Compendium 3. Are you what you eat? Flashcards
What is an enzyme?
An enzyme is a protein that is able to catalyse specific chemical reactions without themselves being altered. They speed up the rate at which reactions occur within the body.
What are some features of enzymes?
- Enzymes are highly specific - an active site on an enzyme can only bind with a specific substrate/reactant
- Each enzyme can only work under specific conditions (pH level and temp)
- Enzymes can be denatured by heat
What are the 7 components of the digestive system?
- Oral cavity and salivary glands
- Pharynx
- Oesophagus
- Stomach
- Small intestine (along with the liver, gall bladder and pancreas as the accessory organs)
- Large intestines
- Anus
What are the 6 functions of the digestive system?
- Ingestion
- Mastication
- Secretion
- Digestion
- Absorption
- Elimination
Name and briefly describe the 4 layers of the digestive tube
- Muscosa - The innermost layer that secrets mucous (the epithelial layer)
- Submucosa - The second most inner layer which contains a large supply of blood vessels and nerves (the connective layer)
- Muscularis - Made of smooth muscle and is i important in peristalsis
- Serosa/Adventitia - The outermost layer that is important for stability (also made of connective tissue)
What is the peritoneum?
The serous membrane inside the abdominal pelvic muscle
What are the 3 components of the peritoneum ?
- Visceral
- Parietal
- Mesenteries
What is the mesenteries?
Epithelial tissue which connects organs together
Greater omentum - connects the stomach to the transverse colon
Lesser omentum - connects the stomach to the liver and diaphragm
What are the 3 phases of swallowing?
- Voluntary phase - the tongue pushes the bolus towards the back of the throat.
- Pharyngeal phase - uvulva closes of the nasopharynx and the bolus touches receptors that trigger the swallowing reflex
- Oesophageal Phase - the bolus is moved down the oesophagus towards the stomach by peristalsis
What is peristalsis?
The mechanism of food moving along the alimentary canal which is controlled by smooth muscle
What is the main function of the oral cavity?
- Masticates food and breaks it down into smaller components
- Creates the bolus
What are the main components of the oral cavity?
- The hard palate
- The soft palate
- Tongue
- Teeth
- Salivary glands
What are the main roles of saliva in digestion?
- Protects the oral cavity
- Secretes amylase (which break down carbs into smaller sugars)
- Secretes lysozymes (antibacterial enzymes)
What are the main functions of the pharynx?
- Uvula prevents food from entering the nasopharynx
- Connects the mouth to the oesophagus
What are the main functions of the oesophagus?
- The epiglottis prevents food from entering the trachea
- Connects the pharynx to the stomach
What are the main functions of the stomach?
- Mixes and churns food to become soupy liquid called chyme
- Produces protein digesting enzymes
What are rugae?
Rugae are the folds in the stomach which allow the stomach to stretch and increase surface area
How often does the stomach empty into the small instestines?
Every 4hrs or 6-8 after a fatty meal
What are the two openings of the stomach?
- Gastroesophageal (cardiac) from oesophagus
2. Pyloric to the duodenum
What is the main function of the small intestine?
The absorption of nutrients and water
What are the 3 divisions of the small intestine?
- Duodenum
- Jejunum
- Ileum