Block 3

Question 1

Stomach functions

Answer 1

1) Store move
2) Mix contents and secretions to form chyme
3) Gastric emptying into duodenum. Controls rate of chyme entering the duodenum
4) Acidi environemnt kills bacteria and parasites
5) Begins protein breakdown process via breakdown of colagen

Question 2

2 ESSENTIAL small intestine functions

Answer 2

1) Mixing: ontraction of circular muscle = sausage like intestine allowing for mixing and breaking of contents
2) move contents ]3-5 hours from duodenum to ileocecal valve

BOTH ARE VIA MYENTERIC PLEXIS

Question 3

Small intestine MIXING

Answer 3

Involved contractio nof smooth muscle
SEGMENTATION = short distance mixing

contraction is via MYENTERIC PLEXUS (SUBSTANCE P AND ACH)

Whereas movement invovles both contraction and relaxation

Question 4

Defecation reflex

Answer 4

1) Enteric NS (weak reflex): stimulates the descending colon and sigmoid to have more mass movements
Inhibits internal anal sphincter (relaxation) via NO and VIP

2) Paraysmpathetic = STRONG REFLEX: further amplifies the efefect of mass movements from descending colon and sigmoid INTO THE RECTUM
inhibits the iNTERNAL ANAL SPHCINTER (RELAXATION via NO and VIP)

Question 5

What are the causes of constipation

Answer 5

1) Narcotic use
2) Colon cancer
3) Hormones
4) Hirsprungs (intrinsic motility)
5) Extrinsic innervation

Question 6

Hirsprungs

Answer 6

Cause of constipation. Loss of nerve cells that enable motility in the colon

Question 7

Factors affecting glandular secretion

Answer 7

1) Tactile stimulation
2) Enteric NS (Tactile stim, gut distension, chemical irritation)
3) PNS (Increases secretion)
4) Symapthetic is net decrease in secretion via decreasing blood flow (constriction)

Question 8

Most intestinal juices are

Answer 8

BASIC

With exception of gastric (acidic)pH 1-3.5

Question 9

Salivary glands produce 2 kinds of proteins

Answer 9

1) Ptyalin

2) Mucus

Question 10

Ileocecal valve control

Answer 10

1) Pressure or irritation at the distal small intestine (ileum) will cause relaxation of spchinter to allow emptying from the small intestine into the cecum (first part of colon)
(pressure in ileum ==> increases peristalsis

2) More fluidity of contents promotes emptying into colon
3) Pressure or irritation in the cecum ==> inhibits peristalsis (pressure in spchinter increases to prevent things from being dumped into the cecum from the ileum)

eg appendicitis

Question 11

Salivary gland 3 types of glands

Answer 11

1) Parotid
2) Submandibular
3) Sublingual

Parotid is ONLY SEROUS (AMYLASE)
SUBmandi and SUBlinguial are BOTH amylase and MUCUS secretions

Question 12

Describe the structure of salivary gland

Answer 12

Acinar cells branching from DUCTS

Acinar cells produce

1) Ptyalin (amylase)
2) Mucus
3) Extracellular fluid

Ducts have active NaCl absorption and K/HCO3 secretion

Question 13

What happens to salivary secretions as they move down the ducts

Answer 13

Active NaCl absoprtion and active KHCO3 secretion

Therefore at the end of the duct saliva is HIGH IN KHCO3 and low in NaCl

Question 14

WHAT IS CONTAINED IN SALIVA

Answer 14

PTALIN (Aamylase) or MUCUS

Question 15

Which substance does saliva start to braekdown

Answer 15

carbohydrates

Question 16

Esophagus

Answer 16

Only produces MUCUS

Question 17

Gastric secretion

Answer 17

Mucus

ALso what is made by Oxyntic gland

Question 18

Where are oxyntic glands

Answer 18

PROXIMAL STOMACH
Compsoed of 3 cell types

1) Parietal cells
2) Chief cells
3) Enterochromaffin cells

Question 19

2 factors that affect gastric secretion

Answer 19

1) Enteric NS via distension of small intestnie, irritation, and acidity in duodenum inhibit gastric secretion
2) Fats+protein breakdown + altered osmolality in duodenum ==> release of secretin –> decreases GASTRIC SECRETION

Question 20

What activates pepsinogen secretion

Answer 20

1) ACh via PNS or ENS

2) HCL

Question 21

PEPTIC ULCER DISEASE

Answer 21

2/3 duodenum

1/3 gastric

Question 22

2 main causes of peptic ulcer disease

Answer 22

H. pylori infection + NSAID use comprise over 95% of cause in duodenal cases

H. pylori is the MAIN cause

Question 23

Causes of peptic ulcer disease

Answer 23

1) H. pyloi
2) NSAIDs: advil, aleve, aspirin
3) Gastrinoma: gastrin secreting tumor. Too much acid secretion from parietal cells

4) viral infection
5) smoking
6) Crohns Disease
7) Lymphoma

Question 24

Peptic ulcer disease

Answer 24

Gastric: Most common cause is H. pylori. other cause is NSAID

Duodenal: most . common cause is H pylori
other cause: Zollinger Ellison syndrome
Occurs with hypertrophy of Brunner glands

Question 25

Bile

Answer 25

Digestion and Absorption

1) Emulsification = decrease surface tension ==> breaks down fats into smaller pieces for absoprtion.
2) Form micelles: SOLUBE IN CHYME–> increase absoprtion of fat breakdown products

Question 26

Bile pathway

Answer 26

Cholesterol ==> primary bile acid ==> secondary bile acid ==> bile salts

Question 27

Purpose of bile salt

Answer 27

Make cholesterol SOLUBLE IN BILE

Question 28

List the 4 causes of gallstones (cholelithiasis)

Answer 28

1) Too much water absorption from bile
2) Too much bile acid absoprtion from bile
3) too much cholesteorle in bile
4) Inflammation in gall bladder epithelium

Question 29

Acute pancreatitis causes

Answer 29

1) Gall stones (most common) when blockk schinter of odi
2) ALcohol (most responsible)
3) Medications
4) Elevated triglycerides
5) Hypercalcemia

Question 30

How does acute pancreatitis present

Answer 30

Severe upper abdominal pain just below the xiphoid process that radiates to the pain (pancreas is retroperitoneal)

Blood tests show elevated amylase and lipase (pancreatic digestive enzymes)

Imaging shows enlargened panreas with blurred boundaries

Question 31

Pancreatic insufficiency

Answer 31

Most common cause is CHRONIC PANCREATITIS

Other causes include alcohol abuse

Affects both exocrine and endocrine function when 90% function is lost
Exocrine = weight loss, steatorrhea (fat in feces)
Endocrine = Diabetes

Question 32

What causes indirect bilirubin elevation

Answer 32

Increased RBC breakdown
Inability of bilirubin-albumin adduct to be taken up by hepaticytes (transprot mechanism messed up)
Inability of hepatocytes to CONJUGATE bilirubin
Hepatocute dysfunction

Question 33

What causes direct bilirubin elevation

Answer 33

Biliary obstruction

Trapping bile duct going into duodenum ie GALL STONE

Question 34

What would a gall stone cause in terms of bilirubin

Answer 34

ELEVATED DIRECT BILIRUBIN