9.1 The Digestive Tract

Question 1

what are the major organs

Answer 1

mouth, pharynx, esophagus, stomach, sm intestince, lg intestine, rectum, anus

Question 2

describe the roof of mouth

Answer 2

separates the nasal and oral cavity

• anterior hard palatte (bones)
• posterior soft palate (muscle, connective tissue)

Question 3

mouth

Answer 3

• tonsils: protect against infections

- salivary glands: produce saliva, keeps mouth moist

Question 4

pharynx

Answer 4

passageway that recevies air nasal cavity and food from mouth

Question 5

why is swallowing a natural reflex

Answer 5

performed automatically, soft palate moves back, trdachea moves up to cover eoglittis

Question 6

esophagus

Answer 6

passageway from pharynx joins stomach which only opens when swallowing

Question 7

peristalaiss

Answer 7

rhythmic contractions that push food along digestive tract

Question 8

spincters

Answer 8

tubes that close when contract open when relax

Question 9

heartburn and vommitting

Answer 9

stomach contents escape into esophagus (acid reflex)

vomitting: forceful expulsion of stomach contents through mouth

Question 10

stomach

Answer 10

-cardiac spinter opens
receives food from esophagus, starts disgestion of proteins, moves food to small intestines
-food leaves stomach as chyme (thick, soupy liquid)
-pyloric spincter closes

Question 11

rugae

Answer 11

deep folds in walls of stomach that allow stomach to fill with food

Question 12

describe columnar epthelium

Answer 12

lines stomach has gastric pits that lead to gastric glandsproduce gastric juice (HCL, pepsinogen, muscus) that kills bacteria

Question 13

descirbe the 3 layers of the stomach

Answer 13

muscle layers: longitudinal, circular, obliquely arranged which moves food along, churns mixing food around digesting

Question 14

small intestine

Answer 14

duodenum: ducts from liver and pancreas to bile duct at duodenum
jejunum: middle part
ileum: immune response to intestinal pathogens

Question 15

describe the villi of the small intestine

Answer 15

mircovilli that absorbs nutrients
-has lacteal: blood/lymphatic capillaries
(glycerol + fatty acids repackaged as lipoproteins)
(sugar + aa carried to all cells)

Question 16

describe 3 hormones

Answer 16

• gastrin: produced by stomach, stimulates stomach to make more gastric juices, stimulate pancreas secrete pancreatic juice, stimulate liver increase bile output, gall bladder release bile
• secretin: cells of duodenum wall, stimulated by acid in chyme
• cholecystokinin: stimulated by partially digested protein, fat

Question 17

large intestine

Answer 17

absorbs water, salts, some vitamins
stores indigestible materials until eliminated
-cecum, colon, rectum, anal canal

Question 18

cecum

Answer 18

pouch at junction sm and large intestine

-has appendix: which fights infections

Question 19

colon

Answer 19

ascending (RHS), transverse (across), descending (LHS), sigmoid (enters rectum last 20cm)

Question 20

anus

Answer 20

defecation: feces forced into rectum
- homeostasis by ridding body of indigestible remains, stretching of rectal wall intiates nerve impulses to spinal cord, rectal muscles contract, anal spincters relax

Question 21

anaerobes

Answer 21

die in oxygen, breakdown indigestible materials, produce vitamins our bodies can absorb and use