Digestion Flashcards
What are the main fuels of the body?
Protein, Fats and carbohydrates.
Protein carohydrates and fats are then broken down into what?
absorbable units (simple sugars, fatty acids and amino acids)
Intracellular digestion occurs by
endocytosis.
What type of animals does intraceullular digestion take place?
Mostly sponges
What is an advantage to extraceullular digestion?
- Expands the range of available food sources by allowing animals to deal with much larger food items.
- Also allows the animal to eat large batches of food that can be stored and digested while the animal continues other activites.
In hydras, coreal and sea anemones the digestion system is called what?
gastrovascular cavity as well as a blind-end sac.
What are some features of the batch reactor:
- Only has one opening
- Pulsed fashion of work
- One batch is processed and eliminated before other
Features of the Continuous flow stirred-tank reactor:
- Hollow tubular cavity
- 2 passages (input and output)
- Continous proessing allows food to come in all day long.
What type of animal uses batch reactor and what kind of animal uses Continuous flow stirred-tank reactor?
Batch reactor: Hydra
Continuous flow stirred-tank reactor: Humans
Features of the plug-flow reactor:
- Bolus of food passes along a tube-like structure
- Continuous digestion
- The composition varies according to position in tube (Different from stirred-tank)
What is the advantage of continous flow stirred-tank reactor to batch reactor?
you can eat a tremendous amount of food and can digest it over a period of time.
The gut tube is divided into 3 main regions:
- ) Foregut
- Midgut
- Hindgut
What are the 7 main parts of the digestive tract of vertebrates?
- Mouth
- Pharynx
- Esophagus
- Stomach (and rumen in ruminants) or proventriculus-gizzard complex in birds
- Small Intestine
- Large intestine
- Anus
What are the three accessory organs?
- Salivary glands
- Exocrine pancreas
- Biliary system (liver and gallbladder)
What are the 5 main processes that occur from ingestion of food to expulsion of wastes:
- Mechanical processing
- Secretion of enzymes and other digestive aids
- Enzymatic hydrolysis
- Absorption
- Elimination
The digestive system is under the control of the?
nervous and endocrine system
The foregut has these 2 important activites at the start of the digestive system:
- Feeding
and - Swallowing
What are the 3 parts of the body that are strongly used in the forgut for the activites of feeding and swallowing?
- Teeth
- Tongue
- Salivary glands: for lubrication
Swallowing (deglutition) is the process of
moving food from the mouth through the esophagus into the stomach.
What muscle pushes the bolus of food in the pharynx?
The tongue
What initiates the swallowing reflex?
When the bolus reaches the pharynx
Pharyngeal pressure receptors send afferent impulses to the
medulla oblongata
Swallowing reflex has two phases:
Oropharyngeal phase(from chewing to push it to pharynx) and esophageal phase (esophagus to stomach)
Three things that happen in the oropharyngeal stage:
- Uvula is elevated and seals off the nasal passage
- Glottis is closed and covered by the epiglottis to prevent food from entering the respiratory airways
- Pharyngeal muscles contract to force bolus into esophagus
Two things that happen in the esophageal stage:
- Peristaltic wave sweeps down the esophagus
2. Gastroesophageal sphincter relaxes to allow bolus into stomach
What causes heartburn?
Inappropriate opening of the gastroesophageal sphincter leads to heartburn. Or if it does not close all the way after the food has entered the stomach.
What is peristalsis:
Peristalsis is ringlike contractions of the circular smooth muscle that move progressively forward
Kim Kardashian drinks beer from a keg…. While being upside down. What allows her to drink upside down?
Because of peristalsis!! If you didn’t have this you couldn’t do this because then the fluid would not go up to your stomach! When we swallow it is not gravity it is the peristalsis.
Esophagus:
Conducts food from headgut to stomach
What happens in the stomach?
Chemical digestion of proteins, fats and carbohydrates
Absorption of products
Do carnivores have shorter midguts than herbivores? True or False!
True! Meat is less difficult to digest than plants.