Digestive system Flashcards
what is mastication
chewing
what moves to cause mastication
dental arches
what does mastication require function of
the entire brain
what does chewing increase
surface area/volume
what causes the enhancing of digestive enzymes
surface area/volume ratio
what is bolus
chewed food + saliva
what does bolus first compress against during swallowing
hard palate
what causes bolus to move into the oropharynx
tongue retracts
what does the bolus elevate
soft palate
what is the result of the soft palate being elevated
nasopharynx is blocked off
when do reflexes of swallowing occur
when bolus enter oropharynx
what happens to keep the bolus from entering the trachea
epiglottis folds
what causes bolus to enter the esophagus
pharyngeal muscles contract and force it through
what causes bolus to move into the stomach
lower esophageal sphincter opens
what pushes bolus further down the esophagus
peristaltic wave
what is the peristaltic wave
involuntary contraction/relaxation wave to push bolus
what causes PSNS vagus nerve stimulation
sight, smell, taste, or thoughts of food
what does the stomach release in response to vagus nerve stimulation
mucus, HCL, pepsinogen, ghrelin, gastrin (my hoe perfers grated garlic)
what causes pepsinogen to convert to pepsin
HCL
when does the gastric phase begin
when food reaches the stomach
what happens in the gastric phase
stretch receptors are activated, gastrin released, gastric lipase released, intrinsic factor
what enhances gastrin secretions
stretch receptors
what type of stimuli is stretch receptors
neural
what happens when gastrin is released into the bloodstream
protein digestion, mixing waves, gastric mobility
what is gastric mobility
stomach contents being moved into the small intestine
what does gastric lipase do
digests fat
what is the intrinsic factor
B12 absorption
what are the main functions of HCL
create an acidic environment, kills microorganisms, unfolds proteins, inactivates enzymes, breaks down cell walls and CT
what is the purpose of an acidic environment
so HCL can secrete pepsingoen
what does HCL inactivate
enzymes in food and salivary amylase
what does HCL break down
plant cell walls and CT in meat
where does bolus move to in gastric emptying
from the stomach to the small intestine
what is the only factor that increases gastric emptying
volume
how does volume increase gastric emptying
it increases stretch receptors which increases pressure
how does osmolarity decrease gastric emptying
water has to offset the osmolarity and it takes time
how does carbohydrate nutrient density decrease gastric emptying
duodenum has osmoreceptors that detect CHO and water is drawn in to offset it, but it takes time
how does fat and protein nutrient density decrease gastric emptying
release of cholecystokinin causes constriction of pyloric sphincter
what is the pyloric sphincter
tube below the duodenum
how does particle size decrease gastric emptying
the heavier particles are sifted and collect at the bottom of the stomach, and they take longer to empty
how does viscosity decrease gastric emptying
makes content thicker, and harder to move out
why does soluble fiber take a long time to gastrically empty
requires water to thin out viscosity which takes time
how are appetite suppressants activated
increase in viscosity
what is dietary fiber
carbs our body can’t digest
where is fiber found
in plant products only, not meat
where is insoluble fiber found
skin of plants
what happens to insoluble fiber in water
it swells like a sponge, but doesn’t dissolve
what happens to soluble fiber in water
it gets thicker, and dissolves
where is soluble fiber found
inner flesh of fruit
what are 2 functions of insoluble fibers
treats constipation and short-chain fatty acids produced
how does insoluble fiber treat constipation
increases the bulk of stool and promotes movement
how does insoluble fiber promote movement
swelling trigger peristalsis
what produces short-chain fatty acids
gut bacteria
how does short-chain fatty acids decrease risk for cancer
dilutes carcinogens
what are 4 functions of soluble fiber
increase viscosity, decrease constipation, help with diabetes, decrease cholesterol levels
how does viscosity increase satiety (soluble fiber)
decreases gastric emptying
how does soluble fiber decrease constipation
stools are softer
how does soluble fiber decrease cholesterol
body uses cholesterol to make more bile that has been lost in feces
how does soluble fiber help diabetes
traps sugar and inhibits amylase
what causes vomiting to occur
irritation in upper GI tract
where is signal sent if irritation is sensed in GI tract
vomit center of the brain
what happens when the vomit center of the brain is alerted
pyloric sphincter relaxes
what happens when pyloric sphincter relaxes when vomiting is gonna occur
contents move from duodenum to stomach via peristaltic waves
