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A&P II - Ch. 7 - Digestive System
Valencia College - Derrickson
267
Anatomy
Undergraduate 2
03/04/2019

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Cards

Term

The cells in our bodies perform a wide variety of activities such as __________, __________, and __________ of substances across cell membranes.

Definition

protein synthesis

cell division

active transport

Term

1. Food must be consumed in order to provide the ______ for these cellular activities.

2. However, the food that you ingest typically contains ________, which are too large to be used by the cells of the body.

Definition

1. energy

2. polymers

Term

The ________ in food must first be broken down into ________ that are small enough to be taken up by cells and then used for energy.

Definition

polymers

- monomers

Term

The process by which the polymers in food are broken down into their constituent monomers is called ________.

Definition

digestion

Term

Digestion involves _____________ that __________ the polymers in the food in the lumen of the digestive tract.

Definition

digestive enzymes

catabolize (break down)

Term

As the monomers are released, they are absorbed from the ______ of the digestive tract into the ______ and then transported to the ______ in the rest of the body.

Definition

lumen

blood

cells

Term

Once inside of the cells, the monomers are further broken down via the process of ____________ in order to provide ATP as the energy source for different cellular activities.

Definition

cellular (aerobic) respiration

Term

The organs of the digestive system are divided into 2 main groups. What are they?

Definition

1. gastrointestinal (GI) tract

2. accessory organs

Term

What consists of organs that collectively form a continuous tube?

Definition

gastrointestinal (GI) tract

Term

Name the organs of the gastrointestinal (GI) tract? (7 total)

Definition

1. mouth

2. pharynx

3. esophagus

4. stomach

5. small intestine

6. large intestine

7. anus

Term

connected to but are not continuous with the organs of the GI tract

Definition

accessory organs

Term

Name all of the accessory organs of the digestive system. (6 total)

Definition

1. teeth

2. tongue

3. salivary glands

4. pancreas

5. liver

6. gallbladder

Term

What are the six basic processes that the digestive system performs?

Definition

1. ingestion

2. secretion

3. motility

4. digestion

5. absorption

6. defecation

Term

In general, the organs of the GI tract consist of the same 4 layers. What are they?

Definition

1. mucosa

2. submucosa
3. muscalaris

4. serosa

Term

inner layer of the GI tract

Definition

mucosa

Term

What are the 3 layers that make up the mucosa of the GI tract?

Definition

1. epithelium

2. lamina propria

3. muscalaris mucosae

Term

located closest to the lumen of the GI

Definition

epithelium

Term

consists of connective tissue containing collagen fibers, elastic fibers, blood vessel, and lymphatic vessels

Definition

lamina propria

Term

consists of a thin layer of smooth muscle

Definition

muscularis mucosae

Term

What does the submucosa consist of? (4 total)

Definition

1. connective tissue containing collagen fibers

2. elastic fibers

3. blood vessels

4. lymphatic vessels

Term

consists of either skeletal muscle or smooth muscle, depending on the organ

Definition

muscularis

Term

1. The muscularis of the mouth, pharynx, and upper esophagus contains ___________.

2. The muscularis of the rest of the GI tract (lower esophagus, stomach, small intestine, and large intestine) contains ___________.

Definition

1. skeletal muscle

2. smooth muscle

Term

1. The smooth muscle is usually arranged into an __________ layer and an ____________ layer.

2. Contraction of the smooth muscle in the muscularis is responsible for ________.

Definition

1. inner circular; outer longitudinal

2. peristalsis

Term

wave-like contractions within the wall of the GI tract that propel food over a long distance in an anal-ward direction

Definition

peristalsis

- Similar to squeezing a tube of toothpaste from the bottom to the top of the tube

Term

What is the function of peristalsis?

Definition

To propel food down the lumen of the GI tract from the esophagus to the anus.

Term

Peristaltic contractions occur throughout the GI tract, but the intensity of these contractions varies depending on the location. They are strong in the ________, moderate in the ________, and weak in the ________.

Definition

esophagus

stomach

intestines

Term

- also called the peritoneum

- the outer layer of the GI tract

- consists of epithelial tissue and connective tissue

Definition

serosa

Term

1. The _______________ consists of about 100 million neurons found within the wall of the GI tract.

2. Arranged into two plexuses (groups) of neurons, what are they?

Definition

1. enteric nervous system (ENS)

2. submucosal plexus and myenteric plexus

Term

- also known as the plexus of Meissner

- located in the submucosa

- regulates GI secretion

Definition

submucosal plexus

Term

- also known as the plexus of Auerbach

- located in the muscularis

- regulates GI motility (movement)

Definition

myenteric plexus

Term

1. __________ nerves innervate the organs of the GI tract via the ________ nerves.

2. Stimulation of these nerves to the GI tract ______ peristalsis and GI secretion of fluids (gastric juice, pancreatic juice, intestinal juice, etc.) into the GI lumen.

Definition

1. Parasympathetic; Vagus (X)

2. increases

Term

1. The organs of the GI tract are also innervated by ________ nerves.

2. Stimulation of these* nerves to the GI tract ______ peristalsis and GI secretion.

3. In addition, stimulation of these* nerves also causes ________ of the blood vessels that supply the organs of the GI tract, which results in shunting blood away from these organs.

Definition

1. sympathetic

2. inhibits

3. vasoconstriction

Term

1. contains the oral cavity

2. surrounded by what 5 parts?

Definition

1. the mouth

2. lips, cheeks, hard palate, soft palate, tongue

Term

- forms the anterior region of the roof of the mouth

- consists of bones (maxilla and palatine) covered by a mucosa

Definition

hard palate

Term

- forms the posterior region of the roof of the mouth

- consists of skeletal muscle that is covered by a mucosa

Definition

soft palate

Term

1. The _____ is an extension of the soft palate.

2. During __________, the soft palate closes off the entrance to the nasal cavity, thereby preventing reflux of food into the nose

Definition

1. uvula

2. deglutition (swallowing)

Term

1. forms the floor of the mouth

2. consists of what 2 components?

