digestive system Flashcards
(82 cards)
1
Q
digestive system consists of
A
- Digestive Tract (Alimentary canal)
- Starts at the oral cavity to anus. - Digestive glands
- Embedded in digestive organs.
- Form accessory glands outside the digestive organ (ex: pancreas)
2
Q
functions of digestive system
A
- Digestion of food (mechanical and chemical)
- Absorption of digested substances
- Excretion of undigested materials (in the form of stool)
3
Q
briefly explain the mechanical and chemical action of the digestive tract
A
mechanical:
cut food into smaller pieces
chemical:
divide/ cut food into smaller size with the use of substances and enzymes.
4
Q
briefly explain the 4 layers of digestive tract
A
- mucosa
- mucosa epithelium
nasa mismo lumen
⇢ esophagus, non-keratinized
⇢ stomach, simple columnar
- lamina propria
loose CT w BV - muscularis mucosae
aka muscularis interna
usually smooth muscle tissue
located on the outermost part of the mucosa
separates the mucosa and submucosa
- submucosa
dense irregular CT
consist of glands and BV - muscularis
2 types of orientation:
- circular muscle layer (inner)
- longitudinal muscle layer (outer) - serosa
CT layer
peritoneum [body lining that helps organs slide smoothly]
*the 4 layers are defined from esophagus onwards to anus. Hard to observe in oral cavity and pharynx
5
Q
this is located on the outermost part of the mucosa
A
Muscularis mucosae
- separates the mucosa and submucosa
6
Q
what type of nerves are found in between
- submucosa and muscularis layer
- muscularis layer
A
- submucosal plexus [control secretion and blood flow]
- myenteric plexus [control muscle movement]
7
Q
where can you see the 4 layers of digestive tract
A
clearly from the esophagus down to the anus
while
mouth and throat (pharynx), it’s harder to tell them apart.
8
Q
what are the 2 regions of the oral cavity
A
Vestibule - anterior to teeth and gums (ex: lips)
Oral cavity proper - rest of the mouth [behind teet]
9
Q
types of lining in the oral cavity
A
- Non-keratinized stratified squamous
Internal surface of lips
Cheeks
Soft palate
Ventral surface of the tongue [underneath the tongue] - Keratinized stratified squamous
Hard palate to gums
Vermillion zone of lips (parts that the lips and skin overlaps)
10
Q
glands in the oral cavity - that produces saliva
A
Labial Glands (Upper & Lower lips)
Buccal Glands (Cheek)
Palatine Salivary Glands (Hard palate)
11
Q
parts of the lips
A
- Vermillion zone of lips (parts that the lips and skin overlaps)
- Outer part of the lips
keratinized stratified squamous
it is where you put lipstick/ lip gloss. - Inner part of the lips
non-keratinized stratified squamous
12
Q
type of muscle found in the lips
A
skeletal muscle
- hence the voluntary movements
13
Q
type of glands found in the lips
A
labial glands
- consists of mucous cells [that produce mucus (helps keep lips moist and smooth).]
14
Q
Muscular organ that plays an important role in mastication, deglutition and speech.
A
tongue
- stratified sq ep [protects from friction]
15
Q
tongue is made out of what type of muscle
A
Histologically made up of skeletal muscle.
16
Q
Protrusions on the tongue in the anterior portion
A
Lingual Papillae
[they r small protrusions (tiny bumps) you see mainly on the anterior portion (front 2/3) of the tongue]
- Filiform Papillae
- most numerous and found all over the dorsal surface of the tongue
★ highly keratinized stratified sq
2.Fungiform Papillae
- flattened surface
- broader and scattered among the filiform papillae
★ lightly keratinized stratified sq & dense irregular CT
- Circumvallate/ Vallate Papillae
- arranged along the sulcus terminalis
- largest but least numerous
★ lightly keratinized stratified sq (but not as much as fungiform) w taste buds - Foliate Papillae
- poorly developed in adults
- consist of parallel ridges and furrows on the sides of the tongue
★ non-keratinized stratified sq with taste buds
17
Q
what type of lingual papillae has taste buds
A
vallate and foliate
- located at the lateral surfaces
18
Q
Ovoid structures containing elongated gustatory (taste) cells
A
Tastebuds
- which turn over w a 7 - 10 day life span
- can detect at least 5 tastetans
19
Q
briefly explain the 5 tastetans that the tastebuds can detect
A
Salty:
Sodium (Na⁺) and other metal ions
Sour:
Hydrogen ions (H⁺) from acids
Bitter:
Alkaloids and toxins (e.g., caffeine)
Sweet:
Sugars and related compounds (e.g., glucose, artificial sweeteners)
Umami:
Amino acids, especially glutamate
*sense of smell works w taste buds.
