digestive system

Question 1

organs of digestive system

Answer 1

1. mouth
2. pharynx
3. esophagus
4. stomach
5. stomach
6. small intestine
7. large intestine
8. rectum

Question 2

accessory glands

Answer 2

liver, gall bladder, pancreas

Question 3

digestion

Answer 3

processing of ingested foods into molecular forms that can be absorbed w/ water and electrolytes

Question 4

motility

Answer 4

muscle contraction mix and advance contents

Question 5

tone

Answer 5

constant low level contraction of smooth muscle maintains steady pressure on contents and returns walls to normal size following distention

Question 6

propulsion

Answer 6

push contents through tract, speed varies by function of tract segment (esophagus v small intestine)

Question 7

mixing

Answer 7

mix foods with digestive juices, help absorption by maintaining contact of contents w/in small intestine walls

Question 8

secretion

Answer 8

exocrine glands secrete digestive juices at specific times throughout tract
- consist of water, electrolytes, enzymes, bile, mucus

Question 9

digestion

Answer 9

breakdown of complex foodstuffs into smaller absorbable molecs

Question 10

CHOs

Answer 10

must be broken into monosaccharides
- some in mouth, mostly small intestine

Question 11

Proteins

Answer 11

broken down by peptidases
- stomach = pepsin, small intestine = other

Question 12

fats

Answer 12

99% of breakdown in small intestine
- first into globules - emulsification require bile - lipases break into monoglycendes and fatty acids - chylomicrons - enter lymphatic vessels - enter circulation in chest

Question 13

mouth

Answer 13

chewing - physical and chemical breakdown
- salivary glands - mucus lubricates and amylase digests polypeptides

Question 14

pharynx/esophagus

Answer 14

add more mucus and move food to stomach

Question 15

swallowing involves

Answer 15

skeletal muscle - pharynx
smooth muscle - esophagus

Question 16

stomach

Answer 16

empty vol = 50 mL - can expand to 1000 mL
- parietal cells = HCl
- chief cells = pepsinogen - pepsin

Question 17

fundus

Answer 17

top part of stomach, lies above esophagus
- no digestion
- contains gas

Question 18

body of stomach

Answer 18

main portion
- thin muscular walls
- main storage area

Question 19

antrum of stomach

Answer 19

bottom
- thick smooth muscle walls
- separate from duodenum by pyloric sphincter
- produce chyme
- regulates movement into small intestine

Question 20

small intestine

Answer 20

final and most stages of digestion here
- most absorption
- 3 segments
- rings of smooth muscle allow segmentation

Question 21

3 segments of small intestine

Answer 21

1. duodenum
2. jejunum
3. ileum

Question 22

small intestine absorption

Answer 22

enhanced w/ perfusion of blood and lymph

Question 23

mucus lining of small intestine

Answer 23

designed for absorption
- epithelial cells w/ variety of transport systems
- large surface area from infoldings
- villi
- microvilli

Question 24

villi

Answer 24

finger-like projections w/in circular folds, incr surface area

Question 25

microvilli

Answer 25

hair-like projections from villi, form "brush border' increase surface area

Question 26

venous drainage from villi

Answer 26

goes directly to liver via hepatic portal vein

Question 27

material absorbed from SI

Answer 27

processed by liver before entering general circulation

Question 28

digested fats can't penetrate intestinal capillaries

Answer 28

absorbed into central lacteal to lymphatic system to systemic blood stream in chest - to liver

Question 29

large intestine sections

Answer 29

- cecum - appendix - colon - rectum

Question 30

colon

Answer 30

receives 500 ml chyme for SI daily - most of it undigestible food, bilirubin, electrolytes, and water

Question 31

main function of colon

Answer 31

concentrate and store feces until defecation

Question 32

LI motility

Answer 32

very slow - contractions of smooth muscle occur at 30 min intervals

Question 33

mass movements

Answer 33

powerful contractions of ascending and transverse colon that drive contents into rectum - 3 to 4 times a day

Question 34

high fecal matter volume

Answer 34

stimulates stretch receptors in wall of rectum (defecation reflex)

Question 35

external anal sphincter

Answer 35

comprised of skeletal muscle - voluntary control of defecation

Question 36

constipation

Answer 36

delayed defecation, feces becomes hard and dry

Question 37

intestinal gas sources

Answer 37

1. swallowed air - most burped from stomach 2. bacterial fermentation - occurs w/in colon as local bacteria breakdown undigested food, amt depends on meal and types of bacteria in colon