The Digestive system Flashcards
What is the digestive system?
The organs take in food and liquids and break them down into substances that the body can use for energy
The function and structure of the digestive tract?
2 membranes separated by fluid protect the organs from surroundings.
Digestive tract is suspended and stabilized by sheets of membrane
What is the alimentary canal ?
long coiled muscular tube from mouth to anus.
The 4 layers of the alimentary canal ?
- Mucosa: muscle
- Submucosa– Dense connective tissue
-Muscularis externa– two smooth muscle layers
-Serosa(Outermost layer) – collagen
The function of the alimentary canal ?
hydrolysis and absorption of food molecules
The function of the mouth ?
Ingestion of food
Mastication – chewing
Mixed with saliva to soften for swallowing
Amylase – begins hydrolysis of starch into maltose
What is the function of oesophagus ?
allow for the passage of material from the mouth and throat to the stomach.
The process of the oesophagus ?
Swallowed food passes from pharynx to stomach by muscular tube
Elastic tissue allows expansion
Stratified epithelium protects against friction damage
oesophageal glands produce mucin to aid transit and protect
What does the stomach contain ?
HCl
Enzymes
Mucous
What the main function of gastric pits?
Mucous cells secrete mucous to protect stomach lining from effects of its own secretions
Why is HCl important in the stomach ?
Provides optimum pH for pepsin and renin
Denatures proteins and aids the breakdown of connective tissue in meat
The function of small intesine?
break down food, absorb nutrients needed for the body, and get rid of the unnecessary components.
The 3 different parts of the small intestine ?
Duodenum
Jejunum
Ileum
Which part of the small intestine is pancreatic juice created ?
duodenum
What does the pancreatic juice do ?
Neutralise stomach acid
Enzymes hydrolyse protein, carbohydrate and fats
The function of the gallbladder ?
The gallbladder stores and concentrates bile from the liver.
The adaptions of small intensines?
Surface area is increased
Enterocytes– absorptive function.
Goblet cells– Exocrine glands that secrete mucin.
Main site of digestion and absorption
The main function of the large intestine?
Colon – water and ion absorption (Cl-, K+, Vitamins)
What are the four parts of Ii ?
Caecum
Colon
Rectum
Anus
The main purposes of digestion ?
Mechanical breakdown
Chemical breakdown
Absorption
The function of liver ?
Water
Mucus
Cholesterol
The function of villi in the small intestine?
Only one cell thick
Rapid absorption
Microvilli on surface
Blood supply
How does carbohydrate absorption occur ?
Glucose co-transports with sodium through symporter utilising ATP to establish sodium gradient
How does amino acid transport ?
Amino acids and small peptides use ATP to absorb into blood
Na+K+ATPase on basolateral membrane to establish Na+ gradient
