Digestive System (Ch 18) Flashcards
another term for digestive system
alimentary canal
why is it called a canal
has lumen (space inside)
4 steps of food processing
Ingestion
Digestion
Absorption
Elimination / Egestion
what is ingestion
process of taking in food
what is digestion
process of breaking down food
2 types of digestion
mechanical and chemical
chemical digestion
involves enzymes that are specific to certain molecules + break them into smaller pieces (enzymatic hydrolysis)
mechanical digestion
Physical grinding up of molecules into smaller pieces
amylase is responsible for ___ of __
hydrolysis of starch
lipase is responsible for __ of __
hydrolysis of lipids and fats
Absorption
Movement of food from digestive to circulatory
how is absorption done and where
diffusion, small intestine
water absorption occurs in
large intestine
water absorption occurs in
large intestine
Elimination
final step of food processing
where does undigested material go
from the large intestine into the outside environment via anus
the __ causes the tube like appearance
alimentary canal
3 types of salivary glands
sublingual, parotid, submandibular (submaxillary)
mechanical digestion in the mouth occurs in form
chewing
3 steps food takes
mouth, pharynx, esophagus
where does chemical digestion also occur
mouth
what does salivary gland produce
saliva
how does saliva enter mouth
through ducts
what does Salivary amylase
break down
Breaks down starch into a compound called maltose
what is starch broken down by
salivary amylase to form maltose
what is maltose composed of
2 glucose molecules (disaccharide)
Pharynx
chamber common to both respiratory + digestive systems
Epiglottis
small piece of cartilage that prevents food from passing into trachea
what happens to larynx when swallowing
the larynx is first pulled upward, causing epiglottis to cover the entrance to the respiratory
what is bolus
food in a ball form
muscular contractions in which food is moved down stomach
peristalsis
what is esophagus
muscular tube that passes food from mouth to stomach
Cardiac orifice (opening)
entrance to stomach
mouth function
Moistens food w/ saliva from salivary glands
begins breakdown of starch
does trachea open or close when breathing
open
function of stomach
- Stores material
- Produces digestive enzymes + gastric juice (HCL + Enzymes)
- where protein digestion occur
HCL function
lowers stomach pH
low pH actives __
pepsinogen into pepsin
rugae (folds)
internal stomach
Pepsinogen
inactive form of pepsin + secreted by chief cells
pepsin
breaks peptide bonds of protein chains (to become a.a.) then moved to small intestine for absorption
Chyme
contents from stomach mixed w/ gastric juices
how does chyme move from stomach to SI
through pyloric sphincter
Pyloric sphincter
band of smooth muscle that regulates food passage from stomach into small intestine
summary of secretion of pepsin in stomach
1.Pepsinogen + HCL are secreted into stomach
2.HCL converts pepsinogen to pepsin
3. Pepsin activates more pepsinogen into pepsin to start a chain reaction
where is chemical digestion completes
SI
what happens in Duodenum
absorption takes place
what is and what happens in jejunum and Ileum
Organs that aid inc chemical digestion
Secretions are drained into duodenum via specific ducts
where is villi and microvilli
duodenum
Absorption
process where nutrients are diffused into bloodstream through villi -> capillaries -> cell memb
project off the villi
microvilli
Villi
small, finger- like projections away from wall of s.i
Supplied w/ capillaries (blood vessels)
3 accessory organs of stomach
liver, pancreas, gallbladder
liver function
1.Detoxification (alcohol)
2.Storage of glucose (in form of glycogen)
3. Produces bile
3. Break down big fat droplets into smaller pieces = emulsification
what is Pancreatic amylase (maltase) function
Breaks down disaccharide into monosaccharides (maltose into glucose)
Responsible for starch digestion
what does pancreas secret
pancreatic lipase
what is pancreatic lipase
Enzyme responsible for breaking down fats into glycerol + fatty acids after emulsified
what does pancreas produce
Produce many digestive enzymes (Pancreatic trypsin + chymotrypsin)
produce hormones (insulin and glucagon)
gallbladder function
Stores bile
Bile from gallbladder released into small intestine
Gallstones (cholecystitis)
what does parietal cells secrete
HCL
what does mucus cells secrete
mucus which protects cells lining
jejunum + Ileum function
Also responsible for absorption of nutrients
Reabsorb some water back into body
where is cecum and appendix in
jejunum and ileum
Cecum
small sac in T shaped intersection where material movies from small intes to large
Appendix
edge of cecum that is a finger like projection
long intestine function
Storage + elimination of solid wastes
Secretion of mucus (goblet cell) to allow passage of solids
large intestine is also decomposition of
organic material w/ help of bacteria (e coli)
- Bacteria feed on waste + indigestible materials (cellulose)
what does large intestine produce
vitamins (k and biotin)
what does rectum do
stores and eliminate waste
3 parts of long intestine
Ascending (going up)
Transverse (across)
Descending (going down)
bile function
breaks down fats to smaller particles
what is enzymes
catalyst and is almost always a protein.
It speeds up the rate of a specific chemical reaction in the cell.
The enzyme is not destroyed during the reaction and is used over and over
enzymes are exported from pancreas via
pancreatic duct into SI
tryptsin
digestion of proteins
2 ways of mechanical digestion
chewing and churning in stomach
3 ways of chemical digestion
- saliva in mouth (salivary amylase)
- acid and pepsin in stomach (HCL)
3.enzymes in SI (p. amylase, lipase, trypsin)
cardiac sphincter regulates
how much will get into stomach
5 pathways of food
- mouth
- salivary glands - pharynx
- esophagus
- stomach
- liver
- pancreas
7.gallbladder - small and large instestive
- anus