Definition

1. tongue

2. mucosa and skeletal muscle

Term

- the outer layer of the tongue

- consists of epithelium and connective tissue

- contains taste buds and lingual glands

Definition

mucosa

Term

1. The ________ of the tongue are involved in the detection of taste.

2. The lingual glands of the tongue are ______ glands that secrete the enzyme __________ into the oral cavity.

Definition

1. taste buds

2. exocrine; lingual lipase

Term

Lingual lipase initiates the digestion of ________ in small globules of fat.

Definition

triglycerides

Term

triglyceride is broken down by lingual lipase into → 2 _______, 1 ________

Definition

fatty acids, 1 monoglyceride

Term

- form the inner layer of the tongue

- responsible for the movements of the tongue during speech and also during ingestion

- Posteriorly, the mouth becomes continuous with the pharynx

Definition

skeletal muscle

Term

1. An adult contains __ permanent teeth, which have replaced the __ deciduous teeth (baby teeth).

2. What are the 4 groups of adult teeth?

Definition

1. 32 (16 on the top and 16 on the bottom); 20

2. incisors, canines, premolars (bicuspids), molars (tricuspids)

Term

1. The teeth insert into the ______ of the alveolar processes of the maxilla and mandible.

2. The border of the alveolar processes is lined by a mucosa called the ________.

Definition

1. sockets

2. gingivae (gums)

Term

1. Each tooth is held in the alveolar socket by a ____________.

2. Recall that the joint formed between each tooth and the alveolar socket via this* is called a ________, which is a type of __________.

Definition

1. periodontal ligament

2. gomphosis; synarthrosis (immovable joint)

Term

A tooth consists of 3 external regions, what are they?

Definition

1. crown

2. neck

3. root

Term

- the exposed part of the tooth that is above the gingiva

Definition

crown

Term

- the part of the tooth that is flush with the gingiva

- connects the crown with the root

Definition

neck

Term

- the part of the tooth that is below the gingiva and inserts into the alveolar socket

Definition

root

Term

What are the layers of the tooth?

Definition

1. enamel

2. dentin

3. pulp cavity

Term

- the outer layer of the tooth

- calcified substance that is harder than bone

- harder than bone because it contains more _________ (i.e. crystals of calcium phosphate) compared to bone.

Definition

- enamel

hydroxyapatite

- Hydroxyapatite crystals make up 97% of enamel’s weight, whereas they comprise only 65% of the weight of bone.

Term

- the middle layer of the tooth

- forms the majority of the tooth

- calcified substance that has a hardness that is intermediate between bone and enamel

Definition

dentin

- Hydroxyapatite crystals constitute about 70% of dentin’s weight.

Term

1. located internally to dentin

2. contains _____, which consists of connective tissue containing blood vessels and nerves

Definition

1. pulp cavity

2. pulp

- In the crown and neck of the tooth, the pulp cavity is dilated.

Term

In the root, the pulp cavity tapers off, forming the ________, which eventually opens up at the end of the tooth as the ________.

Definition

- root canal

apical foramen

Term

The teeth crush and tear food during __________.

Definition

mastication (chewing)

Term

1. exocrine glands that produce saliva

2. Name its 3 pairs.

Definition

1. salivary glands

2. parotid, submandibular, and sublingual

Term

- salivary glands located anterior to each ear

Definition

parotid glands

Term

- salivary glands located beneath the mandible

Definition

submandibular glands

Term

- salivary glands located beneath the tongue

Definition

sublingual glands

- Note that each salivary gland has a duct that empties a portion of the saliva into the oral cavity.

Term

How much saliva is produced by the salivary glands each day?

Definition

1 L

Term

Saliva Composition.

- constitutes 99% of saliva

- This* in saliva dissolves any food taken into the mouth.

Definition

H2O

Term

Saliva Composition.

- The HCO3- ____ in saliva buffer any ingested food that is acidic (like tomato sauce).

Definition

ions (HCO3-, Na+, K+, and, Cl- )

 

Term

Saliva Composition.

Enzyme that hydrolyzes a large starch molecule into several short chains of glucose molecules called ________.

Definition

- salivary amylase

- α-dextrins

Term

The ______ in saliva lubricates food.

Definition

mucus

Term

- an enzyme that destroys bacteria

- the ________ in saliva protects the mouth from pathogens.

Definition

lysozyme

Term

- Recall that __________ is produced by the lingual glands of the tongue, not by the salivary glands.

- Nevertheless, once it is secreted by the lingual glands, it then mixes with the other components of saliva.

Definition

lingual lipase

Term

- also called the throat

- a tube that is located between the nasal cavity and the esophagus

Definition

pharynx

- The pharynx consists of an inner mucosa and an outer muscularis that consists of skeletal muscle.

Term

What are the 3 regions of the pharynx? Describe them.

Definition

1. nasopharynx - the region of the pharynx that is continuous with the nasal cavity

2. oropharynx - the region of the pharynx that is continuous with the oral cavity (mouth)

3. laryngopharynx - the region of the pharynx that is continuous with the larynx and with the esophagus

Term

The pharynx is involved in 2 major functions. What are they?

Definition

1.  Passageway for the movement of food and beverages from the mouth to the esophagus.

2. Passageway for the movement of air from the nose and mouth to the larynx.

Term

- a tube that is located between the pharynx and the stomach

Definition

esophagus

Term

The muscularis in the upper half of the esophagus consists of __________, while the muscularis in the lower half of the esophagus contains __________.

Definition

skeletal muscle

smooth muscle

Term

Each end of the esophagus is modified into a sphincter. What are their names and what do they consist of?

