DIGESTIVE SYSTEM Flashcards
List the 6 features of the gastrointestinal tract
- Mouth
- Pharynx
- Oesophagus
- Stomach
- Small intestine
- Large intestine
List the 6 accessory organs to to the digestive system
- Teeth
- Tongue
- Salivary glands
- Liver
- Gall bladder
- Pancreas
Define:
- Ingestion
- Secretion
- Mechanical processing
- taking in foods and liquids
- addition of water, acids, buffers, and enzymes into GI tract
- physical breakdown of food, mix with secretions, move contents towards anus
Define
- Digestion
- Absorption
- Defecation
- Chemical breakdown
- Uptake of nutrients through epithelial cells into blood or lymph
- elimination of wastes, bacteria and dead cells
What are the functions of salivary glands?
- lubricates and flushes surfaces
- dissolves chemicals that stimulate taste buds
- bacterial control
- chemical digestion
Pharynx function
- respiratory function: Nasopharynx
- Respiratory and digestive function: oropharynx and laryngopharynx
- Swallowing
What are the functions of the oesophagus
-Moves bolus from pharynx to stomach via peristalsis
- Upper oesophageal sphincter: regulates movement into oesophagus
Lower oesophagus sphincter: regulates movement into stomach
What is peristalsis?
Waves of muscular contraction
What are the 3 subsections of the small intestine?
- Duodenum: receives chyme and digestive secretions, neutralises stomach acids
- Jejunum: chemical digestion and nutrient absorption
- The ileum: ends at ileocecal valve (sphincter)
What are the mechanical functions of the small intestine?
- Mixes chyme (food mixed into acidic environment) with secretions
- Increases absorption
- Moves residue forwards
- Begins with segmentation
Followed by peristalsis
What are the functions of the large intestine?
- Absorption of vitamins produced by bacteria
- Reabsorption of remaining water
- Compaction and storage of faeces prior to defecation
- Produces mucous for lubrication
- Motility
What is the defecation reflex?
Parasympathetic spinal reflex stimulated when the colon is stretched, possible to postpone
The epithelium contains gastric glands made of…
- Parietal cells - secrete HCl, kills microbes, activates pepsin
- Chief cells - secrete pepsinogen, converts pepsin by HCl
What is the function of the gall bladder?
Stores and concentrates bile
What is the function of the liver?
Produces and secretes bile
Endocrine cells secrete…
insulin and glucagon
Exocrine cells secrete…
pancreatic juice
What are the pancreatic enzymes?
- Pancreatic amylase
- Proteases e.g., trypsinogen, prolastase
- Pancreatic lipase
How are carbohydrates absorbed?
- as monosaccharides, fructose, glucose and galactose
- They travel in blood to liver, fructose and galactose are converted to glucose, the excess is removed and stored as glycogen
How are proteins absorbed?
- As amino acids
- Travel in blood to the liver,
90% of absorption occurs in the small intestine, what absorption occurs in the large intestine?
- reabsorption of remaining water
- reabsorption of bile salts
- absorption of vitamins produced by bacteria