Test 1 Flashcards
What is the difference between the actual gastrointestinal tract and the accessory digestive organs?
The actual gastrointestinal tract must have a lumen through which food passes, while food does not pass through accessory digestive organs.
Name the structures of the alimentary canal (actual G.I. tract) from the mouth to the anus.
Mouth, oropharynx, Laryngopharynx, esophagus, stomach, duodenum, jejunum, ileum, cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, anus
Give examples of accessory digestive organs.
Salivary glands, liver, gallbladder, pancreas, teeth, tongue
What is ingestion?
Intake of food and/or liquids
What is mastication?
Chewing
Name a skeletal muscle that closes the mouth.
Masseter muscle
Which cranial nerves are involved in mastication?
Trigeminal (5)
What is deglutition? 
 swallowing
Which cranial nerves are involved in deglutition?
Trigeminal, facial, glossopharyngeal, Vagus, Hypoglossal
Does deglutition involve smooth muscle, skeletal muscle, or both? Explain.
Both, moving bolus from the oral cavity to the oropharynx is voluntary, but smooth muscle involuntarily moves bolus to the esophagus and then to the stomach by peristalsis.
What is mechanical digestion?
Physical grinding of food (mastication) to create more surface area for chemical digestion.
What is chemical digestion?
Enzymes are secreted in the mouth stomach and duodenum to chemically break down compounds due to the addition of water (hydrolysis)
Chemical digestion occurs by a process called hydrolysis. What does that mean?
Hydrolysis is the chemical breakdown of compounds due to the addition of water.
Is water a reactant or a product in a hydrolysis reaction?
Reactant
What is absorption?
Chemicals (monosaccharides, amino acids, fatty acids, Monoglycerides) move into the bloodstream.
Where does most absorption occur in the G.I. tract?
The small intestine, particularly the jejunum.
Where does food go once it is absorbed?
Liver
What is defecation?
Ridding of waste (fecal matter) which usually contains cellulose (which cannot be absorbed).
What is a peritoneum?
Serous membrane that lines the abdominal cavity and organs
What is a serous membrane? Name the two tissues that make up a serous membrane.
It secretes water.
- Simple squamous
with - Areolar tissue and blood vessels
underneath
What is parietal peritoneum?
Attached to wall of the abdominal cavity
What is visceral peritoneum?
Located directly on organs in the abdominal cavity
The space between the parietal peritoneum layer and the visceral peritoneum layer is called the ______________________. What does it do?
Peritoneal cavity; it contains fluid to reduce friction between organs
What is meant by intraperitoneal and retroperitoneal organs? Give examples of each.
Intraperitoneal organs are inside the abdominal cavity. (Ex:  stomach, spleen, liver, first and fourth parts of the duodenum, jejunum, ileum, transverse, and sigmoid colon)
Retroperitoneal organs are behind the abdominal cavity. (Ex: kidneys, adrenal glands, aorta, pancreas, duodenum, lymph nodes, prostate, vagina, rectum, inferior vena cava, ascending colon, descending colon
Parietal and visceral peritoneum are connected by folds of tissue called _______________. 
Mesentery
Where is the greater omentum located?
Fatty apron hanging down from the stomach
Where is the lesser omentum located? Which important blood vessels are located in the lesser omentum?
Between the stomach and the liver; hepatic portal vein, hepatic artery, lymph vessels
Where is the falciform ligament located?
It connects the liver to the diaphragm.
Where is the mesocolon located?
It connects the transverse colon to the parietal peritoneum.
Where is the mesentery proper located?
It connects the small intestine to the parietal peritoneum.
Which important blood vessels are found in the lesser omentum?
The hepatic artery, the portal vein, and lymph vessels
The walls of hollow organs (organs with a lumen) generally contain the four basic layers described below:
1. Mucosa: The mucosa is the layer that comes in contact with food (luminal side). The mucosa has three tissue layers. What type of tissue is found in each layer?
A.  epithelium
B. Lamina propria
C. Muscularis mucosa
A.  epithelium: (closest to free surface) simple columnar epithelium
B.  lamina propria: (contains blood vessels) loose areolar connective tissue
C. Muscularis mucosa: (Controls shape of mucus membrane) smooth muscle
The walls of hollow organs (organs with a lumen) generally contain the four basic layers described below:
- Submucosa with nerve plexus(submucosal or Meissner plexus): The nerve plexus of the submucosa regulates glands and the muscularis mucosa, and epithelium to regulate secretion.
- Submucosa: areolar connective tissue (Contains larger blood vessels that branch into lamina propria’s smaller vessels)
The walls of hollow organs (organs with a lumen) generally contain the four basic layers described below:
- Muscularis externa (2 layers?)
A. Inner circular layer of muscle- smooth muscle
B. Outer longitudinal layer of muscle- smooth muscle
Both work to achieve peristalsis.
Sandwiched between the circular and longitudinal layers is the _________________________ that carries impulses for the smooth muscle of the muscularis externa.
Myenteric (Auerbach) plexus
The walls of hollow organs (organs with a lumen) generally contain the four basic layers described below:
- Serosa or adventitia
4.  Serosa (Intraperitoneal organs): areolar connective tissue with simple squamous mesothelium
or
adventitia (retroperitoneal organs): Areolar connective tissue
Define the endocrine system.
Hormones secreted into the blood to act on a specific target organ.
Define the nervous system.