Definition

- upper esophageal sphincter (UES) - consists of skeletal muscle

- lower esophageal sphincter (LES) - consists of smooth muscle

Term

a region of muscle that regulates the opening to the lumen of an organ

Definition

sphincter

Term

Esophagus Function. (5)

1. During swallowing, the ____ opens to allow food to enter into the esophagus from the pharynx. 

2. Once food is in the esophagus, the *** closes, preventing _____  of food into the pharynx.

3. Food is then propelled down the esophagus via ________.

4. The ____ opens in order to allow the food to move out of the esophagus and into the stomach.

5. Once the esophagus is empty, the *** closes in order to prevent reflux of food and __________ into the esophagus.

Definition

1. UES

2. reflux

3. peristalsis

4. LES

5. gastric contents

Term

This is  located between the esophagus and the small intestine.

What are its 4 major regions?

Definition

stomach

1. cardia

2. fundus

3. body

4. pylorus

Term

- the initial region of the stomach

- separated from the esophagus via the lower esophageal sphincter (LES).

Definition

cardia

Term

- the region of the stomach that is superior and lateral to the cardia

Definition

fundus

Term

- the large, central region of the stomach

Definition

body

Term

- the terminal region of the stomach

- divided into 2 subcomponents, what are they?

Definition

pylorus

1. pyloric antrum - located closest to the body of the stomach

2. pyloric canal - located closest to the duodenum of the small intestine

Term

The pyloric canal is separated from the duodenum by the __________, which consists of smooth muscle.

Definition

pyloric sphincter

Term

The stomach consists of the same 4 layers as the rest of the GI tract, what are they?

Definition

1. mucosa

2. submucosa

3. muscalaris

4. serosa

Term

1. The stomach produces __________.

2. Each day the stomach secretes about ____ of this*.

Definition

1. gastric juice

2. 2 L

Term

Gastric juice is produced by __________ that are located in the mucosal epithelium of the stomach.

Definition

gastric glands

Term

Each gastric gland contains 4 cell types, what are they?

Definition

1. mucous neck cells

2. parietal cells

3. chief cells

4. G cells

Term

secrete mucus into the stomach lumen

Definition

mucous neck cells

Term

secretes hydrochloric acid (HCl) and intrinsic factor (IF) into the stomach lumen

Definition

parietal cells

Term

- also called zymogenic cells

- secrete pepsinogen and gastric lipase into the stomach lumen

Definition

chief cells

Term

Pepsinogen is the ______ form of the enzyme pepsin. Pepsinogen is converted into the ______ form pepsin via ____. 

Definition

inactive

active 

HCl

Term

enteroendocrine cells that secrete the hormone gastrin into the blood

Definition

G cells

Term

- a strong acid

- causes gastric juice to have a low pH value of 2

- kills pathogens in food and it provides the acidic pH that is required for pepsin and gastric lipase to function.

Definition

HCl (hydrochloric acid)

Term

- a protease that catabolizes proteins into smaller peptides

- this* functions only in an acidic environment, which is provided by the HCl in gastric juice.

Definition

pepsin

- Note that pepsin is an unusual enzyme in this respect; most other enzymes in the digestive tract (and in the body) require a neutral to slightly alkaline pH (i.e. a pH of 7 to 8) to function optimally.

Term

- Like lingual lipase, this* is an enzyme that catabolizes triglycerides in a small fat globule into fatty acids and monoglycerides.

- Like pepsin, it also requires an acidic pH to function.

Definition

gastric lipase

Term

found in gastric juice; coats the surface of the gastric mucosa, thereby protecting these cells from HCl.

Definition

mucus

Term

a protein that helps vitamin B12 undergo absorption in the small intestine

Definition

intrinsic factor

- We obtain Vitamin B12 from the diet (meat and dairy products) and it is necessary for erythropoiesis.

- If intrinsic factor is not produced, vitamin B12 will not undergo absorption and the individual will have difficulty producing red blood cells -- a condition called pernicious anemia.

Term

The stomach converts food into ______.

Definition

chyme

Term

Once food enters the stomach, the ________ in the lower body and pylorus of the stomach contracts and the food is mixed with gastric juce. The ____, ______, and _______ in the gastric juice further break down the large particles in food into smaller particles, resulting in the formation of chyme. Therefore, chyme is a thin, soupy mixture that consists of partially digested food and digestive fluids.

Definition

- muscularis

HCl

pepsin

gastric lipase

Term

Some of the chyme moves through the pyloric sphincter and into the ________ of the small intestine, a process called __________. This* is a slow process: only __ mL of chyme are emptied at any given time. Realize that this* should be a slow process in order to prevent the small intestine from being overloaded with chyme.

Definition

duodenum

gastric emptying

- 2

Term

About __ L of food can be stored temporarily in the ______ and upper body of the stomach while waiting to be converted into chyme.

Definition

- 2

fundus

Term

1. The stomach produces the hormone ______.

2. ______ in gastric glands secrete this hormone into the blood.

Definition

1. gastrin

2. G cells

Term

The _______ is a gland that is posterior to the stomach and lateral to the duodenum of the small intestine.

Definition

pancreas

Term

The pancreas consists of what 3 external components?

Definition

1. head

2. body

3. tail

Term

The pancreas is both an _______ gland and an _______ gland.

Definition

endocrine

exocrine

Term

Internally, the pancreas consists of what 2 major components?

Definition

1. pancreatic islets

2. acini

Term

- also called islets of Langerhans

- comprise 1% of the total weight of the pancreas and are found scattered throughout the pancreas

Definition

pancreatic islets

Term

Each pancreatic islet consists of a cluster of endocrine cells:

1. ________: secrete the hormone glucagon into the blood

2. ________: secrete the hormone insulin into the blood

Definition

1. alpha (α) cells

2. beta (β) cells

Term

constitutes about 99% of the total weight of the pancreas

Definition

acini

Term

1. Each acinus consists of several ______ cells called ______ cells that secrete pancreatic juice into a small duct.

2. The small ducts that surround these* cells empty into the large ___________.

Definition

1. exocrine; acinar

2. pancreatic duct (duct of Wirsung)

Term

3. The pancreatic duct unites with the __________ to form the _____________, which opens into the lumen of the duodenum. The opening of this* is regulated by a region of smooth muscle that is called the ____________.

