Upper GI I Flashcards
What kind of epithelium lines most of the GI tract
Simple columnar epithelium with glands for most of the tract
Musculature of the GI tract
- skeletal muscle at either end and also in the esophagus
- Smooth muscle throughout most GI
The GI tract possesses an ______ rhythmicity
intrinsic
The GI tract possesses an intrinsic rhythmicity mostly due to the presence of
enteric nervous system
The enteric nervous system exists independently of
external influences including the ANS
The GI tract has Enteric nervous system (which is independent) but also receives input from
sympathetic and parasympathetic nervous systems
What are the peptide neurotransmitters
- Bombesin
- Motilin
- Vasoactive intestinal peptide
Unicellular endocrine cells secrete
neuropeptides
Unicellular endocrine cells are derived from
endoderm (which is unlike intrinsic nerve fibers, which are derived from neural crest)
Intrinsic nerve fibers are derived from
neural crest
What is MALT
mucosal associated lymphoid tissue
What is GALT
gut associated lymphoid tissue
Protective mechanisms of GI include
Production of large amounts of mucous: which assists in lubrication and friction reduction
Rapid turnover of epithelial cells in harsh environments such as the stomach and small intestine
The oral cavity is lined with a mucous membrane lying on a _________ layer
Vascular FECT layer
The mucosa of the lip consists of
- Stratified Squamous epithelium
- Basement membrane
- Lamina propria
The lip is composed of a core of ___________ cells embedded in FECT and covered externally by skin
skeletal muscle cells (obicularis oris)
Within the lamina propria of the lip are ____ and ____ glands
mixed and mucous glands
The dermis of the lip has a rich plexus of _____ which prominent at the ______ of the lip
capillaries, free margin
Internally the lip is lined with ____ keratinized, modified, _________ epithelium lies on a lamina propria with _______ papillae
Poorly, stratified squamous epithelium, high papillae
What is the one exception that makes the cheeks structure different than the lip
the cheek has abundant elastic fibers in the submucosa
- These are continuous with the fibers surrounding the striated muscle and the lamina propria
- This arrangement give a maximum of distensibility to the oral mucous membrane
What gives the cheek’s oral mucous membrane maximum distensibility
abundant elastic fibers in the submucosa are continuous with the fibers surrounding the striated muscle and the lamina propria
what three embryonic tissues interact in the development of the teeth
Ectoderm- which forms the enamel organ
Neural crest and mesoderm give rise to the dental papilla
ectoderm forms what part of the teeth? and influences the development?
- enamel organ
- Consists of cells committed to formation of enamel
- Formed from ectoderm under influence of mesoderm and neural crest
Neural crest and mesoderm give rise to dental _____. Which is
Dental papilla
- dentin
- Cementum
- Pulp
- surrounding CT and periodontal pulp
________ is formed from basal cells of the oral ectoderm
dental primordium
The _________ is an epithelial shelf that grows from the thickened primordial into mesenchyme as a bifid structure
labiodental lamina
The external limb splits later to form a groove that deeps to separate the _____ and the remainder of the _____
lip, mouth
In the development of the teeth the internal limb is the
dental lamina
in the development of teeth cells proliferate to form the _______ in each half-jaw
tooth buds (germs)
In the development of teeth a second set of tooth-buds develops on the _____ side of each developing deciduous tooth plus three more ______ in each half-jaw
lingual, posteriorly
The epithelial bud becomes what parts of the teeth
Enamel organ
Dental papillae
Dental sac (follicle)
The enamel organ forms ______ and caps the _____
Enamel, and caps the dental papilla
Condensation of mesenchyme that gives rise to dentin and pulp
Dental papilla
CT sac that surrounds the enamel organ and dental papilla and forms cementum and the periodontal membrane
Dental sac (follicle)
Cells involved in tooth development
Odontoblasts, Ameloblasts
_____ form the dentin matrix throughout the life of the tooth
Odontoblasts
_____ form single layer of cells lining pulp cavity
odontoblasts
Cytoplasmic extensions of the odontoblasts continuing through the prevention and dentinal layers to the dentin-enamel junction; they occupy a space in the dentin matrix known as dentinal tubules
Tomes’ dentinal fibers (odontoblastic processes)
Dentin is similar to bone but is _____: ___% of matrix is organic (compared to about 35% in bone) and composed mostly of _______
harder, 35% and composed mostly of collagen type I
Increment lines (of Ebner and Owen) are associated with
Odontoblasts
Ameloblasts form _____ which covers only the tooth crown
Enamel
____ is the hardest substance in the body
enamel
Enamel is ____% inorganic salts, about ____ % of which is calcium phosphate in the form of aptitude crystals and ___% organic matter and water
96%, 90%, 4%
Enamel is 96% _____, about 90% of which is _______ in the form of _______ and 4% _____ and _____
inorganic salts, calcium phosphate in the form of apatite crystals, organic matter and water
Enamel is laid down in _____, each of which is formed by one _____
prisms, ameloblast
Each prism is formed by one ____
ameloblast
The secreting apical domains of ameloblasts are called
Tomes’ processes
Ameloblasts are associated with _________ which are periods of rhythmic growth
increment lines of Retzius
Specific organic components, rather than collagen, are unique to enamel and are removed after calcification
Amelogenins
Enamelins
Originates form the dental papilla containing condensed mesenchyme
Pulp
Teeth pulp consists of
fibroblasts, macrophages, peripheral odontoblasts, reticular fibers, nerve fibers, and blood vessels that pass via the apical foramen
Cells of the dental sac differentiate into ______ which deposit cementum on the dentin of the root from neck to apex.
