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PBL > Histology 17 HY > Flashcards

Histology 17 HY Flashcards

1
Q

3 layers of the mucosa

A

epithelium, lamina propria(CT) and muscularic mucosae(SM)

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2
Q

consists of dense irregular connective tissue

A

submucosa

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3
Q

consists in most parts of alimentary tract as 2 layers of smooth mm

A

muscularis externa

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4
Q

beneath the layer of muscularis externa costists of simple squamous epithelium called the mesothelium, and a little CT

A

serosa

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5
Q

Parts of the digestive tract don’t contain serosa such as thoracic pt of esophagus, duodenum, ascending/descending colon, rectum, and anal canal. they instead are attached to the abdominal/pelvic wall by CT called?

A

adventitia

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6
Q

3 functions of the mucosa

A

protections, absorption secretion

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7
Q

the epithelium of the mucosa: one function is a barrier of protection from outside pathogens. in the esophagus what is the epithelium made out of? in the rest of the GI tract

A

non keratinized stratified squamous; simple columnar cells

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8
Q

has an absorptive function is a circumferentially oriented submucosal fold along most of the SI

A

plicae circulares

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9
Q

principal site of absorption for digestion products are mucosal projections that cover the entire surface of the SI

A

villi

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10
Q

tightly packed microscopic projections of the apical surface of intestinal absorptive cells help to further inc the surface available for absorption

A

microvilli

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11
Q

projections from apical plasma membrane epithelial absorptive cells providing more surface for adsorption and has enzymes essential in the final steps of protein and sugar digestion

A

glycocalyx

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12
Q

Secretion by glands is important for lubrication, buffering, as wella s secreting enzymes HCl hormones, water, and antibodies. there are mucosal, submucosal glands as well as ____ glands that lie outside of the digestive tract and deliver their secretions via ducts into the duodenum. Name the 2

A

extramural digestive glands-liver and gall bladder!

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13
Q

where do the mucosal glands extend into? this region also contains blood vessels that transport absorbed substances and lymphatic tissues to protect against pathogens

A

lamina propria

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14
Q

in the ileum extensive aggregates of lymphoid nodules occupy mysh of the lamina propria and subucosa. what are these called

A

peyers patches

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15
Q

this divides the mucosa and submucosa and when it contracts it forms ridges in the mucosa to facilitate absorption and secretion

A

muscularis mucosae

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16
Q

the submucosa contains blood and lymphatics also, as well as parasympathetic and sympathetic nerves. the nerves of the parasympathetic ganglion represent the ___ nervous system-responsible for innervating SM in alimentary canal and can function independently of the CNS. name of plexus in the submucosa?

A

enteric nervous systems-Meissners plaxus

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17
Q

2 locations where the submucosa gontains glands-helps to ID certain regions of the GI

A

esophagus and initial portion of duodenum

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18
Q

Muscularis externa: Inner mm layer is oriented how? outer mm layer oriented how? the 2 layers are divided by connective tissue which contains what(3)

A

circularly; longitudinally; myenteric(auerbachs plexus), blood and lymph vessels

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19
Q

Contraction of the muscularis externa produces peristalsis- contraction of the inner layers causes what? while contraction of the outer layer causes what

A

inner layer-mixes food; outerlayer-propels contents forward

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20
Q

longitudinal SMm layer of muscularis externa thickens in the large intestine to 3 distinct bands called

A

teniae coli

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21
Q

Pharyndoesophageal sphincter(superior), inferior lower esophageal sphincter, pyloric sphincter(controls release of chyme), ileocecal valve, and internal anal sphincter are all made of thickened parts of what muscularis externa layer to create sphincters or valves

A

circular mm layer(inner layer)

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22
Q

GERD is characterized by inflammation of the esophageal mucosa, strictures, difficulty swallowing, and chest pain. what is ti dt

A

abnormal relaxation of inferior esophageal sphincter-allows acid to reflux from stomach into esophagus

