Day 4: Gastrointestinal Flashcards
2 functional parts of the Pancreas
- Exocrine: Acinar cells 2. Endocrine: Islets of Langerhans
It is a lymphatic capillary that absorbs dietary fats in the villi of the small intestine.
Lacteal
Type of contraction involving longitudinal muscles propelling chyme small intestine
Peristaltic contractions
Microvilli give the APICAL region striated appearance called ____.
brush border
Liver receives major blood supply from ____ (2)
hepatic portal vein and hepatic artery
How many percent of bile is not reabsorbed and are lost in feces.
5%
This are liver cells; they are capable of regeneration.
Hepatocytes
It emulsifies lipids.
Bile salts
Activated GALT increases ___(3)
Secretion of Cl, fluid and mucous.
Accessory structures of the GIT (4).
- Salivary gland (3 pairs) 2. Pancreas 3. LIver 4. Gallbladder
What stimulates the GIT? SNS or PNS?
PNS “rest and digest”
Serosa is covered by ____.
visceral peritoneum
It stimulates H secretion by gastric parietal cells, along with gastrin and ACh
Histamine
Length of appendix
2-12cm
This enzyme digests DNA and RNA
nucleases.
Blind pouch at the beginning of the large intestine from which the appendix projects.
Cecum
What converts fats to lipids in the stomach?
Gastric lipase
What triggers the release of CCK?
fatty acids and small peptides
This cell secretes gastrin
G cells
This hormone inhibits the effects of gastin on parietal cells.
Secretin
This is the most energy-rich (dense) type of nutrient.
Lipids
What are reabsorbed in the Large intestine? (3)
water, nutrients, vitamins
Length of the duodenum
10 - 12 inches
Examples of Hormones (GI peptides) 4
Gastrin, CCK, Secretin, Gastric inhibitory peptide
FYI: Enterohepatic circulation also means that some molecules which would not otherwise be very toxic can become extremely hepatotoxic as they reach unexpectedly high hepatic concentrations.
;)
This part of the GIT is specialized for accumulation of food.
Stomach
Where does absorption of bile salts takes place?
from ileum to portal circulation
This controls the GI function. Also referred as “brain of the gut.” It allows autonomous behavior of the GIT.
Enteric nervous system (intrinsic nervous system)
The stomach can absorb ____ (2)
alcohol, ASA
This is the lymphatic tissue in the GI system
GALT (gut associated lymphatic tissue) aka Peyer’s patches
This cells activate lymphocytes of GALT when pathogens are detected.
M cells
6 functions of the liver
- Protein synthesis 2. Bile formation and secretion 3. Detoxification 4. Lipoprotein synthesis 5. Carb metabolism 6. Urea formation from ammonium
This type of GI peptide is released by GI neurons following an ACTION POTENTIAL; it has local effects.
Neurocrines
Categories of GI peptides (3)
Hormones, Paracrines, NEurocrines
Large surface area of the GIT warrants protective functions. This can be in the form of (4)
- Salivary enzymes and Ig 2. Gastric Acid 3. Diarrhea/ vomiting (protective reflexes) 4. GALT and M cells
This is the largest internal organ and receives major blood supply.
Liver
Somatostatin is secreted by endocrine cells of ___(3) in response to decreased luminal pH
stomach, intestine, pancreas
Name 4 lipoproteins.
HDL, LDL, VDL IDL (intermediate density lipoprotein)
Where do most absorption occur?
Small intestine
All of the GIT is supplied by the vagus nerve except for ____(3) which is supplied by sacral parasympathetic nerves.
descending colon, sigmoid colon, and rectum.
This can cause esophagitis.
GERD
The lower esophageal sphincter is at which spinal cord level?
T11 Level
Biliary system is composed of the
Hepatic duct, cystic duct, common bile duct, gallbladder.
