Digestive System 1 Flashcards
What are the four key functions of the digestive system?
Ingestion, Digestion (mechanical & chemical), Absorption, Elimination.
What are macronutrients?
Carbohydrates, fats/lipids, and proteins.
What are the two major anatomical components of the digestive system?
1) Gastrointestinal (GI) tract, 2) Accessory organs.
What structures make up the gastrointestinal tract?
Mouth, oral cavity, oropharynx, oesophagus, stomach, small intestine, large intestine, rectum, anus.
What are the accessory organs of the digestive system?
Teeth, tongue, salivary glands, liver, gallbladder, pancreas.
How long is the GI tract?
~30 feet (9 meters).
What is the function of the mucosa layer in the GI tract?
Secretes mucus, digestive enzymes, and hormones.
What does the submucosa layer contain?
Blood vessels, lymphatic vessels, nerves, and glands.
What is peristalsis?
Coordinated involuntary contraction and relaxation of circular and longitudinal muscles, moving food forward.
What is segmentation in the GI tract?
Mixing movement where food is pushed back and forth, enhancing digestion and absorption.
What is the role of the mouth in digestion?
Ingestion and initial digestion (mechanical and chemical).
What is mastication?
The physical breakdown of food using teeth and tongue.
What enzyme is found in saliva, and what does it do?
Amylase, which breaks down carbohydrates.
What is the composition of saliva?
99.5% water, 0.5% amylase, bicarbonate ions, and electrolytes.
What are the three main salivary glands?
Parotid, sublingual, and submandibular glands.
What is the function of the oesophagus?
Transports swallowed food to the stomach.
What is the role of the cardiac sphincter?
Prevents stomach contents from flowing back into the oesophagus.
What are the three regions of the stomach?
Fundus, body, antrum.
What is the function of the pyloric sphincter?
Regulates the passage of chyme from the stomach to the small intestine.
What is the function of rugae in the stomach?
Ridges that allow stomach expansion and secretion of digestive acids and enzymes.
How long does food stay in the stomach?
2-4 hours.
What is the pH of the stomach?
Strongly acidic, around pH 1-3.
What are the three sections of the small intestine?
Duodenum, jejunum, ileum.
What happens in the duodenum?
Mixing of chyme with digestive secretions from the pancreas and gallbladder.
What is the primary function of the jejunum?
Further digestion and absorption of nutrients.
What is the role of the ileum?
Absorbs remaining nutrients before passing waste to the large intestine.
What structures in the small intestine aid absorption?
Villi and microvilli increase surface area for nutrient absorption.
How long is the small intestine?
3 to 5 meters (~10 to 20 feet).
What is the primary function of the large intestine?
Absorption of water and electrolytes.
What beneficial substances are produced in the large intestine?
Vitamins B12, thiamin, riboflavin, and vitamin K.
What is the function of the caecum?
Starts water and electrolyte absorption and mixes mucus for stool lubrication.
What is the rectum’s role?
Stores feces before elimination.
What are the accessory organs involved in digestion?
Liver, pancreas, gallbladder.
What is the primary function of the liver?
Metabolism, detoxification, storage, hormone synthesis, and bile production.
What is the role of bile?
Helps digest fats by emulsifying them.
Where is bile stored?
In the gallbladder.
What are the two main functions of the pancreas?
Exocrine (enzyme secretion for digestion) and endocrine (hormone secretion for blood sugar regulation).
What are the key digestive enzymes produced by the pancreas?
Amylase (carbs), lipase (fats), and trypsin (proteins).
What are the islets of Langerhans?
Endocrine cells in the pancreas that regulate blood glucose (insulin and glucagon production).
What is the function of the anal sphincter?
Controls the release of stool from the rectum.
What are the four major functions of the digestive system?
Ingestion, digestion, absorption, and elimination.
Where does most digestion and absorption occur?
Small intestine, specifically the ileum.
What is the final step in digestion?
Elimination of undigested waste through the anus.
