • Melena - Bleeding disorders, gastrointestinal inflammation/ulceration • Icterus - Primary liver disease, biliary tract disease/obstruction • _______________ - Portal hypertension, renal sodium retention, hypoproteinemia • Abdominal Pain - Inflammation, congestion • ______________ - Bone marrow suppression, hemolysis, gastrointestinal blood loss • ____________________ - Thrombocytopenia, thrombocytopathy • Hematuria - Infection, coagulopathy, calculi • _______________ - Photoactivation of soft tissue bile salts • Polyuria/Polydispia - Renal medullary solute washout, potassium depletion, hyperadrenocorticism

Depression/Weakness; Anorexia/Weight; Fever; Vomiting; Diarrhea; Acholic (pale colored feces); Ascites (fluid in the abdomen); Anemia; Petecchiae; Pruritis (itchy skin)

Drivers of Evolutionary Development of the Avian GI Tract: • __________ exploitation - powerful selection for variants that accommodate available food types • Flight - restricts development of variations - Weight __________________ - Weight ____________________ - Forelimbs not available for food handling • Predation - limits time for _______________ and food ingestion • Mouth (beak) ‐ Adapted as a "3rd" forelimb - - Food handling - Climbing - Grooming - Social Interactions

Food; reduction; distribution; foraging

Crop Pathology • Similar to Oral Pathology • Trichomoniasis (flagellated protozoan) • Candida albicans (yeast) • Traumatic: - ___________-_________ - ____________ - overheated feeding formula (skin in the crop starts to weaken and a hole can be burned through the skin)

Frost‐bite; Burns

Terminology • _________________ = chickens, quail, turkeys • Columbiform = ________________, doves • Gallinaceous = galliform in nature ‐ chickens • Gramnivorous, gramnivore = grain, seed eater • Carnivore = meat eater - raptors (bald eagle) - Piscivore = fish‐eater • Gizzard = muscular stomach of galliform • ____________________ = Simple stomach of a carnivore

Galliform; pigeons; Ventriculus

ENTERIC NEUROPEPTIDES D. Bombesin Family - _______________-releasing peptide (GRP) is the major bombesin in the mammalian G.I. tract. Roles: stimulation of release of gastrin, stimulation of ____________________ enzyme secretion.

Gastrin; pancreatic

Liver Metabolism in the Obligate Carnivore: Risks for the Development of Hepatic Lipidosis • Imaging Findings - Imaging may be helpful in documenting the lesion. ________________________ is a frequent finding in chronic cases; it may not be observed in early cases. __________________________ is more sensitive in determining early changes in the liver (hyperechogenicity) consistent with fatty infiltration.

Hepatomegaly; Ultrasonography

Liver Metabolism in the Obligate Carnivore: Risks for the Development of Hepatic Lipidosis • Diagnosis - _____________________ changes in the hepatic parenchyma at ultraonography have been cited as a pathognomonic finding, but these changes may be seen in other feline hepatic disorders. Diagnosis should be substantiated by __________________ cytology, or better still, tissue ______________ (percutaneous, trans-abdominal ultrasound guidance, laparoscopy, or open laparotomy). Aspiration cytology has weak ____________________ and ____________________, and may miss other more important diagnoses.

Hyperechoic; aspiration; biopsy; sensitivity and specificity

Stomach - Comparative Anatomy • Three Components: 1. Proventriculus - found with both types 2. _______________ ‐ connection between glandular stomach and lower unit (not present in carnivorous birds) 3. Ventriculus - (grinding or digestion) • ______________ stomach (e.g. raptors, piscivores) • _________________ stomach (gramnivores, omnivores, insectivores) * thin muscles kind of on top and bottom of ventriculus and thick muscles on the sides

Isthmus; Simple; Grinding

Gastro-duodenal Cycle: Gramnivores 1. _______________ closes 2. __________ muscle contracts 3. _______________ opens 4. Duodenal ____________________ sweeps ingesta aborad (downstream) 5. Relaxation of the _______________ and a contraction of the ___________ muscle - grinds food 6. Contraction of the __________________ stomach - last in sequence

Isthmus; Thin; Pylorus; peristalsis; isthmus; thick; glandular

Stomach Pathology • Foreign Bodies • ____________ Sloughing and ________________ blockage • Proventricular __________________ Disease

Koilin; pyloric; Dilatation

Beak & Mouth Pathology • Beak overgrowth: - Malnutrition - ___________ Disease • Traumatic - Beak _______________ • Tongue entrapment - foreign bodies • ___________________________ • ________________ ________________ (oral fungal infection)

Liver; ablation; Trichomoniasis (protozoa parasite that causes plaques in mouth); Candida albicans

Ventricular Motility: Carnivores • Digestion process - 3 phases 1. ____________________ Phase - mixing (short bursts) 2. _________________ Phase - digestion (long periods of quiescence) 3. ______________ ___________________ Phase - unique g.i. function

Mechanical; Chemical; Pellet egestion

Summary: Regulation of Motility • Neural - ____________________ ______________ pacemaker - intrinsic regulation of gastro‐duodenal cycle - External ____________ influences on endogenous patterns - decrease • Hormonal - related to food intake - Similar suite of hormones to those found in mammals - Hormones have different (sometimes opposite functions) - Selective breeding for _____________ has genetically altered presence & activity of some hormones involved in regulation of food intake at the level of the __________

Myenteric plexus; vagal; growth; CNS

More on PDD I think? • _____________________ virus attaches to ganglia of myenteric plexus • Incitement of _________________________ response (lymphocytic‐plasmacytic response) • Pathology follows directly from physiological disturbance

