Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Gastroenterology > Pancreas and Small Bowel > Flashcards

Pancreas and Small Bowel Flashcards

1
Q

What part of the pancreas is sometimes absent as an adult

A

Accessory pancreatic duct and minor papilla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is pancreas divisum

A

Where the ducts are separated

Higher occurance of pancreatitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are endocrine glands

A

Secretion into the blood stream to have an effect on distant target organ - ductless glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are exocrine glands

A

Secretion into a duct to have direct local effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the main endocrine secretions of the pancreas

A

Insulin: anabolic hormone

Glucagon

Somatostatin - inhibitor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the percent of endocrine and exocrine glands of pancreas

A

Endocrine - 2%

Exocrine - 98%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the two pancreatic cells

A

Acini - grap like clusts of secretory units, secrete pro-enzymes into ducts

Islets - derived from branching duct system, lose contact with ducts and become islet, differentiate into alpha and beta cells into blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Composition of islets

A

Alpha cells - 15-20% of islet tissue and secrete glucagon

Beta cells - 60-70 of islet tissue and secrete insulin

Gamma cells - 5-10% of islet tissue and secrete somatostatin

Acini

Islets are highly vascular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the composition of acini

A

Secretory acinar cells

Duct cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the two components of pancreatic juice

A

Acinar cells - decrease volume, viscous, enzyme-rich

Duct and centroacinar cells - increase volume, watery, HCO3 rich

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the fucture of bicarbonate secretion

A

Neutralises acid chyme - preevnts damage to duodenal mucosa, raises pH to optimum range for pancreatic enzymes to work

Washes low volume enzyme secretion out of pancreas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why does HCO3 secretion stop when pH still acid

A

Bile also contains HCO3

Brunners glands secrete alkaline fluid

Duodenal ph<3 - not much more increase in HCO3 secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does HCO3 secretion work

A
  1. Catalysed by carbonic anhydrase - separation of H and HCO3

Na moves down gradiant via paracellular tight junctions water follows

  1. Cl/HCO3 exchange at lumen (AE) , Na/H exchange at basolateral membrane into bloodstream (sodium-hydorgen exchanger (antiporter) typer 1 [NHE-1]

Exchange driven by electrochemical gradients

  1. Na gradient maintained by Na/K pump
  2. K returns to blood via K channel, Cl returns the blood via Cl channel (cystic fibrosis transmembrane conductance regulator (CFTR)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Composition of H and HCO3 in juice

A

Stomach

H+ - gastric juice

HCO3 - blood

Gastric venous blood is alkaline

Pancreas

HCO3 - juice

H+ - blood

Pancereatic venous blood is acidic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are zymogens

A

Pro enzymes which enzymes for digestions are released and stored in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How are enzymes activated in the intestine

A

Pancreas contains a trypsin inhibitor to prevent trypsin activation

Enzymes only activated in duodenum

Blockage of MPD may lead to autodigestion

Activated in duodenum by enterokinase which converts trypsinogen to trypsin

Lipase secreted in active form but requires colipase and presence of bile salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the side effects of Orlistat

A

Increase facal FAT

Pancreatic secretion decreases

Steatorrhoea - fatty stool

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the phases of pancreatic juice secretion

A

Cepahlic phase - sight/smell/taste of food, enzyme rich component only, low volume

Gastric phase - stimulation of pancreatic secretion originating from food arriving in stomach

Intestinal phase - 70-80% of pancreatic secretion - hormonally mediate, both components of pancreatic juice stimulated - enzymes and HCO3 juice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How is the pancreatic juice enzyme secretion controlled by

A

Vagus nerve - cholinergic, vagal stimulation of enzyme secretion

Cholecystokinin (CKK) (Ca/PLC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How is the pancreatic juice bicarbonate secretion controlled by

A

Duct and centroacinar cells

Secretin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the stimulaatory effect snad inhibitory effects of CCK from duodenal 1 cells

A

Stimulatory - Fatty acids and amino acids in lumen

Inhibitory - trypsin

22
Q

What does secretin do

A

Stimulate secretion of H20 and HCO3 from cells lining extralobular ducts

Secretion-stimulated secretion is richer in HCO3 in constrant to acinar secretion because of Cl/HCO3 exchange

23
Q

What is the negative feedback loop of bicarbonate

A

S cells increase scretin

Secretin increas HCO3

Cause pH to decrease

Which will increase production of S cells

24
Q

What is the coupled stimulation reactions of CCK

A

CCK and secretin markedly increase HCO3

Vagus nerve has similar effect to CCK

25
Q

When does pancreatic enzymes release peak

A

30 mins

26
Q

What is the function of the small bowel

A

Absorb nutrients, salt and water

27
Q

What are the dimension of small bowel

A

25cm -duodenum

Jejunum -2.5m

Ileum - 3.75m

3.5cm diameter

28
Q

What is the function of mesentery

A

Suspends small and large bowel from posterior abdominal wall achoring them in place and allowing some movement