Nervous control of the digestive system involves intrinsic nerves (enteric nervous system) and extrinsic nerves (parasympathetic and sympathetic nervous systems)
Define the autonomic nervous system.
Parasympathetic, sympathetic, and enteric nervous systems. The autonomic nervous system can influence the enteric nervous system.
The parasympathetic nervous system ______________ motility and secretion in the G.I. tract.
 increases
The major Parasympathetic nerve intervating gastrointestinal organs is the _______  nerve.
 Vagus
The sympathetic nervous system ____________ motility and secretion in the G.I. tract.
 decreases
The enteric nervous system also includes _____________________ that can detect the presence of certain foods (chemo receptors) or stretch of an organ (stretch receptors)
sensory neurons
The ________ __________ _________ in the G.I. tract helps control motility and secretion. It includes both myenteric plexus and the submucosal plexus listed previously.
intrinsic nervous system
The enteric nervous system is influenced by the _______________ and ______________ nervous systems.
Parasympathetic; sympathetic
Define labia.
Lips
Define labial frenulum.
Tissue connecting the lips to the gums and bones.
Name the tissues found in the gingiva.
Keratinized Stratified squamous epithelium
What’s two bones make up the hard palate?
The Maxilla and Palatine processes
Why would the epithelium of the gums and the epithelium overlying the hard palate be partially keratinized stratified squamous epithelium?
To protect from abrasion from food.
What is the soft palate significance?
It lifts up to seal off the nasopharynx when swallowing.
What is the purpose of the uvula?
Works with soft palate to prevent food from entering the nasal cavity.
What is the purpose of the tongue.
The tongue, anchored to the hyoid bone, helps to create a bolus, and by mixing food with saliva.
Which cranial nerve innervates tongue muscles?
Hypoglossal
What is the purpose of the lingual frenulum?
It anchors the tongue to the floor of the mouth.
What is a bolus?
A ball of food in a specific shape to be swallowed
Name two functions of papillae located on the tongue.
They roughffin the tongues surface and they hold taste buds.
What is the function of the tonsils?
They gather and remove pathogens entering the pharynx in food or in the inhaled air.
Where are the parotid glands located?
Inside the retro mandibular fossa; posterior to the masseter muscle, inferior to the zygomatic arch, anterior to the sternocleidomastoid muscle
Where are the submandibular glands located?
Under the mandible.
Where are the sublingual gland located?
Under the tongue.
Which of the salivary glands has the longest duct?
The parotid glands
What type of cells make up parotid glands?
Serous cells
What type of cells make up submandibular glands?
Combination of serous cells and mucous cells.
What type of cells make up sublingual gland’s?
Mucous cells.
What are some functions of saliva?
Lubricate the mouth, initiate digestion process, ward off bacteria
Name at least 4 key components of saliva:
- Water
-  mucus
- Ions (Na+, K+, Cl+)
- Lysozyme and antibodies
What is the function of the enzyme, Amylase?
Breakdown carbohydrates
Where is amylase made?
Salivary glands (parotid) and The pancreas.
What is the optimal pH for Amylase?
7.0
By what process does amylase break down carbohydrates?
Hydrolysis
How is salvation controlled?
By the parasympathetic nervous system
Which cranial nerves innervate the salivary glands?
Facial and glossopharyngeal
Does parasympathetic stimulation increase or decrease secretion of saliva?
Increases
Which two bones have alveolar sockets for teeth
Maxilla and mandible
What are the functions of the incisors?
Biting, cutting
What is the function of the molars?
Grinding
What is the function of the canines?
Tearing
The number of secondary adult teeth generally follows the same dental formula for the top and bottom jaw: 4 incisors + 2 canines + 4 bicuspids+ 6 molars. this means adults have a total of _______________ teeth.
32
What are deciduous primary teeth?
Baby teeth
The number of deciduous teeth generally follows the same dental formula for the top and bottom jaw: 4 incisors + 2 canines + 4 molars. How many deciduous teeth are found in children?
20
Name each part of the pharynx below and the type of epithelium that is present:
- Nasopharynx- Pseudostratified columnar ciliated epithelium
- Oropharynx- stratified squamous epithelium
- Laryngopharynx- stratified squamous epithelium
Which parts of the pharynx are passageways for both food and air?
Oropharynx; laryngopharynx
Does the pharynx have skeletal or smooth muscle?
Skeletal muscle
The esophagus is ___________ inches long and located in the ____________________.
10;  mediastinum
What is the significance of the upper and lower esophageal sphincter’s?
The upper esophageal sphincter is made up of skeletal muscle. The lower esophageal sphincter is made up of smooth muscle. The upper esophageal sphincter closes after food enters and the lower esophageal sphincter opens.
Name the place where the esophagus perforate the diaphragm?
Esophageal hiatus
Is the esophagus anterior or posterior to the larynx and trachea?
Posterior
What are the four histological layers of the esophagus? What is unique about each layer that helps the esophagus perform its function?
-  mucosa- secretes, absorbs, protects
-  submucosa- secretes mucus
- Muscularis externa- peristalsis by circular and longitudinal layer contractions
- Serosa- reduces friction
Why is it significant that the upper esophagus contain skeletal muscle?
For voluntary swallowing
Deglutition involves three major phases. State what happens in each phase
A. Buccal (voluntary)- makes bolus of food and pushes into oropharynx
B. Pharyngeal (voluntary)- bolus passes through and stimulates tactile receptors/swallow reflex -> Trigeminal and glossopharyngeal -> swallow center(medulla oblongata) -> epiglottis folds and closes off respiratory tract -> food is directed towards esophagus
C. Esophageal (involuntary)- constrictor muscles of the Pharynx contract, forcing food into the esophagus inferiorly. Upper esophageal sphincter contracts (closes) after entry.
