Urinary system 3

Question 1

Urine elaborated in the nephrons is collected in the _____ _______ of each kidney

Answer 1

renal pelvices

Question 2

Urine is conveyed by the ureters from the kidneys to the _______

Answer 2

bladder

Question 3

Urine is stored in the bladder before voiding; urethral resistance is _____

Answer 3

high

Question 4

Relations of the bladder in the male

Answer 4

Anterior:
pubic symphysis
Posterior:
rectum
ductus deferens
seminal vesicles
Superior:
peritoneum
intestines
Inferior:
prostate gland

Question 5

Relations of the bladder in the female

Answer 5

Anterior:
pubic symphysis

Posterior:
vagina

Superior:
uterus

Inferior & lateral:
muscles of the pelvic floor & sidewall

Question 6

What is the role of the Ureter?

Answer 6

Tubes carry urine from each kidney to bladder
25–30 cm long & ~3-4 mm in diameter

Pass urine by peristaltic waves (smooth muscle)
Enter the back of bladder

Urine backflow - prevented by ureterovesical valves

Question 7

Structure of the bladder
Hollow smooth muscle organ
Bladder can be divided into two parts:

Answer 7

1) Body (lying above ureteral orifices)

2) Base (Consisting of trigone and bladder neck

Its muscular wall is formed of smooth muscle cells (detrusor)

Question 8

Anatomy of the Urinary Bladder

(be able to label and name)

Answer 8

Urothelium

Uretal Orifice

detrusor muscle

Ureter

trigone

Pelvic Floor Musculature

Internal sphincter

External Sphincter

Urethra

Question 9

Urinary Bladder

Answer 9

The only involuntary organ in the body under voluntary control

All humans are incontinent at birth

Activation of numerous neurologic reflexes are learned in early life to control the bladder

35+ reflexes coordinate activities of bladder smooth muscle, plus striated & smooth muscle of the urethra

Question 10

Bladder filling and voiding

Answer 10

requires co-ordination between contractile motions of the bladder and reciprocal motions of the bladder neck

Question 11

Bladder filling:

Answer 11

The detrusor is relaxed

The bladder neck is closed

Question 12

Bladder Voiding:

Answer 12

The detrusor contracts

The bladder neck opens

Question 13

Urinary bladder: Micturition reflex
When is ti activated?

Answer 13

when urinary bladder is STRETCHED
= Results in micturition

Question 14

Control of the Micturition Reflex by Higher Brain centres requires coordination:

Answer 14

1. Central nervous system
2. Spinal cord ( integrated sacral region)
3. Autonomic nervous system (pelvic & hypogastric nerves)
4. Somatic nervous system (mainly pudendal nerve)

Question 15

Micturition reflex /
The bladder switches between 2 phases:

Answer 15

Storage Phase <> Voiding Phase

Question 16

Storage phase

Answer 16

As the Bladder fills
pressure stays low
due to a highly elastic nature

Manifestation of Laplace Law:

Pressure = 2 x wall tension
in sphere radius

(pressure ^ = radius ^)

i) Bladder full - pressure is detected
ii) Messages sent to brain

Voluntary & local reflexes cause
a switch to Voiding phase

Question 17

Voiding phase

Answer 17

i) Voluntary signals relax
external sphincter (somatic)

ii) Autonomic contraction
of detrusor muscle

Urethra - excitatory role
which maintains flow till
bladder is empty

Question 18

Micturition Reflex

Answer 18

Cortex Frontal lobe
Social appropriateness

Periaqueductal
Grey Matter

Neuronal input
(Pelvic nerve) to
Dorsal spinal cord

Sensory nerve endings
detect detrusor muscle stretch

Bladder fills

Medial Pontine - Micturition Centre

Motor nerves
Autonomic & Somatic

Ventral spinal cord

Detrusor muscle
contracts

External sphincter - relaxes

Question 19

Autonomic innervation of Bladder
= which type of system?

Answer 19

Parasympathetic system

Question 20

Autonomic innervation of Bladder
= Sympathetic system

Question 21

Pudendal nerve role

Answer 21

voluntary constriction of
external sphincter to prevent micturition

Question 22

Micturition reflex

Answer 22

Activated by stretch of urinary bladder (trigone)

Eventually Action potentials travel along sensory nerves in pelvic nerve to sacral region of spinal cord

Integrated at spine - AP travel Along parasympathetic nerve to urinary bladder
- Bladder contracts

External sphincter normally contracted as result of somatic motor nervous system
- Decreased AP cause Urethral sphincter to relax

Question 23

Micturition reflex

Answer 23

= Normally activated by stretch of urinary bladder (trionge)

• can be activated by irritation from. actuarial infections - in urinary bladder
• desire to void
  -occurs when bacteria pass up along urethra, causing inflammation
• cause by bacteria from the GI tract, eg E.coli
  WBC and RBC in urine