Neurotropic; inflammatory

Liver Metabolism in the Obligate Carnivore: Risks for the Development of Hepatic Lipidosis • Therapy - __________________ support is the cornerstone of therapy of this disorder. Most studies suggest that enteral feeding (by "forced" or encouraged feeding, pharyngostomy, gastrostomy, or enterostomy feeding tube) of commercially available cat foods will effect recovery in ______-_______% of affected animals. Biourge and his colleagues have characterized some of the metabolic changes that take place during fasting in obese cats. They have been particularly interested in the effects of protein, lipid, or carbohydrate supplementation on hepatic lipid accumulation during rapid weight loss in obese cats. They found that small amounts of ______________ administered to obese cats during fasting significantly reduced accumulation of ____________ in the liver, prevented increases in _________________ ______________________ activity, eliminated negative __________________ balance, and appeared to minimize ______________ catabolism. ________________________ supplementation reduced hepatic lipid accumulation, but metabolic abnormalities still developed. Lipid supplementation alone did not ameliorate hepatic lipidosis and even resulted in more severe lipid accumulation than under conditions of fasting alone. The use of ___________________________ agonists (e.g. diazepam, oxazepam, elfazepam) and _____-_________ agonists (e.g., cyproheptadine) as appetite stimulants has been encouraged in anorexic cats. These compounds particularly the benzodiazepine agonists, should be used with caution as they may exacerbate pre-existing hepatic ____________________________. Benzodiazepine agonists have been shown to worsen hepatoencephalopathy in other animal species through activation of the neuronal benzodiazepine/___________ receptor-chloride channel complex.

Nutritional; 90-95%; protein; lipids; alkaline phosphatase; nitrogen; muscle; Carbohydrate; benzodiazepine; 5-HT2; encephalopathy; GABA

ENTERIC NEUROPEPTIDES C. _____________ Family - Methionine-enkephalin, leucine-enkephalin, and dynorphin are the major opioids released from enteric neurons in the G.I. tract. Their major role(s) in the G.I. tract: ____________________ of absorption, __________________ of secretion, ___________________ of intestinal circular smooth muscle, thus stimulation of segmentation type motility.

Opioid; stimulation; inhibition; stimulation

Site of Inflammation in PDD (proventricular dilatation disease) • ____________________: Myenteric plexus - Located in _________________ - Grossly visible owing to lack of ______________________ muscle layer - Intrinsic regulator of gastric motility cycle

Pacemaker; Isthmus; longitudinal

Cloacal Pathology • ___________________ • Prolapses • ________________

Papillomas; Uroliths

ENTERIC NEUROPEPTIDES B. VIP/PHI ─ _________________ Family - VIP is the major enteric neuropeptide of this family, and it is released from enteric neurons in the G.I. tract. Major role(s) in the G.I. tract: ___________________ of G.I. smooth muscle, stimulation of _____________________ fluid (non-enzyme) secretion, secretion of ___________________ fluid.

Secretin; relaxation; pancreatic; intestinal

Consequences of Selection Forces: Compared to mammals, the avian GI tract is.. • ______________ • Lighter • ____________ • Variable in form and function within an individual and within a season • Unique physiology to allow for shorter tract - __________________ - _________________________ • __________ retention time and ________________ retention time is a LOT shorter in the avian GI tract

Shorter; Faster; Refluxes; Antiperistalsis; fluid; particle

ENTERIC NEUROPEPTIDES A. Tachykinin Family - ____________________ _____ is the major tachykinin member of this family. Substance P is released from enteric neurons in the gastrointestinal tract. Major role(s) in the G.I. tract: _____________________ of G.I. smooth muscle, stimulation of _____________________ enzyme secretion.

Substance P; contraction; pancreatic

Summary: Motility • Stomach and duodenum - coordinated cycles - ____________ and __________ Muscle contraction - Proventricular & Duodenal Contractions • Refluxes: - __________________ (2 - 4 times per hour; Coordinated with gastric cycle) - Colonic - ____________ - Cloacal ‐ Colon • Casting Mechanisms - Present in raptors, piscivores, insectivores - Means of egesting ______________________ material

Thick and Thin; Duodenal; cecal; indigestible

• For the sympathetic nervous system the pre-ganglionic cholinergic neruon is __________________________ and the post-ganglionic adrenergic neuron is ____________________________; and in the adrenals the hormones are ________________________ and ____________________________

acetylcholine; norepinephrine; epinephrine and norepinephrine

Molecular Mechanisms of the Fight or Flight Response: • Release of epinephrine from the _______________ ________________ and norepinephrine from ______________________ nerve endings activates _____-adrenergic receptors and leads to an increase in L-type ___________ currents in cardiac and skeletal muscle, which in turn increase the force of contraction of skeletal muscle, and the beating rate and contractility of the heart. This regulation of L-type calcium currents occurs through activation of ______________ ______________ _____-mediated phosphorylation of multiple targets in cardiac muscle, including the cardiac __________________ receptor/calcium release channel required for muscle contraction.

adrenal medulla; sympathetic; β; Ca2+; protein kinase A; ryanodine

V. Portacaval Shunt • Diagnosis - Affected dogs and cats may have only subtle laboratory abnormalities (mild increases in ALT & AST; mild hypo_____________________, hypo__________________, and hypo_________________________; low blood urea nitrogen; and microcytosis). Diagnosis is best achieved by coupling a liver ________________ test (bile salts and/or NH3 quantitations) to a liver _______________ technique, e.g., ultrasonography, scintigraphy, or contrast portal venography. Liver _____________ typically reveals hypoplasia of the portal tracts. • Prognosis and Therapy - The prognosis is generally good if recognized early in the course of the disease. Dogs and cats are best managed with surgical ______________________ or _________________ of the shunting vessel. Some animals, especially those with incomplete attenuation of the shunt, may still require lifelong supportive care following surgical repair.

albuminemia; glycemia; cholesterolemia; function; imaging; biopsy; attenuation or ligation

