Gi Physiology

Question 1

what epithelium is the oesophagus

Answer 1

stratified squaous NK epithelium until diaphragm

below diaphragm = simple columnar

Question 2

What is the muscles like in the oesophagus

Answer 2

inner circualr 
outer longittidinal 
Proximal 1/3 = skeletal 
middle 1/3 = mixed
distal 1/3 = smooth

Question 3

Describe the nerve supply to oesophageal muscle

Answer 3

inner circular = meissners plexus

Outer circular = auerbachs plexus

Question 4

What cells are found in the cardiac tegion of the stomach

Answer 4

cardiac glands - goblet cells

Question 5

What cells are found in the body and fundus of the stomach

Answer 5

goblet cells 
parietal cells 
chief cells 
D cells 
G cells

Question 6

Which cells release somatosatn and what is somatostatins function

Answer 6

D cells release somatostain

it inhibits gastric acid secretions in response to acid in the stomach

Question 7

what is gastrins role?

Answer 7

promtes secretion of gastric acid and histamine

histamine then positivey feedback to promote more acids secretion from parietal cells

Question 8

What inhibits Gastrin

Answer 8

HCl production

Question 9

What are the 3 phases of gastric secretion?

Answer 9

Cephalic
Gastric
Intestinal

Question 10

Describe the Cephalic phase of secretion

Answer 10

Triggered by sight/smell/sounds

increases in PS stimulation to stomach enteric nervous sytem

Question 11

Define Enteric Nervous System?

Answer 11

The enteric nervous system (ENS) is the intrinsic nervous system of the gastrointestinal trac

Question 12

Where does histamine act and what does it do?

Answer 12

Directly on Parietal cells

increases release of gastric acid

Question 13

Where are Pariteal cells located

what do they produce

Answer 13

HCL
Intrinsic Factor
Located in body and fundus

Question 14

Where is B12 absorbed?

Answer 14

Proximal Ileum and requires intrinsic factor to be absorbed which is produced by Parietal Cells

Question 15

Where is folate reabsorbed

Answer 15

proximal jejenum and Ileum

Question 16

What is the role of the duodenum

Answer 16

secretes 3 important things
CCk I cells
Secretin S cells
Mucous - brunners Glands

mix contents from stomach, pancrease and bile ducts

Question 17

Name three features of the jejenum which increase SA

Answer 17

pilicae circualris
villi
microvilli

Question 18

What are the 2 types of motility

Answer 18

segmentation

migrating muscoelectrcial complex.

Question 19

Where does water reabsorption occur?

Answer 19

Illeum Jejenum and Colon

Question 20

What is the role of pancreatic lipase?

Answer 20

Cleave TAG in micelles
Explanation: Pancreatic lipase acts on triacylglycerides (TAG) to produce monoacylglycerides and free fatty acids. It requires the presence of co-lipase to bind. The TAG is found in micelles, which require bile salts to form. VLDL are formed in the liver. - See more at: http://one2onemedicine.com/learning-material/pre-clinical-medical-science/?category=digestive#sthash.Rbu2rvoR.dpuf

Question 21

How is pancreatic tripsynogen activated

Answer 21

All pancreatic enzymes are secreted as inactive zymogens. Trypsinogen is the first to be activated. It comes into contact with enterokinase, an enzyme present on the brush border of duodenal enterocytes, which converts trypsinogen to trypsin. Trypsin then goes on to activate the other pancreatic enzymes. pH has a role in regulating activity but doesn’t activate trypsinogen. - See more at: http://one2onemedicine.com/learning-material/pre-clinical-medical-science/?category=digestive#sthash.Rbu2rvoR.dpuf

Question 22

What is segmentation

Answer 22

Segmentation is method of mixing used in the intestine where several rings of circular muscle contract at one time. This is in contrast to peristalsis that requires sequential circular muscle contraction for propulsion. Churning is a complex method of gastric mixing. Large colonic contraction is called mass peristalsis. Sphincter relaxation is a separate process caused by parasympathetic activation.. - See more at: http://one2onemedicine.com/learning-material/pre-clinical-medical-science/?category=digestive#sthash.Rbu2rvoR.dpuf

Question 23

what innitiates the migratory motor coples

Answer 23

Motilin

Question 24

Which cranial nerves form the efferent limb of the swalowing reflex

Answer 24

9 and ten
: The glossopharyngeal (IX) and vagus (X) nerves are most important in the swallowing reflex. IX is activated by contact on the posterior pharyngeal wall, which stimulates a bilateral output through IX and X for: pharyngeal contraction, soft palate contraction, upper oesophageal sphincter relaxation and closure of the epiglottis over the laryngeal inlet. - See more at: http://one2onemedicine.com/learning-material/pre-clinical-medical-science/?category=digestive#sthash.Rbu2rvoR.dpuf

Question 25

Where does the porta hepatis lie?

Answer 25

between the caudate and quadrate lobe The porta hepatis is an area on the posterior surface of the liver where the hepatic artery and portal vein enter, and the common hepatic duct leaves, the liver. It is located superior to the quadrate lobe, inferior to the caudate lobe, immediately medial to the IVC and slightly superior to the gall bladder neck. The bare area of the liver is superiorly and is in direct contact with the diaphragm. - See more at: http://one2onemedicine.com/learning-material/pre-clinical-medical-science/?category=digestive#sthash.Rbu2rvoR.dpuf

Question 26

What cell type commonly resides in the space of disse?

