Anatomy

Question 1

What do the lumbar splanchnic nerves innervate?

Answer 1

The abdominal part of the hind gut, 2/3 the way across the transverse colon to end of sigmoid colon. Also the into pelvis to innervate viscera of urogenital system.

Question 2

Trace the path of the lumbar splanchnic nerves from CNS.

Answer 2

symp/pre: lateral horn of L1-L2 –>ventral roots of L1-L2–>spinal nerves–>white rami–>sympathetic trunk–>lumbar splanchnic nerves–>aortic plexus (Inferior mesenteric ganglion)
symp/post: inferior mesenteric ganglion–>inferior mesenteric plexus–>abdominal hindgut viscera

or to superior hypogastric plexus and into pelvis for pelvic viscera

Question 3

What are the functions of sympathetic innervation to GI viscera of foregut and midgut?

Answer 3

-contricts blood vessels and inhibits peristalysis

Question 4

What provides sympathetic innervation to the foregut and midgut parts of abdominal GI tract (from terminal esophagus to 2/3 way across transverse colon)?

Answer 4

-greater splanchnic nerves from T5-T12

Question 5

Trace the pathway of the thoracic splanchnic nerves from CNS to abdominal viscera.

Answer 5

symp/pre: lateral horn of T5-12–>ventral root–>spinal nerve–>white rami–>sympathetic trunk–>greater thoracic splanchnic nerves–>enter abdomen through diaphragm –>celiac ganglion
symp/post: celiac ganglion–>celiac plexus and superior mesenteric plexus–>foregut and hindgut organs following arteries

Question 6

What are the functions of parasympathetic innervation to the GI viscera?

Answer 6

-stimulates glandular secretions and promotes peristalsis caused by contraction of smooth muscle in walls of the oragnas

Question 7

What provides parasympathetic innervation to foregut and midgut parts of abdominal GI tract from terminal esophagus to 2/3 way across transverse colon?

Answer 7

-vagus nerves

Question 8

Trace the pathway of parasympathetic innervation to the foregut and midgut parts of abdominal viscera.

Answer 8

para/pre: cell bodies in brainstem–>vagus nerve–>esophageal plexus–>vagal trunks going through esophageal hiatus–>branches to stomach/liver or to celiac and superior mesenteric plexuses to other viscera in foregut and midgut
para/post: in nerve plexuses in walls of viscera

Question 9

What provides parasympathetic innervation to hind gut?

Answer 9

sacral parasympathetics

Question 10

Trace the pathway of parasympathetic innervation to the hind gut.

Answer 10

para/pre: lateral area of S2-S4 spinal cord–>ascend from pelvis and travel across left posterior abdominal wall to reach abdominal parts of hind gut. Does not go through superior hypogastric plexus, aortic plexus, or proximal parts of inferior mesenteric plexus.

Question 11

Where are the viscerosensory pain cell bodies for abdominal viscera?

Answer 11

DRG of T5-L2

Question 12

List the nerve components of the following plexus:

1. aortic
2. celiac
3. superior mesenteric plexus
4. intermesenteric
5. inferior mesenteric
6. superior hypogastric

Answer 12

1. aortic: symp/post, para/pre, VS pain and reflex
2. celiac: symp/post, para/pre, VS pain and reflex
3. superior mesenteric plexus: symp/post, para/pre, VS pain and reflex
4. intermesenteric: symp/post, VS pain
5. inferior mesenteric: symp/post, VS pain
6. superior hypogastric: symp/post, VS pain

Question 13

What are the nerve components of dorsal roots?

Answer 13

Somatosensory at all levels

viscerosensory from T1-L2, and S2-S4

Question 14

Where does the subcostal nerve come from and what does it innervate? What are the nerve components?

Answer 14

From T12. follows below 12th rib. Innervates muscles of abdominal wall and underlying parietal peritoneum. Has lateral and anterior cutaneous branches to skin. Contains SM, SS, symp/post.

Question 15

Where does the iliohypogastric nerve come from and what does it innervate? What are the nerve components?