20
Q
what happens to your taste when the olfactory system is impaired
A
sense of taste becomes bland or dull
- impaired like when u r sick/ flu
21
Q
Funnel- shaped fibromuscular tube
A
pharynx
22
Q
parts of the pharynx and its linings
A
- Oropharynx (behind the mouth)
- non-keratinized stratified squamous epithelium - Laryngopharynx (behind the voice box/larynx)
- non-keratinized stratified squamous epithelium
- ciliated pseudostratified columnar epithelium
*laryngopharynx overlaps with both the nasopharynx and the oropharynx
23
Q
Long muscular tube that serve as a passageway for food from pharynx to stomach
A
esophagus
- uses muscle contractions (peristalsis) to push food down
24
Q
This is where the esophagus meets the stomach.
A
Gastro-esophageal junction
- aka z-line
- non-keratinized stratified squamous to simple columnar epithelium
- common site for esophageal cancer
25
what is the term of the outermost layer when esophagus enters the peritoneal cavity (near the stomach)
serosa
26
upper part of esophagus:
lower part of stomach:
upper part of esophagus: adventitia
lower part of stomach: serosa
*ma’am will accept either of the two to avoid confusion.
27
layers and linings of the esophagus
inner mucosa
★ non keratinized stratified sq
- lamina propria consists of loose CT
- muscularis mucosa or muscularis interna which serves as a barrier btwn submucosa and serosa
submucosa
- glands which consists of mucous cells
- BV
muscularis externa
- inner circular layer
- outer longitudinal layer
serosa/ adventitia
28
this serves as a barrier btwn submucosa and serosa of the esophagus
muscularis mucosa or muscularis interna
29
composition of muscularis externa of the esophagus
Upper region:
Skeletal muscle fibers
Middle region:
Mixture of skeletal and smooth
Lower region:
Smooth muscle fibers
30
A J-shaped hollow organ located in the left upper quadrant of the abdomen.
stomach
31
an acidic semifluid mixture of food and gastric juice.
chyme
- mixture of bolus and gastric juices
32
longitudinal folds in the stomach
rugae
- the structure is not smooth
33
what are the types of glands found in stomach
Fundic (Gastric) Glands
- most numerous and longest
*tubular in shape
Cardiac Glands
- least numerous
- Cells present are the same in fundic glands except that mucus-secreting cells are most numerous.
*circular in shape
Pyloric Glands
- shorter but more coiled
- most of the cells are mucus-secreting cells
*more coiled
34
what is the epithelium of mucosal layer in the stomach
simple columnar
lamina propria (if u can see the loose CT)
35
this separates mucosa and submucosa layer of the stomach
Muscularis interna and submucosa
★ dense irregular CT - submucosa
36
what are the 3 orientation of the stomach
inner oblique layer
middle circular layer
outer longitudinal layer
*these are smooth muscles
*stomach is responsible for chemical and mechanical digestion. hence, the 3 orientations of the layers.
37
what are the type of cells found in fundic (gastric) glands
1. Oxyntic (Parietal cells)
- Pyramidal in shape with oval to round nucleus
- Produce HCl
2. Zymogenic (Chief cells)
- Low columnar cells
- Contain Pepsinogen (active form)
For it to be in an active form, it needs to be exposed in an acidic environment of the stomach
Active form = pepsin
3. Mucous Neck Cells
- Similar to zymogenic cells except for basally located, flattened nuclei
- Contain Mucin:
Surface mucous cell - alkaline mucin
Mucous neck cell - acidic mucin
4. Stem Cells
- Renew the epithelial cell population of the stomach
5. Enteroendocrine Cells
- Also called enterochromaffin or argentaffin cells hormone producing cells
*Chief cells with zymogen granules can be seen under the microscope.
38
what are the types of principal enteroendocrine cells in the gastrointestinal tract
refer to table 15-1
39
what does parietal cells releases
intrinsic factor
hydrochloric acid
40
Located between the stomach and large intestine.
Small Intestine
3 segments:
- duodenum
has many glands
- jejunum
has longer mucous epithelium
- ileum
consists of peyer's patches
41
main function of Small Intestine
absorption of nutrients from digested food
42
how long is the Small Intestine
approx 3 to 5 meters long
43
Crescentic or circular horizontal folds of the mucosa layer of the small intestine
Plicae Circulares (Valves of Kerckring)
- horizontal folds that help increase surface area for digestion and absorption.