Definition

common bile duct

hepatopancreatic ampulla (ampulla of Vater)

sphincter of the hepatopancreatic ampulla (sphincter of Oddi)

Term

The pancreas is involved in 3 major functions. What are they?

Definition

1. produces pancreatic juice

2. produces the hormone insulin

3. produces the hormone glucagon

Term

The acinar cells of the pancreas secrete about 2 L of ________ into the pancreatic duct on a daily basis.

Definition

pancreatic juice

Term

What are the 3 components of pancreatic juice? Which one is the main component?

Definition

1. H2O: main component

2. ions (HCO3- , Na+ , Cl- , and K+ ): The HCO3- causes the pancreatic juice to have a slightly alkaline pH of 7.5 to 8.

3. enzymes: Pancreatic juice contains many types of digestive enzymes that continue to digest food particles in the chyme that enters the lumen of the small intestine

Term

Pancreatic juice enzymes.

What are the 4 proteases in pancreatic juice?

Definition

1. trypsin

2. chymotrypsin
3. elastase

4. carboxypeptidase

Term

Pancreatic juice enzymes.

1. Which proteases of pancreatic juice catabolize proteins into smaller peptides?

2. Which proteases cleave off individual amino acids from smaller peptides?

Definition

1. Trypsin, chymotrypsin, and elastase

2. carboxypeptidase, along with the small intestinal brush border enzyme aminopeptidase

Term

Pancreatic juice enzymes.

1. Pancreatic proteases are initially released as ____________.

2. Trypsinogen is first activated to trypsin by the small intestine brush border enzyme ________.

3. Once activated, trypsin in turn activates the remaining ____________ (chymotrypsinogen, proelastase, and procarboxypeptidase) to produce chymotrypsin, elastase, and carboxypeptidase, respectively.

Definition

1. inactive precursors (trypsinogen, chymotrypsinogen, proelastase, and procarboxypeptidase)

2. enterokinase

3. inactive precursors

Term

an enzyme that hydrolyze triglycerides in a small fat globule into fatty acids and monoglycerides

Definition

pancreatic lipase

Term

enzyme that hydrolyzes starch into α-dextrins, which are short chains of glucose molecules

Definition

pancreatic amylase

Term

1. The pancreas uses its pancreatic juice to further digest ________, ________, and ____ that are in the chyme in the lumen of the small intestine.

2. In order to achieve this goal, the __________ must be open during the digestion of a meal, thus allowing pancreatic juice to move into the small intestine to interact with the chyme

Definition

1. carbohydrates, proteins, fats

2. sphincter of Oddi (When there is no chyme present in the small intestine, the sphincter of Oddi is closed and pancreatic juice remains in the pancreas.)

Term

1. The _____ must be neutralized because pancreatic enzymes as well as small intestinal enzymes require a neutral to slightly alkaline pH to function optimally.

2. In the absence of these enzymes, there is _________ of nutrients.

Definition

1. chyme

2. malabsorption

Term

- weighs about 3 lbs and is the largest gland in the body.

- located below the diaphragm

Definition

liver

Term

1. consists of 2 major lobes: the right lobe and the left lobe

2. consists of cells called _________

Definition

1. liver

2. hepatocytes

Term

1. The liver screens ______ for excess nutrients and toxic substances.

2. The hepatocytes screen the *** from the ____________ for excess nutrients and toxic substances.

Definition

1. blood

2. hepatic portal vein

Term

1. If there is excess glucose, the hepatocytes take up the glucose and store it as _______.

2. Excess ______ (A, D, E, K, and B12) and ______ (iron and copper) in the blood are also removed and stored in the hepatocytes.

3. Any __________ (like drugs and alcohol) are removed and detoxified by the hepatocytes and then either reintroduced back into the blood or excreted into bile.

Definition

1. glycogen

2. vitamins; minerals

3. toxic substances

Term

The liver produces bile.

1. The hepatocytes of the liver also produce bile and then secrete it into the ________ or ________.

2. These* then combine to form the ________, which emerges from the liver.

Definition

1. right hepatic duct; left hepatic duct

2. common hepatic duct

Term

The liver produces bile.

3. The common hepatic duct combines with the ________ extending from the gallbladder to form the __________. This* is so-named because it contains fresh bile from the liver via the hepatic ducts and stored bile from the gallbladder via the ***.

4. The common bile duct eventually unites with the ________ to form the ____________, which empties into the duodenum.

5. Recall that the __________ regulates the opening of the hepatopancreatic ampulla. During the digestion of a meal, this* is open and bile is released into the duodenum to interact with chyme that is present there. When digestion is not occurring, this* is closed and any bile produced by the liver backs up into the cystic duct and then goes to the gallbladder for storage.

Definition

3. cystic duct; common bile duct

4. pancreatic duct; hepatopancreatic ampulla

5. sphincter of Oddi

Term

- a fluid that is yellow to green in color

- pH is slightly alkaline (7.5 to 8)

- the hepatocytes of the liver secrete about ___ of this* on a daily basis. 

Definition

bile

- 1 L

Term

What are the 4 components of bile? Which one is the biggest component?

Definition

1. H2O (majority constituent, makes up 97% of bile)

2. cholesterol

3. bile salts

4. bile pigments

Term

- derivatives of cholesterol

- Examples: glycocholate, taurocholate

- these* are ________; this means that each one* has a hydrophilic region and a hydrophobic region.

Definition

bile salts

amphipathic

Term

The main pigment found in bile is _______, which has a yellowish green color.

Definition

bile pigments

bilirubin

Term

Origin of Bilirubin.

1. Recall that macrophages in the spleen break down worn-out red blood cells. During this process, the __________ of the heme in hemoglobin is eventually converted to bilirubin, which is subsequently released into the blood.

2. The ________ remove the bilirubin from the blood and then secrete it as a component of bile.

3. The ________ of bile promote the emulsification of fat, which is vital to the digestion and absorption of lipids by the small intestine.