IV. Ischemia Re‐Perfusion Injury • Oxygen‐derived free radicals generated during reperfusion initiate a series of events that causes mucosal damage and disruption of the ______________. They directly damage cell membranes by forming __________ ____________________, which also leads to production of a number of inflammatory mediators derived from ________________________ (e.g., platelet activating factor and leukotrienes). These proinflammatory agents function as chemoattractants for _____________________, which migrate into the mucosa, release their own reactive oxygen metabolites, and cause further damage to the ________________ __________________ barrier. An initially minor effect from ischemia is thus amplified into very significant damage to barrier function. Additionally, the inflammatory mediators generated in the gastrointestinal tract can harm ______________ tissues, leading to systemic disease.

barrier; lipid peroxides; phospholipids; neutorophils; intrinsic epithelial; distant

II. Liver Function 9. Vitamin Metabolism - • The liver is importantly involved in vitamin metabolism. The liver produces _________ for absorption of fat-soluble vitamins (A, D, E, K), and the liver is an important site for vitamin _______________. • Vitamin A is stored in both ________________ cells and _____________________. About ______% of total body Vitamin A is stored in the liver, which represents a 1-2 year supply. The liver continues to release vitamin A to maintain normal blood concentrations despite reductions in its hepatic content. Liver and plasma vitamin A concentrations are reduced by _____________________, liver disease, or intestinal _________________________, but signs of deficiency do not appear until abnormalities become severe. • Fat-soluble vitamins K, D, and E require normal bile secretion for absorption. Vitamin _____ is essential for synthesis of the prothrombin-complex clotting factors. • Water-soluble vitamins, except for vitamin ________ (cobalamin), are readily absorbed from the small intestine. These vitamins are used primarily to make ___________________ for use in metabolic processes. Vitamin ____________________________, occurring primarily in hepatocytes, is required to produce some coenzymes. Thiamine is phosphorylated to thiamine pyrophosphate, primarily in the liver and kidney. _________________ acid is a precursor in pyridine nucleotide synthesis, and an initial step in its conversion is nicotinamide synthesis in the liver. Pyridoxine is phosphorylated to its active form in the liver, as is the transformation of pantothenic acid to __________________ ____. Folic acid is converted to its active form in the liver. Large amounts of all water-soluble vitamins except vitamin _____ are stored in the liver.

bile; storage; Kupffer; hepatocytes; 95%; malnutrition; malabsorption; K; B12; coenzymes; phosphorylation; Nicotinic; coenzyme A; C

Avian Crop Variations • Present in galliform (chickens & turkeys) and columbiform (pigeons) species - Pigeons: _______________ structure - Chickens, turkeys, ducks: _____________ out‐pouching • Diurnal Raptors: - Enlarged symmetrical region of esophagus= ________________ • Owls - no crop • Ratites - no crop

bilobed; single; ingluvies

Sympathetic nervous system activation is associated with: • Heart Rate - acceleration (tachycardia) • Lung - increased rate (tachypnea) and airway diameter (___________________________) • G.I. Tract - increased __________________ tone • G.I. Tract - __________________ of peristalsis, secretion, digestion, and absorption • Urinary Tract - __________________ of the urinary bladder • Metabolism - ___________________ blood glucose and lipolysis • Circulation - __________________ of blood vessels to skeletal and cardiac muscle • Circulation - ______________________ of blood vessels to smooth muscle • Optics - dilation of pupil (mydriasis) • Auditory - increased auditory acuity • Reproductive - __________________ of erection • Neural - disinhibition of spinal reflexes

bronchodilation; sphincter; inhibition; relaxation; increased; dilation; constriction; inhibition

II. Liver Function 4. Nucleic Acid Metabolism - • Although the main role of _____________________________________ synthetase is in the urea cycle, it is also involved in the biosynthesis of ____________________ nucleotides.

carbamoylphosphate; pyrimidine

II. Physiology of Gastrointestinal Blood Flow ‐ • The splanchnic circulation is arranged both in parallel and in series. Its three major arteries ‐ the ____________, _________________ ____________________, and ________________ _____________________ ‐ form an extensive anatstomotic network that is directed to the stomach, small and large bowel, spleen, pancreas, and liver. - The hepatic branch of the _____________ artery supplies the liver with _______% of its blood flow. From the other abdominal viscera, blood drains to the huge _____________ vein and constitutes the remaining 75% of the hepatic inflow. Therefore the liver has a ________________ blood supply. - The series of splanchnic vessels terminates with the hepatic veins, which drain nearly all splanchnic blood flow back to the ______________ ___________ ___________.

celiac, superior mesenteric, and inferior mesenteric; celiac; 25%; portal; parallel; caudal vena cava

GASTROINTESTINAL HORMONES C. Neurotensin - Released from the ileal mucosa, it may be involved in the regulation of _______________ ________________.

colonic motility

• The splanchnic circulation is more complicated, both anatomically and functionally, than most other regional circulations. The coronary circulation, for example, serves one major function, i.e., support of myocardial ____________________, but in perfusing the stomach, intestine, pancreas, liver, and colon, the splanchnic circulation sub‐serves __________ secretion from several organs, ______________ and _____________ transport of solutes and fluids in the intestine, motility from the esophagus to the colon, ___________________ digestion in the stomach and intestine, storage and release of blood, and a metabolic storage site for systemic and local/regional needs.

