2. Anatomy Pt. II

Question 1

Hindgut derivatives

Distal 1/3 transverse colon, descending colon, sigmoid, rectum
Receive blood supply from the ____ and its branches
Receive preganglionic sympathetic innervation from ____ nerves
Receive preganglionic parasympathetic innvervation from the ____

Answer 1

inferior mesenteric artery
lumbar splanchnic
pelvic splanchnics (S2-4)

Question 2

Cannon’s Ring is the name for the junction between the ____ and ____ derivatives. It’s essentially a constriction in the ____ colon. It is hard to find anatomically and more easily seen in radiographic studies of the colon than in a gross anatomical one.

The splenic (left colic) flexure is always going to be found significantly more ____ located in the upper left quadrant than the hepatic flexure was in the upper right quadrant

Answer 2

midgut
hindgut
superiorly

Question 3

IMA

• ____ artery
• ____ artery
• ____ branches

Additional rectal arteries are derived from the ____ arteries in the pelvis.

Answer 3

superior rectal
left colic
sigmoidal
iliac

Question 4

Anastomoses exist between the three arteries supplying the abdominal gut
1 Around the ____ and pancreatic head

2 Around the ____ flexure

3- IMA-Iliac anastomoses occur along the ____

Answer 4

duodenum
left colic (splenic)
rectum

Question 5

The RECTUM is ____, lying anterior to the sacrum and differing in aspects of its ____ from the rest of the colon

Answer 5

secondarily retroperitoneal

structure

Question 6

Internally, the rectum features three ____ rectal folds

The terminal rectum is distended to form the ____ just prior to penetrating the ____

Answer 6

transverse
ampulla
pelvic diaphragm

Question 7

The terminal rectum turns posteroinferiorly as it prepares to penetrate the pelvic diaphragm to become continuous with the ____

Answer 7

anal canal

Question 8

Tonic contraction of a ____ helps to maintain fecal continence at the anorectal flexure…

…along with the ____, an involuntary sphincter formed by the circular muscle layer of the upper anal canal

Answer 8

puborectal sling

internal anal sphincter

Question 9

The ____ marks the caudal boundary between the gut and the body wall

The smooth muscle of the
____
plays a role in maintaining fecal continence

Answer 9

pectinate line

internal anal sphincter

Question 10

Recall that bundles of
____ sympathetic axons that pass through the paravertebral chain ganglia without synapsing are called
____

Answer 10

preganglionic

splanchnic nerves

Question 11

Recall too that these fibers synapse in ____ ganglia located anterior to the spine…
and are thus referred to as ____ or…

…____
GANGLIA as they are clustered on the anterior surface of the ____ aorta

Answer 11

collateral
prevertebral
preaortic
abdominal

Question 12

Associated with these
____ ganglia
are similarly named autonomic plexuses that
also contain ____ fibers

Answer 12

sympathetic

preganglionic parasympathetic

Question 13

Both ____ and ____ parasympathetics contribute to the innervation of the abdominal GI organs

Answer 13

cranial

sacral

Question 14

CN X -
VAGUS NERVES
provide parasympathetic innervation to derivatives of the embryonic foregut and midgut via the ____

PELVIC SPLANCHNICS
supply the hindgut from
____

Answer 14

anterior and posterior vagal trunks

S2-4

Question 15

Postganglionic
sympathetics
and preganglionic
parasympathetics
form a dense, mixed
\_\_\_\_
around the branches
of the \_\_\_\_, \_\_\_\_ and \_\_\_\_ arteries
as they course toward their targets

Answer 15

periarterial plexus
celiac
superior mesenteric
inferior mesenteric

Question 16

These extrinsic inputs modulate the function of the ____, in principle an independent network of neurons that provide the foundation for autonomic GI reflexes

Answer 16

enteric nervous system

Question 17

Parasympathetic stimuli
• promote ____
• promote ____

Sympathetic stimuli:
• facilitate contraction of
\_\_\_\_ sphincters
• inhibit both \_\_\_\_
and glandular \_\_\_\_

Answer 17

peristalsis
secretion
smooth muscle
peristalsis
secretion

Question 18

In the abdomen, visceral afferents accompanying sympathetic nerves also transmit ____ from…

• ____ stimulated by excessive ____ of GI viscera
• Strong contractions of ____ in visceral walls

Answer 18

pain
nociceptors
distension
smooth muscle

Question 19

VISCERAL AFFERENTS fibers, also course along with ____ nerves

Some of these convey ____ sensations
arising from ____ responding to distension in the walls of the GI tract

Others convey inputs from ____ e.g. those sensitive to the concentration
of ____ ions in the stomach

Answer 19

parasympathetic
physiologic
mechanoreceptors
chemoreceptors
hydrogen

Question 20

Splanchnics convey these ____ fibers from viscera
to the ____ of spinal nerves ____ via the ____

These pain afferents may stimulate ____ fibers in the dorsal roots of these nerves and produce abdominopelvic
“____”

Answer 20

GVA
dorsal roots
T5-L2
white communicating rami

GSA

Question 21

Pain from pathological ____ is also consistently

referred to specific regions of the body wall

Answer 21

abdominopelvic viscera