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107 Cards in this Set
- Front
- Back
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Factors that affect oxygen delivery (3)
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1. CO: blood pumped by heart per min
2. a-v O2 difference: ration of arterial to venous oxygen concentration 3. arterial oxygen content (CaO2): dissolved oxygen + hemoglobin-bound oxygen (usually constant during exercise) |
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Contractility increases due to:
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sympathetic stimulation
increased HR increased catecholamines |
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Contractility is independent of _______
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fiber length
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Working muscles demand for oxygen met by
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increasing blood flow to working muscle
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Sympathetic vasoconstriction (redistribution of blood)
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reduces blood flow to vascular beds during exercise
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Muscle pump
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contracting skeletal muscles forces blood centrally
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Exceptions to blood redistribution during exercise (3)
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1. Skin
2. Brain 3. Heart |
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Response of skin to moderate intensity exercise
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vasodilation
-cooling response |
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Response of skin to high intensity exercise
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vasoconstriction to concerve CO
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Training increase in CO due to ________
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increase in SV
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Decreased resting HR through training due to ________
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increased vagal tone, decreased sympathetic activity
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Contractility results in _____________
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increased ejection fraction
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Physiological definition of heart failure
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• Pathophysiological state in which heart is unable to pump at a rate commensurate with requirements of metabolizing tissues or can do so only from elevated filling pressure
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Clinical definition of heart failure
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• Heart failure represents complex clinical syndrome characterized by abnormalities of left ventricular function and neurohormonal regulation, which accompanied by effort intolerance, fluid retention, and reduced longevity
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Heart failure: cardiac
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ischemic heart disease
valvular heart disease (obstruction to flow) myocardial injury (secondary to infection or drug toxicity) |
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Heart failure: extracardiac
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Work and demand exceed supply:
Hypertension & renal failure |
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What are the consequences for heart failure?
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Decreased CO
Increased left or right atrial pressure |
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Left failure consequences
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increased left atrial pressure
leads to pulmonary congestion and dyspnea |
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Right failure consequences
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increased right atrial pressure
leads to systemic congestion lower extremity edema |
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Name six predisposing factors to heart failure
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coronary heart disease
hypertension obesity cigarette smoking diabetes valvular heart disease |
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Decompensated failure:
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decrease in contractility worsens
SV not maintained muscle fibers stretched beyond optimal decreased effectiveness of increased EDV |
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Classification of shock
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cardiogenic, hypovolemic, vasogenic, neurogenic
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Common final event of shock?
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hypoxia
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Hemorrhagic shock
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fall in arterial pressure- massive blood volume loss
decrease: venous return, SV, arterial pressure, perfusion to organs |
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Digestive system performs which four processes
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motility, absorption, digestion, secretion
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Rapid transit in GI?
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Esophagus
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Slow transit in GI?
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Small intestine
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Secretion consists of?
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Water, electrolytes, organic constituents specific to digestive process (enzymes, bile, mucus)
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Polysaccharides
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starch/ glycogen
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Disaccharides: sucrose
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glucose and fructose
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Disaccharides: lactose
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glucose and galactose
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Triglycerides + digestion of TAG
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glycerol + 3 fatty acids
2 FA split off--> monoglyceride (glycerol + 1 FA) |
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Mucosa (three layers)
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mucus membrane: inner protective epithelial layer
Lamina propria: middle layer of CT (lymph tissue) Muscularis mucosa: outermost layer of smooth muscle |
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Mucus membrane cell types?
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Exocrine cells: secretion of GI enzymes
Endocrine cells: secretion of GI hormones Epithelial cells: absorption of digestive nutrients |
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Submucosa
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layer of CT-- distensibility
Contains: larger blood & lymph vessels submucosal plexus (meissner's plexus) |
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Muscularis externa:
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Smooth muscle layer
Inner circular layer: contraction decrease diameter Outer longitudinal layer: contraction decrease length Myenteric plexus: regulate gut activity |
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Serosa
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outer CT
serous fluid continuous with mesentery |
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What are the pacesetter cells of GI?
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Interstitial cells of Cajal
In myenteric plexus (muscularis externa layer) Slow-wave potentials-- rate of rhythmic contractions |
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ACh
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contraction
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Relaxation of smooth muscle
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Norephinephrine
Vasoactive intestinal peptide (VIP) Neuropeptide Y |
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Contraction of smooth muscle
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Acetylcholine
Enkephalins (opiates) Substance P |
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SNS
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slow GI tract
preganglionic fibers: short, synapse in ganglia outside GI tract Flight/fight resonse |
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PNS
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upper GIT: vagus n.
lower GIT: pelvic n. increase motility and secretion preganglionic fibers: long, synapse in walls of GI tract (myenteric/submucosal plexuses) |
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Hormones
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CCK
Gastrin Secretin |
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Paracrines
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Somatostatin
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Neurocrines
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Ach, NE, VIP
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Palate
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forms roof of oral cavity, separates mouth from nasal passages
allows breathing & chewing at same time |
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Uvula
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hangs down from palate
seals off nasal passage during swallowing |
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Tongue
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floor of cavity
voluntarily controlled skeletal muscle chewing, speech, taste buds |
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Pharynx
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cavity at rear of throat- links mouth to esophagus
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Tonsils
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lymphoid tissues used in defense
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Occlusion of teeth
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upper & lower teeth fit together when jaws closed
allows food to be ground between teeth |
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Three main purposes for chewing
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grind & mix food with saliva
stimulate taste buds Increase salivary, gastric, pancreatic, bile secretions-- prepare distal GIT for food |
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Which glands produce saliva?
