Digestive System 1

Front 1

What are extramural organs?

Back 1

organs outside of the alimentary cands that include the tongue, teeth, salivary glands, pancreas, liver, and gallbladder

Front 2

the mouth & its structures (tongue, teeth, salivary glands, and tonsils) are known as

Back 2

oral cavity

Front 3

What are 2 regions of oral cavity?

Back 3

Vestibule – space between lips, cheeks, and teeth
Oral cavity proper – lies behind teeth

Front 4

What are the 3 major salivary glands associated with oral cavity?

Back 4

parotid, submandibular, & sublingual

Front 5

The oral cavity is lined by 3 mucosas known as

Back 5

Masticatory mucosa, Lining mucosa
Specialized mucosa

Front 6

The mucosa with stratified squamous dry found in gingival (gums) & hard palate is known as

Back 6

Masticatory mucosa

Front 7

This type of mucosa has stratified squamous wet and is located on:
a. Lips, cheeks, alveolar mucosal surface, floor of mouth, inferior surfaces of
tongue, and soft palate
b. Covers stratified muscle, bone, and glands

Back 7

Lining mucosa

Front 8

This type of mucosa is restricted to dorsal surface of tongue and is associated with taste & thus contains papillae & taste buds

Back 8

Specialized mucosa

Front 9

What contains extrinsic and intrinsic striated muscle; arranged in bundles that run in 3 plans at right angles to each other and is ONLY SITE IN BODY WITH THIS ARRANGEMENT OF MUSCLE

Back 9

tongue

Front 10

What is the sulcus terminus?

Back 10

V-shaped depression that divides dorsal surface into anterior 2/3 and posterior 1/3

Front 11

The tongue has special mucosa known as Lingual papillae that are formed from...

Back 11

mucosa on dorsal surface, anterior to sulcus terminalis
2. Specifically – composed of vascular CT core covered by stratified squamous epithelium

Front 12

filiform, fungiform, circumvallate, & foliate are

Back 12

4 types of papillae

Front 13

Smallest/ most numerous
Conical, elongated projects of CT covered with stratified squamous dry epithelium; tips point backwards (like witches hat backwards)
NO TASTE BUDS:

Back 13

Filiform Papillae

Front 14

What is function of filiform papillae?

Back 14

increase friction between food and tongue

Front 15

Do filiform papillilae have taste buds?

Back 15

NO

Front 16

Where are filiform papillae located?

Back 16

entire anterior dorsal surface in rows paralleling arms of sulcus terminalis

Front 17

Mushroom-shaped projections
Scattered among & project above filiform papillae
More numerous near tip of tongue
Taste buds located in stratified squamous epithelium of dorsal surface

Back 17

Fungiform papillae

Front 18

These glands are 8 – 12 large, dome-shaped structures surrounded by moat-like invagination
Lined with stratified squamous epithelium with taste buds on lateral surface (along walls) and located anterior to sulcus terminalis

Back 18

Circumvallate papillae

Front 19

Ducts of serous lingual salivary glands (_____________ ) empty into base of moats and wash material out of moat to allow rapid response of taste buds

Back 19

Von Ebners glands

Front 20

Thes papillilae are located in lateral edge of tongue; degenerate at age 2
Parallel low ridges separated by deep mucosal clefts aligned at right angles to long axis of tongue.
Lots of taste buds in epithelium of facing walls of neighboring papillae
Serous glands empty into clefts
Covered with stratified squamous epithelium

Back 20

Foliate papillae

Front 21

small opening onto epithelial surface at apex of taste bud

Back 21

taste pore

Front 22

What are 3 principal cell types found in taste buds?

Back 22

neuroepithelial (sensory) cells, supporting (sustentacular) cells, basal cells

Front 23

extend from basal lamina of epithelium to taste pore; microvilli extend toward taste pore and contain taste receptors
Tight junctions with neighboring neuroepithelial or supporting cells
Lifespan is ~10 days

Back 23

neuroepithelial cells that are majority of cells

Front 24

considered immature neuroepithelial cells
Elongated cells extend from basal lamina to taste pore; microvilli & tight jnxs
Lifespan is ~10 days

Back 24

supporting or sustentacular cells that DO NOT synapse with nerve cells

Front 25

These are small cells found in basal region of taste bud near basal lamina
They are stem cells for supporting and neuroepithelial cells

Back 25

basal cells

Front 26

What three nerves do neuroepithelial cells synapse with?