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23
Q

in the esophagus the muscularis externa differs than that found in the rest of the digestive tract in that the upper third is componsed of what type of mm? as you move down this type of mm becomes intermixed with SM until in the distal 1/3 of the tract it is all sm

A

striated mm

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24
Q

the thoracic outermost part of the esophagus is covered by? while the abdominal pt of the esophagus is covered by

A

adventitia; serosa

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25
Q

Glands are present in the esophagus wall, both secrete mucus but there are 2 types
1.)___ lie in submucosa are scattered throughout but more concentrated in upper half.
2.)____ found in lamina propria of mucosa-resent in terminal part of esophagus and sometimes at the beginning of the esophagus

A

esophageal glands proper; esophageal cardiac glands

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26
Q

ESOPHAGEAL GLANDS PROPER SECRETE MUCUS FOR LUBRICATION AND TRANSIENT__ CAN OCCUR IN THEM BECAUSE OF THE VISCOUS NATURE OF THE FLUID. ESOPHAGEAL CARDIC GLANDS SECRETE NEUTRAL MUCUS AND IF NOT FULLY EFFECTIVE and excessive reflux results in ____ aka heart burn–>can progress to GERD

A

cysts; pyrosis

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27
Q

____mm is innervated by somatic motor neurons of the vagus nerve in the esophagus
___mm is inverated by visceral motor neurons of the vagus

A

striated; smooth

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28
Q

4 regions of the stomach

A

cardia, fundus, body, and pylorus

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29
Q

3 histologic regions of the stomach
1.)____ near esophageal orifice contains cardiac glands
2.)___ near proximal pyloric sphincter contains pyloric glands
3.)___ largest part of stomach between cardia and pylorus contains gastric glands

A

cardiac region; pyloric region, fundic region

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30
Q

longitudinal folds in the body of the stomach they do not alter surface area but serve to accomodate EXPANSION and filling of stomach

A

rugae

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31
Q

shallow trenches in the stomach that divide the stomach surface into ___ areas. These grooved areas increase surface area for secretion

A

mamillated areas

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32
Q

numerous openings in the stomach mucosal surfaces are called? gastric glands open into the bottom of these

A

gastric pits-aka foveolae

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33
Q

simple columnar cells line the gastric pits and are caled surface mucous cells. each of these possessa cup of _____ that stain PAS blue reflecting the presence of mucin, lots of bicarb and K helping to protect it from the acidic environment. ___ stimulates the secretion of bicarb and inc the thickness of the mucus coat to help supply nutrients to damaged stomach mucosa

A

mucinogen granules; prostaglandins

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34
Q

the lining of the stomach isn’t absorptive but can absorb some water salts and lipid soluble drugs. 2 drugs that enter the lamina propria by damaging the gastric epithelium to cause problems and also can interfere with the hydrophobic properties of the gastric mucosa

A

alcohol NSAIDs/aspirin

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35
Q

the fundic or gastric glands produce gastric acid and empty into the gastric pits. each gland has a neck and fundic segment. between the gastric pit and the gastric gland is the __ which is where stem cells are located

A

isthmus

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36
Q

In addition to water/electrolytes the gastric gland(beneath the isthmus!) has many different cell types:
1.) ___ cells produce hydrochloric acid aids in protein digestion. HCL also helps to activate pepsinogen
2.) ___ cells produce pepsinogen which gets activated to pepsin by HCL to splite peptides
3.) ____ cells in the gland secrete mucus to contribute to the physiologic gastric mucosa barrier.(secretion is stimulated by vagus)
4.) ___ cells also secrete intrinsic factor that binds B12 and is essential for its absorption in the ileum
5.) ___ cells in the gland secrete gastrin and other hormones that genter circulation or act locally on gastric epithelial cells

A

parietal cells; chief cells;musucus neck cells; parietal; enteroendocrine cells

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37
Q

HCl is bacteriostatic and so most bacteria entering the stomach get destroyed! what bacteria has urease which converts urea to ammonia forming a protective ammonia cloud contributing to its survival in the stomach? lack of intrinsic factor from parietal cells causes what

