Week 9 - The Digestive System Flashcards
(33 cards)
What are the major organs of the digestive system (GIT)?
Oral cavity, pharynx, oesophagus, stomach, small intestine, large intestine (including rectum and anus)
What are the main functions of the digestive system?
Ingestion, mechanical digestion, chemical digestion, absorption, elimination
What organs make up the upper GIT and what is its function?
Mouth, oesophagus, stomach, duodenum; function is food breakdown
What organs make up the lower GIT and what is its function?
Jejunum, ileum, large intestine, rectum, anus; function is absorption and waste elimination
What is the function of the teeth and tongue?
Mechanical digestion through crushing/shearing and shaping food into a bolus
What is the function of salivary glands?
Secretion of amylase to begin carbohydrate digestion
What are the functions of the liver in digestion?
Secretes bile, detoxifies blood, stores iron, glucose, and fat-soluble vitamins
What is the function of the gallbladder?
Stores and concentrates bile
What is the function of the pancreas in digestion?
Secretes enzymes for digestion of proteins, fats, and carbohydrates
What occurs in the oral cavity during digestion?
Mechanical digestion and salivary enzymatic breakdown of food
What is the function of the oesophagus?
Transports food to the stomach
What are the roles of the stomach in digestion?
Churns food, mixes with gastric juices to form chyme
What happens in the small intestine?
Chemical digestion and nutrient absorption
What is the role of the large intestine?
Reabsorbs water, compacts waste into faeces
What are the four layers of the GIT wall?
Mucosa, submucosa, muscularis externa, serosa/adventitia
What are the functions of the mucosa layer?
Secretes mucus, absorbs nutrients, forms barrier
What is the submucosa and its function?
Loose connective tissue with vessels and glands; supports mucosa
Describe the muscularis externa.
Smooth muscle layers (circular and longitudinal) for motility
What is the role of the serosa and adventitia?
Serosa reduces friction; adventitia anchors organs
Describe the muscular arrangement in the oesophagus.
Upper third: skeletal, middle: mixed, lower third: smooth muscle
What unique feature does the stomach have for churning?
An inner oblique muscle layer in muscularis externa
How is the small intestine adapted for absorption?
Presence of villi, microvilli, and plica circularis to increase surface area
What is unique about the muscularis externa of the large intestine?
Has taeniae coli (ribbons of longitudinal muscle) that form haustra
What do mucous cells in the stomach secrete and why?
Mucus and bicarbonate to protect against gastric acid
