Chapter 9

Question 1

6 basic processes in the digestive system

• Inges(on: taking food into mouth.
• Diges(on: mechanical and chemical breakdown of food.
• Secre(on: release of water, acid, buffers, and enzymes into lumen of GI tract.
• Diges(on: mechanical and chemical breakdown of food.
• Mixing and propulsion: churning and movement of food through GI tract.
• Absorp(on: passage of digested products from GI tract into blood and lymph.
• Defeca(on: elimina>on of feces from GI tract.

put in right order

Answer 1

1. Inges(on: taking food into mouth.
2. Secre(on: release of water, acid, buffers, and enzymes into lumen of GI tract.
3. Mixing and propulsion: churning and movement of food through GI tract.
4. Diges(on: mechanical and chemical breakdown of food.
5. Absorp(on: passage of digested products from GI tract into blood and lymph.
6. Defeca(on: elimina>on of feces from GI tract.

Question 2

The accessory digestive organs include:
* teeth: physical breakdown of food.
* tongue and salivary glands: assists
in chewing and swallowing.
* liver, gallbladder and X:
produce or store secretions that
flow into the GI tract for chemical
breakdown of food.

Answer 2

pancreas

Question 3

The wall of the GI tract from the lower esophagus to the anal canal has the same basic,
four-layered arrangement of tissues, from deep to superficial:

• Muscularis
• Submucosa
• Serosa or adventitia
• Mucosa

put in right order

Answer 3

1. Mucosa
2. Submucosa
3. Muscularis
4. Serosa or adventitia

Question 4

. Mucosa is composed of:
1. A layer of epithelium (with …. cells: secrete mucus and fluid and …. cells: secrete hormones)

2. A layer of X tissue (lamina propria) containing: blood vessels, lymphatic vessels and mucosa-associated lymphatic tissue (MALT, prominent lymphatic nodules contain immune system cells that protect against disease).
3. A thin layer of X muscle (muscularis mucosae): its movements ensure
   that all absorptive cells are fully exposed to the contents of the GI tract.

Answer 4

exocrine: mucus etc
Endocrine: hormones
connective
smooth

Question 5

Submucosa consists of areolar X tissue that binds the mucosa to the muscularis. It
contains:

• Blood and lymphatic vessels that receive absorbed food molecules.
• An extensive network of neurons: submucosal X.
• Glands and lymphatic 7ssue

Answer 5

connective
plexus

Question 6

Muscularis:

• Skeletal muscle in the mouth, pharynx, and superior and middle parts of the esophagus
  for voluntary swallowing, and in the external anal sphincter for voluntary control of
  defecation.
• Smooth muscle throughout the rest of the tract: inner sheet of circular fibers and an
  outer sheet of longitudinal fibers. Its involuntary contractions help break down food, mix
  it with digestive secretions, and propel it along the tract.

Between the layers of the
muscularis is a second X of neurons: the myenteric X.

Answer 6

plexus

Question 7

Serosa or adventitial:

• Serosa or visceral peritoneum: superficial serous membrane composed of X
  tissue and epithelium only present in portions of the GI tract that are suspended in the
  abdominal cavity.
• Adventitia: superficial layer of connective tissue in X

Answer 7

connective
esophagus.

Question 8

The ENS contains sensory neurons,
interneurons, and motor neurons:
what do they do?

Answer 8

sensory: chemical changes/stretching
interneurons: sensory info -> motor neurons
motor neurons: contraction and secretion of glands

Question 9

Which of these plexuses controls secretions and which controls GI tract motility?