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Parotid gland (serous cells produce aqueous fluid)
Submandibular gland Sublingual gland |
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Name the three salivary proteins
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Amylase, mucus, lysozyme
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Amylase
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breaks polysaccharides into maltose
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mucus
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facilitates swallowing- moistens food & provides lubrication
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Lysozyme
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antibacterial action- lyses bacteria
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Name the four functions of saliva
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1. solvent for molecules to stimulate taste buds
2. aids speech 3. keeps teeth & mouth clean 4. contains HCO3 buffers (prevent tooth decay) |
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Bradykinin
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Kallikrein-cleaves kininogen to bradykinin
vasodilator, increase BF to salivary glands |
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Cause of Xerostromia?
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decrease in saliva production
salivary gland infections, stones, mumps radiation, chemotherapy medications (BP, depression) |
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Symptoms of Xerostromia?
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dry mouth,
difficulty chewing/swallowing inarticulate speech increased dental caries, facial pain |
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Treatment for Xerostromia?
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no alcohol, tobacco, caffeine
sip water extra care of teeth |
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Upper sphincter of esophagus
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UES
pharyngoesophageal sphincter |
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Lower esophageal sphincter
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LES
gastroesophageal sphincter |
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Achalsia
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LES fails to relax during swallowing, food does not enter stomach
Tx: surgery, drugs to inhibit tone (botox, calcium channel blockers) |
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GERD
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LES: incompetent & gastric contents enter esophagus
occurs with increase in intra-abdominal P (obestity, pregnancy) |
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What are the three main functions of the stomach?
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Storage
Secretes HCl Mixing into chyme |
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30x change in volume in stomach but no change in which two things?
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Stomach wall tension and intragastric pressure
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Receptive relaxation of stomach
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vagovagal reflex
afferent and efferent limbs of reflex carried by vagus nerve |
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VIP
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postganglionic peptidergic vagal nerve fibers
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Peristaltic waves of stomach
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spread to antrum and pyloric sphincter (3/min)
upper regions- thin muscle-weaker antrum- thicker- stronger |
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retropulsion
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chyme hits a closed sphincter- pushed back to antrum
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STOMACH factors that modify gastric emptying
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amount of chyme in stomach (major)
stomach distension chyme fluidity: increase fluidity- faster emptying |
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How long does it take to empty gastric contents into duodenum?
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3 hrs for 1.5 L meal
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DUODENAL factors that modify gastric emptying (4)
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Fat, acid, distension, hypertonicity
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Six causes of vomiting
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touch stimulation
stomach/ duodenal irritation, distention increase cranial pressure rotation of head chemicals psychogenic factors (emotion, smell, anxiety) |
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secretion of gastric juice from cells in gastric mucosa (2 areas)
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oxyntic mucosa (lines body & fundus)
pyloric gland area (lines antrum) |
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Mucous cells (location & secretion)
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line gastric pits & entrance to glands
Secrete: thin watery mucus |
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Chief cells (location & secretion)
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line deeper parts of gastric glands
secrete: pepsinogen |
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Parietal cells
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line deeper parts of gastric glands
secrete: HCl & IF |
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ECL cells
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in gastric glands
secrete: histamine |
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Somatostatin
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D cells
Inhibits: HCl secretion, gastrin release, histamine release *from delta cells in pancreas *released when luminal pH low |
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Zollinger Ellison Syndrome
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Gastrin secreting tumors
increased H+ & duodenal ulcers & gastric mucosa hypertrophy |
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Antagonists
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Somatostatin
Prostaglandins EGF, TGF-a |
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Agonists
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Histamine
ACh Gastrin |
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CCKb
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equal affinity for gastrin and CCK
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CCKa
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specific for CCK
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Omeprazole
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inhibits H+/K+ ATPase, inhibits H+ secretion
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Three functions of HCl (assist with digestion)
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activates pepsinogen into pepsin
aids in breakdown of CT & proteins Kills microorganisms ingested with food (so does salivary lysozyme) |
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Three things decrease gastric secretion:
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meal moves from stomach to duodenum
foods leaves stomach-gastric juice accumulate Fat, acid, duodenal distension |
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Mucus is protective in three ways:
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protects against mechanical injury (lubricant)
protects stomach wall from self-digestion (inhibits pepsin) protects against acid injury (neutralizes HCl) |
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Pancreatic enzymes
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synthesized in RER & golgi of acinar cells
stored in zymogen granules relased by exocytosis |
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Pancreatic proteases
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digest protein
trypsinogen, chymotrysinogen & procarboxypeptidase (inactive) |
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Pancreatic a-amylase
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digest carbs
active- cleaves polysaccs into disaccs |
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Pancreatic lipase
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digest fat
active- hydrolyzes dietary TG into MG + 2FA |
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What is the largest part of pancreatic secretion
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aqueous NaHCO3 (1-2 L/day)
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Where does secretin come from?
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from S cells of duodenum (in response to H+ in duodenum)
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Secretin stimulates extralobular ducts, how does this effect HCO3 secretion?
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It will increase HCO3 secretion
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When does the majority of pancreatic secretion occur?
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during intestinal phase when chyme enters SI
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Name the two major enterogastrones
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secretin & CCK
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What are the 8 functions of the liver?
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Storage, removal of old RBC, Secretion, Excretion, Activation, synthesis, detoxification, produce cellular fuel
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What are the consequences of ileal resection?
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decrease bile salts recirculating, decrease bile salt pool, decrease lipid absorption, increase bile salt excretion, increase fat in fecal matter (steatorrhea)
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Choleretic
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any substance that will increase bile secretion by the liver
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Secretin
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increase bile secretion by the liver ducts
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What is the first role of bile salts?
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detergent action:
convert fat globules into lipid emulsion |
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What is the second role of bile salts?
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micelle formation- facilitate fat absorption
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