digestive system Flashcards
what is the digestive tract or alimentary tract?
starts at the mouth and goes to the anus
major spots
- mouth
- pharynx
- esophagus
- stomach
- small intestines and parts
- large intestine and parts
- anus
what is the G.I. tract?
Gastro Intestinal
subsection
stomach and intestines
what are the accessory organs
- salivary glands
- pancreas
- liver
- gall bladder
- spleen
all do things that help
functions of the digestive system
- mastication
- ingestion
- propulsion
- mixing
- secretion
- digestion
- absorption
- elimination
- mastication
masseter - chewing
chew food so that there is a bigger surface area, more space for the chemicals to get in
- ingestion
food into the stomach/body
- propulsion
movement
- propulsion: deglutition
swallowing
- propulsion: peristalsis
move the food by squeezing on it and stretching the muscle
- starts at the esophagus and goes to the end
- food takes 24-36 hours to go through
- propulsion: mass movements
happen in the large intestine
contraction over a larger space than peristalsis food moves farther, but not more steadily
- mixing
segmental contractions
move food back and forth so that more digestive juices can get in
- secretion
mucus: helps lubricate - want stuff to move along smoothly, helps to liquify the food, helps to protect the digestive tract
ex: lining inside of the stomach is to protect from acid
water: liquify - more liquidy, the greater the surface area
water comes out of the circulatory system and put it back at the large intestine
bile: stored in the gall bladder, breaks down fats - like soap…mixes fat and water
enzymes: make enzymes to help chemically digest the food
- digestion
mechanical: chewing- mechanically breaking apart
chemical: chemically breaking apart
carbohydrates, proteins, fats, trying to break apart to put in the blood
- absorption
take from the digestive tract and put into the circulatory system
- elimination
removing waste products from the body; feces
food that can’t digest or bacteria that no longer need
peritoneum
double layer membrane - abdominopelvic cavity
layers… parietal(outside), visceral(inside/touching an organ)
mesenteries- between organs, help to hold everything in place
retroperitoneal- outside the peritoneum
oral cavity
mouth
1. lips: very outside, -move…help take in food, -skin on lips has less keratin so the skin is more see through
2. cheeks: buccinator -move food between our teeth
3. palate: -hard palate in anterior of the roof of the mouth, -soft palate in the posterior roof of the mouth…moves when you swallow
4. uvula: directs and blocks nose when you swallow
5. tonsils: like lymph nodes, lots of WBCs to fight infections - attract infection to fight it with WBC, -have 3 sets, -can be taken out if getting a lot of infections, -tonsil stones
tongue
made of muscle
inside and outside layer of muscle
intrinsic- flip tongue, extrinsic- tongue out
- move food around so that you can chew and swallow
- taste buds are on Papillae…little bumps
teeth
primary: grow from 6 months-2 years
permanent teeth: grow from 5-11 years
- incisors: for cutting, in the front
- canines: for tearing, pointy
- premolars and molars: for grinding, flat on top
teeth are slightly moveable
enamel
covers teeth
hard and strong
gingiva
gums
tooth fits in
salivary glands
make saliva
- parotid gland
- sublingual gland
- submandibular gland
functions of saliva
- prevents bacteria growth (infection)
- lubrication
- help start the breakdown of starches
- bolus food and saliva mixed together
- make 1-1.5 liters of spit each day
parasympathetic makes…
…saliva
phases of swallowing
- voluntary phase: start to swallow
- pharyngeal phase or reflex: 1-2 seconds
- esophageal reflex: esophagus…make sure food goes down esophagus…takes 5-8 seconds
voluntary phase steps (swallowing)
- tongue pushes food up and back
- soft palate moves up, uvula closes off the nasal cavity
- epiglottis covers the trachea
- esophagus sphincter opens to let food in
- peristalsis moves food down when it gets into the esophagus
esophagus
tube from mouth to the stomach
acid reflex disease: sphincter doesn’t always work…send food back up. acid going up the esophagus could wear away the esophagus
stomach
- size and shape of a stomach varries
- stomach can get stretched out or shrink
pyloric sphincter
“gatekeeper”
from the stomach to the small intestine
rugae
folds in the stomach that allow it to expand.