• submucosal
• myenteric

Answer 9

submucosal: secretions
myenteric: motility

Question 10

Afferent pathway (enteric sensory neurons): ENS contains two major types of sensory
receptors:
1. Xreceptors: respond to certain chemicals in the lumen
2. Xreceptors: respond to stretch

Answer 10

Chemo
Mechano

Question 11

• Sensory fibers send information to the X but also to the prevertebral
  ganglia of the spinal cord, to the spinal cord and to the brainstem

Answer 11

enteric plexuses

Question 12

A/Efferent pathway (enteric motor neurons): govern contrac>on of gastrointes>nal tract
smooth muscle and secre>on of gastrointes>nal tract glands

Answer 12

Efferent

Question 13

Although the neurons of the ENS can func>on independently, they are subject to
regula(on by the neurons of the autonomic/somatic nervous system:
1. Sympathetc division: in/decreases actvity of ENS
2. Parasympathetic division: in/decreases activity of ENS

Answer 13

automatic,

decreases
increases

Question 14

The oral vestibule is the space bounded externally by the X and lips and
internally by the gums and teeth.

• The uvula is a fingerlike muscular structure hanging from the free border of the soft
  palate which prevents swallowed food from entering the nasal cavity.

Answer 14

cheeks

Question 15

The three major salivary glands are: parotid, sublingual, and submandibular. They secrete mucus which contains which digestive enzyme?

Answer 15

amylase

Question 16

• Functions saliva:
  1. Lubricates
  2. Dissolves foods
  3. Begins the chemical breakdown
  of carbohydrates (stach) and
  lipids
  4. Protection: IgA prevents
  a[achment of microbes so they
  cannot penetrate the
  epithelium, and lysozyme kills
  bacteria

Answer 16

ok

Question 17

Chemical digestion in the mouth by two enzymes:

1. Salivary amylase:
   * Secreted by the salivary glands
   * Initiates the breakdown of starch
2. X:
   * Secreted by lingual glands in the tongue
   * Becomes activated in the acidic environment of the stomach and thus starts to work after food is swallowed
   * Breaks down dietary triglycerides (fats and oils) into fatty acids and
   diglycerides

Answer 17

Lingual lipase

Question 18

Pharynx or throat is a funnel-shaped tube that extends from the internal
nares to the esophagus posteriorly and to the larynx anteriorly.

It is divided into three parts:
1. the Xpharynx
2. the oropharynx
3. laryngopharynx or hypopharynx.

Answer 18

naso

Question 19

At each end of the esophagus, the muscularis becomes
slightly more prominent and forms two sphincters:

1. X sphincter: skeletal muscle,
   regulates the movement of food from the pharynx
   into the esophagus
2. X (cardiac) sphincter: smooth
   muscle, regulates the movement of food from the
   esophagus into the stomach

Answer 19

Upper esophageal
Lower esophageal

Question 20

Deglutition or X is the movement of food from the mouth into the
stomach.
* It involves the mouth, pharynx, and esophagus and is facilitated by the secretion
of saliva and mucus.

Answer 20

swallowing

Question 21

Swallowing occurs in three stages:

(1) X stage: the bolus is passed into the oropharynx.

(2) X stage: the involuntary passage of the bolus through the pharynx into
the esophagus: the tongue rises against the palate, the nasopharynx is closed off,
the larynx rises, the epiglo`s seals off the larynx, and the bolus is passed into
the esophagus.
Deglution
(3) Esophageal stage: the
involuntary passage of the
bolus through the
esophagus into the
stomach. Food moves
through the esophagus into
the stomach via peristalsis

Answer 21

Voluntary
Pharyngeal

Question 22

Four parts of the stomach: put in right order from esophagus to duodenum

Fundus
Body
Cardia
Pyloric part

Answer 22

1. Cardia: surrounds the
   opening of the esophagus
   into the stomach.
2. Fundus: rounded por>on
   superior to and to the leb of
   the cardia.
3. Body: large central por>on of
   the stomach.
4. Pyloric part. Pylorus connects
   to the duodenum.

Question 23

stomach functions:

1. Mixes saliva, food, and gastric juice to form X. X: is a soupy liquid result of
   movements of the gastric contents mixed with gastric juice.
2. Serves as reservoir for food before release into small intes>ne.
3. Secretes gastric juice, which
   contains:
   * HCl: kills bacteria and
   denatures proteins.
   * Pepsin: begins the digestion
   of proteins.
   * Intrinsic factor: aids
   absorption of vitamin B12.
   * Gastric lipase: aids
   digestion of triglycerides.
4. Secretes gastrin into blood.

