Chapter 26 Flashcards
____ is the introduction of solid/liquid into the oral cavity.
ingestion
_____ is the voluntary/involuntary muscular contractions for mixing and moving materials through GI tract.
motility
____ is the production/release of digestive enzymes, acid, and bile into the GI tract to aid in digestion.
secretion
_____ is the breakdown of ingested food into smaller structures.
digestion
______ is when food is physically broken down and there are no chemical changes.
mechanical digestion
_______ involves specific enzymes to break chemical bonds, making smaller molecules for absorption
chemical digestion
_____ is the membrane transport of digested molecules, electrolytes, vitamins and water from GI into blood/lymph
absorption
______ is the expulsion of indigestible components
elimination
The mucosa is made of three layers: ______, ______, and _______.
epithelium, lamina propria, muscularis mucosae
The inner most layer of the mucosa is called the _____.
epithelium
Most of the GI tract (stomach, small and large intestines) are made of _______.
simple columnar epithelium
The cells of the oral cavity, or/laryngopharynx, esophagus, and anal canal are called ______.
nonkeratinized stratified squamous
The middle layer of the mucosa is called the ______.
lamina propria
The lamina propr. contains blood and lymphatic vessels, nerves and _______.
MALT
The outermost layer of the mucosa is the _____
muscularis mucosae
Which layer of the the mucosa facilitates the release of secretions from the mucosa into the lumen?
muscularis mucosae
Muscularis mucosae causes slight movement of mucosa to increase ______.
contact with materials within the lumen.
The submucosa is made up of _____ and ______.
areolar
dense irregular connective tissue
The submucosa contains large blood vessels, lymph vessels, _____ and ______.
nerves and glands
The submucosa contains ______, _____ in small intestines.
MALT, peyer’s patches
The submucosal nerve plexus innervates smooth muscle and glands of mucosa as well as glands of __________.
submucosa
The two lanes of the muscular?
inner circular layer
outer longitudinal layer
The inner circular layer surrounds the _____.
GI tract
The outer longitudinal layer runs the _____ of the GI tract.
length
The my centric nerve plexus is located between what two layers?
inner circular layer and the outer longitudinal layer
The mycentric nerve plexus contains both motor neurons of ANS and ________.
visceral sensory neurons
The functions of the muscularis?
peristalsis and mixing
______ is the alternating contraction sequence causing the pushing of ingested materials through the GI tract.
peristalsis
____ is the kneading motion within different regions of GI tract that lack directional movement.
Mixing
Serosa/Adventitia are both composed of _____.
areolar connective tissue
______ covers portions of the GI tract located outside of peritoneal cavity.
adventitia
The retroperitoneal organs
duodenum
pancrea
ascending/descending colon
rectum
The _____ is covered by visceral peritoneum.
serosa
The serosa covers portions of GI tract within the ______ cavity.
peritoneal
Intraperitoneal organs
stomach
jejunum/ileum
transverse/sigmoid colons
The digestive system is regulated by receptors, nervous control and _____.
hormonal control
_____ detect stretch or pressure.
baroreceptors
______ detect presence of specific substances.
chemoreceptors
Hormonal control is regulated by gastrin, secretin and ____.
cholecystokinin or CCK
Gastrin is released from the ____.
stomach
______ and ________ comes from the small intestines.
secretin
choleycystokinin
_______ control through facial, glossopharyngeal and vagus nerves.
Autonomic
________ nervous system contains both submucosal and myenteric nerve plexi.
enteric
____- nerve stimulates myenteric plexus which stimulates submucosal plexus.
Vagus
____ nervous can direct all essential activities of the GI tract in the absence of the ANS.
enteric
Daily secretions of ____ range between 1 and 1.5 liters, with most produced during mealtime.
saliva
Saliva is composed of ____% water and a mixture of solutes.
