Module 17: The Digestive System

Question 1

enzymes are used to

Answer 1

break down carbs into simple sugars, proteins into amino acids and lipids into glycerol and fatty acids

Question 2

3 functions of digestive system

Answer 2

digestion
absorption
elimination

Question 3

Process of digestive system

Answer 3

Ingestion
propulsions (swallowing)
Digestion (mechanical and chemical)
Absorption
Elimination (defecation)

Question 4

Organs of digestive tract

Answer 4

aka alimentary canal or GI tracts

mouth
pharynx
esophagus
stomach
small and large intestine

Question 5

accessory organs of digestive system

Answer 5

teeth
tongue
salivary glands
liver
gallbladder
pancreas

Question 6

serous Peritoneum

Answer 6

simple squamous epithelium that covers connective tissue
found in abdominopelvic cavity below the diaphragm
Above diaphragm = adventitia

Question 7

Visceral peritoneum

Answer 7

covers external surfaces of digestive organs

Question 8

Parietal peritoneum

Answer 8

lines walls of abdominal cavity

Question 9

Extensions (folds) of peritoneum

Answer 9

mesentery (small intestine)
mesocolon (colon)
falciform ligament (Liver)
greater omentum (fatty apron that hangs over stomach and covers colon and small intestine)
lesser omentum (suspends the stomach and duodenum from liver)

Question 10

Functions of peritoneum

Answer 10

holds organs in place
conducts nerves, blood and lymphatic vessels
some fatty parts protect organs

Question 11

Location of peritoneal cavity

Answer 11

space between the visceral peritoneum and the parietal peritoneum

Question 12

Function of peritoneal cavity

Answer 12

serous fluid provides lubrication for 2 layers

preventing friction

Question 13

Layers of the alimentary canal

Answer 13

walls of alimentary canal from the esophagus to the anus

inner to outer layer: mucosa, submucosa, muscularis, serosa

Question 14

Function of mucosa

Answer 14

direct contact with contents of tract
protection
secretion of enzymes, mucus and hormones
absorption of nutrients
pulls mucous membrane of small intestine into folds (plicae circularis)

Question 15

function of Submucosa

Answer 15

connective tissue that binds the mucosa to the muscularis

contains blood and lymphatic vessels, lymph nodules and nerve fibers

Question 16

Function of muscularis

Answer 16

consists of inner circular smooth muscle and outer longitudinal smooth muscle

Exception: stomach has extra layer of smooth muscle (oblique)

Mixes (segmentation) and propels (peristalsis) food and water through digestive tract
Circular layer of smooth muscle forms valves/sphincters

Question 17

Function of serosa

Answer 17

visceral periotneum
Consists of areolar connective tissue covered with simple squamous epis
Protection

Question 18

Oral cavity consists of

Answer 18

cheeks
hard palate
soft palate
teeth
tongue
salivary glands

Question 19

hard palate

Answer 19

roof of mouth
ridges called rugae
breaks down food

Question 20

Soft palate

Answer 20

posterior roof of mouth
uvula hangs from it
assist in swallowing
uvula prevents food from flowing back into the nasal cavity

Question 21

Tongue

Answer 21

lingual frenulum divides tongue in 2 halves

attached and supported by hyoid bone

Question 22

Salivary glands

Answer 22

secrete saliva
Amylase for helps breakdown complex carbs
Lysozyme destroys bacteria

Question 23

Pharynx

Answer 23

bolus of food is forced to back of mouth and onto oropharynx
respiratory/breathing temporarily stopped
Soft palate and uvula move upward and close off nasopharynx
Bolus passes through laryngopharynx and enters esophagus
Breathing resumes

Question 24

main function of pharynx

Answer 24

begins the process of swallowing

Question 25

esophagus

Answer 25

bolus passes through esophageal hiatus

joins the stomach at the cardiac sphincter (lower esophageal sphincter)

Question 26

main function of the esophagus

Answer 26

transportation of food from pharynx to the stomach

Question 27

Stomach

Answer 27

upper left quadrant of peritoneal cavity
divided into the cardiac, funds, body and pylorus
Curved
holds 4L of food
Collapses into longitudinal folds called rugae

Question 28

stomach opens to the duodenum through the

Answer 28

pyloric sphincter

Question 29

Gastric pits

Answer 29

leads to gastric glands in lining of stomach

Mucous neck cells secret mucous
Chief cells secrete pepsinogen and lipase
Parietal cells secret HCl and intrinsic factor
Enteroendocrine cells release gastrin

Question 30

Function of stomach

Answer 30

mechanical and chemical digestion of food that form chyme that enters first part of small intestine (duodenum)

Question 31

Small intestine

Answer 31

6 meters long
first parts = duodenum (receives chyme from stomach)
second part= jejunum
third part = ileum
Bile from liver digests fats
Amylase helps to digest starch
lipase digests fats
proteases help digest proteins

Crypts of lieberkuhn secrete enzymes that chemically digest proteins and carbs

Absorption in walls of small intestine (surface area large due to plicae circulates, villi, microvilli)
Peyers patches are clumps of lymphoid follicles found in abundance towards the end of the small intestine

Question 32

main function of small intestine

Answer 32

completion of digestion and the absorption of nutrients into the blood capillaries and lymphatic vessels

Question 33

Large intestine

Answer 33

1.5m long
extends from ileum to anus
Ileocecal valve connects ileum to large intestine
regions include: cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, anal canal, anus
Appendix is attached to cecum
Teniae Coli are bands of smooth muscle in walls of intestines (cause walls for form pouches called hausfrau)
Epiploic appendages are fat pilled pouches of visceral peritoneum that hang from large intestine

Question 34

Functions of large intestine

Answer 34

absorption of water, electrolytes
synthesis of certain vitamins by intestinal bacteria
elimination of feces

Question 35

Liver

Answer 35

reddish brown, 3lb
largest organ other than skin
divided into right and left lobes
Lobes separated by falciform ligament
Consist of lobules with hepatocytes (synthesize bile)

Question 36

Function of liver regarding digestion

Answer 36

to manufacture bile for breakdown of lipids in duodenum

Breakdown is necessary before lipase can finish the job

Question 37

Gallbladder

Answer 37

pear shaped
attached to liver by cystic duct
duct joints the hepatic ducts from liver to form the common bile duct
base of common bile duct forms hetaopancreatic ampulla (where main pancreatic duct joins the common bile duct)
Common bile duct empties bile into the duodenum

Question 38

function of gallbladder

Answer 38

storage sac for bile

Question 39

Pancreas

Answer 39

head and tail ends
Acinar cells secrete digestive enzymes into tiny ducts which merge into pancreatic duct (which empties into duodenum)
produces amylase, lipase, proteases

Question 40

chemical digestion of carbs

Answer 40

into smaller monosaccharides
first broken down by salivary amylase
pancreatic amylase breaks down into disaccharides
broken down into monosaccharides by sucrase, maltase, lactase
End products are glucose, fructose, galactose

Question 41

Chemical digestion of protein

Answer 41

pepsin and trypsin break proteins down into peptides

peptidase breaks down into amino acids (the end product)

Question 42

chemical digestion of lipids

Answer 42

fats emulsified by bile
lipase acts on emulsified fats and breaks them down into monoglycerides and free fatty acids
End products are monoglycerides and fatty acid chains

Question 43

Chemical digestion of nucleic acids

Answer 43

pancreatic nucleases enter duodenum and cause breakdown into nucleotides
Brush border enzymes break those down into pentose, phosphate, nitrogenous bases