Definition

1. porphyrin ring

2. hepatocytes

3. bile salts

Term

the process by which a large fat globule is converted into many small fat globules

Definition

emulsification

- Emulsification of fats must occur before pancreatic lipase can act on the triglycerides in the fat globule.

Term

Fate of Bile.

1. Bile is released into the lumen of the ________.

2. As bile moves through the small intestine, it mixes with _____, promoting fat emulsification.

Definition

1. duodenum

2. chyme

Term

Fate of Bile.

3. Near the end of the small intestine, the bile salts are absorbed into the blood and eventually return back to the liver via the hepatic portal vein. The hepatocytes remove the bile salts from the blood and use them to make more bile. This process of moving the bile from the small intestine back to the liver is called the ____________, which functions to recycle the bile salts.

4. The rest of the bile components (H2O, cholesterol, and bilirubin) continue into the large intestine as part of chyme and eventually become part of the feces. During this process, bilirubin is eventually converted into a brown pigment called ________. This* is responsible for the brown color of feces

Definition

3. enterohepatic circulation

4. stercobilin

Term

1. A pear-shaped organ that is located underneath the liver

2. What are it's 3 layers?

Definition

1. gallbladder

2. mucosa, smooth muscle, serosa

Term

Gallbladder.

- inner layer

- surrounds the lumen

- consists of an epithelial layer and a connective tissue layer

Definition

mucosa

Term

Gallbladder.

- middle layer

Definition

smooth muscle

Term

Gallbladder.

- outer layer

- connective tissue

Definition

serosa

Term

What are the 2 major functions of the gallbladder?

Definition

1. stores bile

2. concentrates bile

 

Term

1. When digestion is not occurring, the ___________ is closed and bile backs up into the gallbladder for storage.

2. The gallbladder is a small organ and can hold about ____ of bile at one given time. However, the liver secretes about ____ of bile per day.

3. Hence, the gallbladder concentrates the bile (and hence reduces the volume) by removing some of the _____.

Definition

1. sphincter of Oddi

2. 50 mL; 1000 mL

3. water

Term

1. Located between the stomach and the large intestine

2. What are its dimensions?

Definition

1. small intestines

2. Diameter: 1 inch, Length: 20 feet

- The small intestine is the longest part of the digestive tract.

Term

The small intestine consists of 3 major external regions. What are they?

Definition

1. duodenum

2. jejunum

3. ileum

Term

- the initial portion of the small intestine

- this* is separated from pyloric canal of the stomach via the __________

Definition

duodenum

- pyloric sphincter

Term

- the middle portion of the small intestine

Definition

jejunum

Term

- the terminal and longest portion of the small intestine

- this* is separated from the cecum of the large intestine by the __________

Definition

ileum

ileocecal sphincter

Term

The small intestine consists of the same 4 layers as the rest of the GI tract. What are they?

Definition

mucosa, submucosa, muscularis, and serosa

- Note that the mucosa of the small intestine differs from the mucosa of the rest of the GI tract due to modifications in the epithelium and lamina propria.

Term

The epithelium of the small intestinal mucosa contains a superficial covering and lining epithelium that is surrounded by intestinal glands called ______________.

Definition

crypts of Lieberkuhn

Term

The covering and lining epithelium consists of 2 types of cells. What are they?

Definition

1. absorptive cells

2. goblet cells

Term

absorb nutrients (monomers) from the lumen of the small intestine

Definition

absorptive cells

Term

secrete mucus into the lumen of small intestine

Definition

goblet cells

Term

- also called an intestinal gland

- consists of 6 types of cells. Name all 6.

 

Definition

crypts of Lieberkuhn

1. absorptive cells

2. goblet cells

3. Paneth cells

4. S cells

5. I cells

6. K cells

Term

- secrete lysozyme into the lumen of the small intestine

- recall that lysozyme is an enzyme that destroys bacteria; in this case, it is used to kill any bacteria that contaminate the intestinal chyme.

Definition

Paneth cells

Term

enteroendocrine cells that secrete the hormone secretin into the blood

Definition

S cells

Term

enteroendocrine cells that secrete the hormone cholecystokinin (CCK) into the blood

Definition

I cells

Term

- enteroendocrine cells that secrete the hormone gastric inhibitory peptide (GIP) into the blood

- Gastric inhibitory peptide is also called glucose-dependent insulinotropic peptide

Definition

K cells

Term

Each day the crypts of Lieberkuhn secrete about ___ of intestinal juice that mixes with incoming chyme, bile, and pancreatic juice.

Definition

1 L

Term

What are the 3 components of intestinal juice?

Definition

1. H2O -major constituent

2. mucus

3. ions (HCO3 - , Na+ , and Cl- )

- The bicarbonate ions give intestinal juice an alkaline pH, ranging from 7.5 to 8.

- The slightly alkaline pH of intestinal juice helps to provide the ideal environment for small intestinal enzymes and for pancreatic enzymes.

Term

The lamina propria of the small intestinal mucosa contain connective tissue and ______.

Definition

lacteals

Term

- specialized lymphatic vessels involved in fat absorption

- Unlike the rest of the GI tract, the lamina propria of the small intestine contains these*

Definition

lacteal

Term

The mucosa of the small intestine is folded extensively to increase surface area for ________.

Definition

absorption

Term

the movement of digested food (monomers) from the lumen of the gastrointestinal tract into the blood

Definition

absorption

- Most absorption occurs in the small intestine and to a lesser extent in the large intestine

Term

Absorption in the small intestine occurs due to 3 types of folds. What are they?

Definition

1. circular folds

2. villi

3. microvilli

Term

- also called plicae circularis

- folds of the mucosa and submucosa

- increase the absorptive surface area of the small intestine about 3 times

Definition

circular folds

Term

- finger-like projections of the mucosa caused by the folding of its epithelium cells and lamina propria

- give the small intestine a velvety appearance

- increase the absorptive surface area of the small intestine about 10 times

- Each one contains an overlying covering and lining epithelium and a core of capillaries and lacteals from the lamina propria

Definition

villi

Term

1. The thin, folded structure of the villus facilitates ________ of nutrients in the small intestine:

2. Nutrients easily pass from the lumen of the small intestine through the absorptive cells covering the _____ and then into the capillary or lacteal (depending on nutrient type) to complete the absorption process.