 What type of epithelium is found in the stomach mucosa?
Simple columnar epithelium
What is a gastric pit? How does it differ from a gastric gland?
Gastric pit: holes in the lumen of the stomach that branch into gastric glands.
What is the purpose of mucous cells in the lumen?
Protect against acidic gastric juices
List two products of parietal cells in the glands. What function does each product have?
1. H+- creates pH of 3 acidic stomach juices
2. Intrinsic factor-  aids in absorption of vitamin B12 (needed for red blood cell production and nervous function)
What is the zymogen (proenzyme) Made by chief cells in the glands?
Pepsinogen
Hydrochloric acid activates pepsinogen to pepsin. True or false?
True.
Why is the product of chief cells in the glands secreted in an inactive form?
It is important that pepsin is not activated until it reaches the lumen to mix with food or else it will digest the cell membrane of simple columnar cells.
What activates pepsinogen? What does it digest once it is activated?
Hydrochloric acid; pepsin digest proteins by hydrolysis
Name a product of the endocrine G-cells in the gastric glands of the stomach.
Gastrin (flows into blood vessels of lamina propria, goes through the body, comes back to the stomach to act on parietal cells to cause more acid to be made)
In general what is meant by the term enteroendocrine cell?
Intestinal hormone secreting
What type of tissue is found in the submucosa of the stomach
Loose connective tissue in the stomach
Dense irregular connective tissue is found in the esophagus, large intestine and small intestine
What are Ruege? Are Ruege folds of mucosa only or mucosa and submucosa?
Ruege are large visible mucosa and submucosa folds
Name the additional layer of muscularis externa present in the stomach.
1. Inner circular
- Outer longitudinal
- Inner oblique layer
Why does the stomach have three layers of muscularis externa?
For the mechanical processing of food to make chyme
Which layer of muscularis is closest to the submucosa?
Inner oblique layer
What types of tissues are found in the serosa of the stomach
Simple squamous mesothelium and connective tissue
What is the normal pH of stomach juice
pH 3
Is the hydrogen ion pump in the parietal cell membrane on the luminal side of the cell?
Yes
What parts of the small intestine are intraperitoneal and which are retroperitoneal?
Duodenum-  retroperitoneal
Ilium, jejunum-  Intraperitoneal
How long is the small intestine
18ft
What are microvilli (brush border)?
Folds of the cell membrane
What are villi?
Folds of the mucosa only
What are Plicae Circulares(Circular folds)?
Folds of the mucosa and submucosa.
Can plicae circulares easily be seen with the naked eye?
Yes
What kind of epithelium is found in the mucosa of the small intestine?
Simple columnar (for absorption)
Why are there so many goblet cells in the mucosa of the small imtestine?
To create a layer of mucus to protect stomach from acid
What is found in the laminapropria of a villus?
Extensive network of capillaries
What is a lacteal? What is its purpose?
It’s a lymph vessel- absorption of fat and transports materials that can’t enter the blood capillaries
Why does the small intestine have a brush border?
To increase surface area for food absorption
The individual extensions of the brush border are actually _____________.
Microvilli
Are enzymes embedded in the brush border? If so, name them.
Lactase, sucrase, maltase, dipeptidase
Where are intestinal glands (crypts of Lieberkühn)?
Deep between the villi
Which hormones are made by Enteroendocrine cells of the small intestine?
Secretin and CCK
Name a product of Paneth cells and its significance
Lysozyme -> antibiotic to prevent bacterial invasion into the lamina propria, submucosa, and bloodstream
Duodenal (Brunners) glands make _______________. Why?
Mucus; to provide protection from acid and neutralize stomach acid. 
ileum: aggregated lymphoid nodules (Peyer’s patches) consist of cells that ______ _______.
Destroy bacteria
Are lymphatic nodules only located in the ileum? What are lymphatic nodules?
No; aggregates of white blood cells
Blood that comes to the liver comes from two places:
- Oxygenated blood from the aorta (via the hepatic artery)
2. Deoxygenated blood with absorbed foods from the small intestine a (hepatic portal vein)
Both vessels (The hepatic artery and the hepatic portal vein) travel to the liver through a fold of peritoneum called the ________ ________.
Lesser omentum
_______________ contain blood that comes from branches of the hepatic portal vein and hepatic artery.
Sinusoids
The blood from the ________________ brings oxygen.
Hepatic artery
The blood from the ____________________ entering the sinusoid contains absorbed nutrients
Hepatic portal vein
What happens to excess carbohydrates when they are brought to the liver?
Broken down to glucose - Source of energy 
What happens to excess amino acids when they are brought to the liver?
Forms ammonia
What does the liver do with toxic substances that are absorbed into the blood in the small intestine?
Filtered by kidneys and leave body as urine
________ contain bile that is leaving the liver.
Bile canaliculi
What is the only digestive function of the liver?
Liver makes bile to allow enzymes of the pancreas to digest/emulsify fat easier
What is the function of bile?
Emulsify fats
Which cells make bile?
Hepatocytes
Describe what is meant by the term emulsification.
Breakdown fat into small droplets.