Cementoblasts
Cementum has coarse ______(_____) in a bone-like calcified matrix
Collagen fibers (Sharpey’s)
Peridontal membrane is highly _______ active tissue
metabolically
CT formed from dental sac with fibroblasts, osteoblasts, cementoblasts, collagen fibers, blood vessels, and nerve fibers
Peridontal membrane
Peridontal membrane binds _____ to ______
cementum to bony socket
Sharpey’s fibers extend form centum to _____ via the ______
Alveolar wall via the periodontal membrane
Peridontal membrane allows _____ movement
limited
Periodontal membrane absorbs ______ and prevents
absorbs pressures of mastication and prevents this pressure form damaging alveolar bone
Periodontal membrane is affected by diseases such as ______ and _____
diabetes and scurvy
The tongue is composed primarily of a core of _____ and ______, and is covered by a ________
Skeletal muscle and glands, and is covered by a mucous membrane
The anterior two-thirds of the upper oral portion is separated form the posterior one-third of the tongue by the ________
sulcus terminalis
______ appear on the oral portion of tongue as surface projections
Lingual papillae
Lingual papillae are formed of a ________ covered by ________ epithelium
central core of CT lamina propria covered by stratified squamous epithelium
What are the most numerous of all the papillae
filiform papillae
What type of papillae lack taste buds
filiform papillae
Filiform papillae are _____ distributed over the _____ portion of tongue
evenly, entire oral upper portion
_______ papillae are the most numerous of all the papillae and have a ______ appearance
Filiform papillae, conical
What is the function of filiform papillae
gives tongue a rough surface
Fungiform papillae have a ______ appearance
mushroom
Fungiform papillae are ______ in numer
relatively few
Fungiform papillae are interspersed _____ among the _______ rows of ______
singly among the parallel rows of filiform papillae
Taste buds of fungiform papillae are present
only on the oral surface of the epithelium
Taste buds of the circumvallate papillae are located
primarily in the lateral walls
Type of papillae that is rudimentary in humans, but well developed in lower animals
Foliate papillae
Circumvallate papillae are located along the _____ as _____ surrounded by a ____
sulcus terminalis as projections surrounded by a moat (circular furrow)
_______ open into the moat of Circumvallate papillae
Ducts of Von Ebner’s glands
The _______ portion of the tongue is free of papillae but contains the lingual tonsils
pharyngeal
The pharyngeal portion of the tongue is free of ______ but contains the _______
Papillae, lingual tonsils
Taste buds of circumvallate papillae are located
on the lateral walls
Taste buds contain contain ____ types of cells derived form a _________
two, single stem cell
what are the two types of cells in a taste bud
sustentacular cells
taste cells
Spindle-shaped support cells and arranged like barrel-staves to surround the inner taste pro at the base
Sustentacular cells
Each taste cells is long and slender with an elongated _______ and terminates as a short taste hair which projects into the external opening called the
Central nucleus, outer taste pore
Taste cells possess apical ____ with ______ and the basal part of the cell releases ______
microvilli with taste receptors, neurotransmitters
Taste cells are distributed
between the supporting (sustentacular) cells
Except for ____ taste, taste sensation utilize various ________ pathways that result in depolarization of the taste cells
bitter, signal transduction pathways
salt and sour taste utilize ____ transport as a signal transduction mechanism
Ionic
Sour tast involve _____ blockage of ______ to cause depolarization
hydrogen ion blockage, potassium ion channels
Bitter taste involves a _______ state similar to _________
Hypopolarized state similar to retinal cell signal transduction
Sweet taste involves a _____ state
hyperpolarized state
Gustducin (a homologue of retinal transducin) is a G-protein used what taste receptors
Bitter and Sweet
Bitter and sweet taste receptors involves the activation of ______, decrease in ______, and closure of _______ and hypo polarization of the taste cell
G- alpha subunit, decrease in cGMP, and closure of sodium channels and hypolarization of the taste cell
What are the four type of lingual papillae
- Filiform papillae
- Fungiform papillae
- Foliate Papillae
- Circumvallate papillae
What are the 4 layers of digestive tube
- Mucosa (innermost)
- Submucosa
- Muscularis externa
- Outermost layer= Serosa and Adventitia
Characteristic of mucosa of digestive tube
- epithelium-
