Week 12- Digestive system Flashcards
Describe processes and purposes of digestion (mechanical vs. chemical) and absorption.
Mechanical
Starts in mouth-primarily Chewing
Physical breakdown of larger food into smaller components
Describe processes and purposes of digestion (mechanical vs. chemical) and absorption.
Chemical
Requires digestive enzymes
will chemically break down food into the smallest molecules so absorption can occur
Absorption
When molecules move from gi tract into blood or lymph
What happens to ingested material that cannot be digested and absorbed?
will move to large intestine and will become feces to be eliminated
Briefly describe 4 layers of GI tract—describe how absorption occurs in specific layers.
mucosa
innermost layer
where food will touch gi tract-must go through its epithelial cells in order to enter blood or lymph
Briefly describe 4 layers of GI tract—describe how absorption occurs in specific layers.
submucosa
second innermost layer
will connect mucosa to larger armies, veins and lymph vessels
Briefly describe 4 layers of GI tract—describe how absorption occurs in specific layers.
musculares externa
smooth muscle layer
will help in movement of food down gi tract
help in peristalsis and segmentation
Briefly describe 4 layers of GI tract—describe how absorption occurs in specific layers.
serosa
Protective outer layer
What is peristalsis (aka gastric motility)? Which layer is responsible for peristalsis
alternating contraction and relaxation of smooth muscle so food can move through digestive tract
musculares externa
Briefly describe swallowing (voluntary versus involuntary processes)
Voluntary
mouth will chew food and form bolus
then tongue will move bolus to back of throat
moves food to pharynx (line between voluntary and involuntary)
Briefly describe swallowing (voluntary versus involuntary processes)
involuntary
after bolus gets moved into pharynx-
will move bolus from pharynx into esophagus
bolus then pushed into stomach
what brain structure controls swallowing?
medulla oblongata
Know the enzymes secreted from the salivary glands and give their general functions (what do they break down?
Salivary amylase- Carbohydrates
Know the enzymes secreted from the tongue and give their general functions (what do they break down?
Lingual lipase- lipids/fats
Know the enzymes secreted from stomach, and give their general functions (what do they break down?
Pepsin- protein
gastric lipase- lipids/fats
Know the enzymes secreted from the pancreas and give their general functions (what do they break down?
Pancreatic amylase- carbohydrates
trypsin- proteins
chymotrypsin- proteins
pancreatic lipase- lipids/fats
Know the enzymes secreted from small intestine and give their general functions (what do they break down?
Maltase/sucrase/lactase- carbohydrates
peptidase- proteins
Where does chemical digestion BEGIN for each of these molecules: Carbohydrates
in the mouth
because salivary amylase breaks down carbs
Where does chemical digestion BEGIN for each of these molecules: lipids,?
in the mouth
because lingual lipase breaks down lipids/fats
Where does chemical digestion BEGIN for each of these molecules: proteins?
stomach
because pepsin breaks down proteins
Where will the pancreas secrete substances?
Small intestine
specifically duodenum
Where will the gallbladder secrete substances?
small intestine
What will ingested carbohydrates , lipids and proteins get chemically broken down into so that they can be absorbed?
C- Glucose
P-amino acids
L-Fatty acids
How are ingested carbohydrates and proteins absorbed?
go straight into intestinal cells
then go straight into venous side of capillaries
will filter into hepatic system- so liver, then heart, then cells