Bile contains…
Water, bile salts, bile pigment bilirubin, cholesterol
What is the function of bile salts
Emulsifies fat
Where does bile pigment come from?
It’s a breakdown product of hemoglobin in red blood cells
Bile flows from the common hepatic duct into the ________________ duct and then to the gallbladder.
Common bile
Before bile enters the duodenum the common bile duct merges with the _________.
Cystic duct
What is the hepato-pancreatic ampulla (ampulla of Vater)
Small opening that enters into the first portion of the small intestines
What is the significance of the hepato-pancreatic sphincter (sphincter of Oddi)?
Controls the entry of bile and pancreatic juices
Where is the gallbladder located?
Hangs off the liver - connected to bile ducts by cystic duct
Is the gallbladder an intraperitoneal or retroperitoneal Organ?
Intraperitoneal
Why does the gallbladder have rugae?
Allow for expansion
What happens to bile in the gallbladder.?
Stored and concentrated
What causes the gallbladder to release bile?
When we eat a lot of fat, CCK secretes, and the gallbladder contracts
What makes the duodenum secrete cholecystokinin (CCK)?
When fat enters duodenum
Can a person live without a gallbladder? What consequence would it have for a person not to have a gallbladder?
Yes;  diarrhea
Why do you gallstones often develop in the gallbladder?
Bile becomes too concentrated
Name some common components of gall stones
Cholesterol, Bile salts, bilirubin
What part of Deglutition is voluntary?
The buccal phase in the pharyngeal phase are somatic.
What part of deglutition is involuntary?
The esophageal phase is autonomic.
What is the role of the soft palette in Deglutition?
Closes off the nasopharynx to prevent food from entering airway.
Where is deglutition controlled?
Medulla oblongata
What is peristalsis?
Smooth muscle contractions “milk” food through the digestive tract due to the contraction of circular and longitudinal layers in the muscularis externa.
What plexus is located between the circular and longitudinal layers of the muscularis externa?
Myenteric plexus
To which nervous system does the myenteric plexus belong?
Enteric nervous system
Which part of the esophagus is comprised of smooth muscle?
The middle third is a mix of smooth muscle and skeletal; the last lower third is smooth muscle
Does the esophagus contain any skeletal muscle? If so, where?
Yes, the first upper third of the esophagus is made up of skeletal muscle.
Which nerve innervates the esophagus and increases peristalsis?
Vagus nerve (10)
Explain the pathogenesis of Gerd (gastroesophageal reflux disease)?
Stomach acid regurgitates up into the esophagus
Explain the pathogenesis of a hiatal hernia.
Abnormal relaxation or weakening of the Gastroesophageal sphincter.
How does the parietal cell make hydrochloric acid? Write the reaction below
H2O + CO2 + H2CO3 <=> H+ + HCO-3
What is the purpose of the hydrogen ion pump in the parietal cell membrane?
To produce gastric hydrochloric acid by pumping hydrogen ions into the lumen of the stomach
Name three functions of hydrochloric acid in the stomach
A. Increases acidity
B. denatures proteins and breaks down cell walls
C. Kills bacteria.
Name three chemicals that will increase acid production by the parietal cell
A. Histamine (paracrine)
B. Acetylcholine (neutral)
C.  gastrin (endocrine)
Why would it make sense for a patient with a stomach ulcer to take a histamine blocker?
Histamine blockers inhibit hydrochloric acid secretion
What are the two types of digestion
Chemical and mechanical
What is mechanical digestion
Churning aided by three layers of muscle
Why is churning important in the stomach
Causes breakdown of stomach contents
Is pepsinogen a zymogen?
 yes. Pepsinogen is the inactive form. Pepsin is the active form.
Why is pepsinogen secreted in an inactive form
To protect proteins in membranes from being digested by enzymes
Which cell secretes pepsinogen?
Chief cells
What activates pepsinogen?
Hydrochloric acid
What reaction does pepsin catalyze? By what process does that occur?
Hydrolysis of peptide bonds
What is chyme
Milky white substance of food mixed with gastric juice
Is chyme acidic or basic?
Acidic
What is the cephalic phase of stomach digestion
Thinking about or smelling food
Which nerves innervate salivary glands
The glossopharyngeal nerve innervates the parotid gland and the facial nerves innervate the sublingual and submandibular glands
Which nerve innervates gastric glands
Vagus
Is the cephalic phase of stomach digestion primarily under endocrine or nervous control
Nervous
What is the gastric phase of stomach digestion
When food reaches the stomach. The gastric phase is initiated by chemo receptors and stretch receptors of the stomach (enteric nervous system)
 name the primary hormone involved in Endocrine control of the gastric phase
 gastrin
What does gastrin do?
Closes the lower esophageal sphincter, promotes movement of churning chyme, promotes acid secretion of parietal cells
Which nervous systems play a role in the gastric phase?
Parasympathetic nervous system
What is the intestinal phase of Stomach digestion
When food reaches the small intestine. The intestinal phase is initiated by chemo receptors and stretch receptors in the wall of the duodenum
What is cholecystokinin (CCK)?
It is made when fat enters the duodenum. It causes release of bile, makes you feel full, causes contraction of the gallbladder, causes secretion of pancreatic juice rich in enzymes
What is secretin?
Made when hydrogen ions enter the duodenum. Makes pancreas make bicarbonate to bring pH to neutral levels in the duodenum
Where are these hormones (CCK and secretin) made and what do they do?