A

H pylori; pernicious anemia and B12 def

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38
Q

parietal cells are also called what name

A

oxyntic

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39
Q

most abundant cell types in the neck segment of the fundic/gastric glands

A

parietal and mucous neck cells

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40
Q

most abundant cell types located in the fundic segment of the fundic/gastric glands

A

enteroendocrine cells and chief cells

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41
Q

things that can cause pernicious anemia

A

achlorhydria-destroys gastric mucosa-no intrinsic factor; peptic ulcer disease–>ulcers can produce IF; H2 antagonists prevent IF and and acid secretion

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42
Q

H pylori contains LPS antigen that mimics those expressed on gastric epithelial cells what does this cause

A

antibodies develop that bind H pylori and gastric mucosa to cause damage

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43
Q

chief cell stains ___ dt the large amt of rER contained in it. the parietal stains with ___ dt extensive amt of membrane made up of intracellular canaliculus, tubulovesicular system, mitochondria

A

basophilic; eosin

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44
Q

system in parietal cells serving as a reservoir of plasma membran containing active proton pumps? gets inserted into plasma membrane on intracellular canilicular system to inc surgace area and proton pump number available

A

tubulovesicular membrane system

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45
Q

parietal cells have 3 different membrane receptors for substances that activate HCl secretion what are the receptors

A

gastrin receptor(gastrin activation of this receptor is major path for parietal cell stimulation), Histamine H2 receptor, acetylcholine M3 receptor

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46
Q

After parietal cell stimulation
1.) production of __ in parietal cell cytoplasm by carbonic anhydrase rxn
2.) transport of ___ from cytoplasm to lumen of canaliculus by the H/K ATPase pump(K goes into cytoplasm)
3.) Transport of __ and __ from cytoplasm into canliculus through channels.
4.) Formation of ___ from ions that were transported into the lumen of the canliculus

A

H+ ions; H+ ions; K and CL; HCL

47
Q

parietal cells secrete intrinsic factor–> what can cause malabsorption of B12 and pernicious anemia

A

autoantibodies to intrinsic factor or parietal cells!

48
Q

syndrome characterized by excessive secretion of Hcl by continuously stimulated parietal cells–>can’t adequately get neutralized causing gastric/duodenal ulcers. pts get abdominal pain, diarrhea, and steatorrhea.

A

Zollinger Ellison syndrome aka gastrin producing tumor!

49
Q

2 types of enteroendocrine cells-closed(don’t reach lumen) and open(exposed to lumen)-which serve as the primary chemorecetpros sampling the gland lumen and releasing hormones based on info obtained? which secrete in response to neural and paracrine mechanisms

A

open; closed

50
Q

endocrine cells are distributed throughout the gastrointestinal epithelium and are described as a diffuse neuroendocrine system. an exception to this is in the pancreas where they formed accumulations called

A

endocrine islets of langerhans

51
Q

diffuse neuroendocrine systems includes neurons and endocrine that their secretions is regulated by what type of receptors

A

g protein receptors and tyrosine kinase activity

52
Q

neoplastic transformation of the diffuse neuroendocrine system can occur resulting in gastroenteropancreatic neuroendocrine tumors-these most commonly occur where? cause __ syndrome characterized by diarrhea, episodic flushing, bronchoconstriction, and right sided cardiac valve disease

A

appendix; carcinoid syndrome

53
Q

some enteroendocrine cells can be classified as amine precursor uptake and decarboxylation cells(APUD)- there are also APUD cells that are derived from neural crest cells but these ones in the digestive tract are derived from what

A

stem cells that make all the other epithelial cells of the digestive tract

54
Q

enteroendocrine cells produce not only endocrine hormones like gastrin ghrelin that diffuse into the blood but also secrete paracrine hormones-example of paracrine hormone it secretes that inhibits other endocrine cells