Definition

1. absorption

2. villus

Term

- folds of the apical (luminal) membranes of the absorptive cells of the mucosa

- also referred to as the brush border because they resemble the bristles of a brush.

- increase the absorptive surface area of the small intestine about 20 times

Definition

microvilli

Term

Collectively, the circular folds, villi, and microvilli increase the absorptive surface area of the small intestine by a factor of _______.

Definition

600 (3 x 10 x 20)

Term

1. The small intestine ________ the digestion of nutrients.

2. The absorptive cells of the small intestinal mucosa possess several types of digestive enzymes that are located in their brush borders; these _____________ complete the digestion of food.

Definition

1. completes

2. brush border enzymes

Term

What are the 3 types of brush boarder enzymes?

Definition

1. α-dextrinase

2. disaccharidases

3. aminopeptidase

Term

- hydrolyzes α-dextrins into individual glucose molecules

Definition

α-dextrinase

Term

- hydrolyze disaccharides into monosaccharides

Definition

disaccharidases

Term

- hydrolyzes maltose into 2 molecules of glucose

Definition

maltase

Term

- hydrolyzes sucrose into a molecule of glucose and a molecule of fructose

Definition

sucrase

Term

- hydrolyzes lactose into a molecule of glucose and a molecule of galactose

Definition

lactase

Term

1. The small intestine absorbs ______.

2. Once digestion is completed by the brush border enzymes, the ________ are then absorbed by the absorptive cells of the small intestine.

Definition

1. solutes

2. monomers

Term

1. Transporters within the _____________ of each absorptive cell absorb any monosaccharides (glucose, galactose, or fructose) or amino acids that many be present in the small intestinal lumen.

2. Transporters are required for movement across the cell membranes of the absorptive cells because carbohydrates and amino acids are ________, while the phospholipids in the cell membranes are ________.

Definition

1. plasma membrane

2. hydrophilic; hydrophobic

Term

1. Digestion of triglycerides by pancreatic lipase typically liberates monoglycerides and fatty acids, which can be either ________ fatty acids or _________ fatty acids.

2. Recall that fatty acids and monoglycerides are ________; consequently, they can move across the cell membrane of an absorptive cell without the help of a transporter.

Definition

1. long chain; short chain

2. hydrophobic

Term

1. Since ________ fatty acids are so small, they can be absorbed into the blood, which is hydrophilic.

2. _________ fatty acids and monoglycerides, however, are large and hydrophobic. Thus, they cannot be absorbed into the blood directly.

Definition

1. short chain

2. Long chain

Term

Lipid absorption.

1. Once inside of an absorptive cell, several long chain fatty acids and monoglycerides recombine to form triglycerides. The triglycerides are then surrounded by a protein coat, forming a ________, which is a type of ________.

Definition

- chylomicron

lipoprotein

Term

Lipid absorption.

2. The chylomicrons then undergo exocytosis across the basolateral membrane of the absorptive cell and subsequently move into the ______ to become part of the lymph.

Definition

lacteals

Term

Lipid absorption.

3. From the lymph, the chylomicrons eventually are dumped into the blood. Hence, chylomicrons increase the solubility of the ____________ and ____________ in the blood. 

Definition

long chain fatty acids

monoglycerides

Term

The small intestine absorbs H2O.

1. The absorptive cells of the small intestine also absorb water from chyme via ________.

2. About ___ of the 9 L of fluid that enters the small intestine is absorbed.

3. The small intestine is the major site of _____ absorption in the GI tract.

Definition

1. osmosis (i.e. the water follows the absorbed solute)

2. 8 L

3. water

Term

The small intestine secretes hormones.

These hormones include ___, ______, and ___.

Definition

CCK, secretin, and GIP

Term

1. Located after the small intestine and is the last organ of the gastrointestinal tract

2. What is its diameter and length?

Definition

1. large intestine

2. diameter = 2.5 in. | length = 5 ft.

- Compared to the small intestine, the large intestine has a greater diameter (hence the name “large”) and a shorter length.

Term

The large intestine is divided into 3 major external regions. What are they?

Definition

1. cecum

2. colon

3. rectum

Term

- the beginning portion of the large intestine

- this* is separated from the ileum of the small intestine by the __________.

- attached to the lower end of this* is the ______________

Definition

- cecum

ileocecal sphincter

wormlike appendix (also called the vermiform appendix)

Term

1. In humans, the appendix is a __________, which means that it is a useless organ that has no known function in the body.

2. Structurally, it consists of scattered ____________ that plays an insignificant role in immunity.

Definition

1. vestigial organ

2. reticular connective tissue

Term

Name the 4 sections of the colon.

Definition

1. ascending colon

2. transverse colon

3. descending colon

4. sigmoid colon

Term

- the terminal portion of the large intestine

- at the very end of this* is the anus.

Definition

rectum

Term

1. The region of the rectum that opens up to the exterior

2. Surrounded by what 2 sphincters?

Definition

1. anus

2. internal anal sphincter and external anal sphincter

Term

- consists of smooth muscle

- this sphincter is controlled involuntarily

Definition

internal anal sphincter

Term

- consists of skeletal muscle

- this sphincter is under voluntary control

Definition

external anal sphincter

Term

The mucosal epithelium of the large intestine, that like of that small intestine, consists of a ______________ and lining epithelium that is surrounded by deep ____________.

Definition

- superficial covering

crypts of Lieberkuhn

Term

Covering and lining epithelium of large intestine consists of _________ and _________.

