Micturition

Physiology of the Micturition (Process of Urination)

1. Micturition Prof. Dr. Rashid Mahmood

2. 2 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood Micturition © Prof. Dr. Rashid Mahmood

3. Objectives Goal/Aim : Describe mechanism of Micturition Process Specific Objectives: By the end of this session students should be able to Counter-Current Mechanism | © Prof. Dr. Rashid Mahmood 25 April 2018 3

4. Lesson Contents Micturition Physiological Anatomy of Urinary bladder Nerve supply of Urinary bladder Transport of urine to urinary bladder Two Steps of Micturition Cystometrogram Micturition Reflex Control by Higher Centers Abnormalities of Micturition Counter-Current Mechanism | © Prof. Dr. Rashid Mahmood 25 April 2018 4

5. Lesson Contents Micturition Physiological Anatomy of Urinary bladder Nerve supply of Urinary bladder Transport of urine to urinary bladder Two Steps of Micturition Cystometrogram Micturition Reflex Control by Higher Centers Abnormalities of Micturition Counter-Current Mechanism | © Prof. Dr. Rashid Mahmood 25 April 2018 5

6. 6 Micturition Process by which Urinary Bladder empties , when it becomes filled . 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

7. Lesson Contents Micturition Physiological Anatomy of Urinary bladder Nerve supply of Urinary bladder Transport of urine to urinary bladder Two Steps of Micturition Cystometrogram Micturition Reflex Control by Higher Centers Abnormalities of Micturition Counter-Current Mechanism | © Prof. Dr. Rashid Mahmood 25 April 2018 7

8. 8 Physiological Anatomy of Urinary bladder Sensory Motor Sacral Plexus Hypogastric nerves } Smooth muscle of bladder: Detrusor muscle 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

9. Lesson Contents Micturition Physiological Anatomy of Urinary bladder Nerve supply of Urinary bladder Transport of urine to urinary bladder Two Steps of Micturition Cystometrogram Micturition Reflex Control by Higher Centers Abnormalities of Micturition Counter-Current Mechanism | © Prof. Dr. Rashid Mahmood 25 April 2018 9

10. 10 Parasympathetic Sympathetic Somatic Nerve supply of Urinary bladder Dotted lines: Sensory fibers 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

11. 11 Nerve supply of Urinary bladder Sensory Motor Sacral Plexus Hypogastric nerves } Involuntary Voluntary 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

12. 12 Nerve supply of Urinary bladder Sensory Parasympathetic (Pelvic nerves) S-1  S-3 Bladder wall Neck (Posterior Urethra) B. Motor i ) As above ii) Skeletal Motor: Pudendal Nerve 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

13. 13 Nerve supply of Urinary Bladder C. Sympathetic Blood Vessel (L-2, Hypogastric Nerves) (Some sensory nerves pass by way of sympathetic nerves → fullness and pain) 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

14. Q.1 Define Micturition 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood 14 Process by which Urinary Bladder empties , when it becomes filled .

15. Lesson Contents Micturition Physiological Anatomy of Urinary bladder Nerve supply of Urinary bladder Transport of urine to urinary bladder Two Steps of Micturition Cystometrogram Micturition Reflex Control by Higher Centers Abnormalities of Micturition Counter-Current Mechanism | © Prof. Dr. Rashid Mahmood 25 April 2018 15

16. 16 Transport of urine to urinary bladder Collecting Duct → Calyces (Pacemaker activity → peristalsis) → Pelvis → Ureter → Urinary Bladder No change in composition Sympathetic stimulation: ↓Peristalsis Parasympathetic stimulation: ↑Peristalsis 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

17. 17 Flow of urine from ureter into urinary bladder Oblique course Prevents Vesicoureteral Reflux Peristalsis in ureters forces urine into urinary bladder 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

18. Lesson Contents Micturition Physiological Anatomy of Urinary bladder Nerve supply of Urinary bladder Transport of urine to urinary bladder Two Steps of Micturition Cystometrogram Micturition Reflex Control by Higher Centers Abnormalities of Micturition Counter-Current Mechanism | © Prof. Dr. Rashid Mahmood 25 April 2018 18

19. 19 Pain sensation in Ureters Well supplied with pain nerve fibers Irritation (e.g. stone) → stimulation of pain nerve fibers Intense contraction of ureters Sympathetic reflex back to kidney To ↓ the urine output Ureterorenal reflex 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

20. 20 Micturition Two Steps Gradual filling  Threshold Level (Cystometrogram) Emptying / Conscious desire to urinate (Micturition Reflex) 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

21. 21 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood Name the Two Steps of Micturition Q.2