The stomach can stretch and shrink depending on how much you eat
gastric pit
important digestive juices in pit
surface mucous cell
mucus protects from the acid
parietal cells
make hydrochloric acid
chief cells
make pepsinogen
endocrine cells
regulatory hormones
secretions of the stomach
- Chyme
- Mucus
- Intrinsic factor
- HCl
- Pepsinogen
can absorb water through the stomach as well
chyme
bolus, but in the stomach
(what call food in the stomach)
mucus
made in mucus layer
protects stomach from acid
large amounts of alcohol, asprin and salt can damage
intrinsic factor
come out of parietal cells
binds with B12(B12 is connected to waking up and energizing) –> so can dissolve/absolve
HCl
- killing bacteria
- brings pH down to 1-3…really acidic (mucus protects)
- help break proteins down
- turn pepsinogen into pepsin
pepsinogen
helps break down proteins
B12
stomach phases
- Cephalic phase
- Gastric phase
- Intestinal phase
cephalic phase
when taste or smell something
taste, smell or thought can get the stomach started and ready to have food
gastric phase
when the food is actually in the stomach
intestinal phase
when the food starts going into the intestine
there is a trigger from the intestine to turn the stomach back off
mixing wave
80% of stomach moving around is mixing
peristaltic waves
20% of stomach movement is peristaltic waves
few milliliters of emptying with each wave
movements of the stomach
vomiting is protecting
- toxins in what ingested
- at too much
food and liquid stay in stomach between 1-6 hours…lot of fat and protein stay for 6 hours. alcohol and carbohydrates can be faster
hunger pangs
go without food for a long time. stomach may forcefully and painfully contract. 12-24 hours after the last meal/ max intensity of pang happens after 2-4 days without food. after four days doesn’t happen as much
low glucose can cause pain
small intestine
most of digestion happens here
- Duodenum
- Jejunum
- ileum
- each day put about 9 liters of water into the digestive system
- 8-8.5 liters get reabsorbed by the small intestine
1-1.5 liters for large intestine to absorb
duodenum
- 25 cm
- comes after stomach
- liver, gallbladder and pancreas all dumping stuff into the duodenum
jejunum
- 2.5 meters long
- most nutrients are absorbed by end of jejunum
ileum
- 3 meters long
- lymph nodes along to fight infection
- food spends longest time here
modifications to increase surface area
- because of circular folds/plicae folds, the surface area of the intestine is 600x greater than if it was smooth
- the villi contain capillaries and lymph vessels so they can absorb what we digest. on each villi there are microvilli
- microvilli are folds of cell membrane
- food is liquified to get between the villi and absorbed
what dumps into the duatenum
liver, gallbladder, pancreas
most of the digestive enzymes come from the…
pancreas
liver makes ________ and it is stored in the ________
bile, gallbladder
gallstones
hardened bile, if stones get stuck, then may have to take out gall bladder
what gets reabsorbed in the ilium and recycled?
90% of bile is reabsorbed in the ilium and recycled
what is bile made of?
cholesterol
why are fibers good?
fibers speed up digestion and that means there is less cholesterol in the blood
what does the liver inspect?
the liver inspects digested material through the hepatic portal system
everything goes through the liver first too…
detoxify
what does the liver store?
the liver stores
- glycogen
- fat
- vitamins
- copper
- iron
nutrient interconversion
make nutrients…protein and vitamin D
inspect and detoxification
the liver removes ammonia and turns it into urea
- also done with alcohol and other drugs
phagosytosis
to destroy bacteria and old cells…eat it up
parts of the large intestine
Appendix
ileocecal valve
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum
Anal canal
how long is food in the…
Stomach: 1-6 hrs
Small intestine: 2-6 hrs
Large intestine: 18-24 hrs
large intestine
- 1.5 meters long
- moves slower and with mass movements
- about 90% of what goes into the large intestine gets absorbed into the blood
- if moves too slowly, might absorb too much water and might get stuck…constipation
-water and salts get absorbed
-vitamin K is released by bacteria growing in the large intestine
Appendix
- fight infections
- WBC
- “lightning rod”…infection is drawn to it
if the appendix loses, then it can burst
anal canal
two sphincters or “gatekeepers”
- internal: smooth muscle…involuntary
- external: skeletal muscle…voluntary
hemorrhoids
happen in anal canal
- an inflamed or enlarged vein
could be painful or bleeding
- result of strain bowel movements
- a solution is high fiber diet
feces
poop
- made up of undigested food
- bacteria
- sluffed off epithelial cells
when cells die…they fall off
ileocecal valve
one way valve where ilium and cecum meet
ascending colon
on the right side going up
transverse colon
going across
descending colon
left side going down
sigmoid colon
“S” shape
mass movements in the large intestine are…
…common after meals
feces in the rectum causes…
…rectification
time to digest
carbohydrates
- shortest time
- complex carbs takes a little to get into the blood
- simple sugars don’t take long
lipids
- stay in the stomach the longest
proteins
- 2nd longest time in stomach
