4.URINARY BLADDER AND URETHRA human anatomy.pptx

An overview of the pelvic structures in humans.

1. URINARY BLADDER AND URETHRA TERRY HUMAN ANATOMY

2. introduction U rinary bladder : muscular reservoir of urine, lying behind s.pubis . It is commonly involved in clinical conditions such as retention of urine, cystitis, calculus, disorder of micturition, and cancer. Tetrahedral and ovoid in shape when empty and distended respectively. varies in size, shape, position.

3. When empty, the adult urinary bladder lies almost entirely in the lesser pelvis unlike infants and young children (abdominal organ) even when empty because the pelvic cavity is small. The bladder begins to enters the enlarging pelvis by 6 years of age ; however, it is not located entirely within the lesser pelvis until after puberty . when full, it may ascend to the level of the umbilicus.

4. External features Apex :It provides attachment to the median umbilical ligament and lies posterior to the upper margin of the pubic symphysis . Base/fundus: on the posterior surface. Neck :It is the lowest and most fixed part of the bladder Body : btn apex and fundus (detrusor muscle) Nb /Only the superior surface is covered by peritoneum

5. Relation of the base of urinary bladder in the male.

6. Toward the neck of the male bladder, the muscle fibers form the involuntary internal urethral sphincter . This sphincter contracts during ejaculation to prevent retrograde ejaculation (ejaculatory reflux) of semen into the bladder. Trigone formed by ureteric orifices and the internal urethral orifice which are at an angle. The ureteric orifices are encircled by loops of detrusor muscles that tighten when the bladder contracts to assist in preventing reflux of urine into the ureter.

7. . Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

8. Capacity: normal-400-600ml An amount of urine beyond 200 ml causes a desire to micturate . The filling of urine up to 500 ml may be tolerated but beyond this, it causes pain due to tension of its wall. > 800 ml, the micturition is beyond one’s voluntary control . Normal Residual vol. after micturition is 150ml

9. SUPPORTS OF THE URINARY BLADDER The urinary bladder is anchored firmly at its neck, where it is fixed by its continuity with the prostate and urethra. The fixation of the bladder is also helped by the different ligaments of the urinary bladder i.e true and false lig .

10. True Ligaments These are formed by the condensation of pelvic fascia around the neck and the base of the bladder and have a supportive function for the bladder . Includes A) Lateral ligaments (right and left): They extend from the the bladder to the tendinous arch of pelvic fascia . B . Puboprostatic ligaments (2 lateral and 2 medial ) ( a) Lateral puboprostatic : extends from the anterior end of the tendinous arch of pelvic fascia to blend with the upper part of the prostatic sheath . (b) Medial puboprostatic : extends from the back of the pubic bone near the pubic symphysis to the prostatic sheath ). In the female are termed as pubovesical lig . & end around the neck of the urinary bladder.

11. C. Median umbilical lig .: the fibrous remnant of the urachus . It extends from the apex of the bladder to the umbilicus . It maintains the bladder in position anteriorly and superiorly. D. Posterior lig ..( right and left): They extend from the side of the base of the bladder to the lateral pelvic wall . They enclose the vesical venous plexus

12. True lig . of the urinary bladder

13. False Lig . These are peritoneal folds and do not have supportive function as performed by true ligaments. They include: Anteriorly Median umbilical fold, the fold of peritoneum over the median umbilical ligament . 2 medial umbilical folds, the folds of peritoneum over the obliterated umbilical arteries. laterally 2 lateral ligaments is formed by the reflection of the peritoneum from the bladder to the side wall of the pelvis Posteriorly 2 posterior ligaments which are the folds of peritoneum extending from the side of the bladder, posteriorly, on either side of the rectum, to the anterior aspect of the third sacral vertebra.

14. MICROSCOPIC STRUCTURE 3 layers mucous membrane : folded ( rugae ) when the bladder is empty. muscular coat : 3 layered, outer longitudinal, middle circular and an inner longitudinal layer . they cannot be unseparetable due to profuse intermingling of the muscle fibres . Adventitia : made up of fibroelastic tissue. Nb /Since the muscle fibres of the bladder wall are mainly concerned with the evacuation of the bladder they are collectively called the “detrusor muscle .”

15. Blood supply 1.superior and inferior vesical arteries (principal arteries)-branches of anterior division of IIA. 2. Obturator and inferior gluteal arteries. 3. Uterine and vaginal arteries in the female . Inferior vesical artery (vaginal artery in the female): It runs forward to the base of the urinary bladder. It supplies the base of the bladder, prostate, and seminal vesicles in males. It also gives rise to the artery of the vas deferens . V enous drainage The veins of the bladder do not follow the arteries. They form a complicated plexus on the inferolateral surfaces near the prostate called vesical venous plexus -into IIV The plexus communicates in the male with the prostatic venous plexus and in the female with the veins at the base of broad ligament.

