????? Digestion and Absorption

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?????Digestion and Absorption

• ? ?,PhD
• ???????????
• ?? 88206417, 88208252
• Emailxiaqiang_at_zju.edu.cn

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???????

• ??Movement
• ??Secretion
• ??Digestion
• ??Absorption
• ??Elimination

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Structure of the alimentary canal
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• Normal BER frequencies in the gastrointestinal
  system

?????basic electrical rhythm BER
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??????

• ?(??)????
• Enteric nervous system (intrinsic)
• ??(??)????
• Autonomic nervous system (extrinsic)

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????Gastrointestinal hormones

• ???????????????????????????????
• ???????????????????
• Gastrointestinal hormones,Gut hormones

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?????
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?????Mastication and swallowing
The swallowing reflex is coordinated by the
medulla oblongata, which stimulates the
appropriate sequence of contraction and
relaxation in the participating skeletal muscle,
sphincters, and smooth muscle groups.
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The coordinated sequence of contraction and
relaxation in the upper esophageal sphincter, the
esophagus, and the lower esophageal sphincter is
necessary to deliver swallowed food to the
stomach.
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• ??????
• ??????
• ????
• ????

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• ??Gastric juice??
• HCl
• ?????Pepsinogen
• ??Mucus
• ????HCO3-
• ???Intrinsic factor
• pH 0.9-1.5

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• ??-??????Mucus-HCO3- barrier

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??????(Helicobacter Pylori)
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????Pancreatic secretion
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• ??
• pH 7.88.4
• 1500 ml/day
• Isosmotic
• Components
• Pancreatic digestive enzymes secreted by
  pancreatic acini
• Sodium bicarbonate secreted by small ductules
  and larger ducts

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• Secretion of pancreatic digestive enzymes
• Carbohydrates -- Pancreatic amylase
• Pancreatic lipase
• Fat Cholesterol esterase
• Phospholipase
• Trypsinogen
• Proteins Chymotrypsinogen
• Procarboxypolypeptidase
• Proelastase

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?????Acute pancreatitis
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????Secretion of bile by the liver
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• ?????
• HCO3-
• Bile salts
• Phospholipids
• Cholesterol
• Bile pigments

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• ?????
• Emulsifying or detergent function of bile salts
• Bile salts help in the absorption of
• Fatty acid
• Monoglycerides
• Cholesterol
• Other lipids

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Big Droplets of Fat
Small Droplets of Fat
Micelles
Fatty Acids and Monoglycerides
Chylomicron Assembly
Distribution and Processing
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Preventing the cholesterol precipitation
gallstones
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?????

• ????????
• ???????????B???????K
• ??????????,?????????

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In the large intestine, active transport of
sodium, coupled with osmotic absorption of water,
are the primary activities. Microbes here are
active in the production of vitamin K.
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????Defecation reflex
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? ?Body Temperature
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? ?

• ??????????????????????????????
• ????Core temperature
• ????Shell temperature

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Normal core temperature
Site Mean value of temperature Standard deviation Range of variation of temperature
Axillary 36.79oC 0.357 36.0-37.4 oC
Oral 37.19 oC 0.249 36.7-37.7 oC
Rectal 37.47 oC 0.251 36.9-37.9 oC
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The circadian (about a day) rhythm of body
temperature persists even among patients in a
coma in addition to this basic rhythm, fevers,
exercise, and other activities can alter the body
temperature.
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Body temperature is a controlled variable that is
subject to homeostatic regulation. This
cartoon indicates some of the ways that
environmental factors can increase or decrease
body temperature.
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????

• ???????Autonomic thermoregulation
• ???????Behavioral thermoregulation

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??????????Hypothalamus
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?????Renal Physiology
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?????

• ?????????,???????
• ??????
• ??????????????????????
• ???
• ???
• ???????(erythropoeitin)
• ??(renin)
• 1,25-??????(1,25-OH2-D3)
• ????,????(PGE2, PGI2)

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??????????

• ??Filtration
• ???Reabsorption
• ??Secretion

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Substance X is filtered and secreted but not
reabsorbed.
Substance Y is filtered and some of it is
reabsorbed.
Substance Z is filtered and completely reabsorbed.
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Composition in the Filtration Fluid
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Structure of the Filtration Membrane
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???????

• ?????,?????
• ??????????Tm-G
• Tubular transport maximum for glucose
• ???Renal threshold for glucose
• Critical value of the plasma glucose
  concentration when the kidney begins to excrete
  glucose
• 160-180 mg/dL

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??

• ??1000-2000ml/24hr
• ??Polyuriagt2500ml/24hr
• ??Oligurialt400ml/24hr,?lt17ml/hr
• ??Anurialt100ml/24hr,?12hr????

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?????Antidiuretic hormone (ADH)

• ???????Vasopressin
• ?????
• ??????
• ??
• ????????????????
• ????

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Action of antidiuretic hormone on aquaporin (AQP)
transport. AC, adenylate cyclase AP1,
transcription factor AVP, arginine vasopressin
cAMP, cyclic adenosine monophosphate CRE, cAMP
response element CREB-P, CRE binding protein
EP3, prostaglandin receptor PGE2, prostaglandin
E2. (From Brown D, Nielsen S The cell biology of
vasopressin action. In Brenner BM ed Brenner
and Rectors The Kidney, 7th ed. Philadelphia, WB
Saunders, 2004, p 574.)
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???Water diuresis ???Diabetes insipidus
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????Hemodialysis
In a kidney-failure patient undergoing dialysis,
the blood is briefly removed from the body to be
circulated through a dialyzer, where dialysis
fluid and blood move in counter current
directions to remove nitrogenous and other wastes
and adjust osmolarity before the blood is
returned to the body.
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• ????Peritoneal dialysis

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