DIGESTIVE SYSTEM Flashcards
Bile salts help in:
a. Emulsification b. Propulsion c. Defecation d. Detoxification
Emulsification.
Bile salts help in breaking down larger fat molecules into smaller ones a process called emulsification. Propulsion is the act of moving contents along the tract. Passing stools is the act of defecation. Detoxification is neutralisation of harmful substances which largely happens in the liver.
Liver receives blood from:
a. Hepatic artery and portal vein b. Portal vein and hepatic vein c. Hepatic artery and hepatic vein d. Hepatic artery, hepatic vein and portal vein.
Liver receives blood from the hepatic artery and portal vein.
This is the principle bile pigment
Bilirubin is the principle bile pigment.
The liver cells perform all the functions, EXCEPT
a. Storage of glycogen b. Synthesis of bile salts c. Activation of vitamin D d. Secretes enzymes responsible for protein digestion
The liver stores glycogen. It synthesises bile salts that help in fat absorption. It also activates vitamin D. It however has no role in protein digestion.
Which of the accessory organs stores bile?
The gallbladder stores bile and the liver produces it.
These are composed of prominent lymphatic nodules that function in the immune response.
MALT is composed of prominent lymphatic nodules that function in the immune response.
What is the function of the villi in the small intestine?
The function of the villi in the small intestine is to increase the surface area for absorption and secretion
From the superior end downward, the three segments of the small intestine are _________
From the superior end downward, the three segments of the small intestine are the duodenum, jejunum, and ileum
What process is the primary function of the villi of the small intestine?
Absorption
Groups of lymphatic follicles present in the ilieum are called:
a. Peyer’s patches b. Haustra c. Tenia coli d. Lacteals
Groups of lymphatic follicles present in the ilieum are called Peyer’s patches.
The small intestine secretes all the following, EXCEPT
a. aminopeptidase b. enterokinase c. lactase d. lipase
The small intestine secretes aminopeptidase, enterokinase and lactase. The small intestine does not secrete lipase
Which sequence lists the regions of the large intestine in order, from the end of the ileum to the anus
cecum, colon, rectum, anal canal is the sequence of regions (of the large intestine) from the ileum to the anus.
Brush border enzymes digest all the following , EXCEPT
a. maltose b. nucleotides c. triglycerides d. dipeptides
Brush border enzymes digest maltose, nucleotides and dipeptides. The brush border enzymes do not digest triglycerides.
Arrange the segments of the colon in the sequence through which digested material passes prior to defecation: (1) sigmoid (2) transverse (3) descending (4) ascending
4, 2, 3, 1 - order of colon segments when digested material passes to be defecated.
Ascending, Transverse, Descending, Sigmoid.
The large intestine is divided into the caecum, ascending, transverse, descending, sigmoid colon and the rectum and anal canal.
Symptoms of diarrhoea, bloating, abdominal cramps may occur after consumption of milk and dairy products in individuals that fail to produce __________
lactase.
The peritoneum that attaches the large intestine to the posterior abdominal wall is
Mesocolon - The large intestine is attached to the posterior abdominal wall by a double layer of peritoneum called mesocolon.
Mesentry is the peritoneum of the small intestine. The greater omentum is peritoneal fold of the stomach and the falciform ligament is the fold that attaches the liver to the anterior abdominal wall.
Bacteria in the large intestine are responsible for all the following, EXCEPT
a. Fermentation of carbohydrates b. Production of vitamin K c. Decompose bilirubin to stercobilin d. Production of mucus
The production of mucous. The large intestine secretes mucus but it’s bacteria doesnt produce it.
Bacteria in the large intestine are responsible for:
- Fermentation of carbohydrates
- Production of vitamin K
- Decompose bilirubin to stercobilin
Gastrin is responsible for
Increases tone of lower esophageal sphincter
The mucosa of the large intestine secretes ______
The mucosa of the large intestine secretes mucus.
The large intestine secretes mucus but no enzymes. Small intestine secretes peptidase and lactase. The pancreas, stomach and tongue secretes lipase.
What is the job of the hepatocytes (liver cells)?
Hepatocytes secrete bile into the canaliculi (excretory and digestive). Hepatocytes are a specialised epithelial cell (functional) - making up 80% of the liver volume.
What are the bile canaliculi?
Bile canaliculi are canals that carry bile from the hepatocytes to the bile ducts.
Where does bile travel (after produced by the hepatocytes)
Bile travels from hepatocytes to bile canaliculi, to ductules to ducts. A left and right hepatic ducts unite to form the common hepatic duct.
The common duct joins the cystic duct to form the common bile duct.
The common bile duct enters the duodenum of the small intestine.
What are hepatic sinusoids?
Hepatic sinusoid are blood capillaries that contain “kuppfer cells” - phagocytes. They scavange worn out RBCs, WBCs, foreign materials, bacteria.
What is the portal triad?
The portal triad is in the liver and comprises of the bile duct, the hepatic artery branch and the hepatic vein branch.
What is the mucosa of the gallbladder made up of?
- Simple columnar epithelium
- No submucosa
- Three layers of smooth muscle
Contraction of muscle fibers ejects content into cystic duct
Serosa or visceral peritoneum
What is the function of the gallbladder?
Gallbladder functions: store & concentrate bile produced by the liver
What is the hepatic acinus?
The hepatic acinus is the smallest functional liver unit
What types of blood are there in the liver?
Oxygenated blood from hepatic artery. Deoxygenated blood (rich in nutrients) from hepatic vein.
Do drugs and supplements affect liver enzymes?
Yes drugs and herbal supplements can affect the elevated liver enzymes.