Answer 15

L1. Parallels subcostal nerve. Innervates muscles of abdominal wall and underlying parietal peritoneum. Has lateral and anterior cutaneous branches to skin-lower hypogastric region above pelvic bone. Contains SM, SS, symp/post.

Question 16

Where does the ilioinguinal nerve come from and what does it innervate? What are the nerve components?

Answer 16

L1. Parallels iliohypogastric nerve. Innervates skin of lateral body wall along iliac crest and lowest parts of ab wall muscles. Found between EAO and IAO. Contains SM, SS, symp/post. After superficial ring becomes:
Anterior scrotal nerve or anterior labial nerve (only SS, symp/post) - which are anterior cutaneous branches.

Question 17

What does the anterior scrotal nerve and anterior labial nerve innervate?

Answer 17

anterior scrotal nerve: cutaneous innervation to medial thigh, base of penis, anterior scrotal wall including dartos muscle. afferent limb of cremastric reflex (toward CNS)
anterior labial nerve: follows round ligament to supply cutaneous innervation to media thigh, mons pubis, and anterior part of labia majora

Question 18

Where does the genitofemoral nerve come from and what does it innervate? What are the nerve components?

Answer 18

From L1-2. Courses downward on psoas muscle. Innervates skeletal fibers of cremaster muscle and cutaneous innervation to skin of medial thigh. Afferent and efferent limbs of cremastric reflex. Contains SM, SS, symp/post.

Question 19

Define a hydrocele. What can cause it?

Answer 19

definition: increase in serous fluid within tunica vaginalis surrounded the testes. Cuased by injury or inflammation of the epididymis or testis. A patent processes vaginalis in newborn males (10%) can also cause.

Question 20

Define diverticula and diverticulitis.

Answer 20

diverticula-small bag like out pocketings of intestinal lumen adjacent to fatty appendages and taenia coli. commonly seen in sigmoid colon. Diverticulitis is an inflammation of these diverticula.

Question 21

What is volvulus?

Answer 21

-an abnormal twisting of a portion of the bowel on itself, often in the sigmoid region. Leads to ischemia of the bowel.

Question 22

What is superior mesenteric artery occlusion usually caused by? What are the symptoms?

Answer 22

-usually caused by embolism or thrombus at the origin of the SMA. Symptoms are severe abdominal pain in the umbilical or/and epigastric regions after eating. Has high mortality rate.

Question 23

Where does one usually get referred pain from gallbladder inflammation?

Answer 23

In the right shoulder. Inflamed fundus of gallbladder bumps agains under surface of diaphragm, innervated by phrenic nerve. Pain axons in dorsal horns of C3,4,5 where SS from right shoulder also converge in C3,4.

Question 24

In diseases of the liver where portal blood cannot flow through it, what is the collateral venous pathway that the blood can take?

Answer 24

Through esophageal veins that drain into azygous veins to the superior vena cava. High pressure on esophageal veins can cause them to become enlarged.

Question 25

Where is the anastomosis that represents the are of transition between embryonic foregut and midgut?

Answer 25

head of the pancreas and duodenum. There are two branches from celiac artery and two from SMA that anastomose here. Includes the anterior superior pancreaticoduodenal artery.

Question 26

Which structures are derived from/developed in the ventral mesentery of the embryo? (foregut only)

Answer 26

liver, gallbladder, ventral pancreas.
lesser omentum with hepatogastric and hepatoduodenal ligament
falciform ligament
coronary ligament

Question 27

Which structures are derived from/developed in the dorsal mesentery of the embryo?

Answer 27

Greater omentum, splenorenal, gastrosplenic
the mesentery
mesocolon: transverse mesocolon, sigmoid mesocolon

Question 28

What does the right gastroepiploic artery anastomose with?

Answer 28

Left gastroepiploic and left gastric artery

Question 29

How does blood bypass the liver in fetal circulation? Trace the path.

Answer 29

umbilical veins–>portal vein–>ductus venosus–>hepatic veins–>IVC