what happens once stomach contents are moved to the stomach from the duodenum when vomiting is gonna occur
lower esophageal sphincter relaxes
what happens when lower esophageal sphincter relaxes when vomiting is gonna occur
stomach content moves to esophagus, pharynx, and mouth
what are 4 consequences of constant purging
esophageal lesions, tooth decay, cardiac irregularities, and death
what happens when the esophagus gets lesions
scar tissue builds up which affects peristalsis
how do gastric ulcers come about
stomach acid damages digestive tract lining
what are two commons causes of gastric ulcers
pain reliever overuse and helicobacter pylori (bacteria)
how do you treat gastric ulcers
antibiotics
when does the intestinal phase begin
chyme enters duodenum
what does distention of the duodenum cause
inhibits gastrin production and gastric contractions, and stimulates pyloric sphincter contraction
what is secreted during the intestinal phase
alkaline mucus, cholecystokinin (CCK), GIP, secretin (always clean gutter shit)
what is alkaline mucus triggered by
vagus nerve stimulation
what CCK triggered by
protein and fat in chyme
what is GIP triggered by
carbs in chyme
what is secretin triggered by
decrease in pH
what does pancreatic amylase breakdown
carbs and starches
what does proteases breakdown
proteins into amino acids
what does pancreatic lipase breakdown and release
lipids and releases fatty acids
what does nucleases breakdown
RNA and DNA
what is the main purpose of the duodenum
secrete hormones
what is the main function of the jejunum
chemical digestion and nutrient absorption
what is the main function of the ileum
absorb bile acid and B12 and immune functions
what activates the immune functions in the ileum
Peyer’s patches
what is the main component of the small intestine
vili
what is vili
finger like projections
what is inside the vili
lymphatic vessels, nerves, and blood vessels
what makes up vili (on the outside)
epithelial cells
what do the epithelial cells on the vili contain
microvilli
what is the purpose of vili and microvilli
increase surface area
what is a characteristic of the epithelial cells in the small intestine
high turnover rate
what do the epithelial cells in the small intestine contain
digestive enzymes
what is celiac disease
reaction to gluten
what does celiac disease do to the digestive tract
destroys vili
what does celiac disease cause (if you eat gluten)
diarrhea, constipation, bloating, lactose intolerance, and fatigue
how does celiac disease cause diarrhea
water has to offset osmotic pressure of the carbs in the large intestine which causes watery stool
how does celiac disease cause constipation
impairs peristalsis
how does celiac disease cause bloating
when carbs that can’t be digested are moved to the large intestine, the bacteria that breaks it down produces gas
how does celiac disease cause lactose intolerance
microvilli is damaged which has digestive enzymes
how does celiac disease cause fatigue
nutrient deficiency
why do parts of the world have different rates of lactose intolerance
some parts have more access to dairy which means the people there produce more lactase
what is the mesentery
membrane that connects the intestine to the abdominal wall
what does the mesentery contain a lot of
blood vessels
what do the blood vessels in the mesentery aid in
fat storage
what does the large intestine absorb
water, vitamins, and electrolytes
what does the large intestine do in terms of digestion
form feces and send it to the rectum
what is constipation defined by
less than 3 bowel movements a week
what is constipation caused by
lack of fiber and exercise
how does exercise affect constipation
SNS is activated during exercise and PSNS is activated after exercise
does water affect constipation
no, fiber does
what does amylase break down
starch
what is starch broken down into
disaccharides
what are the 3 main enzymes that break down disaccharides
sucrase, maltase, lactase
what does sucrase break down
sucrose –> fructose and glucose
what does maltase break down
maltose –> glucose and glucose
what does lactase break down
lactose –> galactose and glucose
what is glucose
a monosaccharide
how is glucose taken to liver
portal vein
what happens after glucose is sent to liver
used for energy, stored as glycogen or fat, makes amino acids, released into blood
what 3 things does insulin act on
liver, muscles, adipose tissue
what does insulin bind to in muscles and adipose tissue
insulin receptors (IR)
what does insulin sensitivity depend on in muscles
movement
what does insulin sensitivity depend on in adipose tissue
adipose cell size
what does binding of insulin to IR trigger in muscles
glucose and fatty/amino acids move into cell
what does binding of insulin to IR trigger in adipose tissue
glucose and fatty acids move into cell
what happens once glucose moves into cells (in muscle)
it’s stored as glucose