99.5%
_____ is made up of water and salivary amylase, mucin, and ______.
lysozyme
Saliva functions to ____ ingested food.
moisten
Saliva intiates ______.
chemical digestion
Saliva helps to form a _______ of the food that has been ingested.
food bolus
_____ initiates chemical digestion and ______ targets starch.
Saliva
salivary amylase
Saliva acts as a _____ so food molecules dissolve into saliva before they can stimulate taste receptors.
watery medium
Saliva cleans the _____.
oral cavity
Saliva helps inhibit _____ because it contains antibacterial substances: both lysozyme and IgA’s.
bacterial growth
The brains contains _______.
salivary nuclei
______ stimulation keeps oral cavity moist.
parasymphathetic
Parasympathetic stimulation keeps the oral cavity moist. The ____ nerve stimulates the submandibular and sublingual glands. The _____ nerve stimulates the parotid gland.
facial nerve
glossopharyngeal nerve
More saliva will be released in the upper GI in response to chemoreceptors and _____.
mechanoreceptors
Arrival of food into the stomach, especially ____ or ____ stimulates the release of more saliva.
spicy or acidic
Introduction of substances into oral cavity, especially ______ substances will release more saliva in response to super GI chemoreceptors and mechanoreceptors.
acidic
Saliva stimulation occurs when the higher brain centers thought, smell or _____ of food.
sight
______ stimulation results in more viscous saliva by decreasing water content.
sympathetic
_______ is the mechanical digestion in the oral cavity (chewing).
mastication
Mastication centers located within the _____ and _____ regulate coordinated activity of the teeth and the skeletal muscles of the lips, tongue, cheeks, and jaw.
pons and medulla
Mastication reduces the _____ into smaller particles to facilitate swallowing.
bulk
Mastication promotes salivation to help _____ and moisten food into bolus.
soften
Small, ____ molecules can be absorbed directly into the blood from the mouth without chewing or swallowing.
nonpolar
Between 6 and 30 months of age, ____ deciduous teeth will appear (including incisors, canines, and premolars)
20
All 20 deciduous teeth are lost and replaced with ____ permanent teeth (includes all deciduous teeth and molars).
32 permanent
Incisors most anterior, are shapes like chisels and have a ____ root.
single
_______ are designed for slicing or cutting.
incisors
Canines have ____ and a single root.
pointed tip
_______ are designed for puncturing and tearing.
canines
Premolars have a _____ with cusps and 1 or 2 roots.
flat crowns
Premolars are designed for ______ and ______.
crushing and grinding
Molars that are most posterior, have large crowd flat crowns with ____ or more roots.
3
______ are adapted for grinding and crushing.
Molars
The number of each type of tooth is written as a ________ for one quadrant of the mouth (upper and lower shown on separate rows)
dental formula
A dental formula for most adults
ICPM = 2123/2123
A dental formula for most children
ICP = 212/212
_______ or swallowing, is the process of moving ingested materials from the oral cavity to the stomach.
deglutition
The three phases of deglutition.
- voluntary phase
- pharyngeal phase (involuntary)
- Esophageal phase (involuntary)
_______ in the medulla coordinates with the respiratory center (also in the medulla) so there is a pause in breathing.
swallowing center
______ is difficulty swallowing.
dysphagia
If there is damage to the swelling center, the _____ can maintain function.
enteric nervous system
Voluntary Phase of Deglutition
Controlled by the cobra cortex
Chewed food forms bolus and then pushed superiorly against the hard palate
Transverse palatine folds direct bolus toward oropharynx initiating
Pharyngeal Involuntary Phase (1 second)
Swallowing center receives signals from tactile sensory receptors which causes:
Elevation of soft palate and uvula blocking off nasopharynx
Elevation of larynx resulting in epiglottis covering laryngeal opening
Bolus moves through pharynx to esophagus
Esophageal Involuntary Phase
5-8 seconds long as bolus moves through esophagus by peristaltic waves
______ is a normally collapsed, tubular passageway.
esophagus
The ________ contains superior and inferior sphincters which are normally closed, only opening to allow for the passage of a bolus.
esophagus
The _____ of the esophagus is unique and contains both skeletal and smooth muscle.
muscularis
The superior 1/3rd of the esophagus contains only _____. The muscle propels swallowed material out of pharynx quickly for the next ______ to occur.
skeletal muscle fibers
breath
The middle 1/3rd of the esophagus contains _________.
