GI 1

Question 1

what Primary function of digestive system

Answer 1

absorption of nutrients, water and electrolytes from the external environment into the body’s internal environment

Question 2

what is the digestive system central to

Answer 2

regulation and integration of metabolic processes throughout body

Question 3

what is proper functioning of digestive system necessary for

Answer 3

whole-body homeostasis

Question 4

what % of health care costs related to GI system

Answer 4

10%

Question 5

where does digestive system extend from

Answer 5

mouth -> large intestine
15ft in live person

Question 6

what is the GI tract

Answer 6

long tube with muscular walls lined by transporting and secretory epithelial (esophagus to end)

Question 7

order of the digestive system

Answer 7

mouth - pharynx - esophagus - stomach - small int - large int - external environment

Question 8

stomach to anus

Answer 8

the gut

Question 9

digestion

Answer 9

mechanical and chemical breakdown of food primarily occurs in gut

Question 10

what contributes to digestion

Answer 10

secretions from accessory glandular organs
salivary glands, liver, gallbladder, pancreas

Question 11

GI tract is technically what

Answer 11

a continuation of external environment

Question 12

where does digestion begin

Answer 12

in mouth with mastification and addition of saliva

Question 13

what are three salivary glands in mouth

Answer 13

parotid, sublingual, submandibular

Question 14

what are the 4 functions of salivary glands

Answer 14

1. moisten and lubricate food
2. salivary amylase partially digests polysaccharides
3. dissolve some food molecules (taste)
4. lysozyme kills bacteria

Question 15

esophagus

Answer 15

passageway from mouth to stomach

Question 16

what is the esophagus made of

Answer 16

top 1/3 skeletal muscle (voluntary) bottom 2/3 smooth muscle

Question 17

what sphincter are connected to esophagus

Answer 17

upper and lower esophageal sphincters

Question 18

what does the esophagus do

Answer 18

moves food via perstaltic waves (just motility no digestion)

Question 19

where does digestion continue after esophagus

Answer 19

stomach

Question 20

what happens in stomach

Answer 20

mixes food with acid and enzymes to create chyme (lots of mechanical)

Question 21

3 parts of stomach and the valve

Answer 21

1. fundus (upper)
2. body
3. antrum (lower)
   pylorus valve (sphincter)

Question 22

where does majority of digestion and absorption take place

Answer 22

small intestines

Question 23

what is the largest portion of digestive tract

Answer 23

small int 10-12 ft

Question 24

What releases exocrine secretions into duodenum

Answer 24

liver and pancreas

Question 25

3 parts of small intestine

Answer 25

1. duodenum (first 25cm) 2. jejunum 3. ileum (combined 260cm)

Question 26

what passes through the large intestine each day

Answer 26

1.5L of watery chyme

Question 27

what happens in large int

Answer 27

not much digestion water and electrolytes removed (absorption) to created semisolid feces

Question 28

what triggers the defecation reflex

Answer 28

feces entering the terminal section of the large intestine (rectum)

Question 29

5 parts of large int

Answer 29

cecum, ascending colon, transverse colon, descending colon, sigmoid colon

Question 30

what is sphincter between ileum and large int

Answer 30

ileocecal sphincter (valve)

Question 31

what are the sphincter in the rectum

Answer 31

internal anal sphincter (involuntary, smooth muscle) external anal sphincter (voluntary, skeletal)

Question 32

4 GI layers from lumen to abdominal cavity

Answer 32

mucosa, submucosa, muscularis externis, serosa

Question 33

3 layers of mucosa

Answer 33

epithelium lamina propria muscularis mucosa

Question 34

what are two nerve networks of the ENS

Answer 34

submucosal plexus myenteric plexus

Question 35

what is surface area increased by in the stomach

Answer 35

gastric glands (invaginations) rugae (microscopic gastric folds)

Question 36

what is the small intestine's surface area increased by

Answer 36

villi crypts (invaginations) plicae (large foldings)

Question 37

what does the epithelium include

Answer 37

transporting epithelial cells (enterocytes in sm int), endocrine and exocrine secretory cells

Question 38

what part of mucosa is most variable

Answer 38

epithelium

Question 39

what are difference in junctions

Answer 39

very tight in stomach and colon, leaky in small intestine (more absorption)

Question 40

why do GI stem cells have to constantly produce new cells

Answer 40

epithelia have short lifespan ~17 billion replaced daily

Question 41

what is the lamina propria of mucosa

Answer 41

subepithelial tissue containing nerve fibres, small blood vessels, and lymph vessels

Question 42

what is the muscularis mucosae of the mucosa

Answer 42

thin layer of smooth muscle that can alter the surface area available for absorption

Question 43

what is the submucosa

Answer 43

middle distensible layer containing large vessels (lymph +blood) and submucosal plexus

Question 44

muscularis externa

Answer 44

2-3 layers of smooth muscle and myenteric plexus - circular decrease diameter, longitudinal shortens tube

Question 45

what does the myenteric plexus do

Answer 45

controls the smooth muscle (in between 2 layers)

Question 46

serosa

Answer 46

outer covering of dense connective tissue that is continuation of peritoneal membrane, sheets of mesentery hold intestines in place

Question 47

digestion

Answer 47

chemical and mechanical breakdown of food into absorbable units

Question 48

secretion

Answer 48

movement of material from cells into lumen or ECF OR movement of water and ions from ECF to lumen

Question 49

absorption

Answer 49

movement of material from GI lumen to ECF

Question 50

motility

Answer 50

movement of material through the GI tract as result of muscle contraction