contractility; fluid; passive and active; hydrolytic

III. Regulation of Splanchnic Blood Flow Autonomic Nervous System: • Sympathetic Nerves ‐ When the sympathetic nerves are activated the initial response is ___________________ of arteriolar smooth muscle with a reduction in cross‐sectoinal __________ and a rise in __________________ to the flow of blood through the organ. As a result, there is an initial decrease in blood flow mediated by ____-____________________ receptors in vascular smooth muscle. This initial response is short‐lived, however, and blood flow returns to normal for several reasons: activation of vasodilating ____-____________________ receptors; _______________ induced vasodilation; increases in venous return, heart rate, and stroke volume; and, sympathetic ___________________ of hollow viscera. • Parasympathetic Nerves ‐ In secretory organs such as the gastric mucosa and pancreas, parasympathetic stimulation __________________ secretion; this evokes an increase in tissue metabolism, with consumption of _______________ and production of _________, and various metabolites. This result is ______________________ and increase in blood flow. In gut smooth muscle, however, ________________________ stimulates intestinal smooth muscle contractions which may generate high pressures and impede blood flow through the wall of the organ. • Intrinsic Enteric Nerves ‐ _________, released from intrinsic enteric neurons, is probably responsible for the neurally mediated component of vasodilatation during the _____________________ of lipids from the gut.

contraction; area; resistance; α‐adrenergic; β‐adrenergic; hypoxia; relaxation; increases; oxygen; CO2; vasodilation; acetylcholine; VIP (Vasoactive intestinal polypeptide); absorption

GI Tract Anatomy Outline 1. Esophagus, Crop (not all birds have a __________) 2. Proventriculus: __________________ stomach 3. Ventriculus: - _________________ stomach in seed‐eaters (gizzard) - paired musculature - Ventriculus in carnivores (no paired musculature) ‐ digestion 4. Intestine: Duodenum, ileum -- no ________________ as such 5. Ceca: not present in all birds - _________________ recovery - Water Balance: _______% urine by retrograde flow - Fermentation: energy from cellulotic sources

crop; glandular; Muscular; jejunum; Nitrogen; 20%

• Gastrointestinal tracts of a carnivorous hawk, an omnivorous chicken, and 4 herbivorous birds. - Note larger size of __________ in omnivore and herbivores, and particularly in hoatzin. - Ceca are small in ____________ and relatively large in _____________. Although ceca are relatively small in Hoatzins, Emus, and Ostriches, an expanded ______________ (Hoatzins), a much longer ______________ (Emus), or a much longer _____________ (Ostriches) compensates for this.

crop; hawks; grouse; foregut; midgut; colon

Gastrointestinal Motility: Gramnivores • Ventricular Motility: Coordinated gastroduodenal contractions - Isthmus ‐> thin muscles‐> ___________________ (pylorus opens)‐> thick muscles‐> ________________________ - Begins near pylorus and proceeds ___________________ (VD view) - about _____ cycles per minute (each 16 - 20 seconds)

duodenum; proventriculus; clockwise; 3

Colon • Dual Function Organ - Post‐ileal ingesta processing - Water balance (Additional method to achieving ____________________ and ____________ balance as opposed to similar functions achieved in mammalian kidney) - Receives material from Cloaca - _________________ ____________________ • Processes - Absorptive - Water Balance (________________________ sensitive; ________ and ________ absorption and secretion depending on status)

electrolyte and water; reverse peristalsis; Aldosterone; Na and Cl

Criteria for Gastrointestinal Hormones: 1. Found in gastrointestinal ____________________ cells, 2. Present in _______________, 3. Released by physiologic stimuli, 4. Infusion of the substance exerts identical effect, 5. Administration of __________________ blocks the physiologic event.

endocrine; blood; antibody

INTEGRATION OF GASTROINTESTINAL FUNCTION Definition of an event as the physiological result of hormonal action can be difficult: A. None of the peptides localized to gut ____________________ cells can be said to function exclusively as a gastrointestinal hormone. Many are found elsewhere in the body in _______________ (enteric or brain). For example, peptides such as CCK-8, ______________________, _________________________, and substance P occur in both gut endocrine cells and nerves. B. Gut endocrine cells may release peptides into the extracellular fluid from which they diffuse to, and act on, neighboring cells (___________________ effects), or they may act after delivery in the circulation (____________________ effects). C. In studies of release mechanisms it is often difficult to distinguish material derived from endocrine cells and neurons. D. Furthermore, the responses evoked by exogenous application of a substance may reflect actions normally exerted in ___________________, _____________________, or _____________________ regulatory systems. E. The situation is further complicated by the fact that, depending on the mode of administration, some peptides, e.g., the _______________, may act both directly on the gut and indirectly via sites in the __________.

endocrine; neurons; neurotensin, somatostatin; paracrine; hormonal; paracrine, endocrine, or neurocrine; opioids; CNS

Liver Metabolism in the Obligate Carnivore: Risks for the Development of Hepatic Lipidosis • Clinical Features - Most studies suggest that there are no breed, sex, or age predilections. A recent retrospective study by Center and her colleagues suggests that ______________ and _____________-age cats are at greater risk for the illness. _______________ may be a predisposing factor, although the syndrome readily develops in fit animals. It has been suggested that obesity followed by a period of _________________ and weight loss are particularly at risk. Cats affected with this syndrome are often presented with a complaint of anorexia, often of several weeks duration. These cats are also commonly presented with _________________. Other reported clinical signs include _________________, ___________________, weight loss, and diarrhea. Physical examination often reveals dehydration, ________________, jaundice, and _______________________. All of these findings are also reported in cats with acute _______________________ and other hepatobiliary disease.

female and middle-age; Obesity; anorexia; jaundice; vomiting, weakness; cachexia (wasting syndrome); hepatomegaly; pancreatitis

II. Liver Function 5. Coagulation Factors - • The liver synthesizes plasma clotting factors I (___________________), II (_____________________), V, VII, VIII, IX, and X. Factors _____, _______, ______, and ____ are vitamin K-dependent clotting factors. The most important factors in liver disease are those with the shortest half-lives, factors ______ and _______.