Triglycerides are packaged into vesicles called ____; it then goes into the LYMPHATIC system of the small intestine (not the venous system)
chylomicron
This is a common esophageal discomfort, resulting from regurgitation of food and gastric fluid into lower esophagus.
Pyrosis.
2 substances in the stomach which breaks down protein to peptides.
HCl and Pepsin
These are the mucous secreting cells
Goblet cells
This movement propels the luminal contents of the stomach in an aboral direction.
peristalsis
Gastric muscos has numerous openings called ____.
gastric pits
These are finger-like projections of the small intestine mucosa.
Villi
These cells secrete essential digestive enzymes and BICARBONATE throughout the pancreatic duct into duodenum.
Acinar cells
This enzyme is the mostly absent exocrine pancreatic secretion.
amylase
It protects the epithelial lumen from the acidity in the stomach.
Mucous
This is otherwise known as the hepatopancreatic sphincter.
Sphincter of Oddi
Layer of GI wall: Inner most layer. It is a layer of epithelial cells specialized for absorption and secretion.
Mucosa
ENS controls ___ (3)
Contractile, secretory and endocrine functions of the GIT
_______ brings venous blood rich in nutrients from small intestine.
hepatic portal vein
The extraction of bile salts from the portal blood by _____.
hepatocytes
Length of esophagus
10 -12 inches
4 functionally different cells types in the stomach.
- Mucous cells: neutralizes pH 2. Chief cells: Pepsinogen and gastric lipase 3. Parietal cells: HCl (gastric acid) and intrinsic factor 4. Enteroendocrine cells: gastrin and histamine
How many ml of gastric contents is secreted into the duodenum, per stomach contraction?
15 ml
At which GI layers you can find blood vessels? (2)
Submucosa and serosa
Part of the GIT that has the ability to repopulate good bacteria.
Appendix
The portal triad is composed of ___ (3)
Common bile duct, hepatic portal vein, and hepatic artery.
GIP: Stimulates secretion of:_____ Inhibits secretion of: _____
insulin by pancreas …….. gastric H secretion.
Name 2 adrenergics
Epi and NE
This neurocrine is released from adrenergic neurons.
NE
length of small intestine
12 feet (21 feet when not contracted)
Part of the stomach which is between the fundus and the antrum.
Body of the stomach
Anal canal is lined with ______ epithelium
non-keratinized stratified squamous epithelium (wear and tear epithelium)
Where is the target cells acted on by the neurocrines?
nerve endings of a cell (synapse)
Average stomach content volume
1 - 2 liters
This is the last region of the GIT.
Anal canal
This hormone is secreted by small intestine in response to all 3 types of nutrients.
Gastrin Inhibiting peptide
True or False: Cellulose is not digestible because humans don’t have the enzyme to break it down.
True
This is a blind pouch that stores and concentrates bile.
Gall bladder
4 parts of the stomach
- Cardia 2. Fundus 3. Body 4. Pylorus
Length of anal canal
4cm
Drugs may remain in the enterohepatic circulation for a prolonged period of time as a result of the recycling process. Name 4 drugs.
- Statins 2. NSAIDs 3. Morphine 4. Zantac
The bile-mediated dispersion of dietary lipids into micelles provides a greatly increased surface area for the action of _______, which actually digests the triglycerides.
pancreatic lipase
The large intestine mucosa contains numerous tubular glands called _____, which is responsible for mucus secretion.
crypts (pits//depression)/ Crypt of Lieberkuhn
Submucosa consists of ____ (4).
Collagen, elastin, glands, and blood vessels. Note: Collagen and elastin are products of fibroblasts. They are part of the extracellular matrix.
What cells secrete Gastrin?
G cells in stomach
3 pairs of salivary glands
- Parotid glands 2. Submandibular glands 3. Sublingual glands
FYI: GI sphincters are smooth muscles
;)
This layer of the GI wall provides motility of for the GIT.
Circular and longitudinal smooth muscles
NAme 4 essential digestive enzymes secreted by acinar cells.
