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).
What protects small intestine from the highly acidic chyme
goblet cells (secrete mucus) And secretin (hormone) which is secreted by the entry of Chyme. Secretin stimulates the pancreas to release basic bicarbonate ions (HCO3-). into the duodenum using the pancreatic duct. Since HCO3 is basic, it neutralizes the acidic chyme
What hormone is released by small intestine to let other accessory glands know that its time to act
Cholecytokinin (CKK)
Effects of CKK
intestine slows gastric emptying (inhibits transfer of stomach contents to the small intestine)( tells the stomach give me a sec to get ready), stimulates
pancreas to release digestive enzymes, and tells
gallbladder to release bile into the duodenum.
Name three Accessory organs in the digestive system
pancreas, liver, and gall bladder
Where is bile made and stored?
produced by liver and stored and concentrated in the gall bladder
Pancreas secretes what 3 things
HCO3-
(neutralization),
pancreatic amylase (breaks starch down into → maltose) and
proteases (proteins → amino acids).
What 2 things make up the pancreatic proteases
trypsin and chymotrypsin
What is trypsin and chymotrypsin initially release as?
zymogens
What in the duodenum converts trypsinogen to trypsin, which then converts
chymotrypsinogen to chymotrypsin.
Enteropeptidase
Food is moved using ____- to the _____ and ____ for ______
peristalis
jejunum
ileum
absorption
What is vili made of
enterocytes which are lined by microvilli.
What does villi and microvilli do
increase surface
area and absorption efficiency.
What is the invaginations in the intestinal wall that contains cells
that secrete enzymes and produce new epithelial
cells for the lining.
Crypts
inside the villus, what is absorbed into blood capillaries and fats into ____
nutrients are absorbed
fats into lacteals
What is a bolus
food that has been chewed and mixed in the mouth with saliva
Other than bile production, what does the liver do?
blood maintenance
glucose metabolism
protein metabolism
What is blood maintenance
Stores blood. ● Filters and detoxifies blood coming from the digestive system via the hepatic portal system. ● Destroys erythrocytes and bacteria. Kupffer cells (phagocytes) eat bacteria and break down hemoglobin in red blood cells (red) to bilirubin (yellow) for secretion in the bile.
What is Glucose Metabolism
Glycogenesis - converts excess glucose into glycogen for storage in the liver (after meals). ● Glycogenolysis - breaks down glycogen to glucose for bodily use (between meals). ● Gluconeogenesis - converts glycerol and amino acids into glucose when glycogen stores are depleted.
What is Protein Metabolism
1)Synthesizes plasma proteins from amino acids (albumin and blood clotting factors). 2)Converts ammonia (dangerous byproduct of protein metabolism) into urea (safer) for excretion.
Where does water and mineral absorption happen in the large intestine?
cecum (small pouch)
What is the appendix in the large intestine?
A small protrusion from the cecum. Also known as the vestigial structure that can being inflamed (appendicitis) due to lack of care
After the cecum, where does the digested food and water go?
to the colon
What happens in the colon
water absorption is completed, hardened feces.
Where is the feces stored
In the rectum and expelled through the anus
What bacterias serves as a critical function in aiding digestion/
microbiome
Large intestine has 3 functions
- Water absorption.
- Mineral absorption (salts).
- Vitamin production and absorption: in a
mutualistic relationship, bacteria produce
vitamins B and K (absorbed), metabolize
bile acid, and ferment fiber.
Salivary amylase is —-:produced by
: function
salivary glands in the mouth
starch to maltose
Gastric lipase
:produced by
: function
chief cells in stomach
fats - glycerol and fatty and aciid
pepsinogen is later activated to pepsin
-:produced by
: function
chief cells in stomach
proteins to amino acids
pancreatic amylase
-:produced by
: function
pancreas
starch to maltose
enteropeptidase
-:produced by
: function
duodenum
trypsinogen to trypsin