- Stratified squamous transitioning to simple columnar
- May have secretory, absorptive, and/or protective functions
- Lamina Propria
- Loose Areolar CT associated with epithelium
- Contains various glands and GALT
- Muscularis Mucosa
- Made up of one to three layers of smooth muscle
Submucosa of digestive tube
- Dense, irregular CT
- Vascularized
- Contains a nerve plexus: Meissner’s plexus (submucosal plexus)
Muscularis external of digestive tube
- inner circular layer of smooth muscle
- outer longitudinal layer fo smooth muscle
- Myenteric (Auerbach’s) nerve plexus lies between the two layers of muscle tissue
Location of Myenteric (Auerbach’s) nerve plexus and its function(s)
Lies between the inner circular layer of smooth muscle and the outer longitudinal layer of smooth muscle, which make up the Muscularis externa
fxn:
- Regulates the size of the lumen (circular layer of smooth muscle)
- Regulates the rhythmic movement of the GI tract (longitudinal layer of smooth muscle)
Characteristics of Serosa of digestive tube
- composed of dense irregular CT
- Consists of mesothelial lining and a layer of submesothelial CT
- Forms visceral peritoneum
- Covers intraperintoneal portions of abdominal organs
What forms the visceral peritoneum
Serosa of digestive tube
Characteristics of adventitia of digestive tube
- Dense irregular CT with Adipose tissue
- Covers retroperitoneal portions of digestive system
What covers the retroperitoneal portions of the digestive system
Adventitia of digestive tube
Where is Meissner’s plexus located
in the submucosa of digestive tube (also called submucosal plexus)
Sympathetic ________ pass through gut wall to glands and smooth muscle
postganglionic fibers
Parasympthetic ________ synapse with _______ in_____ within the gut wall itself
preganglionic fibers synapse with postganglionic fibers in ganglia within the wall itself
What are the two plexi of the parasympathetics in the gut wall
Meissner’s plexus
Auerbach’s plexus
Function of Meissner’s plexus
regulates local secretions, blood flow, and absorption
Function of Auerbach’s plexus
Coordinates muscular activity of gut wall
_____is the first line of defense and is found coating the luminal surface of the gut mucosal epithelium
IgA
Isolated lymph follicles in the gut are found in the
lamina propria
Specialized squamous epithelial cells (___) in the gut lumen serve to transport food antigens to the lymph follicles, which are in the lamina propria
M cells
What are M cells
Specialized squamous epithelial cells in the gut lumen serve to transport food antigens to the lymph follicles
Antigen stimulated _____ in the isolated lymph follicles of the lamina propria in the gut secrete ____
B cells, IgA
Diffuse lymphoid tissue in the lamina proper of the gut includes
lymphocytes, macrophages, and IgA-secreting plasma cells
Aggregated lymphoid follicles form the ____ of the oropharynx (_______) and ______ in the submucosa of the ileum
tonsils, Waldeyer’s ring, Peyer’s patches
Aggregated lymphoid follicles in the submucosa of the ileum
Peyer’s patches
Functions of the esophagus
digestion (initiated in the mouth)
Addition of mucous to food bolus
The esophageal-stomach epithelial transition zone shows what change in epithelium and is a frequent site of what
stratified squamous transitions to simple columnar
frequent site of cancers
Mucosa of esophagus
- Stratified squamous nonkeratinized epithelium
- Mucous glands are found in the lamina propria and submucosa
Muscularis external of the esophagus transitions from _______ in the upper third to a mixture of ____ and ____ in the middle third and then to ____ only in the lower third
skeletal muscle, skeletal and smooth muscle, smooth
Surface mucous cells of the stomach secrete
protective insoluble mucous
Gastric mucosa consists of
simple columnar epithelium with mucous columnar cells
_____ ar longitudinal mucosal folds that are most prominent in an empty stomach
Rugae
Gastric glands open into ____
gastric pits
The muscularis externa of the stomach has ____ layers of -___ muscle
3 layers of smooth muscle
The third layer of the muscularis externa is ________ layer
inner oblique
What are the regions of the stomach
Cardiac, Fundus, body, Pylorus
The cardiac stomach contains mostly ____ glands
mucous
The fundus and body of stomach contains ______ glands
gastric glands
gastric glands are ______ glands extending down to the _______
long tubular, muscularis mucosae
The gastric glands are composed of
mucous neck cells parietal cells chief cells stem cells enteroendocrine cells
The pyloric stomach contains
mucous glands and enteroendocrine cells
