Week 13: Chp 61: Urinary System Structures

Question 1

Urinary System Consists of?

Answer 1

ureters, bladder, and urethra

Question 2

Ureter

Answer 2

a small, hollow, muscular tube through which urine travels from the renal pelvis of the kidney to the bladder
10 to 12 inches and one is associated with each kidney (2 in total)
-consists of 3 layers: an inner mucous membrane, a middle layer of smooth muscle, and an outer layer of fibrous tissue

Question 3

Ureteropelvic Junction

Answer 3

the narrowing where each ureter joins the renal pelvis
-because these areas represent locations of narrowing in the ureter lumen, they are common sites for obstruction of urine flow related to urinary stones, or calculi

Question 4

Urine through the ureters

Answer 4

urine moves one way through the ureters and into the bladder as a result of the peristaltic contractions of the smooth muscle fibers of the ureters

• these contractions occur as stretch receptors within the renal pelvis detect the increased urine volume
• urine is prevented from backflowing into the kidneys when the pressure in the bladder increases (with coughing or voiding) because the muscles of the bladder and urethra contract to close off the lumen

Question 5

Why is urine prevented from backflowing in the kidneys when pressure in the bladder increases from things such as coughing or voiding?

Answer 5

because the muscles of the bladder and urethra contract to close off the lumen

Question 6

The Bladder

Answer 6

is a muscular reservoir for storing urine until it is excreted from the body

• lies directly posterior to the symphysis pubis
• positioned anterior to the rectum and in women is anterior to the vagina and inferior to the uterus
• when the bladder contains urine, it appears as a sac, when empty it appears as stacked folds within the pelvic cavity
• the bladder is fixed to the abdominal wall by a ligament emerging from the umbilicus; as the bladder fills with urine it expands upward towards the umbilicus
• can hold 600 to 1000 mL of urine

Question 7

Bladder is composed of 3 layers

Answer 7

the outer lining, the middle smooth muscle (detrusor), and the inner epithelium (urothelium)

Question 8

Detrusor

Answer 8

middle smooth muscle of the bladder

-consists of smooth muscle that distend as bladder fills and contract when bladder empties

Question 9

Rugae

Answer 9

when the bladder is empty, the lining contains folds known as rugae
-as the bladder fills and the lining stretches, these rugae disappear

Question 10

Urothelium

Answer 10

inner epithelium of the bladder

• resists the reabsorption of urine, which ensures that urine stays within the urinary tract
• also secretes a unique substance that resists bacterial colonization

Question 11

Trigone

Answer 11

the smooth, triangular-shaped region at the base of the bladder between the entrance points of the ureters and the urethra
-common location of bladder infections

Question 12

Continence

Answer 12

ability to voluntarily control the emptying of the bladder

Question 13

Micturition

Answer 13

“voiding”

• is the act of releasing urine from the body
• is a learned response coordinated by the brain and the spinal nerves that innervate the bladder

Question 14

What happens when the bladder fills with urine?

Answer 14

stretch receptors in the bladder are stimulated, sending impulses to the sacral spinal cord (S2 and S4) and the brain, triggering the urge to void
-if the time to void is suitable, the brain transmits signals to the nerves along the thoracolumbar (T11 and L2) and sacral spine to relax the muscles of the bladder neck, sphincter, and pelvic floor; as these muscles relax, the bladder contracts, and urine is released from the body

Question 15

What happens if the time to void is not suitable?

Answer 15

inhibitor impulses in the brain are stimulated

• signals are transmitted to the thoracolumbar and sacral spinal nerves to contract the muscles of the sphincter and pelvic floor, resisting increasing bladder pressure
• the contraction of these muscles temporarily inhibits voiding

Question 16

The urge to urinate occurs when the bladder is distended with how many mL’s of urine?

Answer 16

200 to 250 mLs

-average adult voids five to six times each day

Question 17

What can affect the normal functioning of the bladder?

Answer 17

medical conditions or trauma involving the brain, spinal cord, or nerves innervating the muscles of the bladder, sphincter, or pelvic floor

Question 18

Incontinence

Answer 18

lack of continence
-difficulty voiding
>conditions are: multiple sclerosis, paraplegia, quadriplegia, spina bifida, and diabetes mellitus

Question 19

Medications that can affect bladder function

Answer 19

opioid pain medications, some antihypertensives, certain antidepressants, some antiemetics, and antihistamines

Question 20

Urethra

Answer 20

is a narrow muscular passage extending from the neck of the bladder to the urinary meatus (the opening at the end of the urethra through which urine exits the body)
-male: 8 to 10 inches
-female: 1 to 2 inches
>the short length of the female urethra allows for bacteria to more easily invade the urinary tract, explaining the increased incidence of UTIs in females when compared with males

Question 21

Internal urethral sphincter

Answer 21

formed by the thickening of the detrusor muscle around the top of the urethra as it exits the bladder

• the smooth muscle of this sphincter contracts, maintaining closure of the urethra to ensure that urine remains in the bladder until the time of voiding
• control is involuntary

Question 22

External Urethral Sphincter

Answer 22

encircles the urethra as it enters the pelvic floor

-composed of skeletal muscle fibers, control is voluntary

Question 23

The nurse is caring for an older adult with intermittent  urinary incontinence. The nurse recognizes that the incontinence is a result of which structure failing to contract to keep urine in the bladder until micturition (voiding)?
A. The detrusor muscle
B. The external urethral sphincter
C. The urethra
D. The internal urethral sphincter

Answer 23

D. Internal Urethral Sphincter