Answer 23

chyme

Question 24

Secretions from several gastric
glands flow into each X (narrow channels)
and then into the lumen of the
stomach.

Answer 24

gastric pit

Question 25

Three types of endo/exocrine gland cells that secrete their products into the stomach lumen. The secretion of these cells= gastic juice

Answer 25

exo

Question 26

Gastric juice consists of: 1. Mucous neck cells: secrete mucus (there are also surface mucous cells) 2. Chief (zymogenic) cells: secrete pepsinogen and gastric lipase. 3. X cells: produce intrinsic factor (needed for absorption of vitamin B12) and hydrochloric acid (HCl)

Answer 26

Parietal

Question 27

One type of enteroendocrine cell: G cell: located mainly in the pyloric antrum, secretes the hormone X into the bloodstream

Answer 27

gastrin

Question 28

Each peristaltic wave moves gastric contents from the body of the stomach down into the antrum: X * The pyloric sphincter normally remains almost, but not completely, closed. * Because most food particles in the stomach initially are too large to fit through the narrow pyloric sphincter, they are forced back into the body of the stomach: retropulsion.

Answer 28

propulsion.

Question 29

Once the food par>cles in chyme are small enough, they can pass through the pyloric sphincter: gastric X. * Gastric emptying is a slow/fast process

Answer 29

emptying slow: only about 3 mL of chyme moves through the pyloric sphincter at a time

Question 30

Chemical digestion in the small intestine depends on the activities of the X, X, and X.

Answer 30

pancreas liver gallbladder

Question 31

The pancreas consists of a head, a body, and a tail and is usually connected to the duodenum of the small intestine by two ducts true/false

Answer 31

true

Question 32

Pancreatic juices are secreted by endo/exocrine cells into small ducts that ultimately unite to form two larger ducts, the X duct (or duct of Wirsung) and the accessory duct. These in turn convey the secretions into the small intestine.

Answer 32

exo pancreatic

Question 33

The X duct joins the common X duct from the liver and gallbladder and enters the duodenum as a dilated common duct called the hepatopancreatic ampulla (or ampulla of Vater).

Answer 33

pancreatic bile

Question 34

The pancreas is made up of small groups of glandular epithelial cells called acini: * 99% of the acini constitute the endo/exocrine portion of the organ and secrete pancreatic juice. * 1% of the acini are the pancreatic (or Langerhans) islets, they form the endo/exocrine portion of the pancreas and secrete the hormones glucagon, X, somatostatin and pancreatic polypeptide.

Answer 34

insulin

Question 35

The pancreas produces pancreatic juice, a clear, colorless liquid consisting mostly of water, some salts, sodium bicarbonate, and several enzymes. * The sodium bicarbonate gives pancreatic juice a slightly X pH that buffers acidic gastric juice in chyme, stops the acton of X from the stomach, and creates the proper pH for the action of digestive enzymes in the small intestine

Answer 35

alkaline (7.1–8.2) pepsin

Question 36

The enzymes in pancreatic juice include: * Pancreatic amylase: X-digesting enzyme * Trypsin, chymotrypsin, carboxypeptidase, and elastase: enzymes that digest proteins into peptides. These enzymes are produced inactive to not digest cells of the pancreas itself. * Pancrease lipase: principal triglyceride–diges>ng enzyme in adults * Ribonuclase and deoxyribonuclease: enzymes that digest ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) into nucleotides. * Trypsin inhibitor.

Answer 36

starch

Question 37

Main function of hepatocytes is to secrete bile, a yellow, brownish, or olive-green liquid. what are hepatocytes

Answer 37

major functional cells of the liver

Question 38

Bile salts (sodium and potassium) play a role in X: the breakdown of large lipid globules into a suspension of small lipid globules Bile salts also aid in the absorption of lipids following their digestion.

