HRR: bladder function/dysfunction

Question 1

What are the structures of the lower urinary tract?

Answer 1

Ureters, bladder, and urethra

Question 2

What are the two junctions of the ureters?

Answer 2

Uretopelvic (ureter to kidney) and uretovesicular (ureter to bladder)

Question 3

What is the detrusor muscle?

Answer 3

Multi-unit smooth muscle of the bladder with no gap junctions between the cells; each cell is innervated to cause relaxation/contraction as needed

Question 4

What is the trigone?

Answer 4

A region of the bladder composed of the internal urethral orifice and the junctions where the ureters connect to the bladder

Question 5

Describe sympathetic innervation to the bladder.

Answer 5

Preganglionic neurons from T10-L2, ganglionic neurons in the inferior mesenteric ganglion and superior hypogastric plexus

Question 6

Describe parasympathetic innervation to the bladder.

Answer 6

Preganglionic neurons in S2-4 and axons that travel along splanchnic nerves

Question 7

Which nerve provides somatic innervation to the external sphincter of the bladder?

Answer 7

The pudendal nerve

Question 8

What do mechanoreceptors in the bladder do?

Answer 8

Help our brains sense stretch of the bladder to determine if there is still room to fill or if it is needing to be emptied

Question 9

What are nociceptor fibers in the bladder?

Answer 9

Afferent fibers that cause us to feel pain when the bladder is too full

Question 10

Where do afferent fibers from the bladder travel?

Answer 10

In pelvic splanchnic nerves

Question 11

What are the roles of sympathetic receptors in the bladder?

Answer 11

NE causes b2 and b3 receptors in the bladder wall to relax, and a1 receptors in the internal sphincter to contract. This prevents urination

Question 12

What are the roles of parasympathetic receptors in the bladder?

Answer 12

Ach interacts with M2 and M3 to cause contraction of the bladder, and NO will cause relaxation of the internal sphincter. These allow urination

Question 13

Describe voluntary control of the external sphincter.

Answer 13

Pudendal nerve causes release of ach, which acts on nicotinic receptors. When the ach stops, the sphincter relaxes.

Question 14

Describe the voiding reflex arc in babies.

Answer 14

As the detrusor muscle expands, it sends mechanosensory information to the spinal cord. The fibers immediately activate the PSNS in the cord as opposed to travel to sensory areas in the brain. This leads to urination not under voluntary control.

Question 15

When does the voiding reflex arc occur?

Answer 15

Babies and various pathologies

Question 16

What happens to pressure waves from mechanosensors at low volumes?

Answer 16

The SNS can suppress them

Question 17

Describe the pelvic to hypogastric reflex.

Answer 17

Bladder expands and activates mechanoreceptors that send signals to the spinal cord via the pelvic splanchnic nerve to activate the SNS in the spinal cord. The SNS sends signals back to the bladder via the hypogastric nerve to relax the detrusor muscle and contract the internal sphincter

Question 18

What is the somatic storage reflex (pelvic to pudendal reflex)?

Answer 18

The bladder expands and activates mechanoreceptors that send signals to the spinal cord via the pelvic nerve. These act on motor neurons in the spinal cord that innervate the external sphincter, which travel to the sphincter via the pudendal nerve to maintain contraction and prevent urination. Pontine storage center will also maintain contraction through the pudendal nerve.

Question 19

Describe the micturition reflex.

Answer 19

1. Pontine micturition center input reaches threshold
2. PSNS is activated, SNS is inhibited, and somatic system is inhibited
3. External sphincter relaxes and bladder contracts

Question 20

What is stress urinary incontinence?

Answer 20

The urethral sphincters are underactive, leading to increased intra-abdominal pressure allowing urine through the weakened sphincters and causing unintended voiding

Question 21

What is urge urinary incontinence?

Answer 21

Overactivity of the detrusor muscle. There is increased urine volume being pushed through sphincters, causing senses of urgency and involuntary voiding

Question 22

Describe overflow incontinence.

Answer 22

Urethral overactivity or bladder underactivity. This leads to the overfilling of the bladder, and the bladder pressure overriding sphincters and leading to involuntary voiding

Question 23

What is neuropathic bladder?

Answer 23

Lesions above S2 leads to hyperactive detrusor muscle, disrupted detrusor/sphincter synergy, and a reduced bladder capacity

Question 24

What is uninhibited bladder?

Answer 24

A form of neuropathic bladder that involves an incomplete lesion, allowing for some remaining voluntary control of urination. However, voiding reflexes will be triggered at reduced volumes

Question 25

What is reflex bladder?

Answer 25

A form of neuropathic bladder in which complete spinal cord lesion leads to no voluntary control; urination occurs through the voiding reflex arc

Question 26

What is flaccid bladder?

Answer 26

Lesion in the sacral spinal cord impacts the ability to regulate bladder function. This leads to paralyzed detrusor muscle, high bladder volumes, and residual volume. This creates an increased risk for infection.