The Lower Digestive System (Lecture 21) Flashcards
What are the major functions of the small intestines?
chemical digestion and nutrient absorption
Where does the small intestines get digestive enzymes from?
pancreas
What does bile come from?
liver
What does bile do in the small intestine?
emulsifies fat so it can be chemically digested
How long is the duodenum?
about 1ft
How long is the jejunum?
about 7-8ft
How long is the ileum?
about 10-11ft
What are the subdivisions of the small intestine?
duodenum, jejunum, ileum
What is the small intestine lined with?
simple columnar epithelium
What is the small intestine suspended by?
the mesentery proper
What does villi do for the small intestine?
increased surface area so absorption can happen
What are circular folds?
bumps in the small intestine
What do circular folds do?
act like speed bumps to slow food down
What is found inside the villi?
blood vessels and lacteals
What are the villi lined with?
simple columnar epithelium
Where are microvilli found?
apical surface of villar cells
What are microvilli collectively known as?
the brush border
What do microvilli contain?
brush border enzymes
What is an inguinal hernia?
intestines push through inguinal canal
What usually happens during an inguinal hernia?
the small intestine pushes through the inguinal canal
How far can an inguinal hernia travel?
all the way to the scrotum
What is an umbilical hernia?
intestines push through the rectus abdominis
What does the ileocecal valve do?
prevents stuff from going back into the ilium
How much does the large intestine absorb?
not much
What does the large intestine absorb?
water and electrolytes
What does the large intestine do?
forces feces toward rectum
What is the large intestine lined with?
simple columnar epithelium
What are mental appendages for?
protection and insulation
How many rectal valves are there?
three
What do the rectal valves do?
separate feces from gas so you don’t poop when you fart
What is the internal anal sphincter?
closer to the inside of the anal canal
What kind of muscle is the internal anal sphincter?
smooth muscle
What is the internal anal sphincter controlled by?
ANS
What is the external anal sphincter?
superficial to the internal anal sphincter
What kind of muscle is the external anal sphincter?
skeletal muscle
What is the external anal sphincter controlled by?
somatic nervous system
What do anal sinuses do?
produce mucus to lubricate anal canal
What is inflammatory bowel disease?
periodic inflammation of intestinal wall
What are the symptoms of inflammatory bowel disease?
cramping, diarrhea, weight loss, intestinal bleeding
What is ulcerative colitis?
a type of inflammatory bowel diesease
What are the accessory digestive organs?
pancreas, liver, gallbladder
Are the accessory organs part of the GI tract?
No
Are the accessory organs part of the digestive system?
Yes
What is the exocrine function of the pancreas?
produce digestive enzymes and secrete them through pancreatic ducts
What cells produce digestive enzymes int he pancreas?
acinar cells
What is the endocrine function of the pancreas?
produce insulin and glucagon
What are insulin and glucagon?
hormones produced in the pancreas
What produces insulin and glucagon?
pancreatic islets
What is the second largest organ?
liver
What is the liver’s digestive function?
produces bile
What is the liver’s functions associated with blood?
stores excess blood nutrients, detoxification of poisons and metabolites and drugs, clean out debris and old RBCs, and produces blood proteins
What are the blood proteins?
albumin, globulins, blood clotting proteins
Does the gall bladder produce bile?
No
What is a hepatocyte?
cell of the liver
What do hepatocytes do?
form bile
What does the hepatic lobule look like?
a stop sign shape
What does the gallbladder do?
stores and concentrates bile
What does the biliary tract do?
carries bile to the duodenum
What are gallstones?
crystallization of cholesterol or calcium and bile salts
What is the mesentery in the peritoneal cavity?
where two layer of the peritoneum come together and sandwiches blood vessels and other things
What does intraperitoneal mean?
in the peritoneum
What does retroperitoneal mean?
behind the peritoneum
What are the intraperitoneal organs?
stomach, jejunum ileum, transverse colon, sigmoid colon, appendix, liver, spleen
What are the retroperitoneal organs?
most of the duodenum, ascending colon, descending colon, rectum, pancreas, kidneys
What are mesenteries?
double layer folds of the peritoneum that suspend and support intraperitoneal organs
What does omentum mean?
apron
What is included in the term mesenteries?
greater omentum, lesser omentum, mesentery proper, mesocolon
