Chapter 24 - Digestive System
Symptoms of Hepatitis
1) Yellowish skin & eyes 2) Abdominal Pain
What are the 6 functions of the digestive system?
1. Ingestion 2. Mechanical processing 3. Digestion 4. Secretion 5. Absorption 6. Excretion "I'M Dead Sexy And Educated"
___________ pairs of salivary gland secrete into the oral cavity.
3 (the parotid, sublingual, and submandibular)
How many lobes does the human liver have?
4 right, left, caudate, quadrate
What happens after chyme arrives in the duodenum?
the intestinal phase begins: NEURAL RESPONSES - enterograstric reflex * inhibits gastrin production and gastric contractions * stimulates pyloric sphincter contraction to prevent further chyme discharge - local reflexes * stimulate mucus production HORMONAL RESPONSES - lipis and carbs stimulate secretion of CCK and GIP - pH below 4.5 stimulates secretion of secretin - partially digested proteins stimulate G cells to secrete gastrin
The dangling process that helps prevent food from entering the pharynx too soon is called
the uvula
Where is the appendix attached?
to the posteromedial surface of the cecum
The function of a lacteal is to
transport products of lipid digestion to the lymphatic system
At the hepatic flexure (aka right colic flexure), the colon becomes the
transverse colon
Enzymes secreted by the pancreas include
trypsin (as trypsinogen), amylase, lipase, nuclease, chymotrypsinogen
An obstruction of the common bile duct often results in _________.
undigested fat in the feces
Function of GIP
Exocrine = decreases gastric H+ secretion Endocrine = increases insulin release
An intestinal hormone that stimulates the release of insulin from the pancreatic islet cells is _________________.
GIP (gastric inhibitory peptide)
What are plicae circulares?
Plicae = folds, circulares = circular; thus, the circular folds of mucosa of the small intestine They are permanent features that do NOT disappear when the small intestine fills.
What are taeniae coli?
Three ribbon-like bands of longitudinal smooth muscle, running the length of the colon
A hepatic triad consists of
a bile ductule, a branch of the hepatic artery, and a branch of the hepatic portal vein
A drug that blocks the action of carbonic anhydrase in parietal cells would result in
a higher pH during gastric digestion
What are haustra and what is their function?
a series of pouches formed by the wall of the colon they permit the colon to expand and elongate
What is the function of pepsin?
an enzyme that digests proteins
What is the largest region of the stomach?
body
Which section of the stomach is known as the "mixing tank" for food and secretions?
body
What does the enzyme amylase digest?
carbohydrates
What part of the stomach connects to the esophagus?
cardia
What are the 4 regions of the stomach?
cardia, fundus, body, pylorus
An intestinal hormone that stimulates contraction of the gall bladder to release bile is ___________.
cholecystokinin (CCK)
The fusion of the hepatic duct and the cystic duct forms the
common bile duct
The duodenal ampulla receives secretions from the ___________.
common bile duct and the pancreatic duct
At the splenic flexure (aka left colic flexure), the colon becomes the
descending colon
Functions of the Kupffer cells of the liver
destroy damaged RBCs destroy bacteria present antigens are phagocytic
What stimulates the secretion of secretin?
drop of pH below 4.5 in the duodenum
Submucosal glands that secrete mucus are characteristic of which section of the small intestine?
duodenum
What part of the small intestine is most likely to develop an ulcer?
duodenum
Where is secretin produced?
duodenum
Which of these enhance the absorptive effectiveness of the small intestine? a) plicae circulares b) the villi c) microvilli d) intestinal movements e) all of the above
e) all of the above
The gastric phase of gastric secretion is triggered by the ________.
entry of food into the stomach
Which sections of the stomach secrete acid and enzymes?
fundus and body
Bile is STORED in the
gallbladder and is produced by the liver to help break down fats.
The hormone that stimulates secretion and contraction by the stomach is ___________.
gastrin
Peyer's Patches are found in the _____________ of the small intestine.
ileum
Where do G cells secrete?
in the pyloric gland
Functions of cholecytokinin
increase production and secretion of all digestive enzymes in the pancreas relax the hepatopancreatic sphincter and contract the gallbladder, ejecting bile and pancreatic juice into the duodenum
Functions of secretin
increase secretion of bile and buffers by the liver and pancreas inhibit secretions of chief and parietal cells
What is hepatitis?
inflammation of the liver
The endocrine function of the pancreas is to secrete what?
insulin and glucagon into the bloodstream to control blood sugar
The part of the digestive tract that plays the primary role in the digestion and absorption of nutrients is the
jejunum
The villi are most developed in the
jejunum
Where are plicae circulares found?
jejunum
Products of fata digestion are transported initially by
lacteals
The basic functional unit of the liver is the
lobule
Double sheets of peritoneum that provide support and stability for the organs of the peritoneal cavity are the
mesenteries
Carbohydrate digestion begins in the
mouth
What does the gastroileal reflex do?
moves some chyme to the colon in response to stretch receptors
Which layer of digestive tract contains the lamina propria and mucous epithelium?
mucosa
What layer of the digestive tract alters the shape of the intestinal lumen and moves epithelial pleats and folds?
muscularis mucosae of the lamina propria in the mucosa
What is between the layer of circular and longitudinal muscle in the muscularis externa?
myenteric plexus
The exocrine portion of the pancreas is composed of
pancreatic acini
How does the pancreas deliver digestive secretions to the duodenum?
pancreatic duct to the duodenal ampulla
Where is pepsin secreted?
pepsinogen is secreted by chief cells in the gastric glands which is converted to pepsin by HCl in the lumen of the stomach
What are the waves of muscular contractions that move the bolus along the digestive tract called?
peristalsis
Which structures enhance the absorptive effectiveness of the small intestine?
plicae circulares villi microvilli
What is the function of G cells?
produce gastrin which stimulates both parietal and chief cells, and contractions of the gastric walls
The pancreas produces __________-digesting enzymes in the form of proenzymes.
protein
The enzyme pepsin digests
proteins
What section of the stomach connects to the small intestine?
pylorus
What section of the stomach empties into the duodenum?
pylorus
Which section of the stomach secretes digestive hormones?
pylorus
Functions of the large intestine include
reabsorption of water and compaction of feces
Approximately the last 15cm of the digestive tract is the
rectum
In response to the hormone cholecystokinin, the pancreas secretes a fluid _________.
rich in enzymes
In response to the arrival of acid chyme in the duodenum, the blood levels of secretin ________________. rise or fall?
rise
What are the prominent ridges in the lining of the empty stomach called?
rugae
The intestinal hormone that stimulates the pancreas to release a watery, bicarbonate fluid is ___________.
secretin
Characteristics of the cardia include
smallest part of the stomach abundant mucus glands whose secretions coat the connection to the esophagus and protect it from stomach acid
Which salivary gland secretes a watery mixture rich in salivary amylase and bicarbonate ion?
submandibular
In which layer of the digestive tract are large blood vessels and lymphatics found in?
submucosa
In what layer of digestive tract are the sensory nerve cells, parasympathetic ganglia, and sympathetic postganglionic fibers located?
submucosal plexus of submucosa
Functions of the liver
synthesis and secretion of bile synthesis of plasma proteins inactivation of toxins storage of glycogen and iron reserves phagocytosis and antigen presentation removal of circulating hormones removal of antibodies
What is the saclike structure that joins the ileum at the ileocecal valve?
the cecum
What is the enormous pouch that extends inferiorly between the body wall and the anterior surface of the small intestine?
the greater omentum