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40 terms

Digestion Lecture 29

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hepatocytes
arranged in lobules
sinusoids
--- in between hepatocytes are blood-filled spaces
kupffer cells
--- phagocytize microbes and foreign matter
bile
Pathway of --- Secretion:
-Bile canaliculi
-Hepatic ducts
-Common Hepatic duct
-Cystic duct from gallbladder and common hepatic duct join to form common bile duct
-Common bile duct and pancreatic duct empty into duodenum
gluconeogenesis
Liver functions in carbohydrate metabolism: turn amino acids into glucose
gluconeogenesis
Liver functions in carbohydrate metabolism: turn triglycerides into glucose
glycogenesis
Liver functions in carbohydrate metabolism: turn excess glucose into glycogen and store in the liver
glycogenolysis
Liver functions in carbohydrate metabolism: turn glycogen back into glucose as needed
Liver
--- Functions in lipid metabolism:
-Synthesize cholesterol
-Synthesize lipoproteins such as HDL and LDL, which are used to transport fatty acids and chlesterol in the bloodstream
-Stores some fat
-Breaks down some fatty acids
Deamination
Liver functions in protein metabolism:
---: removes NH2 (amine group) from amino acids so can use what is left as energy source
-Converts resulting toxic ammonia (NH3) into urea for excretion by the kidney
Transamination
Liver functions in Protein Metabolism:
---: Converts one amino acid into another
-Synthesizes plasma proteins utilized in the clotting mechanism and immune system
Detoxifies
Other liver functions: --- the blood by removing or altering drugs & hormones (thyroid & estrogen)
bilirubin
Other liver functions:
Removes ---: a waste product of red blood cell breakdown
bile salts
Other liver functions:
Releases --- to help digestion by emulsification of lipids
fat
Other liver functions:
Stores --- soluble vitamins, including A D E K
iron
Other liver functions:
Stores --- copper and vitamin B12
phagocytosis
Other liver functions:
--- of worn out blood cells and bacteria
vitamin d
Other liver functions:
Activates --- part of the vitamin activation pathway
Hepatitis
Liver disease:
Inflammation of the liver that can be caused by a variety of viruses, drugs or alcohol
- can lead to cirrhosis
Cirrhosis
Liver disease:
Scarred liver caused by chronic inflammation due to hepatitits, chemicals, parasites or alcohol
Pancreatic Juice
Composition and Functions of ---
1.5 quarts/day at pH 7.1 to 8.2
-contains water, enzymes & sodium bicarbonate
-Digestive enzymes: pancreatic amalyase, pancreatic lipase
trypsinogen
proteases: --- activated by enterokinase (a brush border enzyme)
chymotrypsinogen
proteases: --- activated by trypsin 1
procarboxypeptidase
proteases: --- activated by trypsin 2
proelastase
proteases: --- activated by trypsin 3
trypsin inhibitor
proteases: --- combines with trypsin produced inside pancreas
ribonuclease and deoxyribonuclease
proteases: --- digest nucleic acids
Secretin
Regulation of Pancreatic Secretion:
acidity in intestine causes increased sodium bicarbonate release
CCK
Regulation of Pancreatic Secretion:
Fats and proteins cause increased digestive enzyme release
smooth muscle
Function of the Large Intestine:
Mechanical digestion
peristaltic waves
Function of the Large Intestine:
3 to 12 contractions/minute
haustral churning
Function of the Large Intestine:
relaxed pouches are filled from below by muscular contraction; when full, they contract and move contents to next pouch
bacteria
Function of the Large Intestine:
--- ferment undigested carbohydrates into carbon dioxide & methane gas, and undigested proteins into simpler substances
Gastroilial reflex
Function of the Large Intestine:
when stomach is full, gastrin hormone relaxes ileocecal sphincter so small intestine will empty into large intestine
gastrocolic reflex
Function of the Large Intestine:
when stomach fills, a strong peristaltic wave moves contents of transverse colon into rectum
defecation
-Gastrocolic reflex moves feces into rectum
-Stretch receptors signal sacral spinal cord
-parasympathetic nerves contract muscles of rectum and relax internal anal sphincter
- external anal sphincter in voluntarily controlled
diarrhea
Digestive Health:
-chyme passes too quickly through intestine
-H2O not absorbed
constipation
Digestive Health:
-decreased intestinal motility
-too much water is absorbed
-remedies are fiber, exercise and water
insoluble fiber
Digestive Health Fiber:
-Woody parts of plants (wheat bran, vegetable skins)
-Speeds up transit time & reduces colon cancer
soluble fiber
Digestive Health Fiber:
-gel-like consistency -beans, oats, citrus, white parts, apples
-lowers blood cholesterol by preventing reabsorption of bile salts so liver has to use cholesterol to make more bils