 

Definition

- absorptive cells (absorb H2O from the lumen of the large intestine)

- goblet cells (secrete mucus into the lumen of the large intestine)

Term

also called an intestinal gland

- consists of

a. absorptive cells (absorb H2O from the lumen of the large intestine)

b. goblet cells (secrete mucus into the lumen of the large intestine)

Definition

crypt of Lieberkuhn

Term

Notice that the crypts of Lieberkuhn in the large intestine lack ________ cells (I, K, and S cells) and ______ cells found within the crypts of Lieberkuhn in the small intestine

Definition

- enteroendocrine

paneth

Term

The absorptive cells of the large intestinal mucosa do contain microvilli; however, there are no _____ present.

Definition

villi

Term

Consequently, the absorptive surface area of the large intestine is significantly _____ than that of the small intestine.

Definition

lower

- This should make sense because more absorption occurs in the small intestine than in the large intestine.

Term

The smooth muscle of the large intestinal muscularis is divided into bands called _________ that are visible underneath the serosa.

Definition

taenia coli

Term

The taenia coli are usually contracted, causing pouches called ______ to form in the wall of the large intestine.

Definition

haustra

Term

The large intestine has 3 major functions. What are they?

Definition

1. further processes intestinal chyme using enteric bacteria

2. absorbs H2O

3. forms and stores feces

Term

What does the chyme entering the large intestine consist of?

Definition

1. water (about 1 L)

2. waste products

3. indigestible materials

4. the bile pigment bilirubin

Term

Recall that ________ (but not bilirubin) were absorbed near the end of the small intestine as part of the enterohepatic circulation.

Definition

bile salts

Term

Living within the large intestine are __________ (usually a harmless strain of Escherichia coli).

Definition

enteric bacteria

Term

The enteric bacteria convert some of the chyme’s undigestible carbohydrates and peptides into gases like ______ (CH4), H2, CO2, and ________ (H2S), which smells like rotten eggs

Definition

methane

hydrogen sulfide

- These gases contribute to intestinal flatus (also called flatulence if excessive).

Term

The enteric bacteria convert bilirubin into ________, a brown pigment.

Definition

stercobilin

Term

About ___ mL of the 1 L of H2O that enters the large intestine is absorbed; the remaining passes out of the body as part of the feces.

Definition

900 mL

Term

As H2O is absorbed in the large intestine, the chyme in the lumen gradually solidifies into ______.

Definition

feces

Term

Defecation Reflex

1. __________ that involves peristaltic contractions in the wall of the rectum, thereby extruding feces out of the body.

2. It takes about __ to __ hours for food to complete its course through the digestive system.

3. ________ are digested the quickest, proteins are intermediate, and lipids take the longest.

Definition

1. Spinal reflex

2. 3 to 10 hours

3. Carbohydrates

Term

The regulation of the digestive system involves 3 sequential phases. What are they?

Definition

1. cephalic phase

2. gastric phase

3. intestinal phase

Term

Regulation of the Digestive System.

- the first phase

- during this phase, the sight, smell, thought, or initial taste of food causes salivation and gastric juice production in order to prepare the GI tract for the food that is about to be digested.

Definition

cephalic phase

- The cephalic phase of digestion involves the ANS

Term

Regulation of the Digestive System.

- the second phase

- begins as soon as food enters the stomach

Definition

gastric phase

Term

What 4 activities occur during the gastric phase of digestion?

Definition

1. gastric secretion and motility (this promotes the formation of gastric chyme)

2. contraction of the LES (this prevents reflux of gastric juice into the esophagus)

3. relaxation of the pyloric sphincter (this promotes gastric emptying)

4. gastrocolic reflex

Term

- the presence of food in the stomach causes increased motility in the colon

- this reflex clears out the intestinal chyme/feces from the last meal to make way for the new chyme it is about to receive.

- it is because of this* that a person has an urge to defecate during or just after a meal.

Definition

gastrocolic reflex

Term

The gastric phase is mediated by the hormone ______.

Definition

gastrin

Term

Regulation of Digestive System.

- the third phase

- begins as soon as a significant amount of chyme enters into the small intestine

Definition

intestinal phase

Term

What 3 activities occur during the intestinal phase of digestion?

Definition

1. release of pancreatic juice and bile into the lumen of the small intestine (The pancreatic juice and bile aid the small intestine in the digestion of food particles in luminal chyme)

2. inhibition of gastric motility, secretion, and emptying (This prevents the small intestine from being overloaded with too much chyme)

3. a feeling of satiety is experienced

Term

The intestinal phase is mediated by several hormones: ______, ________, and ___.

Definition

secretin, cholecystokinin, and GIP

Term

Give the name, type, and function of cranial nerve I.

Definition

Name: Olfactory

Type: Sensory

Function: Sense of smell

Term

Give the name, type, and function of cranial nerve II.

Definition

Name: Optic

Type: Sensory

Function: Vision

Term

Give the name, type, and function of cranial nerve III.

Definition

Name: Oculomotor

Type: Motor

Function: Raise eyelids, move eyes, regulate size of pupils, focus of lenses

Term

Give the name, type, and function of cranial nerve IV.

Definition

Name: Trochlear

Type: Motor

Function: Eye movements, proprioception

Term

Give the name, type, and function of cranial nerve V.

Definition

Name: Trigeminal

Type: Mixed

Function: Sensations of the head and face, chewing movements, and muscle sense.

Term

Give the name, type, and function of cranial nerve VI.

Definition

Name: Abducens

Type: Motor

Function: Produce movement of the eyes

Term

Give the name, type, and function of cranial nerve VII.

Definition

Name: Facial

Type: Mixed

Function: Facial expressions, secretion of saliva, taste

Term

Give the name, type, and function of cranial nerve VIII.

Definition

Name: Vestibulocochlear

Type: Sensory

Function: Balance or equilibrium sense, hearing

Term

Give the name, type, and function of cranial nerve IX.

Definition

Name: Glossopharyngeal

Type: Mixed

Function: Taste and other sensations of tongue, swallowing, secretion of saliva, aid in reflex control of blood pressure and respiration

Term

Give the name, type, and function of cranial nerve X.

Definition

Name: Vagus

Type: Mixed

Function: Transmit impulses to muscles associated with speech, swallowing, the heart, smooth muscles of visceral organs in the thorax, and abdomen

Term

Give the name, type, and function of cranial nerve XI.