fibrinogen; prothrombin; II, VII, IX, and X; VII and VIII

Summary: Anatomy • Beaks - many forms - suited to __________ habits • Crop - external storage, slow release • Stomach: - Glandular & Muscular components - Simple stomach - ____________________ - Gizzard - ______________________ - Secretes: _____________, __________, ____________ layer • Intestines: - Duodenum and Ileum - Generally shorter than in mammals of comparable size - __________________ - "compensate" for shorter tracts • Ceca: - Variable presence - ___________ digestion - ________________ recycling - Water balance

food; carnivores; gramnivores; Pepsin, HCl, koilin; Refluxes; Fiber; Nitrogen

Trichomoniasis • Canker, _______________ (sore with a cheesy secretion in the mouth) • T.gallinae (columbiforms, passerines, raptors) ‐ pathogenic • Tri & Tetra.gallinarum (poultry - low path) • Nucleolus, axostile, 4 _______________ and undulating membrane.

frounce; flagella

Cecae & Colon • Variably present - Present in ______________________ birds (fowl) - ______________ cecae - seasonally variable in size - Also present in owls • Ascribed Cecal Functions: - ________________________ - cellulose breakdown - Absorption of nutrients: ________________ ____________ ____________; Amino acids Recovery (via microbial degradation of __________ Acid); ____________ balancing - electrolytes

gallinaceous; Grouse; Fermentation; Volatile Fatty Acids; Uric; Water

PARACRINE SUBSTANCES C. Adenosine - Major role as a paracrine substance is the inhibition of _______________ __________ secretion.

gastric acid

GASTROINTESTINAL HORMONES A. Gastrointestinal Hormone Families 1. Gastrin-CCK Family • Gastrin - Major role in stimulation of _______________ __________ secretion, stimulation of ___________________ enzyme secretion, and _____________ of the pancreas, stomach, and intestinal mucosa. • CCK - Stimulation of gallbladder _____________________, stimulation of pancreatic enzyme secretion, __________________ of the Sphincter of Oddi. 2. Secretin Family - Known as "nature's ________________", in that secretin stimulates secretion of bicarbonate-rich fluid from the ________________, secretin stimulates bicarbonate secretion in _________, and secretin stimulates bicarbonate secretion from the __________________.

gastric acid; pancreatic; growth; contraction; inhibition; anatacid; pancreas; bile; intestine

PARACRINE SUBSTANCES D. Prostaglandins - Gastric prostaglandins are very importantly involved in the maintenance of the _______________ _________________ barrier, e.g., stimulation of _______________________ secretion, stimulation of mucous glycoprotein secretion, stimulation of mucosal _____________ __________, and stimulation of epithelial cell renewal. Prostaglandins also directly _____________ gastric acid secretion in the dog.

gastric mucosal; bicarbonate; blood flow; inhibit

V. Portacaval Shunt • Clinical Features - Affected dogs appear stunted, fail to ___________, and have clinical signs consistent with hepatoencephalopathy, e.g., _________________, ____________________, and _________________. Clinical signs of hepatoencephalopathy (HE) tend to wax and wane and are often interspersed with normal periods. Signs of HE may be exacerbated by a ______________‐rich meal, gastrointestinal hemorrhage, or by supplementation with ____________________‐containing urinary acidifiers. Gastrointestinal signs of intermittent anorexia, _________________, and diarrhea are common nonspecific features of hepatic dysfunction. _______/_______ is another common clinical sign in dogs with portasystemic shunting. Onset of clinical signs with ________________ and delayed recovery from ___________________ events are reported more frequently with canine portosystemic shunts.

grow; anorexia, depression, and lethargy; protein; methionine; vomiting; PU/PD; feeding; anesthetic

II. Liver Function 7. Porphyin Metabolism - • Porphyrins are intermediates of the __________ biosynthetic pathway. Porphyrins are found in hemoglobin, __________________, cytochromes, ________________, and peroxidase enzyme. The liver also serves as an __________________ route for the porphyrins. This is an important factor in the clinical manifestations of the porphyrias.

heme; myoglobin; catalase; excretory

I. Liver Structure • Cords of ________________________ are arranged radially around a _______________ vein. Between the hepatic cords course the sinusoids, which are spaces lined with _____________________ and analogous to capillaries. Between the sinusoidal endothelium and the hepatocytes is the lymphatic space of ___________. At the periphery of the lobule are several portal triads, each containing a ___________ vein, a ______________ artery, and a bile duct. Blood from the hepatic artery and portal vein flows ________________ in the sinusoids whereas bile flows ______________________ into ductules and from there into the _____________________ bile ducts in the portal triads. Bile draining into the __________________ reaches the ductules, which then empty into the bile ducts.

hepatocytes; central; endothelium; Disse; portal; hepatic; centrally; peripherally; interlobular; canaliculi

II. Liver Function 11. Metabolism of Xenobiotics - • Numerous foreign compounds, including drugs, are so ____________________ that they would remain in the body indefinitely were it not for hepatic _____________________________

hydrophobic; biotransformation

Control of Gastric‐Duodenal Motility Two Components: 1. Extrinsic: • CNS _______________________ centers • ____________ mediated • Vagal section (denervation) slows, but does not eliminate motility 2. Intrinsic • No __________ wave motility as in mammals • Intrinsic ____________________ coordinates gastroduodenal cycle: - Gastric cycle: ____________________ and ___________________ components - Duodenal contraction - coordination with stomach contractions

hypothalamic; Vagus; slow; Pacemaker; glandular and muscular

I. Fight or Flight Response When confronted with a stressful situation, animals behave in a rather predictable way, which has been described in the classic work by Cannon (1929) as a default set of reactions directed toward a "fight-or-flight" endpoint. Neurohormonal regulation of this behavioral response has been linked to the activation of neurons in the ________________________ and ___________ __________, leading to the increased input to the sympathetic preganglionic neurons regulating _______________ and _________________ medullary functions. Stress provokes the release of _______________________-releasing factor (CRF) which in turn increases the release of adrenocorticotropic hormone (____________) followed by the production of corticosteroids, and autonomic nervous system-induced release of ___________________________. The outcome of this cascade of reactions is both beneficial (modulation of energy metabolism, _________________________, ________________ and _________________________ reactions) and deleterious (_____________ ____________ and systemic hypertension). The ______________ components of the fight of flight response operate in the short term (seconds to minutes), whereas the __________________ components operate over the long term (hours to days).

