Digestion Flashcards
(38 cards)
1
Q
Digestive system
A
- Specialized to ingest food and move it down tract - GI tract
- even macromolecules are too small to be digested
2
Q
2 types of digestion
A
- physical digestion
- physically breaking food down into smaller peices - chewing, churning …etc - chemical digestion
- chemically breaking things down into monomers and polymers - small enough to be absorbed by bloodstream - hyrdolysis
3
Q
Oral digestion ananotomy
A
Mouth, tounge and teeth
4
Q
Mouth
A
- cavity where food enters body
- secretes saliva from salivary glands
5
Q
Teeth
A
- 32
- responsible for chewing - mastification
- incisors, canines, molars
6
Q
Tongue
A
- large muscle
- studded with taste buds
- rolls food into bolus
7
Q
Salivary glands
A
- secrete saliva triggered by sense of food - smell, taste ..etc..
8
Q
Saliva
A
- liquid that aids in digestion of starch - salivary amylase
- lubricates mouth
- Salivary mucins produce mucus to cover hard part of mouth, and soft part - protection
9
Q
enzyme in mouth
A
- salivary amylase
- gets secreted in presence of starch
- only digests starch in mouth not protiens or fats
- starch turns into maltose via amylose
10
Q
Esophagus
A
- muscular tube
-mouth to stomach - Perstalsis of esophagus clenches food down esophagus
11
Q
1st sphincter
A
esophageal/cardiac sphincter
lets food into stomach from esophagus
12
Q
Stomach
A
- J shaped muscular organ
- physical - churning - and gastric digestion - enzymes + stomach acid -
- stomach is folded = rugae = ability for stomach expansion
- empty stomach = 50 mL full = 1-4 L of food
13
Q
Gastric glands of stomach purpose
A
- to produce mucus to protect stomach from stomach acid
- produce HCl - stomach acid - PH = 1.5-2.5
- produce enzymes
14
Q
Protien breakdown stomach - cascade
A
Pepsinogen - inactive - gets activated by HCl into pepsin - active
Pepsin enxymes hydrolize protiens - polypeptides - into smaller poly peptides
15
Q
Stomach responce to food
A
- Gastrin (hormone from stomach) - tells gastric glands in stomach food is present
- stomach then releases HCl, mucus, enxymes = gastric juice
- gastric juices mix with food to form chyme, 2-3 L secreted daily
- HCl breaks down protiens in chyme
16
Q
two functions of stomach
A
- protien digestion - main
- absorption of water, alc, and certain drugs,
17
Q
stomach disorders
A
ulcer = sores in cells that line digestive track
1. peptic ulcer = thinning of mucus layer in stomach - due to bacteria - bleeding and holes sometimes
2. Esophagael ulcer - cause heartburn
3. Duedenal ulcer - pain, anemia sometimes, bloody poo
18
Q
digestion in animals
A
- regurgitation as defense mechanism
- symbiosis in cows - four chambered stomach - bacteria in their stomach break down cellulose instead of the ensymes we have. their bactereia possess the cellulasee enyme.
19
Q
Small intestine - SI
A
- small diameter but long - 20 feet
- some physical digestion via segmentation
- segmentation is where chyme sloshes back and forth between SI segments
- perstalsis pushes food down intestine
20
Q
function of SI
A
- absorb subunits of marcomolecules by completing digestion
21
Q
Regions of SI
A
- duodenum - 1 ft
- jejunum - 8 ft
- Ileum - 11 ft
all lined with circular ridges
22
Q
duodenum
A
- short and wide
- u shape
- channel from pancreas and livers
- important for chemical digestion of chyme
23
Q
jejunum
A
- contains more folds and secretory glands that duodenum
- keeps breaking down food
24
Q
Ileum
A
- has fewer villi
- absorbs last available food and pushes down remaining food to large intestine
25
villi in the intestine
- finger like progections
- each villi has micro villi on them
- within villi is capillary network - lacteals - trasnport substances from SI to bloodstream and lymph system
- high SA = maximal absorption
26
Accessory organs
- necessary but not part of GI track
- SI has own enymes for digestion - secreted from micro villi
- also has organs to help digest - liver, pancreas, and gallbladder
27
Pancreas
- produces insulin to break down glucose to ATP
- delivers pancreatic fluid to duodenum to transport enymes and antiacids
28
enzymes produces by pancreas
1. pancreatic lipase - free fatty acids from triglycerides
2. pancreatic amylase - digests starch in SI
3. Trypsinogen - trypsinogen = inactivee - trypsin = active - breaks down polypeptides into smaller peptides - not quite amino acids
29
Pancreas secretion of antiacid
secrets antiacid to neutralie chyme - changes PH to 8
- makes up for pancreas lack of mucus layer
30
Liver
- 200 functions
- produces bile = green yellow fluid
- bile emulsifies fats into smaller drops of fat
- increase in fat SA lets lipase work better and faster
- bile = cholesterol salt and billirubin
31
Gall bladder
- stores bile for inbetween meals
- when fatty chyme enters duodenum - gallbladder contracts = bile goes from common duct into duodenum
32
villi responce to food
1. Ensymse
Carbohydrases/disaccharidases: lactase, maltase & sucrase
2. Hormones
I. Secretin
- Stimulates pancreas to release antacid
& enzymes, Slows peristalsis of the stomach
I. Cholecystokinin (CCK)
- Slows peristalsis of stomach, stimulates secretion of bile from gallbladder
- Stimulates secretion of pancreatic enzymes
33
stomach absorption
stomach absorbs water, alc, caffeine
34
SI absorption
monosacharides + amino acids are absorbed by active transport into SI cells
this is then sent to the liver - liver decides what do with monosachs and amino
Monosaccharides are converted into glucose which performs stuff we have learned already
35
SI absorption - fatty absorption
fatty acids + glycerol enter lacteal via diffusion and gets added to lymph
- lymph then carries them to chest which breaks them up into free monomers
36
Large intestine
- finisher
- whatever material remains left to be absorbed is absorbes by LI
- shorten then SI - ft but thicker
- digestion does not occur - only absorption of water, vitamins, minerals ions
37
undigested chyme in LI
- travels through four parts of LI via peristalsis which keeps it moving
1. ascending colon
2. tranverse colon
3. descending colon
4. sigmoid colon
38
LI bacteria and
Bacteria - E.coli break down undigested food
- The bacteria also produce vitamin K & B which the human body needs to survive
- Cause bilirubin to turn brown (this is why feces is brown!)
Fiber (Cellulose): important portion of the diet, decreases chances of colon cancer!
Defecation: after the LI completes reabsorption, watse travels through the rectum, the anus & out the anal sphincter (fecal matter, feces, stool etc.)
Bacteria like E.coli break down undigested food, this provides nourishment for the bacteria!
