Lecture 2: Alimentary Structures Flashcards
What are alimentary structures?
Structures that relate to NOURISHMENT or SUSTENANCE
What are the only places that are ectodermly derived in the GI tube?
Oral cavity
Inferior 1/3 of the anal canal (below the pectinate line)
What do the regions of the gut tube (foregut, midgut, hindgut) have that serves to distinguish them from one another?
- Arterial blood supply
- Innervation
- Relationships to mesentery
Where does the bile duct enter the duodenum?
At the separation between foregut and midgut
How do you separate regions of gut tube?
Foregut is the point of entry of bile duct into duodenum
Midgut to hindgut is proximal 2/3 and distal 1/3 of transverse colon
Is the spleen part of gut tube?
No because it is mesoderm derived
What is in the foregut?
Celiac trunk 1. Esophagus, 2. stomach 3. duodenum (1st and 2nd parts) 4. liver 5. pancreas 6. biliary apparatus 7. gall bladder Below are derivatives of gut tube but not part of GI tract per se 8. Pharyngeal pouches 9. Lungs 10. Thyroid
What innervates the foregut?
- Parasympathetic = Vagus nerve
2. Sympathetic = T5-T9
What innervates the midgut?
- Parasympathetic = vagus nerve
2. Sympathetic = T10-T12
What innervates the hindgut?
- Parasympathetic = Pelvic (splanchnic) nerves (S2-4)
2. Sympathetic = L1-L3
What is the purpose of enteric ganglia?
Ganglia located within the walls of the gut tube
Goal in life of sympathetics are to synapse here
What is the significance of the sympathetic innervation of the gut tube?
Visceral pain will be referred to the T1-L3 dermatomes
Pain from abdominal viscera is carried back to the CNS by sympathetic nerves and is referred to dermatomes of the body wall that match the sympathetic innervation
Pain is POORLY LOCALIZED
Where is pain of the umbilicus referred to?
Small intestine
What is the referred pain to appendix?
T10
McBurney’s point
What is secondarily retroperitoneal?
- pancreas
- duodenum
- ascending colon
- descending colon
Significant for imaging
What are some synonyms for ventral mesentery remnant?
Omentum
Where does esophagus begin?
C6
Cervical Constriction
Cricopharyngeus muscle
Narrowing of the esophagus
Where is the level of the thoracic constriction of the diaphragm?
T4
There the bronchus bifurcates
Where aortic arch is