Renal Anat

Question 1

3 cavities of ‘trunk’?

Answer 1

note: trunk = ‘neck down’ part of body till legs ofc

• thoracic cavity
• abdo cavity (separated from ^ by diaphraagm)
• pelvic cavity

Question 2

What is the peritoneum?

Answer 2

A serous membrane lining the abdo cavity.
- Parietal layer ‘sticks’ to abdo wall
- Visceral layer ‘sticks’ to organs in the abdo cavity

• Between Visceral and Parietal layer of serous peritoneum = ‘Peritoneal space’ (I think)

(search pic to understand!)

Question 3

Micturition is primarily controlled by the parasympathetic nervous system. - Is this True or False and why?

Answer 3

True. Psymp = ‘rest and relax’

Question 4

Explain the process of micturition in infants.

Answer 4

• Micturition is involuntary in infants and young children until they are toilet trained.

(note: MICTURITION is basically PARASYMP-controlled - not rly much of symp. –> because to pee is during ‘rest and relax’)

REFLEX ARC:
- when the bladder reaches its micturition threshold, stretch receptors on bladder wall send signals to spinal segments S2-4 via parasympathetic: pelvic splanchnic nerves

• interneurons (relay neurons) in S2-4 segments relay signals to parasymp Efferent fibres that travel in pelvic splanchnic nerve (agn) to innervate smooth detrusor muscle in bladder wall + internal urethral sphincter
  (bind to nicotinic receptor, etc) –> cause
  1. detrusor contraction
  2. internal sphincter relaxation
• meanwhile, interneurons also relay signals to somatic motor (efferent) fibres that travel in pudendal nerve to innervate external urethral sphincter muscle –> cause
  3. external sphincter relaxation
• thus causing micturition

Question 5

Explain the process of micturition in adults.

Answer 5

• Micturition is voluntary after ‘toilet-training’ when cerbral cortex is matured, thus overriding spinal reflex (that occurs at S2-4)

(note: MICTURITION is basically PARASYMP-controlled - not rly much of symp. –> because to pee is during ‘rest and relax’)

REFLEX ARC:
- when the bladder reaches its micturition threshold, stretch receptors on bladder wall send signals to spinal segments S2-4 via parasympathetic: pelvic splanchnic nerves

• interneurons (relay neurons) in S2-4 segments relay signals to parasymp Efferent fibres that travel in pelvic splanchnic nerve (agn) to innervate smooth detrusor muscle in bladder wall + internal urethral sphincter
  (bind to nicotinic receptor, etc) –> cause
  1. detrusor contraction
  2. internal sphincter relaxation

MEANWHILE, INHIBITION OF REFLEX ARC to control peeing:
- meanwhile, stretch signals from psymp afferent fibres are also transmitted up spinal cord to cerebral cortex where voluntary control happens.

IF OKAY TO PEE:
- cerebral cortex (Pontine Micturition Center) sends signals to somatic motor (efferent) fibres that travel in pudendal nerve to innervate external urethral sphincter muscle –> cause
3. external sphincter relaxation

• thus causing micturition

(IF NOT OKAY TO PEE:
- cerebral cortex (Pontine Micturition Center) sends signals to somatic motor (efferent) fibres that travel in pudendal nerve to innervate external urethral sphincter muscle –> cause
3. (voluntary) external sphincter contraction - prevent relaxation)

Question 6

Spinal cord injuries and the bladder:

1. If spinal cord transection above T12
2. If spinal cord transection below T12

Answer 6

1. ‘Reflex/ autonomic bladder’ because disruption in voluntary control of bladder by cerebral cortex (Pontine micturition centre) - but reflex arc still intact
2. ‘Flaccid/ atonic bladder’ - damage to micturition’s spinal reflex arc damaged parasympathetic outflow to bladder - detrusor muscle paralysed and unable to contract –> bladder fills uncontrollably, (becoming abnormally distended), until overflow incontinence occurs.

Question 7

When the bladder expands upwards into abdominal cavity, what catheterisation could you use?

Answer 7

Suprapubic Bladder Catheterisation

Question 8

2 major functions of pelvic floor?

Answer 8

1. support pelvic organs and prevent ‘prolapse’
2. for urinary continence mechanism (external urethral sphincter in urogenital floor)

Question 9

2 reasons why females tend to UTIs more than males?

Answer 9

1. Shorter urethra - shorter pathway for pathogens to enter and infect urinary tract
2. Urethra closer proximity to anus in females (for colon-ic bact like E. coli to enter)