Urinary Bladder

Present by - anjali tiwari

Roll no - 38

Batch - 2022-2023

Guided by:

Dr. Amit Kumar Singh

(Asso. Prof & HOD)

Dr. Varsha Gupta

(Asst. Prof.)

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Introduction

• The urinary bladder is a muscular organ ,it is temporary store house of urine which gets emptied through the urethra.

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• It's lies in the anterior part of the pelvic cavity.

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• The bladder wall contains specialized smooth muscle, known as Detrusor muscle, it's arranged in whorls and spirals and is adapted for mass contraction rather than peristalsis.

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Introduction

• The urinary bladder is a muscular organ ,it is temporary store house of urine which gets emptied through the urethra.

​

• It's lies in the anterior part of the pelvic cavity.

​

• The bladder wall contains specialized smooth muscle, known as Detrusor muscle, it's arranged in whorls and spirals and is adapted for mass contraction rather than peristalsis.

Introduction

• The urinary bladder is a muscular organ ,it is temporary store house of urine which gets emptied through the urethra.

​

• It's lies in the anterior part of the pelvic cavity.

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• The bladder wall contains specialized smooth muscle, known as Detrusor muscle, it's arranged in whorls and spirals and is adapted for mass contraction rather than peristalsis.

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• Shape -----

Empty bladder is tetrahedral in shape.

Full bladder is ovoid in shape.

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• Position --------

Empty bladder lies entirely within the pelvis, but as it fills it expands and extends upwards into the abdominal cavity, reaching up to the umbilicus or even higher.

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Internal urethral sphincter:

• Males-consists of circular smooth fibers which are under autonomiccontrol.

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• Thought to prevent seminal regurgitation during ejaculation.

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• Females-thought to be a functional sphincter .

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• It is formed by the anatomy of the bladder neck & proximal urethra.

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External urethral sphincter:

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• Has the same structure in both sexes.

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• Skeletal muscle under voluntary control. During micturation, it relaxes to allow urine flow.

External Features

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1. Apex.

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2. Base.

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3. Neck.

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4. Three surfaces (superior and two inferolateral surfaces).

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5. Four borders (anterior, posterior and two lateral).

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Relation

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APEX -

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• It provides attachment to the median umbilical ligament and lies posterior to the upper margin of the pubic symphysis.

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• which represents the obliterated embryonic urachus .

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Relation

BASE -

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In the male:

1. Upper part is separated from rectum by the rectovesical pouch containing coils of the small intestine.

2. Lower part is separated from rectum by the terminal parts of vasa deferentia and seminal vesicles.

3. The triangular area between the vasa deferentia is separated from the rectum by rectovesical fascia (of Denonvilliers).

In the female:

it is separated from the cervix of uterus and by the vesicouterine pouch.

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Relation

NECK -

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• It is the lowest and most fixed part of the bladder. It is situated where the inferolateral and the posterior surfaces of the bladder meet. It is pierced by the urethra.

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• In the male, it rests on the upper surface of the prostate where the smooth muscle fibres of the bladder wall are continuous with those of the prostate.

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• In the female, it is related to the urogenital diaphragm.

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Relation

SUPERIOR SURFACE -

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• In the male, it is completely covered by the peritoneum which separates it from: coils of the ileum,sigmoid colon.

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• In the female, it is covered by the peritoneum except for a small area near the posterior border, which is related to the supravaginal part of the uterine cervix. Here the peritoneum is reflected on to the uterine isthmus forming vesicouterine pouch.

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Relation

INFEROLATERAL SURFACES -

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• The inferolateral surfaces are devoid of peritoneum and in both male and female are related:

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• In front to retropubic space, pubic symphysis, and puboprostatic ligaments.

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• Behind to obturator internus muscle above, and levator ani muscle below.

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Ligaments of the bladder

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True ligaments

They are the condensations of pelvic fascia.

They provide support to the bladder.

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1. Lateral true ligament

2. Lateral puboprostatic ligament

3. Medial puboprostatic ligament

4. Medial umblical ligament

5. Posterior ligament

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True ligaments

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False ligaments

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They are the peritoneal folds.

They don't provide support to the bladder.

1. Median umblical fold

2. Medial umblical fold

3. Lateral false ligament

4. Posterior false ligament

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• It can be examined by cystoscopy, at operation or at autopsy.

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• In an empty bladder, the greater part of the mucosa shows irregular folds due to its loose attachment to the muscular coat.

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• In a small triangular area over the lower part of the base of the bladder, the mucosa is smooth due to its firm attachment to the muscular coat. This area is known as the trigone of the bladder.

