Anatomy and physiology of urinary bladder Explain about how urinary bladder works

1. • Submitted to,
• Ms.
• Government
College of Nursing -
Vadodara
GOVERNMENT COLLEGE OF NURSING
VACCINE CAMPUS VADODARA
Sr.
No.
Name Roll
No.
1 Prajapati
Hardi J
6
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2. Objectives
• Describe the location and structure of the urinary bladder, including its major anatomical components (e.g.,
walls, trigone, ureterovesical junctions).
• Explain the physiological functions of the urinary bladder in urine storage and elimination.
• Discuss the basic mechanisms of the micturition reflex and its role in bladder control.

3. 1. Urinary System
The urinary system, also called the renal system, acts as the body's filtration and disposal unit. It consists
of four main organs:
1. Kidneys: These bean-shaped marvels continuously filter your blood, separating waste products and excess
water from essential components. Think of them as miniature factories processing blood 24/7.
2. Ureters: These two thin tubes act as pipelines, carrying the filtered waste (urine) away from the kidneys and
towards the bladder.
3. Bladder: This stretchy, muscular sac stores urine until it's convenient to eliminate it. Imagine it as a
temporary holding tank.
4. Urethra: This single tube allows you to release the stored urine from the bladder to the outside world. It's the
final "exit door" for the waste products.

4. 2. Urinary Bladder
• It is a Hollow Musculo membranous SAC which acts as a
reservoir for the urine.
• It Is The Most Anterior Element Of The Pelvic Viscera.
• It Is A Sub peritoneal Organ And Has Parietal Peritoneum
Only On Its Superior Surface.
• Urine Enters The Bladder Via Ureters And Exits Via The
Urethra.

5. 3. Anatomical Location
• When "Empty" , the adult urinary bladder is located in the "Lesser pelvis" lying partially superior to and partially
posterior to the pubic Bones.
• As the bladder fil ls it enters the "Greater Pelvis".
• In some individuals, a full bladder may ascend to the level of the "Umbilicus".
• In infants and young children , the urinary bladder is in the abdomen even when empty.
• The Bladder usually enters the Greater Pelvis by 6 Years of age.

6. 3.1. Anatomical Location in Male
• The bladder sits between the pubic symphysis (the joint at the
front of the pelvis) and the rectum (the final section of the large
intestine).
• Imagine it positioned like a water balloon resting on the pubic
symphysis, with the rectum directly behind it.
• The upper part of the bladder, called the apex, points towards the
navel, while the base connects to the urethra, the tube that carries
urine out of the body.

7. 3.2. Anatomical Location in Female
• The bladder is located behind the uterus (the
womb), with the rectum positioned further back.
• Think of it as tucked in behind the uterus, like a
small pouch nestled against the lower back.
• Similar to males, the bladder's apex faces
upwards, and the base connects to the urethra.

8. 4. Surfaces Of The Urinary Bladder
• Superior surface.
• Right inferolateral surface.
• Left inferolateral surface
• Posterior surface.

9. 5. Body Of The Urinary Bladder
• It is lined by Transitional epithelium,
• It holds the urine, before it is voided.
• It can hold 400ml to 1000ml of the urine.
• It is located between the apex and the fundus.

10. 6. The Bladder Wall
1. Mucosa (Innermost): A waterproof lining
called urothelium stretches and folds like origami,
allowing the bladder to expand. Think of it as a
flexible rubber sheet.
2. Submucosa (Supportive Layer): Packed with connective
tissue and blood vessels, this layer nourishes the mucosa and
houses nerves that send "gotta go" signals to your brain.
Imagine it as the castle's well-stocked pantry.

11. 3. Muscularis Propria (The Powerhouse): This thick
layer of smooth muscle, called the detrusor, contracts
with mighty force to expel urine. Think of it as the
castle's drawbridge, lowering when it's time to let go.
4. Adventitia/Serosa (Outer Armor): Depending on location,
this layer is either tough connective tissue (adventitia)
anchoring the bladder or a slippery serosa (peritoneal
membrane) reducing friction. Imagine it as the castle's sturdy
stone walls or a smooth moat.

