Digestion 2 Flashcards
Mastery
Carb protein and fat digestion
Mouth - Chewing
… surface area
… choking
Secretion of
….
* ….
…
* …
Swallowing Reflex
Triggered by …
Contractions coordinated by …
Esophagus
… tube
Separated from stomach by
….
* Heartburn (Acid reflux)
* …
Mouth - Chewing
↑ surface area
↓ choking
Secretion of
Mucous
* Lubrication
Salivary Amylase
* Starch digestion
Swallowing Reflex
Triggered by food in pharynx
Contractions coordinated by Medulla. close epiglottis
Esophagus
Long muscular tube
Separated from stomach by
Gastroesophageal (cardiac) sphincter or valve
* Heartburn (Acid reflux)
* Faulty valve
Diseases of the Esophagus
Hiatal hernia
what is it?
Symptoms
* …
* …
Treat
* …
* …
Hiatal hernia
Part of stomach moves into chest
Symptoms
* Heartburn (↑ with age)
* Or asymptomatic
Treat
* Avoid large food intake / spicy food
* Surgery may be required
Stomach
Sections
-
-
-
Spincters
-
-
Rugae
-
-
4 functions
…
Storage
Mostly in…
Can expand …x
* …mL → …L
Sections
- Fundus
- Body
- Antrum
Spincters
- Gastroesophageal
- Pyloric
Rugae
- Deep folds
- Allow for expansion
4 functions
Storage, Mixing, Secretion, Absorption
Storage
Mostly in body of stomach
Can expand 20 x
* 50 mL → 1 L
Stomach Secretion
Acid
* Activates …
* … cells
Pepsin
* … digestion
* … cells
Mucous
* …
Intrinsic factor
* Helps in absorption of …
Stomach Secretion
… (… cells)
what type of form
Converted to … by … (… cells)
* Stomach pH can drop to …
Secretion
Acid
* Activates pepsin
* Parietal cells
Pepsin
* Protein digestion
* Chief cells
Mucous
* Protects wall from acid
Intrinsic factor
* Helps in absorption of B12 in SI
Stomach Secretion
Pepsinogen (chief cells)
Inactive form
Converted to Pepsin by
HCl (parietal cells)
* Stomach pH can drop to 2-3
Formation of Acid
… Acid
…. pepsin
Breaks down …
Kills …
Stomach wall protects itself with …, …, and ….
Stomach
Mixing and emptying
Formation of …
Some moves into SI – rest is stored
Stomach - Hormones
Gastrin.
… HCl secretion
… pepsinogen
… motility
Stimulated by
…
…
…
Activates pepsin
Breaks down connective tissue and muscle
Kills pathogens
Stomach wall protects itself with mucous, tight
junctions, and high cell replacement
Stomach
Mixing and emptying
Formation of chyme (Glop / slop)
Some moves into SI – rest is stored
Stomach - Hormones
Gastrin
↑ HCl secretion
↑ pepsinogen
↑ motility
Stimulated by
Proteins
Distension
smell
- Gastrin release is also stimulated by the stretching of the stomach walls during a meal, the presence of certain foods (particularly proteins) within the stomach cavity and an increase in the pH levels of the stomach (i.e. the stomach becoming less acidic)
TEST
Absorption very fast on an empty stomach
breakdown mucous wall
Aspirin
Alcohol
Gastritis
… of stomach
* … agents
⬧ eg. …, …, …, …
- … gastritis
⬧ … cause
Symptoms:
* … pain * … * … * …
Peptic (gastric) ulcer
… caused by ….
* Caused in part by …
* what type of bacteria?
* in the …
Symptoms
* …
* ….
Treatment:
* Reduction of…
* Pill?