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Interior of the bladder

• Internal urethral orifice opens in the apex of this trigone.The ureters open at the posterolateral angle of the trigone.

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• Uvula vesicae: It is a small elevation on the trigone posterior to the urethral orifice produced by median lobe of prostate.

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• The ureters open at the posterolateral angles of the trigone. Their openings are 2.5 cm apart in the empty bladder, and 5 cm apart in a distended bladder . The base of the trigone is formed by the interureteric ridge or bar of Mercier produced by the continuation of the inner longitudinal muscle coats of the two ureters .

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Capacity of bladder

• ANATOMICAL CAPACITY: about 1lit. Or more

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• AVERAGE CAPACITY: 120 to 320ml.

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• SENSE OF FILLING: 100 to 150ml.

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• DESIRE FOR MICTURITION: 150 to 250ml.

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• PAINFUL SENSATION: above 450ml.

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Arterial supply

• Superior vesical arteries from the proximal patent part of the obliterated umbilical artery.

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• Inferior vesical arteries from the ant, division of int. iliac artery.

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Venous drainage

• The vesical veins form a plexus on each infero-lateral surface, then drain into the internal iliac vein.

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Lymphatic drainage

• Most of the lymphatic drainage from the urinary bladder terminates in the I external iliac lymph nodes.

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• Few vessels may pass to the internal iliac nodes or to the lateral arotic nodes .

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Nerve supply

• Sympathetic efferent fibres from (T.11.12 & L.1, 2)spinal segments (inhibitory to the muscle wall & motor to the sphincter vesicae).

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• Para-sympathetic efferent fibrespelvic splanchnic n. (S. 2, 3, 4): motor to the muscle wall & inhibitory to the sphincter vesicae.

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CLINICAL ANATOMY

• The interior of the bladder can be examined in the living by cystoscope

A distended bladder may be ruptured by injuries of the lower abdominal

wall.

• The peritoneum may or may not be involved.
• Chronic obstruction to the outflow of urine by an enlarged prostate causes hypertrophy of bladder leading to trabeculated bladder.
• In the operation of suprapubic cystotomy, the bladder is distended with about 300 ml of fluid.

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As a result, the anterior aspect of the bladder comes into direct contact with the anterior abdominal wall, and can beapproached without entering the peritoneal cavity.

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• Emptying of bladder: Emptying of the bladder is essentially a reflex function, involving the motor and sensory pathways.

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• Voluntary control over this reflex is exerted through upper motor neurons, and as long as one pyramidal tract is functioning normally, control of the bladder remains normal .

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• Acute injury to the cervical/thoracic segments of spinal cord leads to a state of spinal shock. The muscle of the bladder is relaxed, the sphincter vesicae contracted, but sphincter urethrae relaxed.

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• The bladder distends and urine dribbles.

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• After a few days, the bladder starts contracting reflexly. When it is full, it contracts every 2–4 hours.
• This is ‘automatic reflex bladder’ Damage to the sacral segments of spinal cord situated in lower thoracic and lumbar one vertebra results in ‘autonomous bladder’.
• The bladder wall is flaccid and its capacity is greatly increased. It just fills to capacity and overflows. So there is continuous dribbling .

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Urinary bladder is one of sites for stone formation

as concentrated urine lies here.

Urinary bladder function and

its control in healthy female

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Abstract

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• Recordings in eight healthy female volunteers of bladder (detrusor) pressure and flow rate, obtained during bladder filling and during voiding, both through the urethra and through a catheter, demonstrate that a model of bladder function in which the detrusor muscle is considered as completely passive during filling and fully activated during voiding is inadequate. Assessment of the detrusor contraction strength by a new method (described in APPENDIX A) shows that in ideal normal voidings the contraction strength rises to values of 11-24 W/m2 and is sustained or rises slightly until the bladder is empty.

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• During unstable detrusor contractions, which even in these healthy women are observed during bladder filling and also during inhibited voidings through the urethra, the contraction is weaker.

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• During voidings through a catheter the detrusor contraction is weak, variable, and fades away before the bladder is empty. An elementary feedback analysis demonstrates that the effect of the micturition reflex governing detrusor behavior differs according to whether or not voiding is taking place. The reflex does not lead to a simple on-off mechanism but to a more complex behavior that is consistent with the observations and that appears to be important for the understanding of pathological obstructed micturition.

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Citation

• Griffiths, D. J., Constantinou, C. E., & van Mastrigt, R. (1986). Urinary bladder function and its control in healthy females. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 251(2), R225-R230.

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REFERENCE

• B.D CHAURASIA Ninth edition vol 1

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• Gray’s anatomy

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