Digestive system Flashcards
main functions of digestive system:
- ingestion
- secretion
- mixing and propulsion
- digestion (mechanical, chemical)
- absorption
- defecation
define bolus:
soft rounded mass of food that is swallowed
define chyme:
semifluid mixture of partly digested food, and digestive secretions
- in stomach and small intestine
define feces:
discharged from rectum, from large intestines
- made up of bacteria, excretions and food residue```
list parts of alimentary canal:
aka gastrointestinal tract
- oral cavity
- pharynx
- oesophagus
- stomach
- small intestine
- large intestine
list accessory digestive organs:
- teeth
- tongue
- salivary glands
- liver
- gallbladder
- pancreas
what is the alimentary canal: general
hollow tube with lumen, layers:
- mucosa
- submucosa
- muscularis
- serosa/ adventitia
features: mucosa
mucous membrane
- epithelial lining: enteroendocrine cells
- lamina propria (areolar ct) MALT
- muscularis mucosae (inner circular/ outer longitudinal layer) - smooth muscle
features: submucosa
areolar ct.
- blood,
- lymph vessels
- submucosal (Meisnner’s) nerve plexus (ENS)`
GENERAL features: muscularis
- internal (circular) and external (longitudinal) muscle layer
- myenteric (Auerbach’s) nerve plexus (ENS)
type of muscle in muscularis layer and eg: skeletal and smooth muscle
skeletal:
- mouth
- pharynx
- superior/ middle part of - - oesophagus
- external anal sphincter
smooth muscle: others
features: serosa/ adventitia
- serous membrane (covered by serous fluid)
- areolar ct.
- blood vessels, lymph vessels, simple squamous epithelium (mesothelium)
adventitia: in oesophagus (single layer of ct.)
features: peritoneum
largest serous membrane: abdominopelvic cavity
- parietal, visceral layers
- peritoneal cavity (serous fluid)
list retroperitoneal organs:
duodenum, pancreas, ascending, descending colon, kidneys, adrenal glands
features: oral cavity
buccal cavity
- cheeks
- tongue
- hard, soft palate
- uvula
- lips, teeth
- oral vestibule
- covered by mucous membrane: stratified squamous epithelium (keratinised in high impact areas)