Study Guide Q (test 4)

Digestion begins in the

mouth

What is NOT a function of the digestive system?

production of ATP

During digestion, the major site of nutrient absorption is the

small intestine

What organ produces bile?

liver

What is the correct order of the major parts of the gastrointestinal tract?

mouth → esophagus → stomach → small intestine → large intestine

What are accessory organs of he GI tract?

Pancreas and Gallbaldder

What are the tunics that make up the GI wall?

Adventitia or serosa

Muscularis

Mucosa

Submucosa

The process of moving substances through the epithelial cells that line the GI tract into the blood or lymph is called?

absorption

T or F

The muscularis of the GI tract contains two layers of smooth muscles: the outer circular layer and the inner longitudinal layer

false

What are the major functions of the muscularis layer of the GI tract?

Peristalsis and Mixing

What are the serous membranes of the GI tract?

parietal peritoneum and visceral peritoneum

Btwn the parietal and visceral peritoneum is the thin?

peritoneal cavity

What are the names of the individual mesenteries associated with specific GI organs?

mesocolon

greater omentum

falciform ligament

What are the general receptors found in the GI tract?

chemoreceptors and mechanoreceptors

T or F

Sensory input from both mechanoreceptors and chemoreceptors is relayed to the CNS in response to stimulation. Autonomic motor output is then relayed through cranial nerves to organs of the GI tract.  These are referred to as the short reflexes

false

The muscularis mucosae is a thin layer of smooth muscle immediately deep (external) to the

lamina propria of the mucosa

Most GI tract organs are lined with a ___________ epithelium

simple columnar

The mucosa of the esophagus is lined with ____________ squamous epithelium

nonkeratinized stratified

Within the abdomen, organs that are completely surrounded by visceral peritoneum are called _______________ organs

intraperitoneal

The greater omentum extends inferiorly like an apron from the ___________ of the stomach and covers most of the abdominal organs

greater curvature

Which of the following might stimulate the cephalic phase of gastric secretion?

the though of food

T or F

Gastric secretion is increased in all three phases (cephalic, gastric, intestinal)

false

Gastric secretion during the intestinal phase is inhibited by the presence of

lipids or low pH

Which phase (s) of gastric secretion is (are) regulated by the medulla oblongata?

all 3 phases are regulated by the medulla oblongata

Function of the stomach include?

chemical and mechanical digestion

Which region of the stomach is continuous with the esophagus?

cardiac region

Which cell of the gastric glands produces pepsinogen?

chief cell

Secretin is released from the duodenum in response to

hydrochloric acid in chyme

What enzyme is produced by the stomach?

pepsin

T or F

Gastrin functions to increase the production of HCl in the stomach

true

In the parietal cells, the enzyme carbonic anhydrase causes a reaction btwn?

CO2 + H2O

Hydrochloric acid is formed when H+ ions and Cl- ions join in the?

duct of the gastric gland

The ion exchange protein in the plasma membrane of parietal cells changes ____________ ions going out for __________ ions coming in

bicarbonate

chloride

T or F

The first step in the formation of hydrochloric acid is the active transport of carbon dioxide into the parietal cells

false

label oral cavity

a) superior labial frenulum

b) hard palate

c) soft palate

d) palatoglossal arch

e)uvula

f) lingual frenulum

g) gingivae

h) inferior labial frenulum

label salivary glands

a) parotid salivary gland

b)sublingual salivary gland

c) submandibular salivary gland

Bolus passes from the pharynx to esophagus

resembles what swallowing phase?

Pharyngeal phase

Bolus passes from esophagus to stomach

resembles what swallowing phase?

esophageal phase

chewing forms bolus

resembles what swallowing phase?

voluntary phase

label stomach structures

a) pyloric sphincter

b) lesser curvature

c) fundus

d) longitudinal layer

e) circular layer

f) oblique layer

g) greater curvature

h) duodenum

The stomach is lined by

simple columnar epithelium

T or F

The esophagus extend from the nasopharynx to the stomach

false

T or F

The esophagus is about 25 meters long

false

T or F

The esophagus lies anterior to the treache

false

T or F

The muscularis of the esophagus is different from other parts of the digestive tract because the superior part of the esophagus consists of skeletal muscle

true

T or F

The esophagus contains both an upper and lower esophageal sphincter that regulated the movement of materials into and out of the esophagus

true

T or F

The esophagus contains numerous mucous glands that produce a thick, lubricating mucus that coats the inner surface of the esophagus

true

What events of swallowing are associated with the Pharyngeal phase?

1. initiated by stimulation of tactile receptors in the oropharynx

2. begins with elevation of the soft palate

3. the upper esophageal sphincter relaxes

What events of swallowing are associated with the Esophageal phase?

1. peristalsis moves food bolus onward

2. the lower esophageal sphincter relaxes

What events of swallowing are associated with Voluntary phase?