what happens once amino acids moves into cells (in muscle)
they become proteins
what happens to glucose levels in muscles when exercising
they drop
why do glucose levels drop when exercising
passive glucose uptake
what causes passive glucose uptake
concentration gradient
what is glucose stored as in the liver
glycogen and triglyercirides
what happens to glucose synthesis in the liver
it decreases
what cells are in the liver that release insulin
islet of langerhans beta cells
what does the pancreas release insulin in response to
glucose levels
what hormone causes the pancreas to release insulin
GIP
what does glucose disregulation cause
diabetes
how does a healthy person regulate glucose
pancreas releases insulin which binds to IR, causing glucose to enter the cell and lower BG levels
what is the problem with glucose regulation in type 1 diabetics
the pancreas doesn’t release insulin so glucose doesn’t move into the cell and BG levels increase
what is the problem with glucose regulation in type 2 diabetics
pancreas releases insulin but can’t bind to IR because the cell is to large and the sensitivity to IR is affected
what does placental hormones do that cause gestational diabetes
they block IR from binding to insulin
what does gestational diabetes cause
macrosomia
what is macrosomia and what causes it
big baby; caused by increase in nutrients
what is the Maillard reaction
sugar and proteins reacting
what does the Maillard reaction lead to
advanced glycation end (AGE)
what is advanced glycation end
products bind to collagen in the arteries, clogging them
how does clogged arteries affect blood flow
decreases it
what is the main cause of cataracts
AGE builds up
what is the metabolic rate like for the eye lens
it’s high
what does it mean for the lens to have a high metabolic rate
needs high turnover rates
what does AGE build up cause to happen to the lens
decreases blood flow –> little regeneration –> debris clumps up
what is the main cause of glaucoma
pressure buildup
what causes pressure buildup in the eye
sorbitol and fructose can’t leave the eye
what creates sorbitol and fructose
glucose converting
how does diabetes impact peripheral nerves
fructose and sorbitol accumulate in nerves
what happens when fructose and sorbitol accumulate in nerves
affects osmolarity
what happens when osmolarity is impacted in peripheral nerves
water is drawn in which affects membrane potential
what happens when membrane potential is affected in peripheral nerves
signal can’t get sent to the brain
how is nerve damage caused
lack of signals being sent to brain –> failure to notice trauma
how does increasing glucose levels impact immunity
decrease in neutrophil development and increase in bacterial growth
how does fructose and sorbitol impact the kidneys
causes damaged nephrons
how does AGE accumulation impact the kidneys
damages vasculature
how does AGE damage vasculature
affects the re-absorptive process which means that kidneys can’t clean the blood
what are 3 symptoms of diabetes
kidneys don’t absorb glucose, fructose and sorbitol production, and poor glucose uptake
what is the result of kidneys not being able to absorb glucose
increase in osmotic pressure which leads to dehydration
how does an increase in osmotic pressure lead to dehydration
there is an increase in water in take which leads to drinking more water which leads to more peeing –> dehydration
why is there poor glucose uptake when it comes to diabetes
cells are using fat for fuel
what do ketone bodies do
decrease pH
what is diabetes insipidus
chronic dehydration
what does the antidiuretic hormone cause
dehydration
what type of diabetes results in tasteless urine
diabetes insipidus
in regards to treating diabetes with lifestyle changes, what is the main goal
decrease blood sugar spikes
what are 3 ways to decrease BG spikes
small, frequent meals; foods with low glycemic index; and insoluble fiber
how does increasing insoluble fiber decrease BG spikes
slows down gastric emptying, entraps sugar, and decreases amylase
what are lifestyle changes you can make to treat type 2 diabetes
weight loss and exercise
how does weight loss help with diabetes
reduces the size of the fat cells
how do you medicinally treat type 1 diabetes
insulin pump
how do you medicinally treat type 2 diabetes
metformin and sulfonylurea
what does metformin do
decrease glucose production in liver
what does sulfonylurea do
increases sensitivity for beta cells which increases insulin production
what do alpha cells in the pancreas produce
glucagon
what does glucagon act on
the liver
what does glucagon acting on the liver cause
breakdown of glycogen
what does the breakdown of glycogen in the liver result in
increase in BG
what hormone does the hypothalamus produce
corticotropic releasing hormone
what does the medulla produce to send to liver
epinephrine
what happens when epinephrine acts on the liver
breakdown of amino acids to make glucose