16. NERVE SUPPLY MOTOR INNERVATION : It is provided by the ANS and somatic fibres . Parasympathetic fibres ( S2 , S3, S4 )-motor to the detrusor muscle and inhibitory to the internal urethral sphincter (emptying of the bladder ) Sympathetic fibres (T11-L2) -inhibitory to the detrusor and motor to the internal urethral sphincter ( filling of the bladder) Somatic fibres (S2-S4, pudendal nerve) - motor to the external urethral sphincter ( voluntary control of micturition) . SENSORY INNERVATION run along the parasympathetic and sympathetic fibres . Concerned with pain and conscious awareness of filling of the bladder.

17. Innervation of the urinary bladder (sympathetic innervation: blue lines; parasympathetic innervation: red lines; somatic innervation: black lines).

18. MICTURATION REFLEX Full bladder-sensory receptors on wall of bladder stimulated-impulse to sacral region (PNS) –signal back to urinary bladder via PNS==CONTRACTION OF DETRUSSOR MUSCLES AND RELAXATION OF IUS= VOIDING This part of reflex is involuntary and predominant in infants and young children. As CNS matures it acquires voluntary control over external urethral sphincter. Micturition center in pons and receives sensory information 4m bladder wall and comm.to cerebral cortex for appropriate action i.e either inhibition or Promotes voiding.

19. Micturition

20. Difference btn children and adult in micturation reflexes In young children, micturition is a simple reflex act and takes place whenever the bladder becomes distended. In the adult, this simple stretch reflex is inhibited by the activity of the cerebral cortex until the time and place for micturition are favorable. The inhibitory fibers pass downward with the corticospinal tracts to the second, third, and fourth sacral segments of the cord. Voluntary control of micturition is accomplished by contracting the sphincter urethrae, which closes the urethra; this is assisted by the sphincter vesicae , which compresses the bladder neck. Voluntary control of micturition is normally developed during the second or third year of life.

21. Suprapubic aspiration of the urinary bladder : When the urinary bladder is distended it peels off the peritoneum from the anterior abdominal wall and comes in its direct contact. Now it can be aspirated suprapubically without any damage to the peritoneum.

22. Suprapubic cystostomy : It is an extraperitoneal approach to open the cavity of the urinary bladder. Indications Drainage purposes, treatment of intravesical conditions, vesical stones, etc., and removal of the prostate. The bladder is distended (if not the case of retention of urine) with about 300 ml of fluid. As a result, the anterior aspect of bladder comes in direct contact with the anterior abdominal wall. The bladder can be now approached through anterior abdominal wall without entering into the peritoneal cavity.

23. UTI- common in male Cystitis Urinary Calculi Bladder ca. Urinary incontinence Urinary retention cystocele Enuresis dysuria

24. urethra The urethra is a tubular passage, which transmits urine and seminal fluid in males and only urine in females . The study of urethra is important clinically to perform procedures of catheterization and cystoscopy . The urethral rupture is also common.

25. Male urethra about 18–20 cm long. It extends from the internal urethral orifice to the external urethral orifice at the tip of the glans penis parts according to its location Prostatic part (passes through the prostate).3cm, widest and most dilatable part of the male urethra. Membranous part (passes through the urogenital diaphragm).2cm, narrowest and least dilatable part of the urethra Spongy or penile part (passes through the corpus spongiosum of penis ).15cm

26. Male urethra: A, left view in the sagittal section ;anterior view (urethra straightened and cut open).

27. Rupture of the urethra The commonest site of rupture is bulb of the penis . The urine extravasates into the superficial perineal pouch and passes forward over the scrotum, penis, and anterior part of the anterior abdominal wall deep to membranous layer of the superficial fascia. If the urethra ruptures above urogenital diaphragm urine escapes above the deep perineal pouch and may pass upward around the prostate and bladder in the extraperitoneal space (deep extravasation) Hypospadias : It is a congenital anomaly in which external urethral orifice is located on the inferior/ventral aspect of penis instead at the tip of the glans penis. It occurs due to failure of the fusion of urethral folds . Catheterization of the male urethra

28. Rupture of urethra: A, rupture of the bulbous urethra leading to superficial extravasation; B, rupture of the urethra above the urogenital diaphragm leading to deep extravasation

29. FEMALE URETHRA About 4 cm long It begins at the internal urethral orifice at the neck of bladder opens in the vestibule of vagina in front of the vaginal orifice Surrounded by urethral gland in its entire length and Paraurethral glands (of Skene ) on each side of the upper part of the urethra, homologous to the male prostate. NB/UTI are much more common in females due to shortness of the urethra and presence of its orifice close to the vaginal and anal orifices.

30. Prostate Secretes fluid that nourishes and protect sperm 3g in wt 5 lobes supplied by the branches of inferior vesical , middle rectal, and internal pudendal a. venous drainage: follows two pathways : (a) Prostatic venous plexus → internal iliac veins → IVC. This pathway explains the metastasis of cancer prostate into the heart and lungs. (b) Prostatic venous plexus → vertebral venous plexus → intracranial dural venous sinuses. This pathway explains the metastasis of cancer prostate into the vertebral column and brain

31. Prostate

32. Seminal vesicles coiled sacculated tubes. The secretion of seminal vesicles is slightly alkaline , containing fructose .

33. Thank you