They are made in the duodenum. They block stomach secretion and shut down the stomach. Promote secretion of pancreatic juice.
What other target organs do CCK and secretin hormones have?
CCK targets the gallbladder, hypothalamus, and pancreas
Secretin targets the pancreas
Approximately how long is food in the stomach? What does that depend on?
2 to 6 hours; how much food and the types of food ingested.
What happens during vomiting
The diaphragm and abdominal wall contracts, gastroesophageal sphincter relaxes, soft palate rises closing off the nasopharynx, food is forced up and out.
Where is the vomiting center located
The emetic center in the medulla oblongata
_______ Enzymes will complete digestion of carbohydrates and proteins.
Small intestine
Although the small intestine does not secrete enzymes that digest __________, __________ digestion occurs in the small intestine.
Fat
The small intestine makes several important hormones such as _________ and __________.
CCK and secretin
__________ of food occurs in the small intestine. (nutrient absorption including 90% of water absorption)
Absorption
Approximately 9 L of water enters the small intestine each day. How much of the 9 L of water is absorbed in the small intestine?
90% or 8.1 L
The small intestine consist of three major parts:
Duodenum, Jejunum, ileum
Is the duodenum retroperitoneal or intraperitoneal
Retroperitoneal. It completes chemical digestion.
Is the jejunum intraperitoneal or retroperitoneal?
Intraperitoneal
What is the purpose of the ileum
Undigested matter passes into the large intestine through the ileum
At which valve does the small intestine begin?
The pyloric sphincter
At which valve does the small intestine end?
The ileocecal valve
Name the two layers of the muscularis externa
Inner circular and outer longitudinal
 Does the muscularis externa consist of smooth or skeletal muscle
 smooth
Which types of movements are possible in the muscularis externa of the small intestine?
Segmental contractions and peristaltic movement in the G.I. tract
What part of the small intestine would have adventitia?
The duodenum
What is segmentation and how does it differ from peristalsis?
Segmentation is the constriction of circular muscle fibers. Segmentation mixes food with gastric juices whereas peristalsis squeezes food along tract.
How is peristalsis controlled?
Involuntarily by the medulla oblongata and vagus nerve
The small intestine makes enzymes that digest ______ and ________. These are found in the _______________ of the small intestine.
Carbohydrates such as small disaccharides (Maltase, lactase, sucrase) and trisaccharides;
Peptides such as dipeptidases and aminopeptidases;
Brush border
What is the general digestive function of the liver
Produces bile
What is the general digestive function of the gallbladder
Stores and concentrates bile
What is the general digestive function of the pancreas
Produces pancreatic juices (enzymes) and hormones
The right and left lobes of the liver are divided by the ___________.
Falciform ligament
What are the other two lobes of the liver besides the falciform ligament?
Caudate lobe and quadrate lobe
Is the liver intraperitoneal or retroperitoneal?
 Intraperitoneal
Where is the pancreas located
Behind the stomach, between the spleen and the duodenum
Is the pancreas intraperitoneal or retroperitoneal
Retroperitoneal
What is meant by the head, the body, and the tale of the pancreas
The head is the closest to the small intestine, the tail is the smallest part and is at the end of the pancreas
Where is the head of the pancreas located
The right side of the body, encircled by the C-shaped duodenum
Pancreatic duct and accessory duct bring pancreatic juice to the ________.
Duodenum
Does the ampulla of Vater only contain pancreatic juice? Explain.
No, also contains bile.
Why does the pancreas have serous acini?
Secretes substances into ducts which then flows to duodenum
Why does the pancreas have pancreatic islets of Langerhans?
(endocrine) hormones made from islets go into blood through blood vessels contained in islets
Are there more serous acini or islets of Langerhans in the pancreas?
Serious acini
Name two hormones made by the islets of Langerhans:
- Insulin
2. Glucagon
Does the majority of the pancreas have an exocrine or endocrine function
Exocrine
What pancreatic enzyme digests carbohydrates?

 amylase
What pancreatic enzymes digest protein
Trysinogen, chymotrypsinogen, procarboxypeptidase
Why are these enzymes secreted in inactive forms pro enzymes or zymogens?
To prevent them from digesting proteins within cell walls of the pancreas or other organs
Explain how each of the pro enzymes below is activated and where the activation occurs:
Trypsinogen
Trypsinogen is activated to typsin by enterokinase in the duodenum.
Explain how each of the pro enzymes below is activated and where the activation occurs:
 chymotrypsinogen
Chymotrypsinogen is activated to chymotrypsin by Trypsin in the duodenum
Explain how each of the pro enzymes below is activated and where the activation occurs: 
Procarboxypeptidase
Procarboxypeptidase is activated to carboxypeptidase by trypsin in the duodenum
____________ Digests fat.
Lipase
Ribonuclease and ________________ digests _________ and DNA respectively.
Deoxyribosenuclease; RNA
Pancreatic enzymes break down food by the process, ____________.
Hydrolysis
What hormone causes the pancreas to make a secretion rich in enzymes?
CCK
Is enterokinase an enzyme in pancreatic juice? If not, where is it made?
No, It is made in mucosal cells of the duodenum
What is the function of enterokinase?
enterokinase (a protease) activates trypsinogen into Trypsin
What is the purpose of bi carbonate in pancreatic juice?
To raise the pH of contents in the duodenum
What hormone causes the pancreas to make a secretion rich in bicarbonate?
