Digestive System

Question 1

afferent response

Answer 1

somatic and receptor

Question 2

efferent response

Answer 2

somatic
autonomic –> sympathetic and parasympathetic make up enteric system (digestive) and can be stimulated by the brain or independently from the brain

Question 3

digestion

Answer 3

breaking nutrients (not already in your body) down to simplest unit (that can then be absorbed)

Question 4

absorption

Answer 4

occurs with enzymes after digestion

Question 5

simple units of carbohydrates

Answer 5

glucose, fructose, galactose

Question 6

esophagus

Answer 6

carries food from mouth to stomach

Question 7

carbohydrate digestion
mouth

Answer 7

mechanical digestion - teeth breaking down food into smaller pieces
chemical digestion - salivary amylase breaks bonds of carbohydrates
saliva lubricates food to make it easier to pass through the esophagus

Question 8

carbohydrate digestion
stomach

Answer 8

chemical digestion stops here
HCl denatures the enzyme by changing its shape and protects us from pathogens that we may eat

Question 9

carbohydrate digestion
small intestine and pancreas

Answer 9

pancreas is an endocrine gland that secretes pancreatic amalyase into the small intestine
small intestine is a 19-20ft long and releases glucose insulin etropic polypeptide (gpi) when it starts to release glucose
brush borders on the small intestine have pores that break bonds to create simplest units

Question 10

carbohydrate digestion
large intestine

Answer 10

packages undigested food

Question 11

glucose paradox

Answer 11

lets glucose pass but expect liver to store it all because glu goes there first but it doesn’t because glucokinase is slow
kidneys and liver make new glucose through gluvoneogeneisis

Question 12

triglyceride

Answer 12

fatty acid chain and a glycerol

Question 13

lipase

Answer 13

enzyme responsible for breaking off fatty acids, polar

Question 14

triglyceride digestion
mouth

Answer 14

mechanical digestion breaks down food into smaller pieces
chemical digestion - lingual lipase breaks up triglycerides but not effective at reaching the ones inside
lubricates food for easy passage to esophagus

Question 15

triglyceride digestion
stomach

Answer 15

gastric lipase doesn’t get denatured
chemical digestion continues because enzyme not denatured

Question 16

triglyceride digestion
small intestine and pancreas

Answer 16

pancreas releases pancreatic lipase in duodenum and breaks off fatty acid chains
enteric lipase in small intestine stimulates CCK –> bile secreted into duodenum and emulsifiers fat to get the polar and nonmolecules to mix
circulates in the blood and stimulates the ventromedial hypothalamus which creates a satiety sensation (feel full)
lateral hypothalamus is he hunger senstation

Question 17

triglyceride digestion
large intestine

Answer 17

fat that does not get absorbed
LDL and HDL

Question 18

fatty acid pathway

Answer 18

fatty acids form a micelle (simplest unit)
enterocyte absorbs it
triglyceride formed
creates a chylomicron
dumped into lymphatic system in thoracic duct
thoracic duct dumps contents in lymph into the heart
heart distributes fat everywhere
fat in blood
endothelial cells have protein lipase
fatty acids go through adipose
tricylceride

Question 19

proteins

Answer 19

amino acid is the simplist unit
1/2 amino acids are essential and are obtained through food
1/2 amino acids are nonessential and body makes it

Question 20

protein digestion
mouth

Answer 20

mechanical digestion
lubricates food
no chemical digestion

Question 21

protein digestion
stomach

Answer 21

secretes pepsinogen (inactive)
releases HCl which converts pepsinogen into pepsin, breaks peptide bonds and denatures the protein, and protects against pathogens

Question 22

protein digestion
small intestine and pancreas

Answer 22

enterokinase converts trypsinogen into trypsin
trypsin converts chymotrypsinogen into chymotrypsin
enterokinase is on the brush boarders of the small intestine
inactive enzymes are converted into active
small intestine contains peptidase that breaks peptide bonds
exocytosis releases enterocytes where the food is for packaging
in the small intestine, water follows chlorine and sodium follows chlorine

Question 23

protein digestion
large intestine

Answer 23

food that doesn’t get broken down is excreted
can package any digested food for subsequent secretion
mix enzymes with water so can get water back
water follows sodium and chloride follows sodium

Question 24

diahrrea

Answer 24

lactose intolerant causes too much solutes and water goes in the opp direction
bilirubin from the breakdown of RBCs can enter the small intestine and gets converted into sterobin which is brown

Question 25

celiac disease

Answer 25

gluten is a protein found in flower converted into gliaden
enterocytes get destroyed by gliadin and there are less cells in the small intestine
stay away from gluten products

Question 26

immunoglobulins

Answer 26

can be passed down in mother’s milk and babies get passive immunity

Question 27

phases of digestion

Answer 27

cephalic phase
gastric phase
intestinal phase

Question 28

cephalic phase

Answer 28

promoted by thinking or smelling of food
increase gastrin (releases it)
peristaltic motion, stomach growling

Question 29

gastric phase

Answer 29

Food enters the stomach —> increase gastrin secretion
Peripheral nervous system activated —> parasympathetic want to store food activates peristalsis (push food)

Question 30

Intestinal phase

Answer 30

Pancreas secretes bicarbonate ions into duodenum to neutralize the enzymes once they leave the stomach without enzyme activity being affected
Small intestine releases secretion that causes pancreas to release enzymes (pancreatic amylase, pancreatic lipase, trypsinogen, chymotrypsinogen)

Question 31

Parietal cells

Answer 31

Respond to increase in gastrin and increase release of HCl
Camp moves to the hydrogen pump from inside the cell to the cell membrane
HCl produced in the stomach

Question 32

Acid reflex

Answer 32

Acid going in wrong direction
Inhibit proton pumps to make less acid in the stomach

Question 33

Chyme

Answer 33

Food particles, acid, enzymes, and small amount of water
Neutralize the acid with bicarbonate ion in pancreatic duct and duodenum
Add more water to mix enzymes with food more effectively and easier to transport
CFTR (cystic fibrosis transmembrane conductance regulator) found on crypts of lieburkutin that helps add water

Question 34

Gastrin pathway

Answer 34

Gastrin binds to receptor ATP —> CAMP
CAMP opens up Cl- channel
Cl- from NKCC channel leaks out of Cl- channel
This Cl- is exchanged for bicarbonate
Cl- leaves, Na+ follows and then H2O follows

Question 35

Peristalsis

Answer 35

Stimulus is the vagus nerve and parasympathetic activation that stimulates the mesenteric plexus

Question 36

Cells of cajal (peacemaker cell)

Answer 36

Always stimulate smooth muscles for peristalsis but is not string enough to reach threshold
Threshold is reached when you eat food and when mesenteric plexus is stimulated
Smooth muscle cells are unitary
Create segments that maximize digestion and absorption called segmentation

Question 37

Perestolic rush

Answer 37

Protects mechanism against pathogens
Perestolic motion should be slow to maximize digestion
Body defects pathogen and Perestolic motion speeds up to reduce amount of pathogen absorbed
More solutes and water large intstine

Question 38

Absorption of nutrients
Secondary active transport

Answer 38

Glucose, amino acid, galactose

Question 39

Absorption of nutrients
Diffusion

Answer 39

Fructose
Fatty acids

Question 40

Absorption of nutrients characteristics

Answer 40

Active transport is more efficient because of energy
Too much fructose, stored in the large intestine so more water and diarrhea
Calcium important for muscle contraction but Vitamin D can affect absorption of calcium duodenum