hypothalamus and brain stem; cardiac and adrenal; corticotropin; ACTH; catecholamines; hemodynamics, immune and inflammatory; stress ulcer; neural; hormonal

III. Regulation of Splanchnic Blood Flow • Local Metabolism ‐ - Increased tissue metabolism resulting from the increased function of the organ causes tissue _______________ and generates release of many vasodilator metabolites such as _________, _______, and _________ ions, amines (histamine), ______________________ (bradykinin, VIP), lipids (prostaglandins), and _____________________ (adenosine, cyclic AMP). To a large extent the relationship of tissue metabolism to local blood flow is that of a servomechanism: increased metabolism consumes substrate and produces ______________ metabolites that increase blood flow to bring in more substrate; decreased metabolism has the opposite effect.

hypoxia (deficiency in the amount of oxygen reaching the tissues); CO2, K+ and Mg2+; polypeptides; nucleotides; dilator

PARACRINE SUBSTANCES B. Somatostatin - As a classic (i.e., non-G.I.) hormone, somatostatin ______________ growth hormone release, inhibits _____________ and ___________________ release, and inhibits TRH-stimulated TSH release. In the G.I. tract, somatostatin inhibits a number of other processes, e.g., inhibition of _______________ release (may be a paracrine effect), inhibition of pancreatic secretion, inhibition of ______________________ contraction.

inhibits; insulin and glucagons; gastrin; gallbladder

Liver Metabolism in the Obligate Carnivore: Risks for the Development of Hepatic Lipidosis • Pathogenesis and Etiology - Feline hepatic lipidosis is now a well-recognized syndrome characterized by ____________________ accumulation of lipid with clinicopathologic findings consistent with _____________________ ____________________. The precise incidence of the syndrome is unknown but pathology surveys have revealed _____% of animals affected with this lesion. While some cases result from _________________ ________________, the majority of cases are felt to result from the ____________________ and biochemical peculiarities of the cat. It has been suggested, for example, that the cat is not very capable of regulating intermediary metabolism during ____________________. Although the biochemistry of this lesion has not been completely worked out, there are several biochemical and nutritional peculiarities that predispose the cat to this syndrome. Some of the known biochemical peculiarities of the cat are: (1) essentiality of dietary ________________ (2) low levels of hepatic __________________ (3) high dietary protein requirements (4) lack of hepatic enzymatic adaptation to low dietary levels of protein (5) relative insufficiency of intestinal _________________ 5-carboxylate synthase activity (6) relative insufficiency of intestinal and hepatic __________________ reductase (7) relative insufficiency of intestinal ornithine transcarbamylase (8) peculiarities in lipoprotein metabolism (9) differences in ______________ acid metabolism

intracellular; intrahepatic cholestasis; 5%; diabetes mellitus; nutritional; starvation; arginine; ornithine; pyrroline; glutamate; orotic

Liver Metabolism in the Obligate Carnivore: Risks for the Development of Hepatic Lipidosis • Laboratory Findings - Clinicopathologic findings are most consistent with an _____________________ ____________________ disorder. Therefore, the most consistent laboratory findings in hepatic lipidosis are increases in serum ________________, serum _________________ ______________________ activity, _______________ aminotransferase, and __________________ aminotransferase. Serum ALT and AST are less consistently elevated than ALP. Elevations in serum gamma-glutamyl transpeptidase are inconsistently seen. More severe and chronic lesions may result in hypo_________________, hypo_____________________, hyper____________________, low BUN, and coagulation abnormalities. A normocytic, normchromic non-regenerative anemia and mild leukocytosis are frequently found in these cats.

intrahepatic cholestatic; bilirubin; alkaline phosphatase; alanine; aspartate; glycemia; albuminemia; ammonemia

II. Liver Function 8. Metal Metabolism - • The liver stores _________ which can be toxic in excessive amounts (hemochromatosis). The amount of iron in the body is largely determined by regulation of its absorption in the upper small intestine. Iron is stored intracellularly as _____________ in a number of tissues, with the liver having a large storage capacity. When the capacity of the liver is exceeded, iron accumulates as _____________________. The liver incorporates copper into specific copper proteins such as ____________________ ____ oxidase, mitochondrial _____________________ oxidase, and ceruloplasmin. Mobilization of copper from hepatocytes takes place by two mechanisms- _________________________ and _________ secretion.

iron; ferritin; hemosiderin; cytochrome c; monoamine; ceruloplasmin and bile

- Bird gizzards are lined with a tough layer made of the carbohydrate-protein complex ____________, to protect the muscles in the gizzard

koilin

II. Liver Function 3. Lipid Metabolism - • The liver is involved in both intermediary metabolism of ____________ (triglyceride synthesis, fatty acid ___________________) as well as __________________ and _____________________ from the gastrointestinal tract (_________ _________ emulsification and ________________________ of ingested lipids).

