Module 17: The Digestive System Flashcards Preview

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Flashcards in Module 17: The Digestive System Deck (43):
1

enzymes are used to

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

2

3 functions of digestive system

digestion
absorption
elimination

3

Process of digestive system

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

4

Organs of digestive tract

aka alimentary canal or GI tracts

mouth
pharynx
esophagus
stomach
small and large intestine

5

accessory organs of digestive system

teeth
tongue
salivary glands
liver
gallbladder
pancreas

6

serous Peritoneum

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

7

Visceral peritoneum

covers external surfaces of digestive organs

8

Parietal peritoneum

lines walls of abdominal cavity

9

Extensions (folds) of peritoneum

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)

10

Functions of peritoneum

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

11

Location of peritoneal cavity

space between the visceral peritoneum and the parietal peritoneum

12

Function of peritoneal cavity

serous fluid provides lubrication for 2 layers
preventing friction

13

Layers of the alimentary canal

walls of alimentary canal from the esophagus to the anus

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

14

Function of mucosa

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)

15

function of Submucosa

connective tissue that binds the mucosa to the muscularis
contains blood and lymphatic vessels, lymph nodules and nerve fibers

16

Function of muscularis

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

17

Function of serosa

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

18

Oral cavity consists of

cheeks
hard palate
soft palate
teeth
tongue
salivary glands

19

hard palate

roof of mouth
ridges called rugae
breaks down food

20

Soft palate

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

21

Tongue

lingual frenulum divides tongue in 2 halves
attached and supported by hyoid bone

22

Salivary glands

secrete saliva
Amylase for helps breakdown complex carbs
Lysozyme destroys bacteria

23

Pharynx

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

24

main function of pharynx

begins the process of swallowing

25

esophagus

bolus passes through esophageal hiatus
joins the stomach at the cardiac sphincter (lower esophageal sphincter)

26

main function of the esophagus

transportation of food from pharynx to the stomach

27

Stomach

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

28

stomach opens to the duodenum through the

pyloric sphincter

29

Gastric pits

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

30

Function of stomach

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

31

Small intestine

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

32

main function of small intestine

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

33

Large intestine

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

34

Functions of large intestine

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

35

Liver

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)

36

Function of liver regarding digestion

to manufacture bile for breakdown of lipids in duodenum
Breakdown is necessary before lipase can finish the job

37

Gallbladder

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

38

function of gallbladder

storage sac for bile

39

Pancreas

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

40

chemical digestion of carbs

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

41

Chemical digestion of protein

pepsin and trypsin break proteins down into peptides
peptidase breaks down into amino acids (the end product)

42

chemical digestion of lipids

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

43

Chemical digestion of nucleic acids

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