Digestive System Overview Flashcards
What are the 9 components of the gastrointestinal tract?
Mouth Pharynx Oesophagus Stomach Small intestine (duodenum, jujenum, ileum) Large intestine (ascending, transverse, descending) Colon Rectum Anus
What are the 5 accessory organs of the digestive system?
Tongue Salivary glands Pancreas Liver Gallbladder
What are the components of the upper and lower digestive system?
Upper: mouth, pharynx, oesophagus, stomach
Lower: small intestine, large intestine, colon, rectum, anus
What are the 6 phases of the digestive process?
- Ingestion
- Propulsion (deglutition and peristalsis)
- Mechanical breakdown
- Digestion (enzymatic breakdown)
- Absorption
- Defecation
What are the 3 principles of digestive regulation?
- A range of mechanical and chemical stimuli can provoke digestive activity (distension, pH, osmolarity, fats)
- Neurons and hormones control digestive activity
- Smooth muscle and glands are the key effectors in the digestive system
What are the 4 layers of the wall of the digestive system?
Mucosa (deep)
- epithelial cells on lamina propria (connective tissue layer)
- thin mm layer of muscularis mucosae gently contracts to vibrate epithelial cells and create furrows
Submucosa
- connective tissue layer containing blood vessels, lymph vessels, and nerves
Muscularis
- 2 muscle fibre layers (longitudinal and circular)
Adventitia or serosa (superficial)
- intraperitoneal organs covered with serosa (fibrous connective tissue)
- retroperitoneal organs covered with adventitia (membranous connective tissue)
What are the 3 unpaired arteries that supply the abdominal viscera, and which areas do they supply?
Celiac trunk (T12) (oesophagus, stomach, duodenum, liver, gallbladder, pancreas)
Superior mesenteric (L1) (pancreas, small intestine, ascending and transverse colon, appendix)
Inferior mesenteric (L3) (descending colon)
What are the 3 branches that the celiac trunk gives off?
Left gastric
Splenic
Common hepatic
What are the 5 paired arteries that supply the abdominal viscera and wall, and which areas do they supply?
Inferior phrenic (t12) (diaphragm, inferior oesophagus)
Adrenal / suprarenal (L1)
(adrenal glands)
Renal (L2)
(kidneys)
Gonadal (L2)
(testes or ovaries)
Lumbar (L4)
(vertebrae, spinal cord, abdominal wall, lumbar region)
What are the 8 arteries that arise from the abdominal aorta and supply the abdominal viscera and wall, and are they paired or unpaired?
Unpaired:
- Celiac trunk
- Superior mesenteric
- inferior mesenteric
Paired:
- inferior phrenic
- adrenal / suprarenal
- renal
- gonadal
- lumbar
At what levels do the celiac trunk, superior mesenteric and inferior mesenteric arteries arise?
Celiac: T12
Super Mesenteric: L1
Inferior Mesenteric: L3
What are the 3 prevertebral / preaortic ganglia? Are these sympathetic or parasympathetic ganglia?
- Celiac Ganglion
- Superior Mesenteric Ganglion
- Inferior Mesenteric Ganglion
(sympathetic neurons)
What is the difference between abdominopelvic splanchnic nerves and pelvic splanchnic nerves?
Abdominopelvic:
- SNS
- synapse at pre-aortic ganglia
Pelvic splanchnic:
- PNS
- from sacral division (S2-4)
- synapse in terminal ganglia in or near target organ / gland
What are the two sources of PNS innervation for the abdominal viscera, and which areas do they innervate?
Cranial:
- CNX Vagus
- via dorsal motor nucleus of vagus
- innervates all abdominal viscera up to left colic / splenic flexure of large intestine
Sacral:
- S2-4
- all abdominal viscera below left colic / splenic flexure of large intestine
What are the 4 types of abdominopelvic splanchnic nerves, are they PNS or SNS, and from which levels do they originate?
- Greater splanchnic (T5-9)
- Lesser splanchnic (T9-10)
- Least splanchnic (T12)
- Lumbar splanchnic (L1-3)
SNS
