Small intestine disease

Jejunum - - - Jejunum and Ileum Figure

• 40% of small intestine
• Few large vascular arcades (loops)
• Long vasa recta
• Large, tall, and closely packed plicae circulares
• Less fat in mesentery than ileum
• Locus of maximum water (90%) and nutrient absorption, except for B12, bile acids, iron, and folate
• 95% of water absorbed

• Ileum - - - Jejunum and Ileum Figure

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  60% of small intestine Many small vascular arcades (loops) Short vasa recta Large, low, and sparse plicae circulares, none distal More fat in mesentery than jejunum Maximum absorption of nonconjugated bile acids, with conjugated bile acids absorbed in terminal ileum B12 and folate maximally absorbed in terminal ileum Endocrine Gut Functions Top Cholecystokinin (CCK): secreted by cells of proximal intestine Secretin: secreted by S cells of proximal intestine Motilin: secreted by M cells of proximal intestine Somatostatin (SMS): secreted by D cells throughout gut Peptide YY (PYY): secreted by L cells of distal intestine Glucagon-like peptide 2 (GLP-2): secreted by L cells of distal intestine   Diverticulectomy: most common treatment for uncomplicated diverticulitis Segmental resection indicated for complicated diverticulitis, neck <1/3 ileal diameter, or inflammation of the base

   

Prostate disease

•  Prostate anatomy
• Supported anteriorly by puboprostatic ligaments, central portions of the pubococcygeus, part of the levator ani muscles (anterior pelvic diaphragm)
• Supported inferiorly by the urogenital diaphragm (transversus perinei muscle and fascia), through which the urethra passes

• Aspects of TURP	Top
  Post-TURP Syndrome: hyponatremia secondary to irrigation; can precipitate seizures and cerebral edema Most common site of primary carcinoma: posterior lobe Most common site of distal metastasis: bone, with osteoblastic lesions showing increased density on CT and radiograph Increases in serum alkaline phosphatase seen with extracapsular carcinoma and metastases

   

  Staging and Treatment ↓

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  Tumor/node/metastasis (TNM) system used Gleason scoring system: additional scoring (1-5) from well differentiated (least aggressive) to poorly differentiated (most aggressive) Transrectal ultrasonography (TRUS) can provide an accurate image of the gland and guide needle biopsies CT can provide evidence of prostatic pathoanatomy, lymphadenopathy, and metastases Optimal treatment for localized prostate cancer remains controversial Intracapsular tumors, no metastases (on T1 and T2 MRI): irradiation, radical prostatectomy with pelvic lymph node excision, or no treatment depending on age, specifics Extracapsular tumors with metastases: hormonal treatment with luteinizing hormone releasing hormone blocker or testosterone blockers, potential orchiectomy; irradiation for pain of bony metastases, chemotherapy for hormone-resistant disease “Chemical castration”: luteinizing hormone releasing hormone (LHRH) antagonists suppress testosterone production in androgen-dependent tumors LHRH antagonists are also called GnRH antagonists (gonadotropin releasing hormone blockers) Alternatives or complements to prostatectomy: x-ray or particle beam therapy, brachytherapy (implanted radiation sources), and cryotherapy

Pancreatic Disease

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Functional Anatomy ↓ Tubuloacinar gland structure with a variety of cell types, including intermingled Islets of Langerhans Parasympathetic and sympathetic nerves are distributed to islets and acini Cells’ secretions are controlled by endocrine and autonomic nervous activities
- Exocrine Functions ↓
Mediated by secretin and cholecystokinin formed by duodenal and jejunal epithelium Acinar cells secrete amylase, lipase, trypsinogen, chymotrypsinogen, carboxypeptidase, and Cl- Ductal cells secrete HCO3- Some secretomotor input comes from vagal parasympathetic fibers
- Endocrine Functions ↓	Top
Alpha cells secrete glucagon Beta cells (central islets) secrete insulin Delta cells secrete somatostatin F or PP cells secrete pancreatic polypeptide Islet cells also produce vasoactive intestinal peptide (VIP), serotonin, neuropeptide Y, and gastrin releasing peptide (GRP) 5 fluorouracil (5-FU) and streptozocin chemotherapy work well for all Insulinoma Most common islet cell tumor, >85% benign symptoms (Whipple’s triad): fasting hypoglycemia, hypoglycemic symptoms (catechol surge, elevated heart rate, sweating), relieved by glucose

Kidney Disease

Intrarenal Arteries and Renal Segments

Ureter Fibromuscular tube with mucosa Upper: renal pelvis to upper border of sacrum Middle: overlies sacrum Lower: border of sacrum to bladder Blood supply: upper from renal arteries, middle from ovarian or testicular arteries, lower from vesical arteries Innervation of Kidneys and Ureters Top Parasympathetic Preganglionic: vagal fibers run through celiac and superior mesenteric plexuses, joining renal nerve plexus for distribution to ganglion cells in renal parenchyma, pelvis, and ureter Sympathetic Preganglionic: fibers run through splanchnic nerves (especially least), celiac, and superior mesenteric plexuses to synapse in aorticorenal ganglia Postganglionic: fibers distributed to smooth muscle of renal vessels and gomeruli Sensory: segmental visceral afferent fibers run parallel to sympathetic fibers to dorsal root ganglia and spinal segments T11-L2  Renal cell carcinoma (hypernephroma): metastasized to lung (most common) or colon Greatest risk factor: smoking Nephroblastoma (Wilms’ tumor): Rare renal malignant tumor of early childhood: 8/million incidence Tumor cells produce renin, leading to hypertension  Associated with hypospadias, cryptorchidism, ocular malformations  Most common secondary renal tumor: breast metastasis

Hernia

Nerves Near the Spermatic Cord ↓

Iliohypogastric: superficial if seen Ilioinguinal: typically superficial to cord Genitofemoral: usually posterior to cord  Inguinal Hernia  Indirect Passes through deep (internal) inguinal ring, inguinal canal, and finally through superficial (external) inguinal ring; follows course of spermatic cord Typically congenital, associated with a persistence of the fetal processus vaginalis (peritoneal tract accompanying the descending testis) Direct Passes directly through posterior wall of inguinal canal, through defect in transversalis fascia, within Hesselbach’s triangle