A

somatostatin

55
Q

agent released from nerve endings and can also be secrteed by enteroendocrine cells to activte afferent neurons to send signals to CNS and enteric nervous system

A

neurotransmitters

56
Q

gastrointestinal peptides haven’t been classified as hormones and they are designated as what type of hormones?examples include pancreatic polypeptide, peptide YY and glucagon like peptide 1

A

candidate hormones

57
Q

cardiac glands of the stomach are composed of what cell type?they are tubular tortous glands and what tey secrete reaches the lumen of the gastric pit va a short duct lined by columnar cells

A

mucus secreting cells

58
Q

pyloric glands are tubular, wide, secretory cells , emptying into the gastric pits, have enteroendocrine cells disperse in them and secret what

A

mucus

59
Q

surface mucus cells of the stomach are renewed how frequently? is dt mitotic activity of isthmus stem cells

A

every3-5 days

60
Q

parietal cells have a long life span (150-200d), chief/enteroendocrine cells life span 60-90d, and mucuous neck cells life span is 6 days.
parietal cells may have originated from a bacterium called neurospora crass why is this a thought

A

the H/K ATPase they possess are very similar to the on ein the bacterium

61
Q

thing sm cells from the inner layer of the muscularis mucosae of the stomach extend into the lamina propria and are thought to help the outflow of what

A

gastric gland secretions

62
Q

the gastric submucosa is of course dense connective tissue containing the messiners plexus this inncervates __ of the submucosa and ___ of the muscularis mucosae

A

vessels; sm

63
Q

the gastric muscularis externa has 3 layers oriented from out to in->longitudinal, circular, and obliquely- these mm are innverated by what plexus? while when actually looking at the stomach this orientation isn’t perfect the basic function of the differently oriented mm is what?

A

myenteric(auerbachs plexus); mix chyme!

64
Q

gastric serosa is continuous with the parietal peritoneum of the abdominal cavity via the __ omentum; and the visceral peritoneum of the liver at the __ omentum

A

greater; lesser

65
Q

enzymes, esp disaccharidases and dipeptidases are located in the microvilli of what cell in the SI

A

enterocytes

66
Q

permanent transverse folds contianing a core of submucosa-most numerous in duodenum and dec number in ileum is an absorptive surface

A

plicae circulares

67
Q

2 other structures that inc the absorptive area in teh SI

A

villi and microvilli

68
Q

villi of the SI are projections of the ___. The have a core of loose CT covered by ____ epithelium. The core of the villus is an extension of the lamina propia and contains many different cells type and also contains a blind ending lymphatic capillary called the _____

A

mucosa; simple columnar; lacteal

69
Q

_____ are glands composed of simple columnar epithelium that continuous with the epithelium of the villi

A

crypts of lieberkuhn

70
Q

lamina propria of SI contain numerous nodules of lymphatic tissue. they are large and most numerous in the ileum and are called

A

peyers patches

71
Q

in the plasma membrane of the microvilli located especially in the durodenum is the enzyme ___ which converts trypsinogen to trypsin(peptide digestion)

A

enteropeptidase(enterokinase)

72
Q

Carbohydrates are also broken down by enzymes in the enterocytes. In pts with a deficiency in the disaccharidase___ they are unable to tolerate milk and suffer from diarrhea

A

lactase

73
Q

3 final products of carbohydrate digestion that get broken down by enzymes in the enterocytes, absorbed into venous capillaries and transported to the liver via the portal system

A

galactose, fructose–>glucose

74
Q

triglycerides are broken down into glycerol and fatty acids. they then get converted to chylomicrons and are taken away from the intestine via? they then are disassembled and used throughout the body

A

lymphatic vessels(lacteals)

75
Q

proteins get digested into amino acids and dipeptides-are dipeptides of certain aa absorbed via a different pathway than that of free amino acids? disease assoc

A

no; hartnups-pts fed dipeptides->free aa seen in blood but when fed free aa not seen in blood