what is gluconeogenesis
breakdown of amino acids to make glucose
what does the medulla activate
hormone sensitive lipase
what does the activation of fat cells via the medulla cause
hormone sensitive lipase to be secreted
what does the secretion of hormone sensitive lipase to breakdown in the fat cells
triglycerides into fatty acids
where are fatty acids from the fat cells sent to
muscle
what do fatty acids do in the muscle
make ATP
what hormone does the pituitary gland release
ACTH which acts on the adrenal cortex
what do glucocorticoids act on
muscle
what does glucocorticoids acting on the muscle result in
breakdown of amino acids
what happens when amino acids are broken down in the muscle
glucose is made (gluconeogenesis)
what is the main function of mucus
protect stomach from acidic environment
what is the main function of pepsinogen
cleave off protein once activated
what causes fasting hypoglycemia
not eating
what happens during fasting hypoglycemia
glycogen isn’t broken down
what cells cause glycogen to not be broken down in fasting hypoglycemia
hypoactive alpha cells
what causes reactive hypoglycemia
eating a meal
what happens during reactive hypoglycemia
insulin reaches peak levels
what cells cause glycogen to not be broken down in reactive hypoglycemia
hypersensitive beta cells
what else can cause hypoglycemia
tumors
where does lipid metabolism start
in the mouth
what does lipase breakdown
triglycerides into fatty acids
what do fatty acids stimulate to make bile
CCK
where do fatty acids send bile once they secrete it
to the gallbladder
what does bile acid interact with in the gallbladder
fat, to emulsify it
what causes fatty acids to be absorbed into intestinal cells
micelles
where do fatty acids go after they exit intestinal cells
chylomicrons
what happens to fatty acids when they enter chylomicrons
they convert to triglycerides
what happens after fatty acids convert to triglycerides
VLDL
where are chylomicrons located
epithelial cells
where do chylomicrons move fat cells to
the liver
what happens to fat in the liver
breaks down in to VLDL
what does VLDL do
transport fat from the liver to muscles and adipose tissue
what is VLDL broken down by
lipoprotein lipase
how is IDL formed
removal of triglycerides from VLDL
how is LDL formed
VLDL and IDL
what does LDL do
fixes injured arteries
what does HDL do
reverse cholesterol transport from tissues to the liver
what does lipoprotein lipase do
breaks down triglycerides into fatty acids to enter the cell
what is the order of lipid metabolism
VLDL to IDL to LDL to immune system to calcium to vessels
what does calcium do in the blood vessels
forms plaque
what causes vessel diameter to decrease
RBC build up
what are two things you can take to treat atherosclerosis
statins and unsaturated fats
what do statins do
increase sensitivity to LDL receptors
what do unsaturated fats do for atherosclerosis
increase sensitivity to LDL and IDL receptors
what does reducing calories do for atherosclerosis
decrease LDL
what does reducing stress do for atherosclerosis
decreases VLDL
how does nicotine impact atherosclerosis
increases LDL and decreases HDL
what does omega 3/6 and baby aspirin do
decreases inflammation
what is the first step in protein metabolism
HCL unfold proteins and pepsin breaks down amino acids
what happens after protein is unfolded in protein metabolism
CCK triggers the release of pancreatic proteases
what happens to the amino acids once they’ve been broken down in protein metabolism
they’re absorbed into the vili of the small intestine
what happens to the amino group
can’t provide energy so it’s excreted in urea
what happens to protein when the energy balance of the body is positive
protein is converted to fat
what does lack of dietary protein cause
kwashiorkor and edema
what characterizes kwashiorkor
impaired growth, increased rate of infection, pot belly, fatty liver, edema, and decreased cognition
what causes impaired growth
decrease in anabolic reactions because of incomplete proteins
what causes and increase in rate of infection
decrease in antibodies
what causes pot belly
worms
what causes fatty liver
decrease in VLDL
what happens when VLDL levels are decreased and how does it cause fatty liver
fat isn’t transported away from liver
what is the relationship of osmotic and blood pressure to cause an edema
osmotic pressure is lower than blood pressure
how does edema work
the protein that cause osmotic levels to increase, moving water from tissue, back to blood, are decreased, so the water stays in the tissue and causes swelling
what causes water to move from arterial blood to surrounding tissues
increased blood pressure
what causes water to go back into the venous blood
osmotic pressure exerted by proteins in the blood
what is the function of ghrelin
appetite
what is the function of leptin
suppress hunger
what is the function of pepsin
protein digestion