lipids; oxidation; digestion and absorption; bile salt; micellarization

V. Portacaval Shunt • Pathogenesis and Etiology - Diversion of portal blood flow to the central circulation depletes the __________ of nutrients, hormones, and growth factors. Portosystemic shunts in dogs are both _________‐hepatic and __________‐hepatic, although most shunts arise outside the liver from the left ______________________ vein. Clinical signs of hepatoencephalopathy dominate the clinical syndrome because of inadequate hepatic clearance of enterically‐derived toxins such as __________________, mercaptans, ___________-____________ fatty acids, gamma‐aminobutyric acid, and endogenous benzodiazepines. Decreased hepatic blood flow and lack of hepatotrophic factors such as _____________, ____________________, and __________________ result in hepatic atrophy.

liver; intra; extra; gastrosplenic; ammonia; short‐chain; insulin, glucagons, and nutrients

II. Liver Function 10. Glutathione Metabolism - • Glutathione (GSH) is synthesized in most if not all ____________________ cells. The liver is particularly active and has relatively high levels of GSH. GSH performs a variety of physiologic and metabolic functions. These include __________ transfer reactions which seem to protect cell ____________________ and ________________, to promote thiol-disulfide reactions involved in protein ________________, protein _____________________, and catalysis, to provide reducing capacity for other reactions, and to detoxify __________________ ___________________, organic ___________________, free radicals, and foreign compounds. GSH also participates in the metabolism of various endogenous compounds.

mammalian; thiol; membranes and proteins; synthesis; degradation; hydrogen peroxide; peroxides

GASTROINTESTINAL HORMONES B. Motilin - The gastrointestinal hormone is very importantly involved in the induction and regulation of the __________________ _______________ _______________. The cyclic release of motilin from the small intestinal mucosa is thought to coordinate gastric, pancreatic, and biliary secretions with phase ______ of the MMC.

migrating motility complex; III

II. Liver Function 12. Hormone Metabolism - • Natural and synthetic hormones are metabolized in the liver. Thus, the liver metabolizes ______________________________ (aldosterone), ___________________________ (cortisol, corticosterone), and ________ steroids (androgens, estrogens, progesterone). Liver disease reduces the capacity for metabolic transformation.

mineralocorticoids; glucocorticoids; sex

Intestinal Function • Motility • Secretion • Digestion • Absorption • On a comparative basis the most significant known differences occur in ________________ __________________

motility patterns

II. Physiology of Gastrointestinal Blood Flow ‐ • The highest tissue flow occurs in the ______________ of hollow organs during their ____________ state of secretion or absorption (____-____ ______ of blood flow per gram of tissue). • The next highest tissue flow is observed in __________ organs, like the pancreas (________ ______ of blood flow per gram of tissue). • The lowest tissue flow occurs in the _________________ outer coat of hollow organs at ________ (________ ______ of blood flow per gram of tissue).

mucosa; active; 2‐4 ml; solid; 0.5 ml; muscular; rest; 0.1 ml

PARACRINE SUBSTANCES A. Histamine - Released from ________________ mast cells and ___________________________ cells, binds to histamine H2 receptors on ________________ (oxyntic) cells, and stimulates acid secretion.

mucosal; enterochromaffin; parietal

II. Physiology of Gastrointestinal Blood Flow ‐ • Each sizable branch of a splanchnic artery coursing over the serosal surface of the stomach or gut gives rise to smaller branches that penetrate the surface and _________________ coat of the organ, and eventually enter an extensive submucosal network of small arteries. From this network the _______________ __________________ originate and carry blood to the dense mucosal capillary beds. The submucosal vascular arrangement guarantees ____________________ _________________________ between segments of the gut and leads to great overlap in the distribution of blood by adjacent arterial branches. Such anatomical collaterialization helps provide protection against a total loss of blood flow to a segment of gut if its major arterial branch is occluded by a __________________ or _________________.

muscular; mucosal arterioles; circulatory communication; thrombus or embolus

Criteria for Enteric Neuropeptides: 1. Found in ________________, 2. Mechanisms for ______________________ exist, 3. Concentrated in nerve ___________________, 4. Released by _______________________ stimuli, 5. Application of the substance exerts identical effect.

neurons; biosynthesis; terminals; depolarizing

II. Liver Function 1. Carbohydrate Metabolism - • The liver is the center of carbohydrate metabolism through its role in maintining _________________________. Carbohydrate stored in the liver as glycogen is hydrolyzed to glucose via _________________________ when a need for glucose develops. When the glycogen available is insufficient, glucose is produced from _____________ ____________ by gluconeogenesis. Glucose is also produced from ________________ and intermediates of glycolysis, such as ______________ acid and ________________ acid. With inadequate glucose in the diet, blood glucose is maintained at the expense of body ________________. Body lipid stores are also depleted during starvation, although lipids do not participate in the maintenance of blood glucose other than serving as an alternate source of energy, since glucose cannot be synthesized from fatty acids.

normoglycemia; glycogenolysis; amino acids; glycerol; lactic acid and pyruvic acid; proteins

Normal Motility of Intestine • Very Rapid • Several ___________ movements of ingesta - Remixes with fresh ____________________ - Permits more complete ___________________ • Complementary to "avian condition" (lighter weight)

orad; secretions; absorption

III. Regulation of Splanchnic Blood Flow • General Hemodynamics ‐ - General hemodynamic factors include cardiac _____________, _________________ ________________ pressure, _______________ of the blood, and blood ________________. Drastic reduction in any of these factors is reflected rapidly by a fall in ____________________________ blood flow.

output; systemic arterial; fluidity; volume; gastrointestinal

Gastro intestinal cycle: Carnivores • Raptors: - No ______________ muscles> simplified gastroduodenal cycle. - A peristaltic wave originating in the _________________________ moves aborad through the _____________________ and into the small intestine.

paired; proventriculus; ventriculus

IV. Ischemia Re‐Perfusion Injury • The observed effects of ischemia reperfusion injury range from increased vascular _____________________ and consequent sub‐epithelial ______________, to massive loss of epithelial cells and _________. Even relatively mild damage to the epithelium disrupts barrier function and can lead to translocation of _________________ and ______________ from the lumen to the systemic circulation. A number of treatments are under development and testing to prevent this cascade of damage, including application of antioxidants such as ______________________ ____________________ and use of drugs such as platelet‐activating factor _____________________ to block the effect of inflammatory mediators.

