Lecture 11 Flashcards
Alimentary III (32 cards)
What levels is the rectum found?
S3 to pelvic diaphragm
Is rectum suspended or retro?
Retro. Attached to posterior pelvic wall
How is the rectum curved?
Anteriorly then posteriorly. Right to left to right.
What folds are located in rectum?
Temporary longitudinal folds in ampulla
Permanent horizontal folds
Describe horizontal folds of the rectum
Commonly three
Semilunar valves
Where does peritoneum attach to rectum?
Upper 1/3 - anteriorly and laterally
Middle 1/3 - anterior only
Lower 1/3 - none
What does reflection of middle attachment of peritoneum to rectum form?
rectovesicular pouch in males and rectouterine pouch in females
What is the sling of muscle at the rectoanal junction called?
puborectalis (wraps around rectoanal junction)
What is the upper part of the anal canal formed by?
folds/columns
What are the lower ends of anal columns joined by?
Transverse folds - valves
What are spaces between anal columns called?
Sinuses
What type of epithelium does the pectinate line separate in the anal canal?
Simple columnar and non keratinised ss
What type of epithelium does the white line/mucocutaenous junction separate in the anal canal?
non keratinised ss and keratinised ss
Describe the anal sphincters
Internal - smooth muscle, controlled by ANS
External - skeletal muscle, voluntary control
Describe the gastrocolic reflex
Increase in motility of the colon in response to stretch in the stomach
Describe continence
Muscle tone keeps anus closed
Puborectalis pulls upper part of anal canal forward and presses on upper part of external sphincter
Relaxation of rectum and sigmoid muscle wall
Describe defacation
Prior to defacation, faeces are held in ampulla until voided
Defacation reflex from medulla
Relaxation of sphincters and puborectalis
Peristalsis in descending and sigmoid colon increases
Contraction of abdominal muscles and diaphragm
Where does the pancreas secrete to (2)?
Exocrine - digestive enzymes via pancreatic duct at greater duodenal papilla
Endocrine - Islets of langerhans (insulin/glucagon) via blood
Origin of pancreas?
ventral pancreatic bud - uncinate process and inferior head
dorsal pancreatic bud - the rest
How does the pancreas rotate during development?
Ventral rotates posteriorly to lie behind dorsal pancreas and the two primordia then fuse
Where is the main pancreatic derived from?
Ventral duct
Is the pancreas suspended or retro?
Retro apart from tail in splenorenal ligament
What is the duct formed from the unification of the main pancreatic duct and the bile duct?
hepatopancreatic ampulla
What is name of ligament between pancreas and spleen?
splenorenal ligament