Secretin
Cholecystokinin (CCK): made by ___________ of the ______________. CCK stimulates the serous acini of the pancreas to secrete pancreatic juice rich in ____________.
I-cells; duodenum; digestive enzymes
Secretin: made by ____________ of the ___________. Secrete stimulates the serous acini of the pancreas to secrete pancreatic juice rich in _____________.
S-cells; duodenum; bicarbonate
Vagus Nerve: What is the effect of the parasympathetic nervous system on the pancreas?
Stimulates insulin secretion
What is jaundice?
Yellow skin caused by a buildup of bilirubin in the blood
Why might pancreatic cancer cause jaundice?
The cancer might block the liver’s bile duct
Why might liver disease cause jaundice?
Portal blood flow is distorted accompanied by a decrease in hepatic clearance of Bilirubin 
Why might a patient with pancreatitis have elevated levels of lipase and amylase in the blood
When pancreas is inflamed, an increase of blood levels of pancreatic enzymes results.
What are the three organs that make enzymes that digest carbohydrates?
Salivary glands, pancreas, small intestine
What enzyme is secreted by salivary glands?
Amylase
The enzyme catalyzes the digestion of
Polysaccharides + H2O -> _____________________
Monosaccharides
The enzyme amylase works by a process called
Hydrolysis
What enzyme digests carbohydrates in the pancreas
Pancreatic amylase
What are the three enzymes that digest carbohydrates in the small intestine
Lactase, sucrase, maltase
Write out the reactions that the enzymes catalyze in the small intestine for digesting carbohydrates.  The enzymes work by a process called __________.
Maltose + H2O = glucose + glucose
Sucrose + H2O = glucose + fructose
Lactose + H2O = glucose + galactose
Hydrolysis
What is the proenzyme and enzyme in the stomach that digests proteins?
Pro enzyme: pepsinogen; enzyme: pepsin
How is the proenzyme pepsinogen activated?
 Hydrochloric acid
The enzyme works by a process called ____________ and catalyze the digestion of
proteins + H2O  = _______________
Hydrolysis; Amino acids
 The pancreas makes pro enzymes _____, ______, and __________; which are activated to the enzymes: ________, _______, and __________.
• Proenzyme: trypsinogen = enzyme: Trypsin
• Proenzyme: chymotrypsinogen = enzyme: chymotrypsin
• proenzyme: procarboxypeptidase = enzyme: carboxypeptidase

How are each of these protein digestingpancreatic proenzymes activated?
Enteropeptidase activate trypsinogen.
Trypsin activates chymotrypsinogen and procarboxypeptidase.
These protein digesting enzymes in the pancreas work by a process called ______________ and catalyze the digestion of
Proteins + peptides + H2O -> ____________
Hydrolysis; amino acids
The small intestine makes the protein digesting enzyme : ________________.
Dipeptidase
Peptidase catalyzes the following reaction:
 Dipeptides + H2O -> __________________
Amino acids
what enzyme is secreted by the pancreas to digest fat?
Lipase
Which cells in the pancreas makes the enzyme lipase that digests fat?
Acinar cells
The enzyme lipase catalyzes the digestion of
Triglycerides + H2O -> ____________
Mono glycerides fatty acids
The fat digesting lipase enzyme works by a process called ___________.
Hydrolysis
Before the enzyme lipase can be affective in digesting fats, the fat must be emulsified by __________
Bile salts
Monoglycerides and fatty acids are brought to the epithelial cell by bile salts in structures called ____________.
Micelles
In which organ is the gastrin hormone made
Stomach
Which cells make the gastrin hormone?
G-cells
What causes the gastrin hormone to be made?
Food entering the stomach
In which organ is the cholecystokinin (CCK)?
Duodenum
Which cells make CCK
I-cells
What causes this CCK hormone to be made?
Fat
In which organ is the secretin hormone made?
Duodenum
Which cells make this secretin hormone?
S-cells
What causes secretin to be made?
Gastric acid
When food reaches the ____________, secretions from the liver and the pancreas are mixed with the food. This _______________ the pH (HCO3 bicarbonate in pancreatic juice)  and ads enzymes that breakdown fats, proteins, and carbohydrates.
Duodenum; raises
What forms do the following foods need to be in in order to be absorbed?
 carbohydrates ->
 proteins ->
 fats ->
carbohydrates -> monosaccharides
proteins -> amino acids
fats -> monoglycerides/fatty acids
Some peptides and disaccharides may still be present when digested food reaches the ________________. There are enzymes inbedded in the _____________ (brush border enzymes) that can digest these small peptides and disaccharides
Jejunum; microvilli
Name the brush border enzymes (disaccharidases) that digest carbohydrates (disaccharides).
Maltase, lactase, sucrase
Name brush border enzymes that digest proteins.
Peptidases
What is meant by brush border?
Microvilli on the cell membrane and the small intestine
How does the brush border differ from a Villus?
Villi are submucosal folds; brush borders are cell membrane folds
What is the pH of the stomach
pH ~ 2
What is the enzyme that digest carbohydrates in the mouth from salivary glands?
Amylase
What is the enzyme that digest fats in the mouth
Lingual lipase
What is the enzyme that digests proteins in the stomach
Pepsin
What is the enzyme that digest fats in the stomach?
Gastric lipase
What is the enzyme that digest carbohydrates in the pancreas?
Pancreatic amylase
What is the enzyme that digests proteins in the pancreas?
