Week 2 Structure and Function of LUT

Question 1

What are the three main layers of the bladder wall?

Answer 1

Urothelium

Lamina propria

Muscularis propria (detrusor muscle)

Question 2

What is the function of the urothelium?

Answer 2

Acts as a barrier (with tight junctions and GAG layer)

Provides afferent signaling

Not fully waterproof (passive passage of urea, Na⁺, K⁺)

Question 3

What structures are found in the lamina propria?

What is it’s purpose?

Answer 3

Blood vessels

Nerve fibres

Myofibroblasts

Functions as a coordination center between urothelium and detrusor muscle

Question 4

What is the function of the detrusor muscle?

What is it’s structure?

How is it inervated?

Answer 4

Contracts during micturition

Arranged in bundles, forms a functional syncytium

Innervated by postganglionic parasympathetic nerves

Question 5

What is meant by “bladder compliance”?

Answer 5

The bladder can store increasing volumes of urine without significant rise in pressure due to its viscoelastic properties (elastin and collagen)

Question 6

When does the sensation of bladder fullness and discomfort typically begin?

Answer 6

Fullness: ~250 mL

Discomfort: ~500 mL

Question 7

What spinal segments are involved in micturition control?

Answer 7

S2, S3, S4 (Onuf’s nucleus in intermediolateral horn)

Question 8

Medical word for urination

Answer 8

micturition

Question 9

What brainstem center is involved in coordinating micturition?

Answer 9

Pontine Micturition Centre (PMC), also called Barrington’s nucleus

Question 10

What is the role of Onuf’s nucleus?

Answer 10

Controls the external urethral sphincter for voluntary control of micturition

Question 11

Describe the positive feedback loop of detrusor contraction?

Answer 11

Question 12

What neurotransmitters are involved in normal bladder function?

Answer 12

Excitatory: Acetylcholine (cholinergic)

Relaxation: Nitric oxide

Inhibitory: GABA and glycine

Question 13

How does spinal cord injury affect bladder function?

Answer 13

Loss of central inhibition leads to reflex voiding

Question 14

What is facilitation?

Answer 14

Facilitation = contraction of detrusor & relaxation of sphincter when bladder less than full e.g anxiety states.

This is a reflex which is normally inhibited

Question 15

Depending on lesions in the following regions, what sort of bladder symptoms would you likely see?

Answer 15

Top - responsible to inhibition of reflexs therefore voiding problems

Bottom - responsible for voiding therefore retention

Question 16

How much urine does a normal person pass per void, and how often?

Answer 16

300–400 mL per void

4–5 times per day, but up to 7 is normal depending on intake

Question 17

What is the ideal tool for assessing urinary habits?

Answer 17

A Bladder Diary (Input & Output Chart) recorded over 3 days

Tracks volume, frequency, nocturia, UI episodes, and intake patterns

Question 18

What is nocturnal polyuria?

Answer 18

> 1/3 of 24-hour urine volume produced between midnight and 8:00 AM

Question 19

What causes poor urinary flow and hesitancy?

Answer 19

Usually bladder outlet obstruction (e.g., BPH, urethral stricture)

Can also be due to an underactive bladder (e.g., spinal cord injury)

Question 20

What causes urinary frequency and nocturia?

Answer 20

Frequency: increased urine production or decreased bladder capacity

Nocturia: nocturnal polyuria, decreased bladder compliance, ageing bladder, or fluid intake patterns

Question 21

What is stress urinary incontinence (SUI)?

Answer 21

Involuntary urine loss during increased intra-abdominal pressure without detrusor contraction

Triggered by coughing, sneezing, laughing, or exercise

Question 22

What is urge urinary incontinence (UUI)?

Answer 22

Involuntary urine loss with a strong urge to void, typically due to detrusor overactivity

Question 23

What does IPSS stand for and assess?

Answer 23

International Prostate Symptom Score

Assesses 7 LUTS: frequency, nocturia, weak stream, hesitancy, intermittency, incomplete emptying, urgency

Includes Quality of Life (QoL) score

Question 24

What is the IPSS scoring scale for symptom severity?

Answer 24

0–7: Mild

8–19: Moderate

20–35: Severe

Question 25

What does a urodynamic assessment do?

Answer 25

Measure detrusor activity (pressure)

Question 26

What are the typical progression phases of bladder outlet obstruction symptoms?

Answer 26

1. Storage symptoms 2. Voiding (obstructive) symptoms 3. Decompensation → residual urine, chronic retention, bladder failure 4. Renal failure (in severe or neglected cases)

Question 27

What medications are used for overactive bladder?

Answer 27

Antimuscarinics: Solifenacin, Fesoterodine, Oxybutynin β3-agonist: Mirabegron Botox: Intradetrusor injections for refractory cases Lifestyle modifications also important

Question 28

What are treatment options for stress urinary incontinence?

Answer 28

Pelvic floor exercises Weight loss Surgery: Autologous sling (e.g., rectus abdominis) Artificial sphincter

Question 29

What is the first-line treatment for bladder outlet obstruction (e.g., BPH)?

Answer 29

**Medical therapy:** Alpha-blockers: Tamsulosin 5-alpha reductase inhibitors (5ARI): Finasteride **Surgical options:** TURP (transurethral resection of the prostate) Laser prostatectomy