Digestive System II Flashcards
!!What is the goal of eating? What is the main purpose of the small intestine? How is it highly adapted for nutrient absorption? Know how the following are absorbed by the intestinal tract: carbohydrate, proteins, lipids, vitamins (fat soluble vs water soluble), electrolytes, water, alcohol
Absorption
Absorption, increase surface area (villi, brush border), rolls chyme over (plicae), increases surface area w/o increasing volume
What are segmentations and what is their role? What is intestinal juice and what is its composition? What are the brush border enzymes. How are lipids absorbed? Know the path of lymph flow.
Segmentaions: localized mixing, sm. intestines, mechanical digestion, braings mass into ocntact w/ enzymes
Intestinal juice: H2O, enzymes ( sm. intestines brush border, pancreas bicarbonate and enzymes, liver bile) mucous, bicarbonate (increase pH of chyme)
Brush border enzymes: disaccharases, chymotrypsin, trypsin
Lipid absorption: bile salts surrounds lipid (micelles), moves to lacteal-lymph duct-enters blood between jugular and left subclavian veins
Lymph flow: sm. intestines inside villus lacteal is found-lymphatic vessel-thoracic duct-left subclavian vein-superior vena cava
What is lactose intolerance and what are its symptoms?
No lactase
Bacteria loive undigested lactose
Ferment it
Gas, diarrhea, bloating
H+ breath test
What is the role of the following enzymes in digestion: amylase, disaccharides (sucrose, lactase, maltase), lipases, nucleases, pepsin, trypsin, chymotrypsin.
Amylase: carbs
Disaccharides (sucrase, lactase, maltase): suagrs
Lipases: lipids
Nucleases: RNA/DNA
Pepsin: protein
Trypsin: protain
Chymotrypsin: protein
What is pancreatic juice and what are its main components? How is secretion of pancreatic juice regulated? The pancreas has both an endocrine and an exocrine function. What are these functions?
Pancreatic juice: pancreatic enzymes activated by brush border in sm. intestines, bicarbonate, pancreatic amylase, pancreatic lipase, nucleases, proteases, trypsin, chymotrypsin
Regulated by negative feedback
Endocrine: Islets of Langerhans (glucagon & insulin), provides negative feedback
Exocrine: digestive
Why do enzymes have to be activated by the brush border?
So it does not destroy the pancreas
??Know the functions of the liver. Know what would happen in the body if each of these functions failed.
Metabolic regulation, chemical storage & detox, defense, bile production, plasma proteins
Hepatitis, Cirrhosis
Know the function of the gall bladder. What are the main components of bile? Know blood flow to the liver and up to the heart.
Gallbladder: stores bile
Components: H2O, ions, bilirubin, cholesterol
Blood flow: O2/de-O2 blood- hepatic sinusoids- central vein- hepatic vein- inferior vena cava, right atrium of heard
How is bile release controlled? How is bile broken down?
Triggered by muscular activity
some excreted through feces
reabsorbed in sm. intestines
returned by blood to liver
What is hepatitis? Know the types of hepatitis and how they are transmitted?
Inflammation of liver
A, E: fecal-oral route
B, C, D, E: sex, blood, saliva, tears
D: co-infected with B
What is cirrhosis? What is the main culprit for cirrhosis?
Fatty liver
alcoholism & sugar
What are the functions of the large intestine? Know the movements in the large intestine. What role does bacteria play in the large intestine?
Defecation, sythasize B5 and K, absorption of H2O ions Na and Cl
Movements: Mass movement, haustral churning
Bacteria ferments undigestible material
What are the components of feces? What is fiber? What is its role in some chronic diseases?
Feces: H2O, salts, epthelial cells, bacteria, indigestible stuff
Fiber: Insoluble (keeps you regular), soluble (binds to cholesterol, removes it in feces
Benefits: less obesity, diabetes, CV disease, hemorrhoids, diverticulitis
Explain defection.
Pooping
1. Baroreceptor-sacral spinal cord
2. Motor impulse-parasympathetic-colon, rectum, anux
3. Opens internal sphincter
4. External sphincter voluntary control
5. Levator ani muscles contracts pulls anual canal up past poop
6. Helped by diaphragm and ab muscles
