CH2: accessory organs/absorption

Question 1

What is the role of the pancreas?

Answer 1

Ductless endocrine cells that secrete hormones into the blood
Digestive enzymes produced by acinar exocrine cells

Question 2

What does pancreatic juice contain?

Answer 2

Water
Electrolytes
Bicarbonate (neutralize HCl)
Pancreatic digestive enzymes

Question 3

How are pancreatic secretions regulated?

Answer 3

The primary stimuli is secretin
Responds to presence of acidic chyme
- CCK
- secreted by I cells of proximal small intestine and enteric nerves
- responds to the presence of fat and partially digested proteins in the diodenum

Question 4

What is an example of a disorder of the pancreas

Answer 4

Pancreatitis
- zymogens become activated and digest pancreatic tissue

Question 5

What is the structure of the liver?

Answer 5

Consists of lobes made of lobules
It uses portal circulation to circulate blood and bile
Bile canaliculi
- where bile is transported

Question 6

What is the function of the liver in digestion?

Answer 6

The liver produces bile
- a fluid composed of bile acids, salt and cholesterol
- bile acts like detergent to emulsify fat

Question 7

Where is bile produced and stored?

Answer 7

Produced in the liver but stored in the gallbladder

Question 8

What is the function of the gallbladder?

Answer 8

Concentrates and stores bile
The recirculation and excretion of bile
- most bile salts are reabsorbed

Question 9

What is a disorder of the gallbladder?

Answer 9

Gallstones

Question 10

Where does the absorptive process start?

Answer 10

It begins in the duodenum and continues throughout the jejunum and ileum

Question 11

Is absorption fast or slow?

Answer 11

It is rapid, a few hours

Question 12

What are the absorption methods

Answer 12

Diffusion
Facilitated diffusion
Active transport
Pinocytosis/endocytosis

Question 13

How does diffusion occur?

Answer 13

Some substances such as water and small lipid molecules, cross membranes freely
This follows the concentration gradient ( moving from higher to lower concentration )

Question 14

How does facilitated diffusion occur?

Answer 14

A specific carrier is needed
This carrier may affect the permeability of the membrane
Steps:
- carrier loads particle on outside of cell
- carrier releases particle on inside of cell

Question 15

How does active transport occur?

Answer 15

Substances that need to be concentrated on one side of the cell membrane or other require active transport, which involves energy expenditure
Energy supplied by ATP and Na
Steps:
- carrier loads particle on outside of the cell
- carrier releases particle on inside of cell
- carrier returns to outside to pick up another particle

Question 16

How does pinocytosis occur?

Answer 16

Some large molecules are moved into the cell via engulfment by the cell membrane
Steps:
- substance contracts cell membrane
- membrane wraps around or engulfs the substance
- the sac formed separates from the membrane and moves into the cell

Question 17

What does the mechanism of absorption depend on?

Answer 17

Solubility (fat vs water)
Concentration or electrical gradient
Size of molecule

Question 18

What happens to materials that are not absorbed in the small intestine?

Answer 18

They continue to the colon?

Question 19

Review this chart of absorption

Answer 19

Question 20

What are examples of digestive system disorders?

Answer 20

Gastroesophageal reflux disease
Peptic ulcers
Inflammatory bowel disease
Celiac disease
Chronic pancreatitis

Question 21

What is GERD and its risk factors?

Answer 21

Lower esophageal sphincter does not close properly
Risks:
obesity, alcohol, hiatal hernia, pregnancy, smoking, certain medications

Question 22

How is GERD treated?

Answer 22

Decrease alcohol, stop smoking, lose weight
Do not lie down 2-3 hours after eating
High fat foods before bedtime worsen symptoms
Foods: acidic, onion, garlic, chocolate, coffee
Antacids
Proton pump inhibitors
H2 blocker
Surgery to strengthen lower esophageal sphincter muscle

Question 23

What is a peptic ulcer?

Answer 23

A lesion in the mucosa of the stomach or duodenum extending into the muscularis mucosa
Risks:
smoking, acidic drinks…

Question 24

What is IBD?

Answer 24

Ulcerative colitis and crohns disease
Inflammation of the mucosa
Nutrient transit time is decreased
Nutrient malabsorption

Question 25

What is celiac disese?

Answer 25

Allergy to gluten Triggers immune and inflammatory responses Digestion and absorption impaired

Question 26

What is chronic pancreatitis?

Answer 26

Inflammation of the pancreas Decreased function Malabsorption of fat

Question 27

What is the Roux-en-Y Gastric Bypass "RYGB" surgery?

Answer 27

the most commonly performed weight-loss procedure in the United States The surgeon separates the upper portion of the stomach from the lower portion. The upper portion (or the "pouch") is then connected to a limb of the small intestine, called the "Rouxlimb." The new stomach pouch restricts the amount of food you can eat, making you feel full after eating only a small amount of food. Macronutrient and micronutrient deficiencies occur following this Fat malabsorption