Definition

Name: Accessory

Type: Motor

Function: Turning movements of the head, movements of the shoulder and viscera, voice production

Term

Give the name, type, and function of cranial nerve XII.

Definition

Name: Hypoglossal

Type: Motor

Function: Tongue movements

Term

inflammation and enlargement of the parotid glands accompanied by moderate fever, malaise (general discomfort), and extreme pain in the throat, especially when swallowing sour foods or acidic juices

Definition

mumps

Term

multi-step procedure in which all traces of pulp tissue are removed from the pulp cavity and root canals of a badly diseased tooth

Definition

root canal therapy

Term

the LES fails to close adequately after food has entered the stomach, the stomach contents can reflux (back up) into the inferior portion of the esophagus

Definition

gastroesophageal reflux disease

Term

- smooth muscle fibers of the sphincter fail to relax normally, so food does not pass easily from the stomach to the small intestines

- a narrowing of the pyloric sphincter that must be corrected surgically

Definition

pylorospasm and pyloric stenosis

Term

forcible expulsion of the contents of the upper GI tract (stomach and sometimes duodenum) through the mouth

Definition

vomiting (emesis)

Term

- inflammation of the pancreas, as may occur in association with alcohol abuse or chronic gallstones

- usually affects people over 50 years of age and occurs more frequently in males

Definition

pancreatitis and pancreatic cancer

Term

yellowish coloration of the sclerae, skin, and mucous membranes due to a buildup of a yellow compound called bilirubin

Definition

jaundice

Term

if bile contains either insufficient bile salts or lecithin or excessive cholesterol, the cholesterol may crystallize to form ________

Definition

gallstones

Term

the absorptive cells of the small intestines fail to produce enough lactase, which is essential for the digestion of lactose

Definition

lactose intolerance

Term

- because it is lipid-soluble, this* begins to be absorbed in the stomach

- alcohol dehydrogenase, present in gastric mucosa cells, breaks down a lot of the alcohol to acetaldehyde

Definition

absorption of alcohol

Term

inflammation of the appendix that is preceded by obstruction of the lumen of the appendix by chyme, inflammation, foreign body, etc.

Definition

appendicitis

Term

generally slow-developing benign growths that arise from the mucosa of the large intestine

Definition

polyps in the colon

Term

blood that is hidden, not detectable by the human eye

Definition

occult blood

Term

consists of indigestible plant carbohydrates found in fruits, vegetables, grains, and beans

Definition

dietary fiber

Term

tooth decay, involves a gradual demineralization of the enamel and dentin

Definition

dental caries

Term

collective term for a variety of conditions by inflammation and degeneration of the gingivae, alveolar bone, periodontal ligament, and cementum

Definition

periodontal disease

Term

- 5-10% of the population develops this*

- ulcers that develop in areas of the GI tract exposed to acidic gastric juice

Definition

peptic ulcer disease

Term

sac-like outpouchings of the wall of the colon, occur in places where the muscalaris has weakened and may become inflamed

Definition

diverticular disease

Term

among the deadliest of malignancies, ranking 2nd to lung cancer in males and 3rd to breast cancer in women

Definition

colorectal cancer

Term

inflammation of the liver that can be caused by viruses, drugs, and chemicals, including alcohol (several types: A, B, C, D, E)

Definition

hepatitis

Term

condition caused by malfunction of the myenteric plexus in which the LES fails to relax normally as food approaches

Definition

achalasia

Term

a rumbling noise caused by the propulsion of gas through the intestines

Definition

borborygmus

Term

painful ulcer on the mucous membrane of the mouth that affects females more often than males, usually between ages 10 and 40

Definition

canker sore

Term

distorted or scarred liver as a result of chronic inflammation due to hepatitis, chemicals that destroy hepatocytes, parasites that infect the liver, or alcoholism

Definition

cirrhosis

Term

inflammation of the mucosa of the colon and rectum in which absorption of water and salts in reduced

Definition

colitis

Term

the visual examination of the lining of the colon using an elongated, flexible, fiber-optic endoscope called a colonoscope

Definition

colonoscopy

Term

diversion of feces through an opening in the colon, creating a surgical "stoma" (artificial opening) that is made in the exterior of the abdominal wall

Definition

colostomy

Term

difficulty in swallowing that may be caused by inflammation, paralysis, obstruction, or trauma

Definition

dysphagia

Term

air in the stomach or intestine, usually expelled through the anus

Definition

flatus

Term

a sudden illness caused by ingesting food or drink contaminated by an infectious microbe or a toxin

Definition

food poisoning

Term

endoscopic examination of the stomach in which the examiner can view the interior of the stomach directly to evaluate an ulcer, tumor, inflammation, or a source of bleeding

Definition

gastroscopy

Term

varicosed (enlarged or inflammed) superior rectal veins, develop when the veins are put under pressure and become engorged with blood

Definition

hemorrhoids

Term

protrusion of all or part of an organ through a membrane or cavity wall, usually the abdominal cavity

Definition

hernia

Term

inflammation of the gastrointestinal tract that exists in 2 forms: (1) Crohn's disease and (2) Ulcerative colitis

Definition

inflammatory bowel disease

Term

disease of the entire GI tract in which a person reacts to stress by developing symptoms associated with alternating patterns of diarrhea and constipation

Definition

irritable bowel syndrome (IBS)

Term

a number of disorders in which nutrients from food are not absorbed properly

Definition

malocclusion

Term

infectious disease of the GI tract that results in loose, urgent bowel movements, cramping, abdominal pain, malaise, nausea, and occasionally fever and dehydration

Definition

Traveler’s diarrhea

Term

chronic disorder characterized by self-induced weight loss, negative perception of body image, and physiological changes that result from nutritional depletion

Definition

anorexia nervosa

Term

disorder that typically affects young, single, middle-class white females, characterized by overeating at least twice a week followed by purging by self-induced vomiting

Definition

bulimia

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