Provides conduit for blood vessels, nerves and lymphatic vessels

29
Q

Facts about villi

A

Only in small intestine

Motile

Rich blood and lymph supply

1 cell thick

Dominated by enterocytes - columnar absorptive cells

30
Q

What are the different cell types in small bowel

A

Enterocytes

Scattered goblet cells

Enteroendocrine cells

Paneth cells

Stem cells

31
Q

Facts about enterocytes

A

Specialised for absorption and transport of substances

Short lifespan of 1-6 days

500flod of surface area of small bowel to folds, villi and microvilli

32
Q

Facts about microvilli

A

Make up the brush border

Surface of microbilli covered with glcocalyx

33
Q

What is the glycocalyx

A

Rich carbohydrate layer on apical membrane

Serves as protection from digestional lumen yet allows for absorption

Traps a layer of water and mucous known as unstirred laeyr

Regulates rate of absoprtion from intestinal lumen

34
Q

Facts about goblet cells

A

2nd most abbundatn epithelial cell

Mucous - large glycoprotein that gacilities passage of amterial

Increase abundance of goblet cells along entire length of bowel

35
Q

Facts about enteroendocrine cells

A

Columnar epithelial cells

Lower parts of crypts

Hormone secreting - influences gut motility

36
Q

Facts about paneth cells

A

Bases of crypts

Large, acidophilic granules

Antibacterial enzyme lyosozyme - protect stem cells

Glycoproteins and zinc to aid number of enzymes

Engulf bacteria and protozoa

Regulating intestinal flora

37
Q

Facts about stem cell sin GI tract

A

Undifferentiated cells

Eptihelial stem are essnetial in GI tract to continually replenish surface epithelium

Divide by mitosis

Migrate to tip of villus

Old cells digested and reabsorbed

38
Q

Why do enterocytes have a rapid turnover

A

Enterocytes are first line defense agaisnt GI pathogens

Effects of agents will be diminished

Lesions will be short live

If escaltor like transit diminised, severe intestinal dysfunction will occur - radiation

39
Q

How is the duodenum distinguish

A

Presence of brunner’s glands

Submucosal coiled tubular mucous glands secreting alkalin fluid

Open into base of crypts

40
Q

Difference between jejunum and ileum

A

Jejunum - wider, redder, thicker, numerous plicae circulares

Arterial arcades more sufficient in ileum

41
Q

Functions of small bowel motility

A

Mix ingested food with digestive secretions and enzymes

Facilitate contact between contents of intestine and intestinal mucosa

Propel intestinal contents along alimentary tract

42
Q

Types of motility in small bowel

A

Segmentation - mixes content, contraction of circular muscles, more frequent contractions in duodenum, net effect is movement to colon

Peristalsis (propelling) - sequential contraction of adjacent rings, propels towards colon, travels only 10m

Migrating Motor Complez - smooth muscle contractions sweeping through gut, begin in stomach to colon, next wave starts in duodenum, prevents migration of colonic bacteria into ileum

43
Q

Digestion in the duodenum

A

Occurs in an alkaline enviornment

Enter through main pancreatic duct and common bile duct

Eptihelium also produces its own digestive enzymes

44
Q

How does digestion of carbs work

A

Salivary alpha amylase which is destroyed in stomach

Pancreatic alpha amylase - needs cl for optimum activity and slightly alkaline pH, actsm mainly in lumen, digestion of amylase products and simple carbs happen at the brush border

45
Q

How are the carbs absorbed

A

Glucose adn galactose - secondary active transport - SGLT-1 on apical membrane

Fructose - facilitated diffusion - GLUT-5 on apical membrane

GLUT-2 facilitats exits at basolateral membrane

46
Q

How are proteins digested

A

Protein digestion begins in lumen of stomach by pepsin

Pancreatic proteases secreted as precursors - lumen of small bowel (trypsinogen)

Trypsin activated by enterkinase

Trypsin makes singel amino acids and oligopeptides

47
Q

How do enterocytes absorb proteins

A

Via action fo H+/oligopeptide cotransporter PepT1

Small peptides are digested to AA by peptidases in cytoplasm

48
Q

How is the digestion of lipids happening

A

Secretion of bile salts and pancreatic lipases

Emulsification - increase surface area

Enzymatic hydrolysis of ester linkages - colipase complexes with lipase, prevents bile salts displacing lipase from fat droplet

Solubilisation of lipolytic products in bile salt micelles

49
Q

How does the absorption of lipids happen

A

FA and MG leave micelles and enter enterocytes

FA and MG resyntehsized in triglycerides by monoglyceride acylation (major) and phosphatidic acid pathway (minor)

Chylomicrons - lipoprotein particles synthesised as an emulsion(80-90% TG) phospholipids, protein, in golgi

Chylomicrons secreted across basment membrane by exocytosis

Lymph transports them away from bwoel

50
Q

What is the ileocaecal valve

A

Prevents balck flow of bacteria into ileum

Relaxation and contraction controls passage of amteral into colon

Gastroenterology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions