Histo Of Small Intestine Flashcards
Mucosa of SI
Viewed with the naked eye, the lining of the small intestine shows a series of (temporary or permanent?) ____ or ____ shaped folds called _______
Permanent
circular or semilunar
plicae circulares
Plicae circulares are composed of _____ and _____ layers
They are best developed in the _____
The entire mucosa is covered by (short or long?) outgrowths called ___
mucosa and submucosa
jejunum
Short
villi
Intestinal villi
Are _____ outgrowths that project into the _____
Each villus has a core of (loose or dense?) connective tissue that extends from the ______
It contains:
______ , _____ and plasma cells, smooth muscle fibers, fenestrated capillaries and a ______
mucosal
lumen
Loose
lamina propria
Fibroblasts; lymphocytes
lacteal
lacteal is a _______
central lymphatic
Intestinal villi
In the duodenum, they are ___-shaped but gradually assume ___-like shapes moving towards the ileum
leaf
finger
Intestinal villi
They are covered by a ______ epithelium of absorptive cells (______) and _____ cells
simple columnar
enterocytes
goblet
Intestinal crypts
Between the villi are small openings of (short or long?) _____ glands called intestinal crypts or ________
Short
tubular
crypts of Lieberkükn
The epithelium of each villus is discontinuous with that of the intervening glands
T/F
F
The absorptive cells are ______ cells each with _____ nucleus in the (apical or basal?) half of the cell
tall columnar
an oval
Basal
At the apex of each absorptive cell, is a homogeneous layer called the _______
striated /brush border
When viewed with the electron microscope, the striated border is seen as a layer of (sparsely or densely?) packed ____ covered by ______
Densely
microvilli
glycocalyx
Each absorptive cell is estimated to have an average of _____ microvilli
3000
1 mm2 of mucosa contains about _______ microvilli
200 million
Microvilli greatly ___ease the area of contact between the intestinal surface and the nutrients
This function is shared also by the _____ and the _____
Incr
plicae circulares and the villi
It is estimated that plicae circulares increase the intestinal surface ___-fold, the villi increase it ____-fold, and the microvilli increase it ___-fold
Together, these processes are responsible for a ___-fold increase in the intestinal surface, resulting in a total absorptive area of ___ m2
three
10
20
600
200
Absorptive cells absorb the nutrient molecules produced by digestion
T/F
T
Goblet cells
Are interspersed between the ____ cells
They are (more or less?) abundant in the duodenum and (more or less?) numerous in the ileum
These cells produce _____ that are ____ to form _____
absorptivE
Less
More
glycoprotein mucins; hydrated;
mucus
mucus function to ____ and ___ the lining of the small intestine
Protect and lubricate
Paneth cells
Are (endocrine or exocrine?) cells with (small or large?) ___philic secretory granules
They are located in the (apical or basal?) portion of the intestinal crypts below the ___ cells
Exocrine
Large
eosino
Basal
stem
Paneth cells
They undergo exocytosis to release _____,_______, and _____
These bind and breakdown membranes of _____ and ____ cell walls
lysozymes, phospholipase A2, and defensins
microorganisms
bacterial
Paneth cells function:
———- _____
Regulates ______ of the intestinal crypts
Innate immunity
microenvironment
Micro fold cells
Are specialized epithelial cells for _______ of ____ and _____
Located in the ____ overlying the ____________
M cells contain _____ and _____
They are important in the defense provided by mucosal immunity
transport of particles and microorganisms
ileum; lymphoid follicles of Peyer patches
macrophages and lymphocytes
Lamina propria of the small intestine
It is composed of loose connective tissue containing extensive blood and lymph microvasculature, nerve fibers, smooth muscle cells and lymphoid tissue
The lamina propria penetrates the ____ of ______, bringing with it microvasculature, lymphatics, and nerves
core of each intestinal villus
Lamina propria of the small intestine
Smooth muscle fibers inside the villi are responsible for their ______ which are important for _______
Contractions of the _____ also produce local movements of the plicae circulares that help propel lymph from the _____ into submucosal and mesenteric lymphatics
rhythmic movements
efficient absorption
muscularis mucosae
lacteals
Submucosa of the small intestine
Present in the (proximal or distal?) part of the duodenum are large clusters of (straight or branched?) _____ mucous glands, called the ________ glands
Proximal
Branched
tubular
duodenal (Brunner)
Brunners glands
They possess (small or large?) excretory ducts opening among the intestinal crypts
_____, which is the product of the glands is (alkaline or acidic ?) (pH __-___)
Small
Mucus
alkaline; 8.1-9.3
Mucus from brunners gland
______ the mucous membrane
Brings the intestinal contents to the optimum pH for _____ enzyme action
Neutralizes chyme entering the _____ from the _____
Protects
pancreatic
duodenum
pylorus
In the ileum both the ____ and ___ contain the lymphoid nodule aggregates known as _______, an important component of the __________________
lamina propria and submucosa
Peyer patches
mucosa-associated lymphoid tissue (MALT)
Muscularis of SI
Composed of an internal _____ layer and an external _____ layer
Between these muscle layers is the ____(——) nerve plexus (produce peristalsis)
The serosa of SI
Covered by a (thin or thick?) serosa
circular
longitudinal
myenteric (Auerbach)
Thin
Lacteals
Lymph vessels of the intestine begin as (open or closed?) tubes in the ____ of ____
Lacteals run to the region of ______ above the _____, where they form a plexus
From there they are directed to the ____ where they surround _____
Closed
cores of villi
lamina propria
muscularis mucosae
submucosa
lymphoid nodules
Lacteals anastomose repeatedly and leave the intestine along with the blood vessels
T/F
T
Lacteals are especially important for _____ absorption
lipid
Celiac disease- disorder of small intestine’s ____ that causes _____ and can lead to damage or destruction of the ___
Mucosa
malabsorption
villi
Leiomyomas- (benign or malignant?) tumors of smooth muscle cells.
benign
Most common type of tumors in the stomach and small intestine is ????
Leimyomas
Crohn disease- (acute or chronic?) ___________ disease that occurs most commonly in the _____ or _____.
Causes excessive _____ activity and _____ in any or all the tract producing pain, localized bleeding, malabsorption and diarrhea
Chronic
inflammatory bowel
ileum or colon
lymphocytic; inflammation
