Digestive System Flashcards
digestive tract formed from…
1) gastrointestinal tract: tube that stretches from mouth to anus
2) accessory organs: teeth, tongue, salivary glands, pancreas, liver and gall bladder
functions of digestive tract
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)
visceral smooth muscle characteristics
- thick + thin myofilaments
- lack myofibrils/sarcomeres (no striation)
- cells are spindle shaped w/ one nucleus
- arranged in sheets & operates as unit (syncytium)
- gap junctions
peritoneum
- largest serous membrane
- peritoneal cavity filled w/ serous fluid
mesentery characteristics
- 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
mesentery function
- holds organs + store lipids
mesentery: omentum
- folds of visceral peritoneum
greater omentum: mesentery that covers transvers colon + small intestine (protection, stored energy + insulation)
lesser omentum: connects stomach + duodenum to liver
mesentery: peritonitis
inflammation of peritoneum
retroperitoneal organs
located posterior to peritoneum
- pancreas, duodenum, ascending + descending colon and kidneys
parietal peritoneum
located on anterior surface of organ
adventitia
CT located on posterior surface of organ
layers of digestive tract
- extending from esophagus to anal canal
- hollow an similar layers as reproductive, respiratory + urinary tract
layers: serosa
- adventitia in esophagus
- areolar CT + simple squamous
- outermost, protective layer in peritoneal cavity
retroperitoneal organ layers
- contains both serosa + adventitia
- anterior surface from peritoneum
- posterior surface from adventitia
layers: muscularis externa
- layer of visceral smooth muscle
- motility caused by contractions
- inner circular + outer longitudinal layer (myenteric nerve plexus b/w layers)
layers: submucosa
- areolar CT
- binds mucosa to muscularis externa
- contains lymph + blood vessels
layers: mucosa
- innermost layer (faces lumen)
- composed of mucous membrane and 3 layers
mucosa: muscularis mucosa
- located nearest to submucosa
- smooth muscle (permits motility in mucosa)
mucosa: lamina propria
- areolar CT
- located in center of mucosal layer
- contains blood, lymphatic vessels + tissues
mucosa: mucosal epithelium
- mouth, pharynx, esophagus & anal canal -> stratified squamous
- stomach, small + large intestine -> simple columnar
- lots of goblet cells responsible for mucous production
mouth
- oral cavity includes: lips, cheeks, palate, tongue
- lined by mucosa (stratified squamous) & skeletal muscle
- mouth contains: tongue, palate, salivary glands + teeth
mouth: tongue
- 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)
mouth: palate
hard: anterior from maxilla and palatine bones
soft: posterior from uvula and skeletal muscle arch (rise to close nasopharynx)
mouth: salivary glands
- parotid, submandibular & sublingual gland
- contains 99.5% water + 0.5% dissolved solutes
- lysozyme: digests bacterial structures prevent oral infections
- salivary amylase
