What structures are included in the distal GI tract?
What is the function of the distal GI tract?
What is the holding area for faeces?
Which nerve fibres supply the rectum to detect its level of "fullness"?
Muscle sphincters in the distal part of the anus (contract / relax) to prevent defecation.
Muscle sphincters in the distal part of the anus (contract / relax) to allow defecation.
The rectum is located within the ___ cavity.
Which muscle forms the pelvic floor?
Levator ani muscle
Which tracts pass through the levator ani?
At which line does the sigmoid colon become the rectum?
At which vertebral level is the recto-sigmoid junction found?
Which part of the rectum stores most of the faecal material and is found superior to the levator ani?
The walls of the rectal ___ can relax to accomodate faeces.
What lies anterior to the inferior rectum in males?
What lies anterior to the inferior rectum in females?
Vagina and cervix
When naming pouches, what does "vesico/vesical" mean?
What is the pouch found in the abdominal cavity of males?
What are the two pouches found in the abdominal cavity of females?
Rectouterine pouch (of Douglas)
Which muscle supplies support for the pelvic organs?
Which branch of the sacral plexus supplies the levator ani?
"Nerve to levator ani"
The pudendal nerves supply the levator ani. At which vertebral levels do these nerves originate?
s2,3,4 keeps the pelvis off the floor
Which muscle of the levator ani acts like a sphincter to constrict the rectum voluntarily?
Which two anal sphincters maintain faecal continence?
Internal anal sphincter
External anal sphincter
Which type of muscle makes up the internal anal sphincter?
Which type of muscle makes up the external anal sphincter?
The anal canal is found inferior to the ___ junction.
Which autonomic nerves contract the internal anal sphincter?
fight or flight - why would you defecate while running away from a lion
Which autonomic nerves relax the internal anal sphincter?
Which stimulus relaxes the internal anal sphincter?
Distension of the rectal ampulla
Which nerve stimulates the contraction of the external anal sphincter?
Which part of the body is found below the levator ani?
Generally, which arms of the nervous system supply structures in the pelvis?
Generally, which arms of the nervous system supply the perineum?
Sympathetic nerves from which spinal cord levels supply the rectum and anal canal?
T12 - L2
Where do rectum / anal canal sympathetic nerves synapse?
Inferior mesenteric ganglia
How do post-synaptic sympathetic nerves travel to the rectum and anal canal?
Sympathetic nerves (contract / relax) the internal anal sphincter.
Sympathetic nerves (inhibit / stimulate) peristalsis.
Parasympathetic fibres supply the rectum / anal canal from which spinal cord levels?
S2 - S4
How do parasympathetic nerves travel to the rectum / anal canal from S2 - S4?
Pelvic splanchnic nerves
Where do parasympathetic nerves supplying the rectum / anal canal synapse?
In the walls of the rectum / anal canal
Parasympathetic nerves (contract / relax) the internal anal sphincter.
Parasympathetic nerves (inhibit / stimulate) peristalsis.
Which nerves piggy-back on the parasympathetic nerves as they return back to S2-S4 on the way to the CNS?
Which somatic nerves travel from S2-S4 to contract the external anal sphincter and puborectalis?
Somatic motor (via the pudendal nerves, S2-S4)
Which nerve, a branch of the sacral plexus, supplies the external anal sphincter?
Which two holes in the pelvis transmit the pudendal nerve?
Greater sciatic foramen
Lesser sciatic foramen
In women, which event can damage pudendal nerve fibres or external anal sphincter muscles?
Why may a woman be incontinent after childbirth?
Tearing of perineum inc. nerves, muscle and external anal sphincter
What is the pectinate line?
Line between endoderm and ectoderm
arterial, venous, lymphatic and nerve supplies differ above and below
What are the major lymph nodes draining pelvic organs, from inferior to superior?
Which artery supplies the hindgut organs?
Inferior mesenteric artery
Which artery supplies the remainder of the GI tract after the hindgut?
Internal iliac artery
Which arteries anastomose to supply the rectum and anal canal?
Inferior mesenteric artery
Internal iliac artery
Which vein drains the rectum and anal canal above the pectinate line?
Inferior mesenteric vein
Which venous system drains the hindgut?
Portal venous system
Which vein drains the anus below the pectinate line?
Internal iliac vein
Which venous system drains below the pectinate line?
Systemic venous system
Are rectal varices and haemorrhoids the same thing?
What are rectal varices?
Dilation of portal-systemic anastomoses due to portal hypertension
What are haemorrhoids?
Prolapses of rectal venous plexuses
Which areas, near the anal canal, are filled with fat and loose connective tissue?