GI and Lower UT Final Flashcards
Lower Urinary Tract
Consists of the bladder and urethra, which transports urine from out of the body.
The Ureters, bladder, and urethra (except the terminal portion) are lined by a special form of transitional epithelium called urothelium.
Female: Ureters lie close to the uterine arteries and are vulnerable to injury in operations on the female genital tract
The close relationship of the female genital tract to the bladder make possible the spread of disease from one tract to the other.
Congenital anomalies of the Ureters
May contribute to obstruction of the flow of urine and thus cause recurrent UTI and pyelonephritis
Uteropelvic junction (UPJ) obstruction – Most common cause of hydronephrosis in infants and children
Dilation (hydroureter), elongation, and tortuosity of the ureters may occur as congenital anomalies or as acquired defects
Acute and Chronic Cystitis
Bacterial pyelonephritis is frequently preceded by infection of the urinary bladder, with retrograde spread into the kidneys
The common agents: E. coli, Proteus, Klebsiella, and Enterobacter. Women are more likely to develop cystitis as a result of their shorter urethras.
Predisposing factors include, DM, instrumentation, and immune def
Triad of symptoms
- Frequency
- Lower abdominal pain
- Dysuria
Can be a 20 complication of an underlying disorder associated with urinary stasis, such as a prostatic enlargement, cystocele of the bladder, calculi, or tumors
Bladder & Urothelial Neoplasm
Bladder cancer ~7% of cancers and 3% of cancer mortality in the US
The cast majority of bladder cancers (95%-97%) are urothelial carcinomas
Most common in the bladder but can be seen at any site where there is urothelium, from the renal pelvis to the distal urethra.
Incidence is higher in men than in women and ~80% are 50-80 yrs
Bladder cancer, with rare exceptions, is not familial.
- Cig Smoking (50-80%)
- Chem Carcinogens (Aryl Amines)
- Long term exposure to analgesics
- Heavy long-term exposure to cyclophosphamide
- Irradiation
Clinical course of Bladder Cancer
Painless hematuria, frequency, urgency, and dysuria
Pyelonephritis or hydronephrosis (ureteral orifice involved)
Urothelial tumors – tendency to develop new tumors after excision
Prognosis depends on the histologic grade and the stage at diagnosis
The clinical challenge – Early detection and adequate follow-up
Four Morphologic Patterns
- Papilloma
- Invasive papillary carcinoma
- Flat non-invasive carcinoma
Flat invasive carcinoma
Male genital tract
Generate and transport sperm, produces sex hormones, aids in urination
Includes: penis, scrotum, testes, duct system, and accessory glands
The seminiferous tubules are the site of the germination, maturation, and transportation of the sperm cells within the male testes
The seminiferous tubules are surrounded by a specialized epithelium containing Sertoli cells that provide protection and nourishment to germ cells
Penis
External genitalia – contains erectile tissue
Deposits sperm through ejaculation
Consists of three erectile tissues: the corpus spongiosum and two copora cavernosa
Average length is 2-5 inches when flaccid, and 4-7 inches when erect
Foreskin – sheath of loose skin covering penis
Smegma – oily secretion produced by the glans combined with shed skin cells
Scrotum
Sac of skin that contains the testes, epididymis, and lower spermatic cords
Maintains testicular temperature for spermatogenesis
The scrotum contracts to draw the testes closer to the body to warm them
The scrotum relaxes to drop the testes further from the body to cool them
Testes
Produce sperm and sex hormones
Spermatogenesis develops in most males by age 16 – involves H-P-G axis
Seminiferous tubules produce sperm
Epididymis stores sperm until ejaculation for maturation
Adrenarche – Onset of androgen-dependent body changes -> growth of axillary and pubic hair, body odor, and acne
Gonadarche – The earliest gonadal changes of puberty
Testosterone (primary androgen)
Gives males their 20 sex characteristics and sex drive
Regulates metabolism and protein anabolism
Inhibits pituitary secretion of gonadotropins
Promotes K+ excretion and renal Na+ reabsorption
Contributes to male pattern baldness and acne
Duct system
Deliver sperm from the testes to the exterior
Includes: Epididymis, vas deferens, spermatic cord, ejaculatory duct, and the urethra
Semen – Sperm and ejaculatory fluid from the seminal vesicles
Accessory glands
Prostate gland
-secretes a fluid that mixes the semen that decreases acidity, increases sperm motility, and prolongs sperm life
Cowper’s (Bulbourethral gland)
-Secrete another alkaline fluid into the urethra to naturalize acidity caused by urine transportation
Phimosis
Foreskin cannot be retracted from the glans penis
Causes: poor hygiene, infections, and sometimes carcinoma
Complications: urinary obstruction and pain
Paraphimosis – foreskin is retracted and cannot be returned ove the glans penis
