DAT bio Chapter 11.8 digestive system Flashcards
Intracellular digestion
within cells (eg: amoeba pseudopods bring food inside its single cell for digestion)
Extracellular digestion
outside of cells
(eg: humans digest food then brings
nutrients into its cell for further
processing)
Mechanical Digestion
physical breakdown
of food
Chemical Digestion
chemical breakdown
of food, using enzymes.
whats in saliva that helps break down starch into maltose?
salivary amylase
what does the pharynx separate into?
the trachea and esophagus
Function of epiglottis
blocks the opening to the trachea, prevents choking
Food goes down what tube
esophagus (tube structure that guides food to stomach
How is the food pushed down?
using peristalsis (rhythmic waves of contraction)
Structure of eophagus
The upper third of the esophagus
consists of skeletal muscle, the lower third
consists of smooth muscle, and the middle third
is a mixture of the two.
Food enters the stomach using what
cardiac sphincter
Function of cardiac sphincter and structure
Its a ring of muscles
that also churns food (mechanic) and breaks down protein and fat using enzymes (chemical)
Stomach lining is filled with what
gastric pits that leads to gastric glands
What protects the stomach lining from acid?
mucus that is produced from mucous cells
Food entry causes the stomach to _____,
signaling _____ to release ______, a hormone
with two functions:
distend
G cells
Gastrin
Gastrin has what 2 functions
- Stimulates parietal cells to release
extremely acidic gastric juice - Stimulates chief cells to secrete gastric
lipase (breaks down fats to fatty acids +
glycerol) and pepsinogen (a zymogen -
an inactive enzyme precursor) which is
activated to pepsin in acid. Pepsin cleaves
peptide bonds (proteins → amino acids).
What is chyme
(acidic, semi-digested food) that goes from stomach to small intestine
Chyme exits to the small intestine using what
pyloric sphincter.
Small intestine is responsible for what
for 90% of digestion and nutrient
absorption.
small intestine is composed of 3 parts
duodenum (digestion), jejunum, and ileum (absorption) -
remember DJ Eye (D > J > I).