Digestive System Flashcards
List the main nutrient groups.
Carbohydrates, Fats, Proteins, Vitamins, Minerals & trace elements
What is the purpose of the digestive system?
To absorb nutrients to make them available to cells
What is the difference between macronutrients and micronutrients in terms of digestion?
Macronutrients require digestion (breakdown), while micronutrients do not
Give examples of the functions of carbohydrates in the body.
Immediate energy (or stored as glycogen in liver and muscle), glycoproteins. Fibre’s role includes the release of protective fatty acids, synthesis of vitamins by the gut microbiome, binding cholesterol, and improving transit time
What are the main functions of proteins in the body?
Structural (collagen, elastin, muscle contractile apparatus), globular (hormones, enzymes, haemoglobin, plasma proteins). Also a secondary source of energy
What are the key roles of fats in the body?
Energy store, myelin (white matter), phospholipids (plasma membranes)
Differentiate between water-soluble and fat-soluble vitamins.
Water-soluble vitamins include B, C, folic acid, pantothenic acid, biotin. Fat-soluble vitamins include A, D, E, K. Vitamins are used in metabolic reactions and function in physiological processes
Give examples of minerals and trace elements and their general functions.
Examples include Calcium, phosphate, sodium, potassium, iron, iodine. They are involved in cell signalling, membrane potential, and formation of functional molecules
What is Basal Metabolic Rate (BMR)?
The minimum energy expenditure to sustain life e.g. breathing, heart contraction, etc. It constitutes about 73% of energy use
Name the two main components of the digestive system.
Gastrointestinal tract (10m) and Accessory organs (salivary glands, pancreas, liver and gallbladder)
List the organs of the upper digestive tract.
Mouth, oesophagus, stomach and duodenum
List the organs of the lower digestive tract
Jejunum, ileum and large intestine
Name the four abdominopelvic quadrants.
Right upper, Right lower, Left upper, Left lower
What are the layers of the digestive tract wall?
- Mucosa, 2. Submucosa, 3. Muscularis, 4. Serosa/Peritoneum
Briefly describe mechanical digestion.
Muscular contraction of the digestive tract moves food continuously in an action known as peristaltic wave.
Mastication(chewing) in the mouth and churning in the stomach are examples
Briefly describe chemical digestion.
Enzymes break down large food molecules into smaller molecules. This occurs in various parts of the digestive tract, starting in the mouth with saliva
What are the main components of saliva and their functions?
Water, mucus, bicarbonate, lysozyme, amylase, and lipase
What is the role of the stomach’s oblique muscle layer?
To allow churning motion to turn the bolus into liquid chyme
Name three specialised cells found in the gastric pits of the stomach mucosa and what they secrete.
Neuroendocrine cells: release hormones that control acid release.
Chief cells: secrete lipase and pepsinogen. Parietal cells: secrete hydrochloric acid and intrinsic factor
What is the primary site of chemical digestion and mineral absorption in the small intestine?
The duodenum
What is the role of bile? Where is it produced and stored?
Bile is for the emulsification of fats and fat-soluble vitamins into micelles. It is produced by the liver and stored in the gallbladder
How is the absorptive surface area increased in the jejunum and ileum?
By circular folds (plicae circulares), villi, and microvilli (brush border)
How are water-soluble nutrients absorbed and transported after absorption in the small intestine?
They enter the villi capillary bed and are transported to the liver via the hepatic portal vein
How are fats and fat-soluble vitamins absorbed and transported after absorption in the small intestine?
They are packaged into chylomicrons, absorbed into the villi lacteal, and transported through the lymphatic system