both skeletal and smooth muscle
The inferior 1/3rd of the esophagus contains ______ which is continuous with the muscular that extends throughout the stomach.
smooth muscle
The ____ is inferior to the diaphragm, anterior to the pancreas and the holding sac is in the left upper quadrant.
stomach
The stomach mixes ______ with secretions released from the stomach wall.
ingested food
The stomach mechanically digests the contents into a semifluid mass called _____.
chyme
The stomach completes _______ of both protein and fat.
chemical digestion
Absorption in the stomach is limited to small, non polar substances such as _____ and ______.
alcohol and aspirin
One essential function of the stomach is the release of the ______.
intrinsic factor
The intrinsic factor is needed for the absorption of vitamin _____ in the ileum of the small intestines.
B12
There are ___ types of secretory cells of the gastric epithelium.
five
In the stomach, four of the five secretory cells of the gastric epithelium produce _____ of gastric juices a day.
3 liters
The fifth secretory cells of the gastric epithelium secretes _____.
a hormone
_____ cells line the stomach lumen, extend into gastric pits.
surface mucous cells
Surface mucous cells secrete _____ product within mucin to surface where mucin hydrates and becomes a mucus layer. This prevents ulceration of the stomach lining.
alkaline
The ____ cells prevents ulceration of the stomach lining.
surface mucous
_____ cells line the base of gastric pits into the gastric glands, inter mixed with parietal cells.
mucous neck cells
Mucous neck cells produce an _____ which helps maintain the acidic conditions resulting from the secretion of the HCl.
acidic mucin
The mucous neck cells still act a a _____.
protective layer
_____ cells release intrinisic factor.
parietal cells
_____ is a glycoprotein required for the absorption of vitamin B12 needed for production of normal erythrocytes.
intrinsic factor
B12 deficiencies can result in ______.
pernicious anemia
______ cells release hydrochloric acid.
Parietal cells
Hydrochloric acid is not formed in parietal cell, forms in _______ after H+ and Cl- released from cell.
lumen
Normal stomach pH levels range from ______.
1.5 - 2.5
Hydrochloric acid converts inactive pepsinogen into active _____.
pepsin
______ kills most microorganisms that enter the stomach.
Hydrochloric acid
Hydrochloric acid contributes to the breakdown of plant cell walls and ______.
animal connective tissue
______ cells are the most numerous within gastric glands.
chief cells (peptic)
Chief cells (peptic) produce and secrete packets of _____ containing the inactive form of pepsin, pepsinogen.
zymogen granules
Chief cells are activated by both HCl and other _______.
active pepsin molecules
______ chemically digests denatured proteins into small peptide fragments.
Chief cells (peptic)
Chief cells produce ______, which is an enzyme with limited role in fat digestion (10% - 15%)
gastric lipase
______ are distributed throughout gastric glands.
G-cells
_____ secrete gastrin into the blood.
G-cells
G cells secreting gastrin stimulates _______ and secretions
stomach motility
Three stimulatory molecules responsible for HCl regulation; _______, ________, and _________.
acetylocholine
gastrin
histamine
______ is a neurotransmitter from enteric neurons.
acetylcholine
_____ is a paracrine hormone released from ECL cells.
histamine
_______is a hormone released from G cells.
gastrin
______ and _______ stimulates parietal cells directly.
histamine and acetylcholine
Gastrin stimulates release of histamine from ______ to indirectly stimulate parietal cells.
ECL cells
Somatostatin released from enteroendocrine cells when pH of stomach is ______.
too low
______ inhibits acid secretion by directly affecting parietal, ECL, and G cells.
Somatostatin
______ is the mixing of bolus with gastric juice to form chyme.
gastric mixing
_______ is the movement of acidic chyme from stomach through pyloric sphincter into duodenum.
gastric emptying
stomach motility steps
?
Peristaltic wave establishes a _________ on contents in pylorus than pressure exerted by pyloric sprinter to stay closed.
greater pressure on contents
Stomach motility causes ____ to empty into small intestines at a time.
3 mL
Peristaltic wave passes sphincter changing the _____.
pressure gradient back
greater pressure at sphincter than against contents thus sphincter closes causing a ________.
retropulsion