Trypsinogen(typsin), Chymotrypsinogen(chymotrypsin), Procarboxypeptidase(Carboxypeptidase)
Enteropeptidase activates trypsinogen, while Trypsin activates chymotrypsinogen and procarboxypeptidase.
What enzymes digest fat in the pancreas
Pancreatic lipase
What enzymes digest carbohydrates in the small intestine?
Lactase, Sucrase, and Maltase
What enzymes digest protien in the small intestine
Dipeptidase and aminopeptidase
Once the foods are broken down to monosaccharides, amino acids, or fatty acids and monoglycerides, they can be absorbed through the __________________ of the _____________ into the blood.
Epithelial cells; small intestine
Where in the small intestine does most absorption occur?
Jejunum
Monosaccharides and amino acids move through the epithelial cells into the blood vessels of the lamina propria. They are then carried to the liver by the ____________________.
Hepatic portal vein
Glucose and polar amino acids are absorbed by a process called ________________ Into the cell and then into the bloodstream.
Facilitated diffusion
What is facilitated diffusion?
Passive movement of molecules across the cell membrane following the concentration gradient.
Does facilitated diffusion require ATP?
No.
What symporter (cotransporter) is used for glucose and some amino acid absorption?
Sodium glucose symporter
Where is the sodium glucose symporter located?
small intestine
The blood vessels in the lamina propria lead to the ____________________ which carries the nutrients to the __________.
Hepatic portal vein; liver
Explain why ATP is indirectly needed for absorption using a Na+ symporter. (this type of transport is called secondary active transport.)
To pump sodium out and potassium into the cell to keep the sodium concentration in the cell low.
Fatty acids and monogglycerides are brought to the surface of the simple columnar epithelial cell by ______________.
Micelles
_____________ (bile salts surrounding fat) help keep these fat soluble in the intestinal juice. Once at the surface of the epithelial cell, the fats are absorbed into the cell.
Micelles
Monoglycerides and fatty acids are absorbed into the epithelial cell by ____________.
Diffusion
Some fatty acids are so _________ that they can follow the same route as amino acids and glucose, because they are ______________.
Short; water soluble
Which blood vessel transports these short fatty acid chains to the liver?
Hepatic portal vein
Long fatty acid chains are not absorbed directly into the blood because they are ________.
Nonpolar
Once absorbed, the simple columnar epithelial cells reassembled the monoglyceride and fatty acids into Lipoproteins called ______________.
Chylomicrons
Why do long chain fatty acids have to be part of a lipoprotein?
Because they’re non-polar
Long fatty acids take a different route. They are first transported into a lymph vessel called a ________________ and then to the ______________ vein.
 Lacteal; subclavian
How much water absorption occurs in the small intestine?
90%
How does the sodium glucose symporter assist with water absorption?
Water will follow sodium and glucose
Are vitamins digested? Are minerals digested?
Fat soluble vitamins only
Which vitamins must be absorbed with fat (fat soluble vitamins)?
Vitamin a, D, E, K
Which vitamin requires intrinsic factor for absorption?
Vitamin B 12
What cell makes intrinsic factor?
gastric parietal cells
What vitamin is needed for calcium absorption?
 vitamin D
Name some common nutrient minerals?
Iron Fe, magnesium Mg, iodine I, calcium Ca, sodium Na, sulfur S, potassium K, phosphorus P, chlorine Cl
Is the entire large intestine intraperitoneal?
No
Is the appendix intraperitoneal?
Yes
Why is a ruptured appendix so dangerous?
A rupture spreads infection throughout the abdomen
What type of epithelium is found in the large intestine mucosa?
Simple columnar
Why does the large intestine have so many goblet cells?
Mucus helps fecal matter glide along the tract
Muscularis: longitudinal bands of contracted muscle called ______________. The contracted muscle causes the colon to pucker creating _____________. __________ causes _________.
Taeniae coli; haustra
Taeniae coli causes haustra.
What type of tissue is found in the serosa of the large intestine?
Simple squamous
There is no significant ___________ digestion in the large intestine. there is significant water absorption (_________% of the water from the G.I. tract) as well as Biosault and vitamin absorption.
Chemical; 90
What is the Gastroileal reflex?
Peristalsis moves chyme into the cecum
What is haustral churning?
When haustra distend with fecal material, they contract.
Mass peristalsis:
Strong wave of peristalsis from transverse colon to rectum initiated by food in the stomach (also called the Gastrocolic reflex or simply “mass movement”)
The absorption of 90% of water causes undigested food to become ________.
Solid
What do colonic bacteria do that benefits the human host?
Keeps harmful bacteria at bay
What is flatus and why does it occur?
Gas produced by swallowing air or from bacterial fermentation
Bacteria makes vitamins _____ and _____ that can be absorbed in the large intestine
K; B
Why are epithelial cells found in feces?
When we make new cells in the epithelium, the old are sloughed off and becomes part of the feces.  The epithelium is keratinized.
What is the significance of the breakdown product of bilirubin?
Causes brown color of feces
Is defecation somatic or autonomic?
Somatic
Stretch receptors in the rectum are stimulated when the rectum is distended with feces. This initiates the _____________.
defecation reflex
Is the defecation reflex parasympathetic or sympathetic?
 parasympathetic
Which part of the spinal cord is involved in this reflex?
Sacral spinal cord
Is the defecation reflux carried by the vagus nerve?
No, pelvic nerve
Explain the steps of the defecation reflex.
