lower urinary tract

Question 1

Which structures lead into renal pelvis

Answer 1

Minor and major calyces

Question 2

What type of muscle is in the renal pelvis

Answer 2

Smooth muscle

Question 3

How does fluid move down ureter

Answer 3

Peristaltic contractions

Question 4

How long are the ureters

Answer 4

30 cm

Question 5

What type of epithelium is the mucosal layer

Answer 5

Transitional epithelium, 3-8 cells thick

Question 6

What layers of smooth muscle are there

Answer 6

Inner: longitudinal
Outer: circular/spiral
Extra outer layer of longitudinal

Question 7

How often are peristaltic waves generated

Answer 7

1 to 6 per minute

Question 8

What causes generation of an action potential

Answer 8

Dilation of renal pelvis - from pacemaker cells in hilum

Question 9

What is the movement of urine along the ureter known as

Answer 9

Peristalsis or vermiculation

Question 10

How do ureters pass into bladder

Answer 10

At an oblique angle to prevent backflow

Question 11

What layers of the bladder are there

Answer 11

Detrusor outer muscle layer (longitudinal and circular muscles)
Inner mucosal layer (transitional epithelium folded into rug when bladder is empty, highly elastic)

Question 12

What is the trigone

Answer 12

Triangular area bounded by openings of ureters and urethra entrance - acts as a funnel

Question 13

Storage capacity of urine

Answer 13

1L

Question 14

Internal urethral sphincter

Answer 14

Loop of smooth muscle
Convergence of detrusor muscle
Involuntary control

Question 15

External urethral sphincter

Answer 15

Circular band of skeletal muscle where urethra passes through urogenital diaphragm
Acts as a valve with resting muscle tone
Voluntary relaxation = micturition

Question 16

Micturition reflex inhibited/facilitated by…?

Answer 16

Inhibited by higher centres in the brain

Facilitated by cortical centres in the brain

Question 17

At what rate does the bladder fill

Answer 17

1 mL/min

Question 18

What type of micturition contractions occur

Answer 18

Periodic reflex contractions of short duration that occur above 200mL

Question 19

Which nerves usually inhibit micturation

Answer 19

Hypogastric and pudendal nerves

Question 20

What nerve is stimulated during bladder distension

Answer 20

Pelvic nerve - which stimulates the hypogastric nerve

Question 21

What happens when the hypogastric nerve is stimulated

Answer 21

Relaxation of bladder detrusor muscle
Constriction of internal sphincter
External sphincter held closed by pudendal nerve
- known as guarding reflexes

Question 22

What happens when the pelvic nerve is stimulated

Answer 22

Contraction of detrusor muscle

Relaxation of internal sphincter

Question 23

Full bladder sensation conveyed to what

Answer 23

Thalamus and cerebral cortex

Question 24

Neural disruption of micturition

Answer 24

Paraplegia (periodic but unannounced bladder emptying)
Partial spinal cord damage (frequent urination)
Crush injury of dorsal roots (overflow incontinence - atonic bladder)

Question 25

Problems with micturition reflex

Answer 25

Stroke injury/Alzheimer’s disease/brain tumour
Bladder sphincter muscles can lose tone
Urinary retention (enlarged prostate gland)

Question 26

the 3 types of urinary incontinence

Answer 26

Loss of sensory nerves (injury - no signals from stretch receptors)
Involuntary bladder contractions (injury)
Heightened urge incontinence (sensitive bladder - foods/caffeine)

Question 27

What can Ach cause

Answer 27

Contraction of detrusor muscle and internal sphincter relaxation