Gastrointestinal system 2 Flashcards
What are the 2 major components of the GI system?
- The GI tract
- Accessory glands
What is the GI tract?
Several organs joined in series to process food and digestion products
What are the acessory glands?
Secrete various fluids & enzymes to aid the digestive process
What are the organs that make up the GI tract?
- Mouth
- Pharynx
- Oesophagus
- Stomach
- Small intestine
- Colon
- Rectum & anus
What is the role of the mouth in digestion?
- Begins with mastication (chewing)
- Secretion = saliva lubricant
- Salivary amylase - digests starch and glycogen
What is the oesophagus?
Muscluar tube from pharynx to stomach
What is the muscle distribution in the oesophagus?
- Upper 1/3 = skeletal muscle
- Lower 2/3 = smooth muscle
What is the upper esophegal sphincter like?
Found in the upper 1/3 - made up of skeletal muscle
Found between the pharynx & oesophagus
What is the lower oesophegal sphincter like?
Lower 2/3 - made of smooth muscle
Found between the esophagus and stomach
What are the stages of the swallowing reflex?
1 - Tongue pushes bolus against soft palate & abck of mouth, triggering swallow reflex
2 - Upper esophegal sphincter relaxes while epiglottis closes to keep swallowed material out of the airways
3 - Food moves downward into the oesophagus, propelled by peristaltic waves and aided by gravity
What is the function of the stomach?
- Stores food after swallowed
- Secretes gastric juice (isotonic with respect to the plasma)
- Releases food into the intestine slowly –> this is regulated by the pyloric sphincter
What is the empty volume of the stomach?
50mL
What is the full volume of the stomach?
1000mL
What is the components of the structure of the stomach?
- The body
- Antrum
- Contractions
- Mix chyme
- Gastric emptying
- Stomach expands to accommodate food
- Rugae
What is the rugae in the stomach?
Folds that flatten on expansion of the stomach