76
Q

Enterocytes are columnar cells have microvilli on their apical surface which forms a ___ border. in the microvilli they contain actin filaments which insert into the _____ ___ which contracts allowing microvilli to spread apart allowing for a more absorptive area

A

striated border; terminal web

77
Q

_____ establish a barrier between the intestinal lumen and the epithelial intercellular compartment

A

tight junctions

78
Q

enterocytes are also secretory cells they not only secrete H20 and electrolytes to balance the intestinal fluid but also synthesize and secrete _____ ___ that get inserted into the plasma membrane

A

glycoprotein enzymes

79
Q

goblet cells secrete mucus increase in number from duodenum to ileum. the cell rests on the basal lamina. the basal portion of the goblet cell contains the nucleus rER and mitochondria. apical to the nucleus are many _____ that get filled with large mucinogen granules

A

golgi apparatus

80
Q

cell type in SI maintaining mucosal innate immunte by secreting antimicrobial sustances helping to regulate the normal bacterial flora of the SI

A

paneth

81
Q

Paneth cells secrete ___ which digests the cell wall of certain bacteria and ___ which function as mediators of CD8

A

lysozyme; alpha defensins

82
Q

enteroendocrine cells in the SI like the stomach have open and closed cells: activation of taste receptors on the open cells activates ____ cascade that regulate GI functions by acting on the brain-gut-adipose axis

A

g protein signaling cascade

83
Q

2 hormones released by enteroendocrine cells fo the SI that inc pancreatic and gallbladder activity and inhibit stomach secretory function and motility

A

CCK and secretin

84
Q

hormone secreted by enteroendocrine cells that stimulates insulin release

A

GIP(gastric inhibitory peptide)

85
Q

hormone secreted by enteroendocrine cells that initiate gastric and intestinal motility

A

motilin

86
Q

epithelial cell overlying peyers pathches have microfolds(not villi) their function is to get antigens from gut lumen and transport them into the vicinity of CD4 cells on the basolateral surface

A

M cells

87
Q

gastric associated lymphatic tissue is prominent in the _____ of the digestive tract and works with M cells and epithelial cells to sample antigens in the space

A

lamina propria

88
Q

the mucosal surface of SI is constantly challenged by microorganisms. plasma cells in the lamina propria secrete ___ antibodies which bind polymeric immunoglobulin receptor on the basal membrane of epithelial cells. the complex then gets transported to the apical surface where it is released into the gut lumen. The complex is cleaved by the secretory component extracellularly and is now known as secretory IgA

A

IgA

89
Q

Secretory IgA is reall important in preventing attachment and invasion of pathogens. ex. it binds a glycoprotein on the viral envelope of __ virus preventing its attachment, internalization and replication

A

HIV

90
Q

The duodenums submucosa has __ glands which secretes highly alkaline stuff to neutralize the chyme delivered to duodenum

A

brunners glands!

91
Q

In the SI:Contraction of the muscularis externa produces segmentation and peristalsis contractions- contraction of the inner layers causes what? while contraction of the outer layer causes what

A

inner layer(circular mm)-mixes food; outerlayer(longitudinal)-propels contents forward

92
Q

Intestinal stem cells are located in the base of the intestinal gland-what transcription factor determines the fate of differentiating cells in the intestinal stem cell niche? expression causes goblet enteroendocrine and paneth cell formation; inhibitiion creates enterocytes

A

Math1

93
Q

sacculations between teniae coli on external surface of cecum and colon

A

haustra coli

94
Q

small fatty projections of the serosa on the outersurface of the colon

A

omental appendices

95
Q

major cell difference type in colon vs SI

A

colon contains crypts of lieberkuhn but NO villi!

96
Q

primary function of the columnar absorptive cells in the colon

A

rebsorption of water and electrolytes-have tight junctions!