Lipase, protease, amylase, nucleases.
Volume of saliva produced by Salivary glands in a day?
1 Liter
What cells produce secretin?
S cells of the duodenum
There are nonadrenergic and noncholinergic receptors in the GI which binds to ___ (3)
5-hydroxytryptophan, GABA, substance, P
Secretion of gastrin is inhibited by
low pH in stomach
Enzyme secreted by the stomach (2)
- pepsinogen; activated into PEPSIN 2. HCl: secreted by parietal cells
Major lipase activity comes from which organ?
Pancreas
ENS sends information DIRECTLY to ____ (3)
smooth muscles, secretory glands, and endocrine cells
Secretin promotes secretion of _____
pancreatic bicarbonate
Enterocytes are covered with tiny projections called ____.
Microvilli (intestinal cell)
Bile duct and pancreatic duct empty into ____.
Duodenum (at major duodenal papilla)
ENS receives input from (2)
- SNS and PNS 2. Mechanical receptors (stretch receptors) and chemical receptors in mucosa
Layers of the GI wall (4)
- Mucosa 2. Submucosa 3. Circular and longitudinal smooth muscle 4. Serosa
5 Actions of CCK
- Contraction of gall bladder 2. Secretion of pancreatic enzymes 3. Secretion of Bicarbonate from exocrine pancreas 4. Growth of exocrine pancreas and gallbladder 5. Inhibition of gastric emptying
This is necessary for digestion and absorption of lipids in the small intestine.
Bile or Gall
Food is broken down into absorbable molecules, namely: (3)
Carbs, protein, lipids
This neurocrine stimulates food intake.
Neuropeptide Y
Somatostatin inhibts: (2)
- secretion of other GI Hormones 2. Inhibits gastric H secretion
Hormones (GI peptides) are secreted into ______ and enter the ______.
portal circulation ……… systemic circulation
This is the first part of the GIT that has peristalsis.
Esophagus
This describe the movement of food from mouth toward anus.
ABoral direction or anterograde movement.
The hepatic portal system is the venous drainage for these organs (4).
Pancreas, spleen, stomach and intestines.
This duct collects the EXOCRINE secretion of the pancreas and bicarbonate.
Pancreatic duct
This is the salivary gland that gets swollen when a patient has mumps.
Parotid glands
Muscle layers of the esophagus (2)
- Inner circular muscle 2. Outer longitudinal muscle
pH of stomach
1.5 - 2
This is necessary for emulsification of lipids.
Bile
The islets of langerhand secretes (2)____ into the bloodstream.
insulin and glucagon
The liver can synthesize proteins, such as ___ (2)
prothrombin and albumin
Gastrin releasing peptide is released from _____ onto G cells.
vagal nerve endings
Action potential causes release of neurocrines which interacts with the receptors on _____.
postsynaptic cell
FYI: Any duct is lined by epithelial cells!
;)
When bile salts loose sodium ions it becomes ___.
bile acids
The majority of the pancreatic tissues are ___.
exocrine
The lacteals drains blood back into the venous system at the junction of ___.
Left SC and Left IJ veins.
What is the shaped of the duodenum?
C-shaped
Name of the sphincter in the mouth.
Obiscularis oris
Parotid gland empties next to the
second maxillary molar
The large intestine has which type of muscle layer?
longitudinal muscle layer
The gallbladder is attached to _____
inferior surface of the liver
These are finger-like projections of the stomach GI wall.
Microvilli (single layer thick)
Stomach is capable of considerable expansion, can hold an average volume of ___. L
2-3 liters (americans)
It receives pancreatic enzymes, used for digestion.
Small intestine
This hormone cause contraction of gallbladder, thereby ejecting bile into small intestine.