permeability; edema; villi; bacteria and toxins; superoxide dismutase; antagonists

II. Liver Function 2. Protein Metabolism - • The liver is an important site of _______________ metabolism. Amino acids and proteins absorbed from the intestine or produced in the body are delivered to the liver. The liver ____________________ amino acids and can convert them to __________________________ and _____________. Deamination produces _____________-__________ acids, which can be metabolized for energy or used for synthesis of monosacchardies and fatty acids. The liver synthesizes amino acids from intermediates of carbohydrate and lipid metabolism by ___________________ and _________________________. • Amino acid transaminations: _________________ + alpha-ketoglutarate ↔ pyruvate + glutamate Aspartate + alpha-ketoglutarate ↔ oxaloacetate + glutamate • The liver synthesizes many proteins, including albumin and ___________________, most alpha-globulins, and some of the beta-globulins. _____________________ and clotting factors V, VII, VIII, IX, and X are produced in the liver, as well as ceruoplasmin, ferritin, and many serum enzymes. • The most important mechanism for detoxifying ammonia is conversion of ammonia to __________ in the urea cycle.

protein; deaminates; carbohydrates and lipids; alpha-keto; amination and transamination; Alanine; fibrinogen; Prothrombin; urea

Instances of Orad Propulsion of Ingesta (5) • Refluxes of GI contents (orad movements) 1. gizzard to _______________________ during GD cycle 2. small intestine to _________________ (duodenal reflux) 3. colonic antiperistalsis 4. cloaca to _____________ or __________ (cecal filling) • (5) Egestion (casting) - special case in carnivorous birds • Thus, there are five circumstances where movement of gastro‐intestinal contents is __________

proventriculus; gizzard; colon or ceca; orad

IV. Ischemia Re‐Perfusion Injury • Reperfusion injury to the gastrointestinal tract, especially the mucosa, is thought to be due primarily to generation of _________________ ________________ ________________, including superoxide, hydrogen peroxide, and hydroxyl radicals. These oxidants are generated within the ______________ and also in the numerous local ____________________ activated during the course of ischemia.

reactive oxygen species; mucosa; leukocytes

IV. Ischemia Re‐Perfusion Injury • Damage to the gastrointestinal barrier due to ischemia and ____________________ injury is a common and serious condition. Ischemia occurs when blood flow is insufficient to deliver an amount of _______________ and __________________ necessary for maintenance or cell integrity. Reperfusion injury occurs when blood flow is restored to _________________ tissue. • Gastrointestinal ischemia results from two fundamental types of disorders, both of which can compromise the epithelial barrier: - ________-__________________ ischemia results from systemic conditions such as circulatory shock, _____________, or congestive heart failure - __________________ ischemia refers to conditions that directly disrupt gastrointestinal blood flow, such as _______________________, volvulus, or thromboembolism.

reperfusion; oxygen and nutrients; ischemic; Non‐occlusive; sepsis; Occlusive; strangulation

II. Liver Function 13. Immune Surveillance - • The "____________________________" system in the liver removes substances from the circulation that are harmful. It is most important in removing microbes, endotoxins, _____________________, and exotoxins from the portal circulation after their absorption from the intestine.

reticulendothelial; enterotoxins

II. Liver Function 6. Bile Secretion - • Bile is a slightly alkaline isosmotic solution of bile _________, bile _________________, _______________________, cholesterol, electrolytes, and ___________. Bile salts are synthesized from cholesterol and conjugated to an amino acid (usually _______________ or ______________). They are secreted into the biliary tract where they undergo storage in the gallbladder and are subsequently delivered to the small intestine. Intestinal bacteria may transform some of these primary bile acids into __________________ bile acids. Ileal re-absorption of bile salts permits _______________________ re-circulation; portal blood returns the bile acids to the liver for re-uptake, ________________________, and re-secretion.

salts; pigments; phospholipids; water; taurine or glycine; secondary; enterohepatic; reconjugation

Criteria for Paracrine Substances: 1. Mechanism for ___________________ exists, 2. Demonstration of peptide in _______________________ fluid, 3. Demonstration of peptide ____________________ on paracrine cell. 4. Effect demonstrated with __________________ cells.

secretion; extracellular; receptors; isolated

Esophageal Structures • Post‐pharyngeal (no __________________) esophagus - ___________ side of neck • Crop • Post‐crop esophagus

sphincter; Right

GASTROINTESTINAL BLOOD FLOW I. The Splanchnic Circulation ‐ The splanchnic (digestive tract plus ______________) vasculature constitutes the largest regional circulation that is derived from the aorta. More than ____/____ of the output from the left ventricle flows through the splanchnic vessels. The major function of the splanchnic circulation is to support the broad range of activities associated with the digestive system ‐ _______________, secretion, digestion, and absorption. In addition, the splanchnic circulation serves as a storage site for a large volume of blood that can be mobilized during _________________. The splanchnic circulation can be seriously affected by disorders of the _______________ circulation (e.g., congestive heart failure) and by ___________/__________________ diseases of the splanchnic circulation (e.g., arterial thrombosis, ischemia reperfusion injury, and portacaval shunting).

spleen; 1/4; motility; exercise; general; local/regional

Functions of the Crop • Food _______________: feeding strategies influence size • Digestion for _______________________ to feed young (penguins) • Crop _________ Production - pigeons/flamingoes - hormonal control (_________________) - Protein, fat and water - No ______________________ component - Fed to young by regurgitation

storage; regurgitation; milk; prolactin; carbohydrate