Topic 8 - Digestive system II Flashcards
(20 cards)
What are the parts of the upper digestive tract?
- mouth
- pharynx & Esophagus
- stomach
- gastric secretion
What are the functions of the mouth?
Chewing:
- mechanical digestion
- Produces bolus (smaller food pieces)
Salivary Secretion:
- autonomic control/triggered by multiple stimuli
- dissolves food => taste
- protection (cavities)
What are the 3 main salivary glands?
- Sublingual gland
- Submaxillary gland
- Parotid gland
Which salivary gland produces mucus & which produces serous (H2O)?
Serous = Parotid gland
Mucus = Sublingual gland (mainly sub. but also submaxillary gland to)
What is a sphincter?
Muscle encircling duct/tube/orifice in a way that contraction closes up hole (constricts lumen)
How does the swallowing reflux work?
- Pressure created when tongue bushes food against soft palate & back mouth
- Epiglottis folds over larynx (prevent food entering airways)
- Respiration stopped & upper oesophageal sphincter relaxes as food enters oesophagus
- Waves of peristaltic contraction push food towards stomach (gravity helps)
- Lower oesophageal sphincter opens
What are the functions of the stomach?
- Receive & provide temp. storage of food/liquids
- Mix foods & H2O (with gastric secretory products)
- Grinding food => make small to enhance digest. & permit passage
- Regulate exit of chyme into duodenum (response to stim)
What do the gastric glands (in stomach) release?
- acid
- pepsinogen
- mucus
- bicarbonate
- intrinsic factor
- water
What hormones (and neurons) regulate gastric secretion?
- prostaglandins (less)
- ACh (more)
- Histamine (more)
- Gastrin (more)
What is a peptic ulcer?
From an imbalance b/w mucosal-damaging (acid/pepsin) & mucosal-protecting agents (mucous, biocarb. etc.)
What are parts of the lower digestive tract?
- Pancreatic & billary secretions
- Bile
- Small & large intestines
What are the main functions of the lower digestive tract?
- gastric motility
- Gastric secretion
- Digestion
- Absorption
What does the pancreas secrete?
- Digestive enzymes (trypsin/chymotrypsin, lipase & amylase)
- Fluid rich in biocarb. ions (to neutralise acidity)
What does the liver secrete?
Bile = biocarb. cholesterol, phospholipids, bile salts etc.
*Bile stored gallbladder
What is the main function of the liver?
To filter & process the nutrient rich blood delivered to it
What do bile salts do?
Aid fat digestion & absorption through 2 things:
1. Emulsification (results in increase SA exposed fat for digest by panc. lipase)
2. Micellular formation (contain hydrophilic shell & hydrophobic core ->products of fat digestion can be carried
What are the main functions of the small intestine?
- Motility
- Secretion
- Digestion
- Absorption (majority if things are absorbed in S.I
What are the 3 parts of the small intestine?
- Duodenum
- Jejunum
- Ileum
*S.I has villi & microvilli for more SA to increase absorption
What are the main functions of the large intestine?
- Motility
- Secretion
- Absorption
What are the 3 parts of the large intestine?
- Colon
- Rectum
- Anus