12. 7. Micturition Reflex and Bladder Control
• Storage stage
• The sympathetic nervous system suppresses bladder contractions and increases tone in the
bladder neck and internal sphincter via the hypogastric nerve.
• Urine is transported into the bladder by the ureters, resulting in increased pressure within
the bladder.
• Stretch receptors in the bladder send signals via afferent fibers of the pelvic nerve to the
sacral spinal cord, which then sends signals via the pudendal nerve to contract the external
urethral sphincter, maintaining urinary continence.
• Voiding stage
• When bladder stretch reaches the micturition threshold, afferent bladder signals cause the
sacral segment to stimulate the Pontine micturition center. Sensations of fullness and pain
are evaluated by higher cerebral centers.
• Cerebral centers initiate toilet seeking

13. • Stretch receptors in the bladder wall detect increased
volume, sending sensory signals via afferent fibers to the
spinal cord.
• Voluntary bladder control refers to the ability to consciously
manage the release of urine.
• Higher brain centers, particularly the prefrontal cortex, play
a pivotal role in this process by interpreting signals from the
bladder, allowing individuals to suppress or initiate
urination based on social and environmental cues,
demonstrating the sophisticated coordination between neural
pathways and conscious decision-making.

14. 8. Fundus Of The Urinary Bladder
• It is base of the bladder.
• It has the shape of inverted triangle.
• It faces postero-inferiorly and , is formed by the
posterior wall of bladder.
• Trigone of the urinary bladder is found on the
fundus.

15. 9. Trigone Of Urinary Bladder
• It is smooth triangular part of urinary bladder.
• Mucosal lining of trigone is smooth and firmly
attached to the underlying wall of the bladder.
• Formed by Right and left ureteral orifices.
• Once the trigone of urinary bladder is stretched to a
certain degree, signal is sent to the brain that
bladder needs to be emptied.

16. 10. Ureteral Orifices
• These are Slit like openings through which ureters
enter the bladder on the posterolateral angles of the
trigone of urinary bladder.

17. 11. Mercier's Bar
• A curved fold of mucous membrane extending
across the bladder between the two ureteric orifices,
produced by a transverse bundle of muscle fibres.
Mercier emphasized the importance of these muscle
fibres in prostatism.
• It is a mucous membrane present between the two
ureteral orifices.
• It is also called "lnter Ureteral Fold"

18. 12. Neck Of Urinary Bladder
• The neck of the urinary bladder, also known as the
bladder neck, is a muscular region at the base of the
bladder where it connects to the urethra.
• This structure regulates the flow of urine, serving as
a sphincter to control the release of urine from the
bladder into the urethra.
• It is the lowest portion of the bladder through which
the "Urethra" arrises.

19. 13. Internal Urethral Sphincter
• It is comprised of smooth muscle that is located at the
junction of urethra and the urinary bladder.
• It is innervated by S2-S4 nerves of the pelvic plexus.
• It's function is to constrict the internal urethra ,preventing
the urine leakage and also prevents the Retrograde
ejaculation (Ejaculatory Reflex ) of semen into the
bladder.

20. 14. Detrusor Muscle
• It is also referred as " Muscularis Propria".
• It is smooth muscle , found around the wall of bladder.
• It is comprised of inner and outer longitudinal, and
middle circular layer.
• This muscle is relaxing during accumulation of urine in
the bladder, and contracts only during urination to void
and empty the bladder.

21. 15. Posterior Relations Of Urinary Bladder
 In males
• Vas Deferan
• Seminal Vesicle
• Rectum
• Retro Vesical Fascia
• Peritoneum
 In Females
• Vagina
• Part of Uterus
 Superior Relations in male
• Peritoneum
• Coils of ileum
• Sigmoid colon
 Superior Relations in Females
• Uterus
Lateral Relations
• Obturator Internus
• Levator ani

22. 16. Male Pelvis – Sagittal Section

23. 17. Female Pelvis – Sagittal Section

24. 18. Arterial Supply
• Branches of internal iliac arteries.
• Superior vesical arteries supply
anterosuperior parts of the bladder.
• In males, inferior vesical arteries supply
the fund us and neck of the bladder.
• In females, vaginal arteries replace the
inferior vesical arteries and send small
branches to posteroinferior parts of the
bladder.
• Obturator and inferior gluteal arteries also
supply small branches to the bladder.

