Abdomen Lecture Notes Pt. 2 Flashcards
Receives tributaries from the SMV and IMV
Hepatic Portal Vein
The umbilicus and iliac crest are located at L4, but their cutaneous dermatome is
T10
The transpyloric plane cuts the kidneys in half and is also where part of the pancreas is. It is at the level of
L1
Divides the 4 quadrants horizontally
Transumbilical plane (L4)
Provide better differentiation between soft tissues
MRI’s
Appear as cross sections as viewed from the FOOT of a patient
-So observers left is the patients right
CT scans
In a CT, we want to find the vertebral body first. then just anterior to the vertebral body is the
Abdominal aorta
Then just to the right of the abdominal aorta is the
IVC
The abdominal aorta gives off the left renal artery at
L1-L2
The abdominal aorta gives off the left gonadal artery at
L2
In a CT of T12, we can clearly see the
Left colic flexure
Travels between the abdominal aorta and superior mesenteric artery
Left renal vein and uncinate process of duodenumm
Branches off posterior to the IVC
Right renal artery
Just inferior to where the SMV and splenic vein come together, we have the
Hepatic Portal Vein
We can see the pyloris of the stomach as we move into the 1st part of the duodenum in a CT at the level of
L1-L2
Each of the 3 prevertebral ganglion are associated with one of the big 3
Aorta branches (celiac trunk, SMA, IMA)
The only splanchnic nerves carrying parasympathetic fibers
Pelvic splanchnics
Ganglia in the wall of the organ we are innervating that are found in plexuses
Terminal ganglia
Provide EXTRINSIC innervation of the gut
Sympathetic and parasympathetic innervation
The enteric nervous system is intrinsic, meaning it is located in the walls of the
Bowel
The enteric nervous system is made up of which two major plexuses?
- ) Myenteric Plexus
2. ) Submucosal Plexus
Extrinsic nerve fibers run on blood vessels leading to the
Bowel
When the outer longitudinal layer of bowel muscle relaxes in front of the bolus and the inner circular layer contracts behind the bolus we get
Peristalsis
Disease where there are regions of the bowel without myernteric or submucosal plexus’s
-most common region is rectosigmoidal plexus
Aganglionic Megacolon (Hirschsprung’s)
In Hirschsprung’s, the constricted segment is the aganglionic segment because the extrinsic nerve fibers cause
Tonixc contraction
Allows relaxation of the colon
Intrinsic innervation
Have to go through the diaphragm to get into the abdomen for abdominal innervation
-Range from T5-T9
Greater thoracic splanchnics
The transition from midgut to hindgut happens immediately after the
Proximal 2/3 of transverse colon
Because of rotation of the forgut, where is the
- ) Left Vagus nerve
- ) Right vagus nerve
- ) Anterior
2. ) Posterior
Pass through the celiac ganglion and are distributed on the celiac trunk to organs
Posterior Vagal nerve fibers
There is communication between the celiac, SM, and IM plexuses which allows the vagus nerve to provide parasympathetic innervation from
Esophagus to proximal 2/3 of transverse colon
You could cut or burn segments of the bowel without feeling it. But what would you feel?
Ischemia or pressure
Dull and poorly localized pain due to the fact that the bowel has less nerve endings than skin
Visceral pain
The dermatomal segment for the umbilicus is
T10
What is the lowest dermatomal segment of the gut for visceral pain?
L1
Shows up in T6-upper T8 dermatomes
-Forgut Pain
Epigastric pain
Shows up from T-8 to upper part of T11 dermatomes
-Midgut pain
Umbilical pain
Shows up in T11-T12 dermatomes
-Hindgut pain
Suprapubic pain
The gall bladder refers pain to the
-described as being in the right shoulderblade
T7 dermatome
When an injured organ comes in contact with the body wall we get
Parietal Pain
Has rebound tenderness, meaning it doesn’t hurt when you press on the organ but it hurts when you release
Parietal pain
Uses VENTRAL rami for the entire pathway
Parietal pain
The right an left kidneys can be seen in a cross section at what level?
L2
-But really T12-L3
Infant kidneys can be described as being
Lobulated
What is the pathway of urine through the kidneys?