Back 26

Synapse at base with afferent sensory neurons of CN VII (facial), CN IX (glossopharyngeal), or CN X (vagus)

Front 27

What are the 5 basic stimuli for taste?

Back 27

sweet, salty, bitter, sour, unami (taste of glutamate, aspartate & MSG – asparagus, tomatoes, cheese, & meat)

Front 28

Detection of taste occurs over entire tongue and uses this pathway

Back 28

interaction of food/beverage molecules w/ taste receptors of neuroepithelial cells which initiates signaling pathway in neuroepithelial cells --- activates ion channels generating nerve impulse in post-synaptic sensory neuron

Front 29

this nerve carries all tastes

Back 29

Facial nerve (CN VII)

Front 30

The glossopharyngeal (CN IX) only carries

Back 30

sweet & bitter tastes

Front 31

General sensation in tongue is percieved what 2 nerves in what areas?

Back 31

Anterior ⅔ - CN V
Posterior ⅓ - CN IX

Front 32

Anterior ⅔ - CN VII
and Posterior ⅓ - CN IX are associated with

Back 32

Taste

Front 33

CN XII (hypoglossal) is related to _____
in tongue

Back 33

Motor

Front 34

Hollow tube of varying diameter; extends from esophagus to anal canal
with same basic structural organization throughout length known as

Back 34

GI tract

Front 35

Wall has 4 layers throughout GI tract and are called:

Back 35

mucosa, submucosa, muscularis externa, and serosa/adventitia

Front 36

The Mucosa has 3 components that vary from region to region

Back 36

1.Lining epithelium,
2. Lamina propria - CT underneath lining epithelium
3. Muscularis mucosa – smooth muscle layer underneath lamina propria; contraction changes surface area for secretion and/or absorption

Front 37

dense irregular CT w/ large blood vessels, lymphatics & nerves
1.Glands in esophagus
2.Glands in sm intestine (duodenum)
is known as what layer?

Back 37

Submucosa

Front 38

usually 2 layers of smooth muscle (skeletal muscle in upper 1/3 of esophagus & in anal sphincter)

Back 38

Muscularis externa

Front 39

2 layers of muscle in the muscularis externa are

Back 39

Inner circular – contraction reduces the diameter of lumen
Outer longitudinal – contraction shortens the tube

Front 40

this consists ONLY of CT; found where wall of tube is DIRECTLY ATTACHED or FIXED to adjoining structures (body wall &/or retroperitoneal organs)

Back 40

Adventitia

Front 41

serous membrane (simple squamous epithelium - mesothelium) & small amount of underlying CT is known as _____________

Back 41

Serosa

Front 42

3 principal functions of mucosa are

Back 42

barrier, absorption, and secretion.

Front 43

Description of mucosa as a barrier

Back 43

epithelium separates external luminal environment of tube from tissues & organs of body; prevents entry of antigens, pathogens, etc.

Front 44

Mucosa has Absorption function which occurs________

Back 44

via projections of mucosa/submucosa into GI tract lumen and serves to increase surface area

Front 45

4 structures that contribute to the absorption function of mucosa are:

Back 45

plicae circularies, villi, microvilli and glycocalyx

Front 46

submucosal folds (in small intestine)tha increase absorption capability are known as_________

Back 46

Plicae circulares

Front 47

_______are mucosal projections; cover entire surface of small intestine; principal site of absorption

Back 47

Villi

Front 48

_______are intestinal absorptive cells which increase surface available for absorption;

Back 48

Microvilli

Front 49

_______provides additional surface for adsorption; localization for enzymes essential for final digestion steps for proteins & sugars

Back 49

glycocalyx coat

Front 50

several products are secreted depending on region including:

