Digestive System

Question 1

structures of the GI tract

Answer 1

mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus

Question 2

mechanical digestion

Answer 2

breakdown of large food particles into small particles by physical means (i.e the teeth grind and mash food into smaller bits)

Question 3

chemical digestion

Answer 3

chemical alteration of food (i.e protein is chemically digested into amino acids)

Question 4

2 forms of movement

Answer 4

segmentation: alternate contraction and relaxation of stomach muscles digest food mechanically and mix with digestive juices
peristalsis: a rhythmic alternating contraction and relaxation that pushes food forward through the GI tract

Question 5

serosa

Answer 5

made up of: mesentery, mesocolon (peritoneal membranes//behind GI organs), and omentum (front)
helps anchor the digestive organs, blood/lymph vessels, and nerves to the abdominal organs

Question 6

ENS

Answer 6

enteric nervous system

regulates GI motility and secretion; its activity is modulated via autonomic nerves, the parasympathetic nervous system

Question 7

mouth

Answer 7

digestion begins immediately

includes: teeth, tongue, salivary glands, and several other structures

Question 8

teeth

Answer 8

masticate (chew)
deciduous (baby teeth)
gingiva (gums)

Question 9

dentin

Answer 9

majority, bonelike material of tooth

Question 10

pulp

Answer 10

nerves, blood vessels, and CT

beneath dentin: pulp cavity

Question 11

periodontium

Answer 11

the tissues that surround the teeth include: gums, bone, soft tissue

Question 12

tongue

func.

Answer 12

facilitates chewing, swallowing, and repositioning of food

contains taste buds

Question 13

frenulum

Answer 13

anchors tongue to floor of mouth

Question 14

salivary glands

Answer 14

parotid (largest), submandibular, sublingual (smallest)

digestive enzyme: salivary amylase (ptyalin)

Question 15

hard & soft palates

Answer 15

hard: anterior, separates oral cavity from nasal
soft: uvula blocks food from entering nasal cavity

Question 16

pharynx

Answer 16

involved in deglutition (swallowing)

only the oropharynx and laryngopharynx are part of the GI tract

Question 17

esophagus

Answer 17

hollow tube that carries food from pharynx to stomach via the pharyngoesophageal sphincter and the LES (relax: open // contraction: closed)

Question 18

pyrosis

Answer 18

heartburn

Question 19

GERD

Answer 19

gastroesophageal reflux disease

Question 20

stomach

func.

Answer 20

1) secretion of gastric juices, includes: digestive enzymes, hydrochloric acid (HCl), and intrinsic factor
2) digestion of food. mostly mechanical, limited chemical
3) absorption of small quantities of water and dissolved substances… absorbs only alcohol quickly
4) secretion of gastric hormones
5) regulation of rate at which partially digested food is delivered to the duodenum via pyloric sphincter

Question 21

layers of stomach

Answer 21

mucosa, submucosa, muscle, and serosa

Question 22

muscle layers

Answer 22

longitudinal, oblique, circular

Question 23

glands of the stomach

Answer 23

exocrine: {gastric juice} 3 secretory cells; mucous cells: secrete mucus, chief cells: secrete digestive enzymes, parietal cells: secrete HCl and intrinsic factor
neuroendocrine: g cells: secrete gastrin [released in response to vagus nerve stimulation and the presence of amino acids and small peptides in the stomach]

Question 24

small intestine

func.

Answer 24

1) receives chyme from stomach and digestive juices from liver (bile) and pancreas (digestive enzymes); digestion is completed in small intestine
2) absorbs the end-products of digestion and key substances as iron and vitamins
3) moves the unabsorbed content into large intestine

Question 25

small intestine | parts

Answer 25

{most digestion and absorption occur in the duodenum and first third of the jejunum} duodenum: receives chyme and other digestive enzymes from liver, pancreas, and gallbladder jejunum ileum: func. to complete the process of absorption of end-prod, b12, and bile salts; ileocecal sphincter prevents reflux of contents from the cecum

Question 26

wall of small intestine

Answer 26

microvilli villi; within each villus {absorptive capillaries} {lacteal}

Question 27

Protein, Carbs, Fats digest order

Answer 27

Protein and Carbs go to the liver first before being distributed throughout the body Fats breakdown later and the end-products enter the lacteal, forming a milky-white lymph called chyle

Question 28

hormones of the small intestine

Answer 28

secretin: stims pancreas to release sodium bicarbonate {nature's own antacid}; makes chyme alkaline cholecystokinin: stims gallbladder to contract releasing bile; stims pancreatic release of digestive enzymes; slows gastric emptying

Question 29

large intestine | sect.

Answer 29

``` cecum colon {ascending, transvers, descending, sigmoid} rectum anal canal anus ``` tenia coli: connective band causing pucker haustra: bulbous pouches

Question 30

large intestine | func.

Answer 30

1) absorption of water and electrolytes 2) synthesis of certain vitamins by intestinal bacteria (K and some B) 3) Temp. storage of feces 4) Elimination of waste from body (defecation)

Question 31

liver | func.

Answer 31

Main: Synthesis of bile salts and secretion of bile 2) synthesis of plasma proteins 3) storage; glycogen // fat-soluble vitamins 4) detoxification 5/6) metabolize carbs and proteins 7) metabolize fat 8) phagocytosis

Question 32

pancreas | func.

Answer 32

{pancreatic enzymes are the most important of all digestive enzymes} secretes both exocrine and endocrine substances exocrine: digestive enzymes and alkaline secretion (neutralizes highly acidic chyme)

Question 33

gallbladder | func.

Answer 33

pear-shaped sac attached beneath the liver | concentrate and store bile

Question 34

carbohydrates | types

Answer 34

sugars: monosaccharides (glucose, fructose, galactose)& disaccharides (sucrose, maltose, and lactose) starches: polysaccharides

Question 35

polysaccharides breakdown

Answer 35

1) amylases breakdown poly into disacc | 2) dissacharidases breakdown dissac's into mono

Question 36

protein types digested by?

Answer 36

building blocks = amino acids several amino acids together = peptide many amino acids together = polypeptide very long chains of polypeptides = protein enzymes called proteases

Question 37

protein types digested by?

Answer 37

building blocks = amino acids several amino acids together = peptide many amino acids together = polypeptide very long chains of polypeptides = protein enzymes called proteases

Question 38

fat types digested by?

Answer 38

long-chain fatty acids attached to a glycerol enzymes called lipases bile emulsifies the large fat globules into thousands of tiny particles that lipases breakdown for absorption

Question 39

bile | func.

Answer 39

emulsification of fat prevent reformation of large fat globules help with absorption of fat-soluble vitamins (A, D, E, K)