What is the bile like that is secreted by the liver?
- 800-1000ml of bile secreted by the liver each day.
- pH is alkaline, 7,4-8.4.
- Composed of water and cholesterol, bile salts (sodium and potassium), bile pigments - mostly billirubin (from breakdown of aged RBCs)
What is the function of bile?
The bile is excretory and secretory.
Bile helps to break down large lipid molecules, into small lipid molecules - by process of emulsification.
What is the function of the liver?
LIVER FUNCTIONS:
- Filtering waste (bacterias and poisons)
- Processing nutrients (metabolism - of carbohydrate, lipid, proteins)
- Storing fuel for your body (glycogen, vitamins, minerals)
SPECIFIC FUNCTIONS ALSO INCLUDE:
- Detoxification
- Phagocytosis
- Excretion of bilirubin
- Synthesis of cholesterol
- Activation of vitamin D
What is function of carbohydrate metabolism in the liver?
Maintains a proper blood-glucose level. Glycogen is the storage form of glucose, in the liver (used when blood-glucose levels are high). Glycogen can later be broken down when glucose is needed.
What is function of lipid metabolism in the liver?
Lipid metabolism in the liver:
- Stores some triglycerides
- Breaks fatty acids to generate ATP
- Synthesizes lipoproteins to transport fat
- Synthesizes cholesterol
Protein metabolism in the liver functions by way of_____
Protein metabolism in the liver essentially means taking the amino acids (which were broken out from proteins) and then using these aminos to create other proteins (which the body needs).
PROTEIN METABOLISM:
- Removes an amino group so amino acids can be used for either ATP production or carbohydrate metabolism
- Synthesize plasma proteins
Within which organ do most drugs detoxified? And where do hormones get metabolised?
Drugs are detoxified in the liver, hormones are metabolised in the liver
Where is bilirubin metabolised and excreted?
Bilirubin is metabolised in the small intestine and excreted in the feces.
Synthesis of bile salts in the liver assist with____
Synthesis of bile salts in the liver assist with lipid absorption.
The liver can store glucose in the form of glycogen. What else is stored in the liver?
In addition to glycogen (glucose) the liver also stores vitamins (A, B12, D, E, K) and minerals (Fe, Cu).
What do Kupffer cells do?
Kupffer cells are specialised macrophages that eat up dead cells, allowing phagocytosis to occur in the liver.
Why does the liver send nutrients (proteins, fats, cholesterol & vitamins) into your blood stream?
The liver send nutrients into your blood stream, to be used for energy and to build healthy tissue.
What is bile
Bile is a fluid that dissolves fat - takes place in eth small intestine. Fats need to be dissolved so they can be absorbed in the blood stream. Bile reaches the small intestine via small tubes (called ducts) that are connected to the liver cells. These ducts connect to become the bile duct, which carries bile from the liver to the gallbladder (holding area for the bile) then bile is delivered to the small intestine. Emulsification of bile takes place in the small intestine.
Can you live without a liver?
No you can not live without a liver.
The majority of digestions and absorption occurs in the _________
The majority of digestions and absorption occurs in the small intestine.
The small intestine is how long and wide?
The small intestine is 3M long, and 2.5cm in diameter.
What are the three parts of the small intestine?
The small intestine consists of the duodenum, jejunum & ileum
Tell me about the duodenum
the duodenum is the shortest part of the small intestine, connected to the stomach and the jejunum.
Tell me about the jejunum.
1 meter long, connected betweek duodenum and illeum
Digestion of carbohydrates occurs where / via which enzymes?
Carbohydrates are digested in the mouth via salivary amylase, and in the small intestine via pancreatic amylase & via the brush border enzymes (maltase, sucrase, lactase)
Digestion of protein occurs where / via which enzymes?
Protein digestion starts in the stomach as hydrocholoric acid unfolds protein, and pepsin breaks proteins in to peptides.
Then, in the small intestine, pancreatic digestive enzymes breaks down to peptides into amino acids. This also occurs via the brush border enzymes - aminopepidate and dipepidase.
Digestion of lipids occurs where / via which enzymes?
Lipids are digested in the mouth via lingual lipase, and in the small intestine via pancreatic lipase (triglycerides become fatty acids of monoglycerides). Bile also emulsifies lipid globulets in the small intestine.
What is the anatomy of the large intestine?
The large intestine is 1.5meters long and 6.5cm wide. It is the terminal portion of the GI tract.
Cecum > ascending colon > transverse colon > descending colon > sigmoid > rectum > anal canal
What are the functions of the large intestine?
The large intestine completes absorption (after small intestine where most takes place). It also produces certain vitamins, and is responsible for the formation and expulsion of feces.
Small intestine anatomy
3 meters long x 2.5cm wide.
Chemical digestion in large intestine includes…
No enzymes are secreted in the large intestine, however mucous is.
There is a lot of bacteria in the colon, which ferments. Undigested carbs become carbon dioxide and methane gas.
Undigested proteins become smaller substances (indoles) producing odor.
Decomposes bilirubin into stercobilin, producing brown colour.
How is feces formed?
After 3-10 hours in the large intestine, chyme becomes semi-solid in transverse colon (90% of water is lost) and it is now feces.
feces consists of
water, inorganic salts, dead epithelial cells, cellulose (indigestible parts of food) and bacteria
What are the phases of gastric secretion & motility?
Cephalic phase (stomach gets ready - though/small/sight of food) Gastric phase (perostalsis continues, influenced by hormones, puts chyme into duodenum) Intestinal phase (hormones decrease (CCCK< GIP) decrease stomach secretion & emptying) & increase intestinal activity.