Back 50

1.Mucus - lubrication, buffering of tract lining
2.Digestive aids: enzymes, hydrochloric acid, peptide hormones, & water
3.Antibodies from underlying CT

Front 51

Glands of GI tract develop from invaginations of luminal epithelium & include:

Back 51

mucosal glands, submucosal glands, and extramural glands

Front 52

_____extend into lamina propria

Back 52

Mucosal glands

Front 53

________deliver secretions directly to lumen of mucosal glands OR via ducts that pass through mucosa to luminal surface

Back 53

Submucosal glands

Front 54

__________lie OUTSIDE the digestive tract & deliver secretions via ducts that pass through wall of intestine to enter the lumen; examples are liver and pancreas

Back 54

Extramural glands

Front 55

The Lamina propria generally contains:

Back 55

glands, blood and lymphatic vessels, and tissues

Front 56

Some basics about Glands in lamina propria:

Back 56

Mucosal glands extend into lamina propria throughout length of alimentary canal
b.Esophagus and anal canal contains mucus-secreting glands which lubricate epithelial surface and provide protection

Front 57

Lamina propria contains blood and lymphatic vessels that are important for

Back 57

a. In segments where digestion occur (small and large intestines), absorbed products of digestion diffuse into blood and lymphatic vessels
bTypically blood vessels are fenestrated and collect most of absorbed metabolites
c.Lots of lymphatic vessels which collect some absorbed lipids and proteins

Front 58

Lamina propria contains lymphatic tissue that include: :

Back 58

a. Immunologic barrier - protection
b. Diffuse lymphatic tissue (lymphocytes & plasma cells)
c. Nodules (Peter’s patches in ileum)
d. Eosinophils, macrophages, & neutrophils

Front 59

Deepest portion of mucosa is________

Back 59

Muscularis mucosa

Front 60

Muscularis mucosa contains 2 layers of SM known as the

Back 60

inner circular & outer longitudinal layer------
Contraction produces movement of mucosa facilitating absorption & secretion; occurs independent of peristaltic movement of GI tract

Front 61

Submucosa consists of:

Back 61

Dense, irregular CT, blood vessels and lymphatic, some glands(esophagus & initial region of duodenum) and aid in identifying specific segment or region of GI tract

Front 62

nerve plexus (network of intersecting nerves) called ________ which primarily regulates secretion & blood flow

Back 62

submucosal or Meissner’s plexu

Front 63

Enteric nervous system (preganglionic and postganglionic parasympathetic nerve fibers) is primarily responsible for

Back 63

innervating smooth muscle layers.
It can function independent of CNS

Front 64

_________are mainly sympathetic origin

Back 64

Visceral sensory fibers

Front 65

_______are excitatory on GI functions

Back 65

Parasympathetic (terminal) ganglia

Front 66

______generally 2 concentric and thick layers of smooth muscle--inner circular and outer longitudinal

Back 66

Muscularis Externa:

Front 67

________contraction compresses and mixes luminal contents by constricting lumen

Back 67

Inner circular

Front 68

4 sphincters (valves) at specific locations in tract

Back 68

Pharyngoesophageal sphincter,Pyloric sphincter ,Ileocecal valve ,Internal anal sphincter

Front 69

____________prevents entry of air; prevents gastric reflux thru creation of pressure difference between esophagus and stomach

Back 69

Pharyngoesophageal sphincter

Front 70

__________junction between pylorus of stomach and duodenum; controls release of chime (partially digested stomach contents) into duodenum

Back 70

Pyloric sphincter

Front 71

___________ junction between small and large intestines; prevents reflux of colon contents (lots of bacteria)

Back 71

Ileocecal valve

Front 72

___________most distally located sphincter; surrounds anal canal; prevents passage of feces into anal canal from undistended rectum

Back 72

internal anal sphincter

Front 73

_____________ contraction propels luminal contents by shortening tube

Back 73

Outer longitudinal

Front 74

Thin CT layer present between 2 layers contains containing_________ ganglions of postganglionic parasympathetic neurons and neurons of enteric nervous system which primarily control motility of GI smooth muscle
Also contains blood and lymphatic vessels.