CCK
Enzymes found in the mouth (2)
amylase: breaks down starch lingual lipase: breaks down fats
4 Major Activities of the GIT
- Motility 2. Secretion 3. Digestion 4. Absorption
After lipids are digested and absorbed, bile salts are recirculated to liver via _____
Enterohepatic circulation
Normal GI transit time
12 - 50 hours
Composition of Bile (4)
- Water (85%) 2. Bile salts (10%) 3. Bile pigments 4. Cholesterol
Name 6 examples of neurocines.
- ACh 2. NE 3. Vasoactive Intestinal Peptide (VIP) 4. Gastrin-Releasing Peptide (GRP) 5. Neuropeptide Y 6. Substance P
These peptides are released from endocrine cells of the GIT.
Hormones
The liver secretes ____ into the hepatic duct.
bile
Bile salts emulsify lipids, forming ______, to prepare them for digestion by lipase’s (mainly pancreatic lipase).
Micelles
Most of the enzymes that digest polysaccharides are on the surface of the _____.
enterocytes (in small int.)
Pepsinogen is converted to pepsin (a proteolytic enzyme) by which substance?
HCl
In patients receiving enema, to which side you should position your patient?
Left (sigmoid colon)
It is a muscular tube that conveys food from pharynx to stomach.
Esophagus
This is the outermost layer; a connective tissue.
Serosa
Histamine is secreted by
Enterochromaffin-like cells in the stomach
This GI peptides are secreted by endocrine cells of GIT and act LOCALLY within the same tissue that secretes them.
Paracrines (somatostatin: has inhibitory actions; Histamine)
2 types of pathways for the regulation of GI function.
- Long reflex pathway: (from brain and spinal cord down to the GIT) 2. Short reflex pathway: mediated by enteric plexus.
Gleeting is squirting from which salivary gland?
Submandibular gland
What stimulates the production of Secretin?
response to H and fatty acids
Enteric nervous system is composed of ___ (2)
- Myenteric plexus 2. Submucosal plexus Note: also included are the sensory receptors and interneurons
Part of the small intestine that connects with the stomach.
Duodenum
2 main functions of Gastrin
- Promotes H secretion by gastric parietal cells 2. Stimulates growth of gastric muscosa
How many percent of bile salts secreted from the liver are old/ recycled?
95% old, 5% new
FYI: Nerves and lymphatics run deep into the submucosa
;)
What forms the common bile duct?
Hepatic duct and Cystic duct
Two types of Motility Contraction
- Segmentation Contraction 2. Peristaltic contraction
This is the connection between the ENS and the ANS.
Myenteric plexus
What triggers the secretion of neurocrines?
Action potential
This neurocrine is released from cholinergic neurons.
ACh
The primary site for the completion of digestion and almost all absorption of nutrients
Duodenum
Gastric juice converts food into semi-liquid called ___.
chyme
This peptide decreases acid secretion by stomach.
Somatostatin (growth hormone - inhibiting hormone)
This is needed for B12 absorption.
Intrinsic factor
GI peptides regulate functions of GIT tract, namely: (5)
- Contraction and relaxation of smooth muscle wall and sphincter 2. Secretion of enzymes for digestion 3. Secretion of fluid and electrolytes 4. Trophic effects 5. Some regulate secretion of other GI peptides.
Neutralizing H allows for pancreatic enzymes to digest ____.
fats
Where is the receptor site for somatostatin located?
Parietal cells
This prevents the stomach from digesting it self.
Mucus
What stimulates the release of Gastrin by G cells? (3)
- Protein 2. Distention of stomach 3. Vagal stimulation.
______ empty into bottom of gastric pits.
gastric glands in FUNDUS and BODY
What cells secrete CCK?
I cells of small intestine
Specific cell that lines only the SMALL intestine
Enterocyte (a columnar epithelial cell)
This type of contraction involves circular muscle sending chyme in both oral and aboral directions. Intestine then relaxes allowing chyme to merge back together.
Segmentation contraction
Name 1 cholinergic
Acetylcholine