- Function: Similar to the rugae of the stomach (which are folds in the stomach lining), but plicae circulares are found in the small intestine and are permanent (not temporary like rugae).
44
cells found in the small intestine
1. Stem Cells
- Differentiate into different types of cells.
2. Enterocytes
- Replace the absorptive cells of the lining epithelium.
- Responsible for the absorption of the small intestine.
3. Goblet cells
- Secretory in function Mature enterocytes.
4. Paneth cells
- Large pyramidal cells Capable of phagocytosis.
- Capable of phagocytosis
5. Enteroendocrine cells
- Same function with the enteroendocrine cells of the stomach.
- Release of hormone secretions.
45
DUODENUM
mucosal layer:
submucosa layer:
muscularis layer:
JEJUNUM
mucosal layer:
submucosa layer:
muscularis layer:
ILEUM
mucosal layer:
mucosa and submucosa layer:
submucosa layer:
ODENUM
mucosal layer:
★ simple columnar w villi (has goblet cells)
submucosa layer:
- muscularis interna
- Brunner's gland:
neutralize acid from the stomach
muscularis layer:
- circular muscle layer (smooth)
-outer longitudinal muscle layer
JEJUNUM
mucosal layer:
★ simple columnar w villi and goblet cells
- paneth cells
submucosa layer:
- muscularis interna of mucosal layer which separates the mucosa and submucosa
- Meissner’s plexus:
nerves that is responsible for contracting the digestive tract
muscularis layer:
- inner circular layer
- Auerbach's plexus:
contraction of small intestine
- outer longitudinal layer
ILEUM
mucosal layer:
★ simple columnar w villi and goblet cells
- Crypts of Lieberkühn:
consist of paneth cells which are responsible for phagocytosis.
- Lamina propria -loose CT
mucosa and submucosa layer:
- GALT
submucosa layer:
- muscularis interna of mucosal layer
★ dense irregular CT
46
Brunner’s glands function
neutralize the acid from the stomach.
once the duodenum receives the bolus coming from the stomach, it will neutralize it.
*duodenum has glands located at the submucosa layer while the rest of the intestine, its glands, is located at the mucosa layer.
47
function:
- Meissner’s plexus
- Auerbach’s plexus
- nerves that is responsible for contracting the digestive tract
- contraction of the small intestine
48
largest lymphoid organ
Mucosa-Associated Lymphoid Tissue (MALT)
- overlaps the mucosal and submucosal layer.
MALT vs GALT
- MALT is distributed in different organs. Once distributed in different organs, its term would be different.
- When MALT went to digestive system, it will be called Gut-Associated Lymphoid Tissue (GALT).
49
Most distal segment of digestive tract
large intestine
50
function of large intestine
water and remaining nutrients are absorbs
remaining material is stored as feces before being removed by defecation
51
true or false:
Crypts of Lieberkuhn in large intestine is a little shorter than small intestine
false - longer
[glandular structures in the mucosa.
longer than those in the small intestine and help with mucus secretion to lubricate the waste.]
*Crypt of Lieberkuhn is heavily infiltrated by GALT:
mixture of loose CT and lymphoid tissue.
52
linings of the following:
Esophagus:
Stomach:
Small intestine:
Large intestine:
Esophagus:
non-keratinized stratified sq
Stomach:
simple columnar with vili which has many glands at the mucosal layer
Small intestine:
part of jejunum
Large intestine:
simple columnar w goblet cells
53
A short narrow and wormlike tubular evagination of the cecum.
vermiform appendix
★ tall columnar cells w microvilli
- heavily infiltrated by GALT
54
Act as a temporary storage for feces.
rectum
55
An opening at the far end of the digestive tract through which stool leaves the body.
anus
56
Longitudinal mucosal folds in anal canal
Rectal Columns of Morgagni
★ stratified sq ep
57
what are the accessory glands of digestive system
forms distinct organs outside the digestive tract:
Salivary glands
Exocrine part of pancreas
Liver
Gallbladder
58
what does salivary glands secretes
collective secretion of the salivary gland is called saliva,1.5L per day
*classified into minor and major salivary glands
[Minor salivary glands
➔ small glands scattered in the mouth (like in lips, cheeks, and tongue).
Major salivary glands
➔ larger glands like the parotid, submandibular, and sublingual glands.]