97
Q

Numerous goblet cells are contained in the colon that secrete a lot of mucus what does this allow

A

facilitate elimination of solid waste

98
Q

Columnar absorptive cells predominate over goblet cells but the ratio decreases where in the large intestine? LI also has most of the same cells as the SI except what cell type

A

rectum; paneth cells

99
Q

intestinal cells in the LI just like in the SI arise from a single stem cell population: for both parts of the intestine cell turnover rates are the same: for absorptive and goblet cells how long do they last? what about enteroendocrine cells

A

6 days; 4 weeks

100
Q

Lamina propria of LI is similar to the rest of the digestive tract but a few features are different:
1.) ______ lies between epithelium and venous capillaries is very thick. participates in regulation of water and electrolyte transport into the vascular compartment
2.)______fibroblast population that regularly replicate adjacent to stemcells; migrate with epithelial cells but their fate is unknwon
3.)______ is continuous with the ileum but is more extensively developed and large lymphatic nodules distort the regular spacing of intestinal glands and extend into the submucosa
4.) _____ is generally absent some does drain within the muscularis mucosae

A
  1. collagen table 2. pericryptal fibroblast sheat 3. GALT 4. Lymphatic vessels
101
Q

Muscularis externa of the LI: in cecum and colon the outer layer in part is condensed into large bands called ____ . between these bands the regular longitudinal layer forms a thin sheet. in the rectum, anal canal, and appendix the longitudinal sm that is seen also in the SI is uniformly thick

A

teniae coli

102
Q

muscularis externa: teniae coli penetrate the inner circular mm layer at irregular intervals. this leads to discontinuous contraction and the formation of ____
(note also that the LI muscularis externa still does segmentation adn peristaltic contractions)

A

haustra coli

103
Q

cecum forms a blind pouch creating the appendix-what is the difference though between the muscularis externa of the appendix v the cecum

A

muscularis externa of the cecum has tenaie coli while appendix has uniform longitudinal sm layer

104
Q

in many adults normal structure of the appendix is lost and blockage either by fibrous tisse, thick mucus or stool entering the appendix from the cecum can cause

A

appendicitis

105
Q

common tumor of enteroendocrine cells found in the appendix

A

carcinoid

106
Q

The really neat thing that occurs in the Large intestine when a patient has Ulcerative colitis assoc with LI lymph tissue? this allows you to monitor active inflammation occurring in UC and the progress of treatment

A

in pts with UC the normal absent lymphatic tissue in the LI actually proliferates so if lymphatic vessels inc in UC it signals active inflammation but if they dec it means that the pt is responding to treatment

107
Q

what is so cool about the large intestine and the presence of adenomas in it dt the lymphatic distribution in the LI

A

adenomas that develop have slow rate of metastasis dt absence of lymphatic channels and so if it is confined to the mucosa you can snip it off and thats adequate treatment

108
Q

upper part of rectum is distinguised from the rest of the large intestine dt the presence of

A

transverse rectal folds

109
Q

Anal canal has longitudinal folds called anal columns. between these columns are anal sinuses. the anal canal can be divided into 3 zones based on epithelial lining:
1.)____ zone: found in upper 1/3 of anal canal contains simple columnar epithelium
2.)____ zone in middle 1/3 of canal has stratified suamous columnar epithelium between simple columnar epithelium and stratified squamous epithelium
3.) ___ zone found in lower 1/3 of canal lined by stratified squamous epithelium and continuous with perineal skin

A

colorectal zone, anal transtional zone, squamous zone

110
Q

Anal glands extened into submucosa and muscularis externa. sometimes they get surrounded by diffuse lymphatic tissue which can lead to the formation of

A

pathologic fistulas(between anal canal and perianal skin)

111
Q

apocrine glands found in the skin surrounding the anal orifice

A

circumanal glands

112
Q

submucosa of the anal columns contain superior rectal actery and rectal venous plexus enlargement of these is called what

A

internal hemorrhoids

113
Q

what forms the internal anal sphincter

A

circular layer of muscularis externa

114
Q

what forms the external anal sphincter

A

striated mm of the pelvic floor

PBL (19 decks)

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