Answer 26

Stellate (Ito ) cell Explanation: The space of Disse is a microscopic area located between hepatic sinusoidal endothelial cells and hepatocytes. It is the location of stellate cells, which become active during inflammation and produce fibrous tissue. Kupffer cells are found within the sinusoidal lumen. Very few plasma cells are resident in the liver in the absence of pathology.

Question 27

What is the role of phosphoglucomutase

Answer 27

Phosphoglucomutase (PGM) converts glucose-1-phosphate to glucose-6-phosphate and back. When glucose is added to, or cleaved from, glycogen it is in the form of G-1-P. But hexokinase forms G-6-P and for glucose to leave the cell glucose-6-phosphatase removes the phosphate residue from the 6'position. -

Question 28

How is billirubin metabolied inside hepatocytes

Answer 28

In hepatocytes bilirubin is conjugated with glucuronic acid by bilirubin-UDP-glucuronyl-transferase. This increases it's water solubility before it is exported into bile canaliculi. The CYP450 system enzymes do not normally act on bilirubin.

Question 29

What is urobilligen

Answer 29

Water soluable billirubin metabolite

Question 30

How does hepcidin function?

Answer 30

Explanation: Hepcidin acts to reduce serum iron levels by preventing the efflux of iron from enterocytes. It binds to ferroportin, the channel that allows iron to exit enterocytes, and causes its degradation. When enterocytes are shed into the bowel lumen iron is lost with it. Hepcidin does not control secretion of transferrin or ferritin. -

Question 31

What cranial nerve supplies tatse function to anteriro 2/3 of the tongue

Answer 31

Explanation: The chorda tympani branch of the facial nerve (CN VII) supplies taste to the anterior 2/3. General sensation is provided by the lingual nerve, a branch of trigeminal (CN V). For the posterior 1/3 of the tongue (past the sulcus terminalis) both taste and general sensation are supplied by the glossopharyngeal nerve (CN IX).

Question 32

What is abdominal mesentery

Answer 32

Explanation: Mesentery is double-layered peritoneum that attaches the small bowel to the posterior abdominal wall at the level of L2. Contains blood vessels, nerves and lymphatics supplying the bowel. There are ligaments that hold organs in position e.g. right cardiac ligament attached to the liver. The omentum is connective tissue that attaches to the large bowel. The peritoneum is a single-layered epithelium: parietal lining the anterior abdominal wall and visceral covering the organs. -

Question 33

What organs are entirley retroperitoneal

Answer 33

Explanation: The organs that are entirely retroperitoneal are: pancreas, kidneys, ascending and descending colon, rectum and the aorta. Most of the 1st part of the duodenum is not retroperitoneal but the remainder is. - See more at: http://one2onemedicine.com/learning-material/pre-clinical-medical-science/?category=digestive#sthash.Rbu2rvoR.dpuf

Question 34

Within what structures does the epiploic foramen lie?

Answer 34

Explanation: The epiploic foramen (foramen of Winslow) is part of the abdomen where is communication between the greater and lesser peritoneal sacs. It is located in the gastro-hepatic ligament, which forms part of the lesser omentum.

Question 35

Which structures define the anteror and posterior borders of the Pouch of Douglas

Answer 35

Uterus rectum Explanation: The Pouch of Douglas s also known as the recto-uterine pouch. It is the most inferior point in the abdominal cavity in women. The equivalent area in men would be the recto-vesical pouch. -

Question 36

What name is given to the outpouchings of fat on teh serosa of large bwels?

Answer 36

Explanation: Appendices epiplocae are small pouches of fat present on the surface of large bowel. They are one of the 3 macroscopic features of large bowel, the other two are haustrae (partial folds in the bowel) and taeniae coli (longitudinal bands of muscle on the surface of the bowel). Plicae circulares (or valvuliae conniventes) are complete folds of the bowel in small intestine. Brunner's glands are alkaline secreting structures only in the duodenum.

Question 37

What is the dentate line?

Answer 37

The dentate line marks the division between endodermal-derived and ectodermal-derived epithelium in the rectum therefore at this point the epithelium changes from simple columnar to stratified squamous. The foregut-midgut division is at the level of ampulla of Vater. The transpyloric plane is at the midpoint symphysis and thoracic inlet. McBurney's point describes the appendix position. The inferior epigastric vessels pierce abdominus rectus at the arcuate line. -

Question 38

Porta Hepatis

Answer 38

The porta hepatis is the point where the hepatic vein and common hepatic duct exit the liver; and the hepatic artery and portal vein enter. It is on the posterior aspect, between the right and left lobes, inferior to the caudate lobe and superior to the quadrate lobe. It is just medial to the IVC and superior to the cystic duct which branches off the common hepatic duct after it exits the porta hepatis. -

Question 39

what structure define the borders of CAlots triangle?

Answer 39

Explanation: Calot's triangle describes the important anatomical structures around the gall bladder with the aim of identifying where the cystic artery branches off the right hepatic artery, which should lie within the triangle. The superior border is the inferior edge of the right liver lobe, the inferior border is the cystic duct and the medial border is the common hepatic duct. -