Penis becomes constricted and edematous
Medical emergency
Complications: gangrene
Hypospadias and Epispadias
Abnormal urethral opening due to malformation of the urethral groove and urethral canal
Opening on the ventral surface of the penis (hypospadias) or on the dorsal surface (epispadias)
May be associated with failure of normal descent of the testes and with malformations of the urinary tract
Hypospadias, the more common of the two, occurs in ~1 in 300 live male births
Clin Sig:
Urinary tract obstruction and an increased risk of UTIs
Cause of sterility
Disorders of the scrotum
Varicocele
Dilation of veins in spermatic cord (pampiniform plexus)
Inadequate or absent valves in the spermatic veins
Hydrocele
Scrotal swelling due to collection of fluid within the tunica vaginalis (serous membrane that covers the testes)
Imbalance between fluid secretion and reabsorption
Spermatocele
Painless diverticulum of the epididymis locates between the head of the epididymis and the testis
Contains milky fluid that contains sperm
Testis and Epididymis
In the Epididymis, the most important and frequent conditions are inflammatory diseases, whereas in the testis the major lesions are tumors
Congenital anomalies
Undescended testes (cryptorchidism)
Rare – absence of one or both testes
Fusion of the testes (synorchism)
Cryptorchidism – Risk factors
Found in approx. 1% of 1 Y/O boys
Complete or partial failure of the intra-abdominal testes to descend into the scrotal sac
Associated with testicular dysfunction and an increased risk of testicular cancer
Risk factors: prematurity, low-birth-weight, family history of problems of genital development, maternal alcohol use during pregnancy, maternal cigarette smoking or secondhand smoke exposure during pregnancy, maternal diabetes, and paternal exposure to pesticides
Cryptorchidism – Complications
Testicular descent: Transabdominal phase, inguinoscrotal phase
Asymptomatic, and comes to attention when the scrotal sac is discovered to be empty
Complications: Sterility, risk of developing testicular cancer
During the first year of life the majority of inguinal cryptorchid testes descends spontaneously into the scrotum. Those that remain undescended require surgical correction
Vascular Disorders: Testicular Torsion
Twisting of the spermatic cord typically cuts off the venous drainage of the testis. If untreated, leads to testicular infarction – surgical emergency
Neonatal torsion – in utero or shortly after birth
Adult torsion - sudden onset of testicular pain
Cause: bilateral anatomic defect that leads to increased mobility of the testes (bell-clapper abnormality)
Testicular Tumors
Testicular Tumors – Pathogenesis
Originate from intratubular germ cell neoplasia (ITGCN)
These atypical germ cells retain the expression of transcription factors OCT 3/4 and NANOG, which are important in maintenance of pluripotent stem cells
Clin Features
Characteristic feature – Painless enlargement of the testis
Any solid testicular mass should be considered neoplastic until proven otherwise
Lymphatic spread to the retroperitoneal para-aortic nodes-> mediastinal and supraclavicular nodes
-Biological markers – hCG, AFP,LDH
Hematogenous spread – primarily to the lungs
Seminomas tend to remain localized to the testis for a long time -> ~70% present at clinical stage I
Prostate
Weight – 20 gm – Retroperitoneal organ encircling the neck of the bladder and urethra, and is devoid of a distinct capsule
Four biologically and anatomically distinct zones or regions: the peripheral, central, transitional, and periurethral zones
Most Hyperplasias – transitional zone
Most Carcinomas – Peripheral zone
Testicular androgens control the growth and survival of prostatic cells. Castration-> widespread apoptosis-> atrophy of the prostate
Inflammation, benign nodular enlargement, and tumors
Benign Prostatic Hyperplasia BPH
BPH Etiology and Pathogenesis
The main androgen in the prostate, constituting 90% of total prostatic androgens, is dihydrotestosterone (DHT)
DHT is formed in the prostate from testosterone through the action of an enzyme called type 2 5a-reductase, located almost entirely in stromal cells
DHT binds to the nuclear androgen receptor (AR) present in both stromal and epithelial prostate cells
Binding of DHT to AR-> stimulates the transcription of androgen-dependent genes (fibroblast growth factor (FGF) family and transforming growth factor (TGF)-B)
FGFs, produced by stromal cells, are paracrine regulators of androgen-stimulated epithelial growth during embryonic prostatic development, and some of these pathways may be “reawakened” in adulthood to produce prostatic growth in BPH. TGF-B serves as a mitogen for fibroblasts and other mesenchymal cells, but inhibits epithelial apoptosis
DHT-induced growth factors act by increasing the proliferation of stromal cells and decreasing the death of epithelial cells
BPH Clinical Features
Prostate Cancer