1. food bolus forced into the oropharynx

2. food bolus pushed by tongue against the hard palate

T or F

The epithelial lining of the oral cavity has a transitional epithelium

false

T or F

Mastication is the process of chemically reducing food bulk into smaller particles to facilitate swallowing

false

G-cells of the gastric glands in the stomach produce a hormone called __________ that stimulates stomach secretion and motility

gastrin

The intestinal phase of digestion involved both the intestinal reflexs and the release of 2 primary hormones __________ and secretin

CCK

label regions/structures of small intestine

a) duodenum

b) duodenojejunal flexure

c) jejunum

d) ileocecal valve

e) ileum

_____________ performs most chemical digestion and absorption

Jejunum

_______________ receives bile and pancreatic juice

Duodenum

______________ controls entry of material into large intestine

Ileum

Ranking the small intestine features from largest to smallest

circular folds, villi, microvilli

1. circular folds

2. villi

3. microvilli

_____________ is a hormone released from the small intestine primary in response to fatty chyme in the intestinal lumen

CCK

What is the GI tract?

continuous tube that includes

oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, and ends at the anus

What are two alternative names for the GI tract?

digestive tract or alimentary canal

Why are the contents in the lumen of the GI tract no considered part of the body?

until they are absorbed

What are accessory digestive organs?

teeth, tongue, salivary glands, liver, gallbladder, pancreas

What are the 6 general functions of the digestive system?

Ingestion, Motility, Secretion, Digestion, Absorption, elimination

What occurs in Ingestion?

is the introduction of solid and liquid nutrients into the oral cavity. It is the first step in the process of digesting and absorbing nutrients

What occurs in Motility?

voluntary muscular contractions (by skeletal muscle)

involuntary muscular contractions (by smooth muscle) for mixing/moving materials through the GI tract.

What occurs in Secretion?

is the process of producing and releasing substances that facilitate both digestion and the movement of contents within the GI tract.

What occurs in Digestion?

1. Mechanical digestion is the breaking of ingested material into smaller pieces without changing its chemical structure.

2. Chemical digestion involves the activity of specific enzymes to break down complex molecules into smaller molecules so that they can be absorbed.

What occurs in Absorption?

involves membrane transport of digested molecules, electrolytes, vitamins, and water across the epithelial lining of the GI tract into the blood or lymph. Absorption occurs primarily within the small intestine.

What occurs in Elimination?

is the expulsion of indigestible components through the anal canal.

What are the four tunica of the GI tract wall?

mucosa

submucosa

muscularis

adventitia (serosa)

What is the innermost tunic?

mucosa

What type of epithelium is found in most of the GI tract: stomach, small intestine, large intestine?

simple columnar epithelium

What type of epithelium is found in portions that must withstand abrasion: esophagus, anal canal?

nonkeratinized stratified squamous epithelium

What underlies the epithelial layer? 

What tissue composes it?

lamina propria

areolar CT

What is the deepest layer of the mucosa? 

What tissue composes it?

Muscularis

thin layer or smooth muscle

What do the autonomic nerves in the submucosa form?

submucosal nerve plexus or Meissner Plexus

What are Peyer patches?

larger aggregates of lymphatic nodules in the submucosa

What tissue composes muscularis tunic?

smooth muscle tissue

What are the two layers of the muscularis tunic?

inner circular layer and outer longitudinal layer

What do the autonomic nerves of the muscularis form?

myenteric nerve plexus or Auerbach nerves

What is the function of the muscularis?

motility

What is segmentation?

backward and forward mixing that blends secretions with ingested material within GI tract

but does not result in directional movement of lumen contents

What is peristalsis?

sequential contraction of the muscularis within the GI tract wall that moves like a wave

one-way movement

What is a sphincter?

rings of smooth muscle that are between regions of the GI that relax and contract

What is the function of a sphincter?

1. control the movements of materials into the next section of the GI tract

2. prevent backflow

What organs located in which regions have a serosa or adventitia?

Only GI structures that are intraperitoneal organs have serosa as their outermost tunic

What are some exceptions to the typical pattern of the GI tract wall?

esophagus: nonkeratinized stratified squamous in its mucosa to protect lining

Stomach: 3 layers of smooth muscle in the muscularized to help with mechanical digestion of swallowed food

What two systems regulate the digestive system?

nervous and endocrine

What is the ENS?

An array of both sensory neurons and motor neurons, which extends from the esophagus to the anus.

Located within the submucosal plexus and the myenteric plexus of the gastrointestinal (GI) tract wall.

Innervates the smooth muscle and glands of the GI tract and mediates the complex coordinated reflexes for the mixing and propulsion of materials through the GI tract.

Which division promotes GI activity? 

parasympathetic

What is the impact of the parasympathetic on motility/sphincters?

stimulates GI motility and relaxes GI tract sphincters

Which division opposes GI tract activity?

Sympathetic

What is sympathetic impact on motility/sphincters/blood vessels? 

inhibits GI tract motility

contracts GI tract sphincters

vasoconstricts blood vessels within GI tract wall

What type of receptors are involved in GI reflexes?

Baroreceptors and chemoreceptors

detect stretch of the GI tract wall

Baroreceptors

monitor the chemical content of the material within the lumen, including the presence of protein and acid

chemoreceptors

What term describes reflexes that only involve the ENS?

short reflex

What term describes reflexes that involves the CNS?

long reflex