Back 74

myenteric (Auerbach’s) plexus

Front 75

Slow, rhythmic contraction of muscle layers; controlled by enteric nervous system is known as __________and is marked by constriction and shortening of tube moving contents thru GI tract

Back 75

Peristalsis (waves of contraction)

Front 76

2 areas of muscularis externa within GI tract have striated muscle in externis

Back 76

Wall of proximal portion of esophagus (pharyngoesophageal sphincter) & external anal sphincter

Front 77

The Stomach also has variation on muscle normally found in GI tract...

Back 77

3rd obliquely oriented layer of smooth muscle present deep to circular layer

Front 78

Large intestine has a variation of SM in externa compared to normal muscle found in GI.....

Back 78

longitudinal smooth muscle layer thickened to form 3 distinct, equally spaced longitudinal bands called teniae coli (contraction facilitates shortening of tube to move its contents)

Front 79

equivalent to visceral peritoneum (described in gross anatomy)
Most superficial layer of regions of digestive tract suspended in peritoneal cavity
Continuous with both mesentery and lining of abdominal cavity
Contains large blood and lymphatic vessels & nerve trunks

Back 79

Serosa

Front 80

Covers region of digestive tract not covered by serosa
Includes: thoracic part of esophagus, duodenum, ascending and descending colon, rectum, and anal canal (structures fixed to cavity wall by CT - adventitia)

Back 80

Adventitia

Front 81

_________ is a fixed muscular tube; delivers food & liquid from pharynx to stomach

Back 81

Esophagus

Front 82

Mucosa of the esophagus includes

Back 82

1.Stratified squamous wet epithelium – protection
2.Lamina propria similar to remainder of digestive tract
a. Diffuse lymphatic tissue
b. Lymphatic nodules present (often close to esophageal mucous glands)
c. Esophageal cardiac glands; similar in appearance to cardiac glands of stomach; secrete neutral mucus to lubricate/protect luminal wall; location – terminal/beginning region of esophagus
3. Muscularis mucosa – longitudinally organized smooth muscle; unusually thick in proximal portion  probably aids in swallowing

Front 83

What is in Submucosa of esophagus:

Back 83

1. Dense irregular CT
2. Larger blood & lymphatic vessels; nerve fibers, & ganglion cells
3. Esophageal glands proper
4. Diffuse lymphatic tissue & lymphatic nodules

Front 84

Nerve fibers and ganglion cells in submucosal area of esophagus________

Back 84

submucosal (Meissner’s) plexus

Front 85

Esophageal glands proper in the esophagus:

Back 85

secrete acidic mucus which lubricate/protect luminal wall

Front 86

What types of gland/duct found in esophagus region?

Back 86

Small, compound, tubuloalveolar glands
Excretory duct - stratified squamous epithelium; usually appears dilated; often transient cysts form due to viscous secretion

Front 87

Diffuse lymphatic tissue & lymphatic nodules present__________

Back 87

mostly in upper and lower parts of esophagus, where submucosal glands are more prevalent

Front 88

Muscularis externa of esophagus has 2 muscle layers ______and________

Back 88

Inner circular
Outer longitudinal

Front 89

In contrast to rest of digestive tract: use to ID regions of esophagus in lab!!-upper, middle, lower

Back 89

a.Upper 1/3 contains striated muscle (continuation of muscle of pharynx)
b.Middle 1/3 contains mix of striated and smooth muscle
c.Lower 1/3 contains only smooth muscle

Front 90

__________is present between outer and inner muscle layers.Contains nerves and ganglion cells and innervates muscularis externa and produces peristaltic activity

Back 90

Myenteric (Auerbach’s) plexus

Front 91

What is innervation of esophagus:

Back 91

1.Striated muscle of upper 1/3 innervated by somatic motor neurons of vagus nerve, CN X
2.Smooth muscle of lower region innervated by visceral motor neurons of vagus that synapse with postsynaptic neurons (cell bodies located in wall of esophagus)