* … in severe cases
Gastritis
Inflammation of stomach
* Irritating agents
⬧ aspirin, alcohol, coffee, tobacco
- Helicobacter gastritis
⬧ Bacterial cause
Symptoms:
* Epigastric pain * Bloating * Nausea * Blood in vomit
Peptic (gastric) ulcer
Hole caused by inflammation and necrosis
* Caused in part by pepsin
* Helicobacter pylori
* stomach and duodenum
Symptoms
* Pain
* Bleeding (hematemesis or melena)
Treatment:
* Reduction of contributory factors(smoking and drinking)
* Antacids
* Surgery in severe cases
Small Intestine
… feet long. …diameter
Duodenum, jejunum, and ileum
Site of …, …, and …
Alternate between … and …
21 feet long 1 cm diameter
Duodenum, jejunum, and ileum
Site of digestion, secretion, and absorption
Alternate between segmentation and peristalsis
SI Digestion
Secretions from … and … dump into the …
Gall bladder
* …
Pancreas
* …
* …
* …
* …
* …
* ….
Secretions from pancreas and gall bladder dump into the duodenum
Gall bladder
* Bile
Pancreas
BAT PLaN
* Bicarbonate (neutralizer)
* Amylase
* Trypsin, chymotrypsin
* Pepsidases ( carboxipepsidase, aminopepsidase)
* Lipase
* Nucleases
where are they from
substrate they breakdown
action
A small bolus of food enters the SI
Triggers release of …
… acts on … and … to increase release of…
… is released if … is distended or if fat content in … increases
Gastric Inhibition
… of duodenum inhibits …
Allows time for … and … in SI
A small bolus of food enters the SI
Triggers release of the hormone, CCK
CCK acts on pancreas and gall bladder to increase release of enzymes and bile
CCK is released if duodenum is distended or if fat
content in SI increases
Gastric Inhibition
Distention of duodenum inhibits gastric emptying
Allows time for digestion and absorption in SI
SI Absorption
Amino acids, sugars
Into …
Fatty acids
Into ….
* Then into …
Via …
SI Absorption
Carbohydrates
… absorbed
First … of jejunum
… hours to empty stomach
Fats, proteins
… to digest
… hours to empty stomach
Fat-soluble vitamins
- With …
Water-soluble vitamins
- By …
Water reabsorption by osmosis
- Follows …
SI Absorption
Amino acids, sugars
Into villi capillaries
Fatty acids
Into lacteals of lymph vessels
* Then into blood
Via Carriers
Carbohydrates
Quickly absorbed
First ½ of jejunum
2-3 hours to empty stomach
Fats, proteins
Slower to digest
8-10 hours to empty stomach
Fat-soluble vitamins
- With micelles
Water-soluble vitamins
- By carriers
Water reabsorption by osmosis
- Follows solutes (95%)
Secretin (hormone)
Released if …
Effects of Secretin
Causes … to release …
* Neutralizes …
… bile formation in liver
Inhibits …
Electrolyte and Water Absorption
Along length of ….
…. are absorbed in duodenum
… is coupled with absorption of glucose and
amino acids
… absorption is regulated by vitamin D and
parathyroid hormone (PTH)
Released if SI is acidic. Acid in duodenum
Effects of Secretin
Causes pancreas to release bicarbonate
* Neutralizes acid
↑ bile formation in liver
Inhibits gastric motility
Along length of SI
Iron and calcium are absorbed in duodenum
Na+ is coupled with absorption of glucose and
amino acids
Ca2+ absorption is regulated by vitamin D and
parathyroid hormone (PTH)
GASTRIN SECRETIN CCK MOTILIN
site of production
stimulus for production
target organ
activity
Diseases of the Small Intestine
Malabsorption syndrome
… can’t absorb nutrients
* fats and minerals…
* leads to …, …
Causes
* Disease of …
* Blocked …
Diet therapy
* Bleeding (… vitamin K)
* mal…
Regional enteritis
- eg.
* Often SI
Exacerbation / remission
Malabsorption syndrome
SI can’t absorb nutrients
* fats and minerals left in gut
* Diarrhea, foul feces
Causes
* Disease of intestinal wall
* Blocked exocrine ducts
Diet therapy
* Bleeding (↓ vitamin K)
* malnutrition
Regional enteritis
Crohn’s disease
inflammatory bowel disease (IBD)
* Often SI
Exacerbation / remission