Nephrons in cortex –> Medullary pyramids –> Collecting tubules of renal pupilla –> Minor Calyces –> Major Calyces –> Renal Pelvic –> Ureter
Compression of left renal vein and 3rd part of duodenum by SMA
-Pain after eating
Superior mesenteric artery (nutcracker) syndrome
Kidney stones cause “loin to groin” pain where pain fibers travel in
Sympathetics
Located in the outer cortex and inner medulla of the kineys and made up of Nephrons (cortex) and collecting tubules (mostly medulla)
Uriniferous tubules
Ball of capillaries where urine formation begins
Glomerulus
Filtrate moves from glomerulus into PROXIMAL portion of
Nephron tubules
Filter blood to remove wastes as Urine
-Arrises from metanephrogenic blastema
Nephrons
An extension of the renal artery
Glomerulus
How does blood get to the Glomerulus?
Renal artery –> segmental artery –> interlobar artery –> arcuate artery –> interlobular artery –> afferent arterioles –> glomerulus
The urogenital ridge is made up
- ) Medially of?
- ) Laterally of?
- ) Gonadal ridge
2. ) Nephrogenic ridge
Initial non-functional kidney system located in the cervical region that completely regresses in week 4
Pronephros
The 2nd kidney system that is located in the thorax-abdomen and briefly serves as a filtration system, but mostly regresses
Mesonephros
The mesonephros is made up of which three things?
- ) Mesonephric (Wolfian) Duct
- ) Ureteric bud
- ) Metanephros (metanephrogenic blastema)
Lateral to the mesonephros
- Mostly regresses in females
- Forms male internal genital system
Mesonephric (Wolfian)Duct
Serves as collecting system for temporary, regressing mesonephros
Mesonephric duct
Comes off caudal end of mesonephric duct
-forms collecting components of adult kidney
Ureteric Bud
Forms in the sacral region where it forms the nephrons of adult kidney
Metanephros
The interactions between the metanephros and ureteric bud can be described as being
Reciprocal induction
Made from the developing kidney
-aids in lung development
Amniotic fluid
Increased amniotic fluid which indicates an abnormality such as GI atresia or anencephaly
Polyhydramnios
As the kidney initially develops close to the bladder, it receives blood from the
Median sacral artery (branch off internal iliac)
Lined by transitional epithelium called urothelium
Urinary bladder
Keeps urine from leaking back into the ureters
Vesicouretal reflux
Located just inferior to the bladder in males
-surounds urethra in that area
Prostate
Located on the posterior side of the bladder
Seminal vesicles and bulbourethral glands
Splits into urogenital sinus and rectoanal canal
0divided by urorectal septum
Cloaca
Enters the posterior side of the urogenital sinus to form the bladder trigone
-Pulls ureters in so they empty into the trigone
Mesonephric ducts
Defect in anterior ventral midline during fusion of lateral body folds that results in bladder being located outside abdominal wall
Bladder Extrophy
Located in the testes and contain sertoli and germ cells
Seminiferous tubules
Lead to ducts called rete testis which then lead to efferent ductules
Seminiferous tubules
The seminiferous tubules are surrounded by connective tissue that contains
Leydig cells
Induced by primordial germ cells from the yolk sac during weeks 4-6
Gonad formation
Travel through the allentois and will later give rise to sperm and eggs
Primordial germ cells
Formed from gonadal ridge mesoderm after induction by primordial germ cells
Primitive sex cords
In males, the primitive sex cords will proliferate and form the medullary cords of the
Testes
These medullary cords will then give rise to the
Seminiferous tubules and rete testes
The primitive sex cords will proliferate in cortical surface of ovary in females and the cortical cells will become
Follicles
Secrete the Mullerian Inhibiting Factor (MIH), which prevents the paramesonephric duct from forming
Sertoli Cells
Forms from the prostatic urethra
Prostate
Forms the uterine tubes, body of uterus, cervix, and upper portion of the vagina
Paramesonephric ducts
The lower portion of the vagina is derived from the
Urogenital sinus
Form along the cloacal membrane where endoderm and ectoderm meet without intervening mesoderm
External Genitals
The cloacal membrane eventually forms the
Genital tubercle, Cloacal fold, and Genital swellings (i.e. labiosacral fold)
The cloacal membrane is then divided by the urorectal septum into
Anterior urethral fold and posterior anal fold