Answer 38

emulsification

Question 39

In addition to secreting bile, necessary for the absorption of fatty foods, the liver performs other vital functions: 1. metabolism of carbohydrates: helps maintain adequate blood glucose levels, among other functions. 2. lipid metabolism. 3. protein metabolism: deaminate amino acids, convert ammonium (toxic) into urea, synthesize most plasma proteins: globulins, albumin, prothrombin and fibrinogen. 4. Processes drugs (detoxifying function) and hormones. 5. Excretes bilirubin. 6. Storages of substances: glycogen, vitamins (A, B12, D, E and K) and minerals (iron and copper). 7. Phagocytosis: thanks to Kupffer cells. 8. Activation of vitamin D (along with the skin and kidney).

Answer 39

ok

Question 40

Small intestine is divided into pieces, place in order of pyloric sphincter to ileocecal sphincter 1. Jejenum 2. Ileum 3. duodenum

Answer 40

1. Duodenum: the first part of the small intestine, is the shortest region, and is retroperitoneal. It starts at the pyloric sphincter of the stomach and is in the form of a C-shaped tube that extends about 25 cm until it merges with the jejunum. 2. Jejunum: is the next portion and is about 1 m long and extends to the ileum. 3. Ileum: is the final and longest region of the small intestine. It measures about 2 m and joins the large intestine at a smooth muscle sphincter: ileocecal sphincter.

Question 41

immune system is important in the small intestine: 1. Small intestinal mucosa has an abundance of mucosa-associated lymphoid (ssue (MALT). 2. Solitary lymphatic nodules are also found (particularly in the distal part of the ileum). 3. Groups of lymphatic nodules (X), are also present in the ileum

Answer 41

Peyer’s patches

Question 42

most of absorption takes place in the ....

Answer 42

small intestine

Question 43

epithelial layer of small intestine: 1. Absorptive cells: contain enzymes (brush-border enzymes) that digest food and possess microvilli that absorb nutrients in small intestinal chyme. 2. Exocrine cells: * X cells: secrete mucus. * X cells: secrete lysozyme (bactericidal enzyme), and are capable of phagocytosis. Paneth cells may have a role in regulating the microbial population in the small intestine.

Answer 43

Goblet: mucus Panet: lysozyme

Question 44

Endocrine cells in small intestine: * S cells: secrete the hormone secretin * CCK cells: secrete the hormone cholecystokinin (CKK) * X cells: secrete the hormone glucose-dependent insulinotropic peptide (GIP)

Answer 44

K

Question 45

Small intestinal mucosa contains many deep crevices lined with glandular epithelium. * Cells lining the crevices form the intestinal glands, or crypts of Lieberkühn, and secrete X

Answer 45

intestinal juice.

Question 46

Chyme remains in the small intestine for x-x hours.

Answer 46

3–5

Question 47

From absorptive epithelial cells, X, amino acids and SCFA are transported in the X

Answer 47

monosaccharides blood

Question 48

X and monoglycerides are recombined to form triglycerides, -> become coated with proteins (chylomicrons) -> lymphatic vessels

Answer 48

Long-chain fatty acids

Question 49

Digestive activities occur in three overlapping phases: 1. Cephalic phase: neuronal mechanism 2. Gastric phase: neural and hormonal mechanisms 3. Intestinal phase: neural and hormonal mechanisms explain

Answer 49

cephalic: before food is swallowed gastric: food in the stomach intestinal: food leaves stomach

Question 50

during cephalic phase, The brain stem activates: * Facial (VII) and glossopharyngeal (IX) nerves: stimulate the salivary glands to secrete saliva. * X nerve: stimulate the gastric glands to secrete gastric juice.

Answer 50

Vagus

Question 51

gastric phase: NEURAL REGULATION: when the food enters the stomach: 1. Stomach distends and activated stretch receptors in its walls. 2. X buffer the stomach acid, pH de/increases and chemoreceptors are activated.

Answer 51

Ingested proteins increases

Question 52

* From the stretch receptors and chemoreceptors, nerve impulses propagate to the submucosal plexus, where they actvate parasympathetic/sympathetic and enteric neurons.

Answer 52

parasympathetic