25. 19. Venous Drainage
• The veins draining from the bladder correspond to the
arteries.
• Veins from the Vesical venous plexus drain into the
internal iliac veins.

26. 20. Innervation Of Urinary Bladder
• Pelvic Nerve (Parasympathetic nerve) comes from the sacral region of spinal cord. It is not under
our control. It causes contraction of the Detrusor muscle.
• Pudendal nerve (Somatic nerve) causes contraction of External Sphincter. We are firing pudenda!
nerve when we are trying to hold our urine.
• Hypogastric nerve (Sympathetic nerve) causes relaxation of Detrusor muscle and contraction of
Internal sphincter.
• Afferent Pelvic nerve that is sensory and comes from the detrusor muscle. It is stimulated when the
bladder is stretched.

27. 21. Lymphatic Drainage Of Urinary Bladder
• In both sexes, lymphatic vessels leave the superior surface of the bladder and pass to the "External
iliac lymph nodes".
• Those from fundus pass to the "Internal iliac lymph nodes".
• Some vessels from the neck of bladder drain into the "Sacral" to "Common iliac lymph nodes".

28. 22. Summary
• Location and Structure: The bladder resides in the pelvis, with a unique layered wall for elasticity
and contraction.
• Micturition Reflex: Stretch receptors trigger nerve signals, coordinating bladder filling and
emptying through the spinal cord and pontine micturition center.
• Advanced Anatomy: Deeper layers reveal specialized cells for protection, blood supply, and nerve
control.

29. 23. Conclusion
• Understanding the urinary bladder, from its intricate anatomy to complex physiology, empowers
nurses to provide competent and compassionate care.
• Continuous learning, research, and collaboration with healthcare professionals pave the way for
improved bladder health and well-being for all.

30. 24. Assignment
1. Match the following layers of the bladder wall with their functions:
1. Mucosa:
(a) Protection and elasticity (b) Sensory nerve endings (c) Muscle contraction for voiding
2. Submucosa:
(a) Supports blood vessels and lymphatics (b) Houses ureterovesical junctions (c) Provides lubrication
3. Muscularis propria (Detrusor muscle):
(a) Inner layer for bladder shortening (b) Middle layer for compression (c) Outer layer for stability
4. Adventitia/Serosa:
(a)Anchors bladder to surrounding structures (b) Covered by peritoneum in males (c) Facilitates nerve supply
2. Choose the CORRECT statement about the micturition reflex:
(a) It is a purely voluntary process controlled by the brain.
(b) Stretch receptors in the bladder directly trigger muscle contraction.
(c) The pontine micturition center plays no role in bladder control.

31. 25. References
1. Boron, W. F., & Boulpaep, E. F. (2017). Medical physiology (2nd ed.). Elsevier. (Chapters 26 &
27)
2. Drake, M. J., & Haider, A. (2015). Bladder outlet obstruction: Etiology, evaluation, and
management. Therapeutic advances in urology, 7(6), 246-259.
https://www.tandfonline.com/doi/abs/10.1080/00405841.2012.662873
3. Guyton, A. C., & Hall, J. E. (2011). Textbook of medical physiology (12th ed.). Saunders
Elsevier. (Chapters 29 & 30)
4. Parsons, M. B., & Smith, C. A. (2012). Emerging stem cell therapies for bladder regeneration.
Current opinion in organ transplantation, 17(5), 556-562.
https://pubmed.ncbi.nlm.nih.gov/35107689
5. Urological Nursing Society. (n.d.). Bladder health. https://quizlet.com/200922542/chapter-66-
care-of-patients-with-urinary-problems-flash-cards/
6. World Health Organization. (2021, May 31). Urinary tract infections (UTIs).
https://www.who.int/publications-detail-redirect/WHO-FCH-CAH-05.11