59
what type of digestive enzymes does salivary glands contain
a clear, watery fluid that contains 2 digestive enzymes
- Lingual lipase [stats fat digestion in mouth]
- Ptyalin or Salivary amylase [begin breakdown of sugars into sugars]
60
what are the major salivary glands
Parotid glands
Submandibular (Submaxillary) glands
Sublingual glands
61
what is the parenchyma and stroma of the salivary glands
Parenchyma: Glandular epithelium
- Secretory units in the form of acini (alveoli)
Stroma: Connective tissue
- Capsule: Envelopes the gland
- Septae: divide the glands into lobes
62
briefly explain crescents of Giannuzzi or Demilunes of Heidenhain
cellular formation in the shape of a half-moon
contain serous cells at the distal end of mucous tubuloalveolar secretory unit
63
function of myoepithelial cells
help secretory units [like acini and ducts] to eject secretons
*flattened, contractile, stellate cells [star-shaped]
64
briefly explain the 2 types of intralobular ducts
1. striated/ secretory duct
★ simple cuboidal or columnar
- formed by union of intercalated ducts
2. intercalated duct
★ simple sq to low cuboidal
- segment of duct system that directly drains an acinus
*when intercalated ducts merge w e/o it is called striated duct
65
it is formed when striated ducts converge and unite
interloular duct system
- drains the entire lobes
★ stratified columnar ep
66
formed when lobar ducts merge which opens into the oral cavity
excretory ducts
★ stratified columnar > pseudostratified columnar > non-keratinized sq
- ep is enveloped by dense CT
67
what is the largest and smallest of the salivary gland.
largest:
parotid gland - purely serous glands
smallest:
sublingual glands
68
location of
- Parotid Gland
- Submandibular (Submaxillary) Gland
- Sublingual Glands
Parotid Gland:
below and anterior to the pinna of the either ear at the region of the mandible
Submandibular (Submaxillary) Gland:
on submandibular fossae on the inner aspect of the mandible, below the floor of the oral cavity.
Sublingual Glands:
Almond shaped glands located on the floor of the mouth, underneath the tongue between the mandible.
69
in the parotid gland what is the apical portion of serous cells which is filled
eosinophilic zymogen granules
70
it is smaller with very few adipose cells in the CT stroma compared to Parotid gland.
Submandibular (Submaxillary) Gland
71
what is the main excretory duct of parotid, submandibular and sublingual gland
parotid gland: Stensen’s Duct
- main excretory duct opposite to the the upper 2nd molar tooth
submandibular gland: Wharton’s Duct
- majority of the secretions are mucous
sublingual gland:
SMALLER - ducts of Rivinus
→ open directly to sublingual papilla under the tongue and some into the Wharton's Duct.
BIGGER - duct of Bartholin
→ also drains into the Wharton's Duct
72
pancreas:
color and length
location
weigh
color: a soft, pinkish
length: 12 to 15 cm
located: across the posterior abdominal wall from duodenum to the spleen posterior to the stomach.
weigh: 60 to 140g
*Consists of a head, body and a tail
73
this serve as a passageway for blood and lymphatic vessels and nerves in pancreas
lobules
74
briefly explain endocrine and exocrine of pancreas
Endocrine:
- Composed of the Islets of Langerhans (small aggregates of pale- staining cells)
Exocrine:
- Secretion is called Pancreatic Juice (1.2L a day)
75
Grapelike, clusters of epithelial cells in pancreas
Pancreatic Acini
- Each acinus consists of a single layer of 40 to 50 closely- packed low columnar or pyramidal cells.
76
briefly explain the 2 excretory ducts of pancreas
2 Excretory Ducts of Pancreas: formed when interlobular ducts unite
★ wall is Simple Columnar Epithelium supported externally by Dense CT with some smooth muscle fibers
1. DUCT OF WIRSUNG
- Main excretory duct
→ usually joins the common bile duct to form the heptopancreatic ampulla (Ampulla of Vater) that opens into the duodenum.
2. DUCT OF SANTORINI
- Accessory excretory duct
77
liver:
weigh
location
weight: abt 1.5kg
located: right under the diaphragm and fits into the diaphragm's concavity
78
what are the several unequal Lobes that liver is divided into
Right
Left
Quadrate
Caudate
79
what is the stroma and parenchyma of the liver
Stroma: Connective tissue
- Glisson’s Capsule - made up of collagen and elastic fibers
Parenchyma: Hepatocytes
80
gallbladder:
shape
location
lining
shape: a pear- shaped, hollow pouch
location: right edge of the visceral surface of the liver
★ Simple columnar epithelium
81
what does the gallbladder store
temporarily store bile produced by the liver
82
what facilitate the entry of bile to the duodenum
Sphincter of Oddi