22. Lesson Contents Micturition Physiological Anatomy of Urinary bladder Nerve supply of Urinary bladder Transport of urine to urinary bladder Two Steps of Micturition Cystometrogram Micturition Reflex Control by Higher Centers Abnormalities of Micturition Counter-Current Mechanism | © Prof. Dr. Rashid Mahmood 25 April 2018 22

23. 23 Micturition A. Filling of Bladder: Stress relaxation Up to 300 ml, little rise in pressure Beyond 300-400 ml, rapid ↑ in pressure 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

24. 24 Cystometrogram 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

25. 25 Micturition No Micturition 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

26. 26 Cystometrogram Micturition contractions= Micturition waves Periodic acute increases in pressure May last a few seconds to > a minute May rise a few cm to >100 cm of water 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

27. Lesson Contents Micturition Physiological Anatomy of Urinary bladder Nerve supply of Urinary bladder Transport of urine to urinary bladder Two Steps of Micturition Cystometrogram Micturition Reflex Control by Higher Centers Abnormalities of Micturition Counter-Current Mechanism | © Prof. Dr. Rashid Mahmood 25 April 2018 27

28. Q. 3 What is a Cystometrogram ? 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood 28

29. 29 Autonomic cord reflex Contraction of Detrusor muscle Inhibited / facilitated by brain B. Micturition Reflex 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

30. 30 Components of Micturition Reflex (Stretch Reflex) Stimulus: Receptors Afferent N: C.N.S Efferent Nerve Effector Response: Stretch a. Bladder Wall b. Neck Sensory stretch receptors Sensory Fib. Of Pelvic nerve. S-2 & S-3 Motor Fib. Of Pelvic Nerve Detrusor Contraction of Detrusor Muscle As the bladder continues to fill, the Micturition reflexes become more Frequent and Powerful 25 April 2018

31. Micturition reflex 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood 31

32. 32 Self-Regenerative Reflex: i . Progressive and Rapid increase of Pressure ii . Sustained Pressure iii. Relaxation Fatigue 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

33. 33 Micturition Reflex Fatigue Powerful enough to Inhibit External Sphincter through Pudendal nerve 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

34. 34 Micturition Reflexes gradually become more and more powerful and frequent  Inhibition of external Sphincter through Pudendal Nerve Inhibition of External sphincter 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

35. Lesson Contents Micturition Physiological Anatomy of Urinary bladder Nerve supply of Urinary bladder Transport of urine to urinary bladder Two Steps of Micturition Cystometrogram Micturition Reflex Control by Higher Centers Abnormalities of Micturition Counter-Current Mechanism | © Prof. Dr. Rashid Mahmood 25 April 2018 35

36. 36 Control by Higher Centers Pons Facilitatory (and inhibitory?) centers Midbrain Facilitatory center Posterior hypothalamus Facilitatory center Cerebral cortex Normally inhibits the External sphincter Voluntary urination By volunteer contraction of abdominal muscles 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

37. Lesson Contents Micturition Physiological Anatomy of Urinary bladder Nerve supply of Urinary bladder Transport of urine to urinary bladder Two Steps of Micturition Cystometrogram Micturition Reflex Control by Higher Centers Abnormalities of Micturition Counter-Current Mechanism | © Prof. Dr. Rashid Mahmood 25 April 2018 37

38. 38 Abnormalities of Micturition Atonic Bladder Damage to sensory fibers Bladder filling to maximum capacity Overflow incontinence Automatic bladder Damage to spinal cord above Sacral Regions No control by brain Uninhibited neurogenic bladder Partial damage in spinal cord or brain stem Facilitative impulses > inhibitory impulses Frequent Micturition 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood

39. Q.4 What is meant by Atonic Bladder? 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood 39

40. Learning Resources Guyton and Hall (Text book of physiology), 13th Edition Berne & Levy Principles of Physiology ( Koeppen BM), 6th Edition Human Physiology, Silverthorn Human Physiology : from cells to system, Lauralee Sherwood, 9th edition Vascular distensibility & Functions of Arterial and Venous System | © Prof. Dr. Rashid Mahmood 40 25-Apr-18

41. Summary Urinary bladder is supplied by Sympathetic (Hypogastric nerves), Parasympathetic (Pelvic nerves) and Pudendal nerves Sensory supply to bladder wall and bladder neck is through Parasympathetic nerves Motor supply to detrusor muscle and posterior urethra is through Parasympathetic nerves Motor supply to external sphincter is through Pudendal nerve Process of micturition occurs in two steps: gradual filling upto a threshold level and emptying through micturition reflex or conscious desire to urinate Micturition can be facilitated or inhibited voluntarily 41 25-Apr-18

42. Thank You 25 April 2018 Micturition | © Prof. Dr. Rashid Mahmood 42 Questions ? Comments ? [email protected] [email protected] ppt also available at https://www.slideshare.net