Digestive System

Question 1

digestive tract formed from…

Answer 1

1) gastrointestinal tract: tube that stretches from mouth to anus
2) accessory organs: teeth, tongue, salivary glands, pancreas, liver and gall bladder

Question 2

functions of digestive tract

Answer 2

1) ingestion
2) digestion
- mechanical digestion: chewing food + peristalsis
- chemical digestion: enzymes + acids break down
3) absorption: end products taken into blood + lymph
4) defecation: elimination of waste + undigested materials (poops)

Question 3

visceral smooth muscle characteristics

Answer 3

• thick + thin myofilaments
• lack myofibrils/sarcomeres (no striation)
• cells are spindle shaped w/ one nucleus
• arranged in sheets & operates as unit (syncytium)
• gap junctions

Question 4

peritoneum

Answer 4

• largest serous membrane

- peritoneal cavity filled w/ serous fluid

Question 5

mesentery characteristics

Answer 5

• double layer of peritoneum (2 fused serous membrane)
• from wall of abdominal cavity it extends to digestive organs (route for blood vessels, lymphatics + nerves)
• dorsal attach to posterior abdominal wall
• binds large + small intestine to wall

Question 6

mesentery function

Answer 6

• holds organs + store lipids

Question 7

mesentery: omentum

Answer 7

• folds of visceral peritoneum

greater omentum: mesentery that covers transvers colon + small intestine (protection, stored energy + insulation)

lesser omentum: connects stomach + duodenum to liver

Question 8

mesentery: peritonitis

Answer 8

inflammation of peritoneum

Question 9

retroperitoneal organs

Answer 9

located posterior to peritoneum

- pancreas, duodenum, ascending + descending colon and kidneys

Question 10

parietal peritoneum

Answer 10

located on anterior surface of organ

Question 11

adventitia

Answer 11

CT located on posterior surface of organ

Question 12

layers of digestive tract

Answer 12

• extending from esophagus to anal canal

- hollow an similar layers as reproductive, respiratory + urinary tract

Question 13

layers: serosa

Answer 13

• adventitia in esophagus
• areolar CT + simple squamous
• outermost, protective layer in peritoneal cavity

Question 14

retroperitoneal organ layers

Answer 14

• contains both serosa + adventitia
• anterior surface from peritoneum
• posterior surface from adventitia

Question 15

layers: muscularis externa

Answer 15

• layer of visceral smooth muscle
• motility caused by contractions
• inner circular + outer longitudinal layer (myenteric nerve plexus b/w layers)

Question 16

layers: submucosa

Answer 16

• areolar CT
• binds mucosa to muscularis externa
• contains lymph + blood vessels

Question 17

layers: mucosa

Answer 17

• innermost layer (faces lumen)

- composed of mucous membrane and 3 layers

Question 18

mucosa: muscularis mucosa

Answer 18

• located nearest to submucosa

- smooth muscle (permits motility in mucosa)

Question 19

mucosa: lamina propria

Answer 19

• areolar CT
• located in center of mucosal layer
• contains blood, lymphatic vessels + tissues

Question 20

mucosa: mucosal epithelium

Answer 20

• mouth, pharynx, esophagus & anal canal -> stratified squamous
• stomach, small + large intestine -> simple columnar
• lots of goblet cells responsible for mucous production

Question 21

mouth

Answer 21

• oral cavity includes: lips, cheeks, palate, tongue
• lined by mucosa (stratified squamous) & skeletal muscle
• mouth contains: tongue, palate, salivary glands + teeth

Question 22

mouth: tongue

Answer 22

• composed of skeletal muscle
• covered by mucosa
• lamina propria makes papillae (some have taste buds)
• dorsal surface has lingual glands (fluid = lingual lipase that digest fats)

Question 23

mouth: palate

Answer 23

hard: anterior from maxilla and palatine bones
soft: posterior from uvula and skeletal muscle arch (rise to close nasopharynx)

Question 24

mouth: salivary glands

Answer 24

• parotid, submandibular & sublingual gland
• contains 99.5% water + 0.5% dissolved solutes
• lysozyme: digests bacterial structures prevent oral infections
• salivary amylase

Question 25

salivary glands: parotid gland

Answer 25

- located inferior + anterior to ears - produce thin saliva (lacks mucus except in salivary amylase) - mumps is a disease that results from viral infection/inflammation of parotid gland

Question 26

salivary glands: submandibular gland

Answer 26

- located bottom of mouth | - produce fluid containing amylase + mucus

Question 27

salivary glands: sublingual glands

Answer 27

- located below tongue (floor of mouth) | - produce mucus

Question 28

mouth: teeth

Answer 28

- found in gum covered by maxillae + mandible - mechanically breakdown food - children: deciduous/primary/baby teeth - adult: secondary/permanent

Question 29

TEETH: crown

Answer 29

- composed of dentin w/ enamel overlay | - above gum

Question 30

TEETH: neck

Answer 30

boundary b/w enamel + cementum

Question 31

TEETH: root

Answer 31

composed of dentin w/ cementum overlay

Question 32

TEETH: periodontal ligaments

Answer 32

attach root to jaw bones

Question 33

TEETH: pulp cavity

Answer 33

contains pulp (blood vessels, nerves, CT + lymph vessels) enclosed by dentin

Question 34

TEETH: root canal

Answer 34

ext. of pulp cavity into root

Question 35

TEETH: dentin

Answer 35

calcified CT similar to bone, but avascular

Question 36

TEETH: enamel

Answer 36

acellular, avascular, highly calcified (hardest substance)

Question 37

TEETH: cementum

Answer 37

calcified, avascular CT