Contents of the Abdomen

Question 1

Basic Histology

Answer 1

Serous: outer membrane; encloses several body cavities; secrete a lubricating fluid; outer epithelial layer (secretory) and inner layer (connective tissue with vessels)
Muscular: longitudinal or circular; responsible for movement of contents
Mucosal: inner layer; lines internal organs or cavities exposed to external environment; secrete mucus; involved in absorption

Question 2

GI Tract

Answer 2

Oral cavity: teeth - accessory organs, assist mechanical digestion; palate - rest of mouth, soft palate blocks nasal cavity during swallowing; tongue - accessory organ, taste, assist mixing, swallowing; salivary glands - secrete saliva
Pharynx: directs food to oesophagus; blocks entry to trachea
Oesophagus: muscular tube (25cm long); posterior to trachea; upper edge (pharynx) pierces diaphragm; opens to stomach
Stomach, small intestine, large intestine

Question 3

Stomach Anatomy

Answer 3

Most dilated part of alimentary canal
Between oesophagus and small intestine
J-shaped; lies under diaphragm and under the heart
2 opening, curvatures, surfaces
Mechanical (muscle) and chemical (gastric juices) digestion
Cardiac orifice (link to oesophagus) and pyloric orifice (link to small intestine)
Lesser curvature (superior border) and greater curvature (inferior border)
Pyloric and cardiac sphincters
3-layered muscles - longitudinal, circular and oblique

Question 4

Small Intestine

Answer 4

Convoluted tube
Pylorus of stomach to ileocaecal junction
5 metres in length, subdivided into 3 parts
Where digestion and absorption take place
Duodenum: 20-25 cm long; retroperitoneal; C shaped; 4 parts - superior, descending, horizontal, ascending; where the duct from pancreas and gall bladder open (bile and pancreatic juices); ends at duodenal-jejunal flexure
Jejunum/ileum: 3 m long; site of absorption (large SA, further increased by circular folds, villi and microvilli; motility); motility: one attached edge and one free edge; ends at ileocaecal junction

Question 5

Large Intestine

Answer 5

Terminal division of GI tract - from end ileum to anus
1.5m length; greater cross secrion than small intestine
4 parts: ascending, transverse, descending, sigmoid (r to left)
Ascenting/descending are retroperitoneal
Absorption of water, from faeces and expelling these
Rectum/anus - sphincters close outside world except when defecating

Question 6

Branches of Superior and Inferior mesenteric

Answer 6

Superior: distal part duodenum to proximal 2/3 transverse colon; jejunal and ileal branches; middle and right colic; ileocaecal
Inferior: distal 1/3 transverse colon to 1/2 way down anal canal; left colic; sigmoid; superior rectal

Question 7

Blood/Nerves/:ymph

Answer 7

Foregut: celiac artery, portal vein, celiac nodes, celiac ganglia for symp and vagus for parasymp
Midgut: superior mesenteric artery and vein, superior mesenteric nodes and ganglia (symp) and vagus (para)
Hindgut: inferior mesenteric artery and vein and nodes and ganglia (symp), pelvic splanchnic (para)

Question 8

Autonomic Innervation

Answer 8

Sympathetic innervation: splanchnic nerves, sympathetic trunk and ganglia
Parasympathetic innervation: vagus nerve (CN X), pelvic splanchnic nerves (S2-4)