Lecture: Digestion Flashcards
How long is the duodenum?
10 inches
How long is the jejunum?
3 feet
How long is is ileum?
6 feet
Functions of villi and microvilli
- Increase surface area
- Location of brush border enzymes
- Cell division
Absorption of monosacharides into epithelial cells…
- glucose and galatose - sodium symporter
- fructose - facilitated diffusion
Absorption of amino acids and dipeptides into epithelial cells of the duodenum and jejunum
Active transport with Na or H ions
Celiac phase
- Receptors for sight, smell, and taste of food are activated
- Thoughts of food
Gastric phase
- Stretch receptors in stomach detect distention
- Chemoreceptors detect increased pH of gastric juice
Intestinal phase
- Stretch receptors detect distention of duodenum
- Chemoreceptors detect fatty acids and glucose
What increases gastric gland secretions, motility, and causes pyloric sphincter relaxation?
Gastrin
What decreases stomach secretions?
Secretin
What decreases stomach emptying
Cholecystokinin (CCK)
Distention of the duodenum causes release of…
CCL and secretin
Acidity in the SI causes secretin release which causes…
increased sodium bicarbonate release by the pancreas
Fats and proteins in the SI cause CCK release, which causes…
increased digestive enzyme release by the pancreas
Regulates the amount of chyme released into the duodenum
Enterogastric reflex
When the stomach is full, gastrin hormone relaxed the ileocecal sphincter so the SI empties into the LI
Gastroileal reflex
When the stomach fills, peristaltic waves move contents of transverse colon into rectum
Gastrocolic reflex
When rectum fills, input of sacral spinal cord returns command to expel feces
Defecation reflex
Which reactions break down complex organic compounds to provide energy
Catabolic
Which reactions synthesize complex molecules from small molecules, requiring energy?
Anabolic
Decrease in energy content of a molecule
Oxidation
Increase in energy content of a molecule
Reduction
Breakdown of glucose to pyruvate and lactate
Glycolysis
Breakdown of glycogen into glucose
Glycogenolysis
Formation of glycogen from glucose
Glycogenesis
Formation of new glucose from other substrates
Gluconeogenesis
