Gastrointestinal System Flashcards
What are the functions of the digestive tract?
- Transport
- Digest intake
- Absorb nutrients
- Excretion
What is the general structure of the digestive tract?
- Mucosa (inner lining)
- Submucosa (Meissner’s Plexus)
- Muscle (Auerbach/Myenteric Plexus)
- Serosa
What is the Meissner’s Plexus made up of?
Blood vessels
Glands
Nerve tissue
What is the nerve layer in the muscle of the digestive tract?
Auerbach/Myenteric Plexus
What is the type of nervous system in the digestive tract?
Enteric nervous system
What are the THREE phases of swallowing?
- Oral (voluntary)
- Pharyngeal (reflex)
- Oesophageal (reflex)
How long is the oesophagus and what type of cells does it have?
25cm long with squamous cells
What is Peristalsis?
Wave of muscle contraction
What are the top, middle and bottom parts of the stomach?
Top: Fundus
Middle: Body
Bottom: Antrum
What are the FIVE cell types in the stomach?
- Goblet
- Parietal
- ECL
- Chief cells
- Hormone secreting
Name the Gastric Acid Secretagogues
- Histamine
- Acetylcholine
- Gastrin
How long is the small intestine and what are the THREE parts of it?
5m long
Duodenum (12in)
Jejunum
Ileum
What is the structure of the mucosa in the small intestine?
Folded in microvilli
What are interstitial cells of Cajal?
Pacemaker cells that moves chyme towards the colon in peristalsis
Where is bile stored and where does it empty into?
Stored in the gallbladder
Emptied into the duodenum
Are digestion and absorption regulated?
No
Motility and secretions are by hormones and neural mechanisms
Name some glands in intestinal mucosa?
- Paracrine
- Autocrine
- Endocrine
What does Meissner’s Plexus control?
Secretion
What does Auerbach/Myenteric Plexus control?
Muscle layers
What does Parasympathetic nerves do to digestive activity?
Increases digestive activity
What are the THREE phases in the regulation of gastric function (acid secretion)?
- Cephalic
- Gastric
- Intestinal
What stimulates the CEPHALIC phase release?
Sight
Smell
Food taste
Reflex
How is the CEPHALIC phase mediated?
By vagus stimulating parietal cells
What stimulates GASTRIC phase release?
Distension of stomach
Presence of food
How does GASTRIC release phase regulate itself?
Self regulation by negative feedback
What stimulates INTESTINAL phase inhibition?
Chyme in duodenum
What does the inhibition of gastric acid release?
Secretin
Name TWO proteins that inhibit parietal cells
- CCK
- GIP
How are intestinal functions regulated?
Neural regulation by enteric nervous system
What are the THREE reflexes linked with intestine function regulation?
- Gastroileal
- Illeogastric
- Intestino-intestinal
What proteins increase pancreatic and liver bile secretions?
CCK and Secretin
Where does digestion begin?
Mouth
What is the function of pancreatic amylase?
Digests carbohydrates in duodenum
Name some intestinal enzymes
Maltase
Sucrase
Lactase
What are the only digestible sugars?
Glucose
Galactose
Fructose
What is the function of pepsin in the stomach?
Convert proteins into short chain amino acids for absorption
What is the function of bile salts?
Emulsify droplets of triglycerides
Where do enzymes from the pancreas attach to bile?
To the head of bile which is fat soluble