Mass peristalsis squeezes fecal matter from the transverse, descending and sigmoid colon into the rectum. Stretch receptors detect stretching and trigger defecation reflex, carries the reflex involving the sacral spinal cord results in the urge to defecate
What is the role of the internal anal sphincter?
Sensation of needing to defecate
Is the internal anal sphincter made of smooth or skeletal muscle
 smooth
What is the role of the external anal sphincter?
Voluntary control of defecation by contraction of abdominal muscles and relaxation of external anal sphincter
Is the external anal sphincter made of smooth muscle or skeletal muscle?
Skeletal muscle
What enzymes are released by the salivary glands To digest carbohydrates?
Amylase
The enzyme amylase in salivary glands catalyzes the digestion of ???
Polysaccharides + H2O = monosaccharides
The enzyme amylase works by a process called ___________.
Hydrolysis
What enzyme is made by the pancreas to digest carbohydrates?
 pancreatic amylase
The enzyme pancreatic amylase made by the pancreas to digest carbohydrates catalyze is the digestion of ???
Polysaccharides + H2O = monosaccharides
The enzyme pancreatic amylase made by the pancreas to digest carbohydrates works by a process called _________.
Hydrolysis
What enzymes does the small intestine make to digest carbohydrates?
Lactase, Sucrase, Maltase
Write out the reactions that the enzymes (lactase, sucrase, maltase) catalyze:
Maltose + H2O = glucose + glucose
Sucrose + H2O = glucose + fructose
Lactose + H2O = glucose + galactose
The enzymes lactase, sucrase, and maltase work by a process called _______.
Hydrolysis
What is the proenzyme and enzyme made in the stomach to digest protein?
The proenzyme is pepsinogen and the enzyme is pepsin
How is the proenzyme pepsinogen activated?
HCl
The enzyme pepsin works by a process called ____________ and catalyzes the digestion of _________ + ________ = ____________
Hydrolysis
Proteins + H2O = amino acids
What pro enzymes and enzymes in the pancreas digest protein?
Trypsinogen -> trypsin
Chymotrypsinogen -> chymotrypsin
Procarboxypeptidase -> Carboxypeptidase
How are each of these proenzymes (trypsinogen, chymotrypsinogen, procarboxypeptidase) activated?
Enteropeptidase activates trypsinogen. Trypsin activates chymotrypsinogen and procarboxypeptidase.
Trypsinogen, chymotrypsinogen , and Procarboxypeptidase works by a process called _____________ and catalyzes the digestion of _____+_____+______=________.
Hydrolysis
Proteins + peptides + H2O = amino acids
What enzyme does the small intestine secrete that digests proteins?
Peptidases
Peptidase is catalyze the following reaction:
_____+_____=_______
Dipeptides + H2O = amino acids
What enzyme in the pancreas digest fat?
Lipase
Which cell in the pancreas makes the enzyme lipase?
Acini or acinar cells
The enzyme lipase catalyzes the digestion of:
________+_______=_________
Triglycerides + H2O = monoglycerides/fatty acids
The enzyme lipase works by a process called _______.
Hydrolysis
Before the enzyme lipase can be effective, the fats must be emulsified by ___________.
Bile salts
In which organ is the hormone gastrin made?
Stomach
In which organ is the hormone cholecystokinin (CCK) made?
Duodenum
In which organ is the hormone secretin made?
Duodenum
Which cells mke gastrin?
G-cells
Which cells make cholecystokinin?
I-cells
Which cells make secretin?
S-cells
What causes gastrin to be made?
Food entering the stomach
What causes cholecystokinin to be made?
Fat
What causes secretin to be made?
Gastric acid
Do anabolic or catabolic processes require energy?
Anabolic requires energy and catabolic releases energy
Metabolic importance of carbohydrates?
To produce energy
Metabolic importance of fats:
Necessary for absorbing vitamins
Metabolic significance of proteins:
Amino acids needs
Explain the significance of nitrogen balance
Quantitative difference between amount of nitrogen intake and the amount excreted
Describe positive nitrogen balance
When nitrogen intake exceeds output (in cases of increased protein synthesis)
Describe negative nitrogen balance.
When output exceeds the intake of nitrogen.
Water soluble vitamins:
B, C
Fat soluble vitamins:
K, A, D, E (stored in liver)
Metabolic importance of minerals:
Cofactors for enzymatic reactions
Metabolic importance of water:
Breaks bonds
Which nutrients can be catabolized in the body to yield ATP?
Carbs, fats, proteins
Functions of ATP in the body:
Transportation of molecules across membrane;
Supplying energy for muscle contraction;
Circulation of blood
ADP + P = ATP
ADP + P + energy = ATP + water
Give 3 examples of wastes produced during cellular metabolism:
CO2, H2O, salts, urea, uric acid
When carbs, proteins, and fats are digested, they are absorbed by the small intestine into the blood as _______, _______, and ________ (via a lacteal), respectively.
Monosaccharides, amino acids, chylomicrons
What are carbs digested to?
Starch -> monosaccharides
What are proteins digested to?
Protein -> amino acids
What are fats digested to?
Triglyceride -> 2 fatty acids and monoglyceride
What vitamins are present in chylomicrons?
K, A, D, E
Why do we need vitamin K?
It’s needed by the liver to make clotting factor
Why do we need vitamin A?
Needed for epithelium and photopigments
Why do we need vitamin D?
Needed for absorption of calcium in GI tract
Why do we need vitamin E?
Antioxidant; wound repair
