Anatomy

Question 1

Upper urinary tract

Answer 1

• kidney (produces urine)
• ureter (transports urine toward the urinary bladder)
  = ARE PAIRED

Question 2

Lower urinary tract

Answer 2

• urinary bladder: temporarily stores urine prior to elimination
• urethra: conducts urine to exterior; in males, also transports semen
  = ARE UNPAIRED

Question 3

Position of the kidney + about the kidney

Answer 3

• typical adult kidney = 10cm long, 5.5cm wide, 4cm thick
• represents 0.5% of body weight
• receives 20-25% CO
• located on either side of vertebral column
• high in abdominal cavity, protected by 11th + 12th ribs
• right kidney lies inferior to left kidney
• kidney located in a retroperitoneal position (behind the peritoneum)
• superior surface capped by adrenal gland (produces hormones e.g. cortisol, aldosterone, adrenaline)
• close to aorta + VC
• hilum: point of entry/exit for renal artery, veins + ureter

Question 4

Position of kidney maintained by:

Answer 4

• supporting fat + connective tissues,
• overlying peritoneum (big bag intestines are in)
• contact with adjacent, visceral organs

Question 5

Three layers of connective tissue protect + stabilise the kidney:

Answer 5

• Fibrous (renal) capsule: a tough layer that surrounds the kidney
• Perinephric fat (adipose capsule): surrounds the fibrous capsule
• Renal fascia: tough fibrous outer layer that anchors kidney to the surrounding tissue

Question 6

External structure of kidney

Answer 6

• kidneys are ensheathed by a shiny, tough fibrous capsule
• renal vein: exits kidney via the hilum on the medial border
• renal artery: enters at the hilum behind the vein
• renal pelvis: exits at the hilum behind the artery and droops down to become ureter
• anterior to posterior: VAP

Question 7

The kidney: internal macroscopic structure

Answer 7

• The kidney is made up of 2 layers and a renal sinus (internal cavity)
• renal cortex = outer layer
• renal medulla = inner layer (made up of 6-18 triangular structures called renal pyramids)
• pyramids separated by cortical tissue = forming the renal columns
• tip of the pyramid is the renal papilla (projects into renal sinus)
• renal lobe = one renal pyramid, overlying cortex and adjacent columns
• urine is produced in a renal lobe and drains into a minor calyx
• 4-5 minor calyces merge to form a major calyx
• 2-3 major calyces form renal pelvis (a large funnel-shaped chamber, fills most of renal sinus)
• renal pelvis drains into the ureter which drains the kidney –> bladder

Question 8

The ureters

Answer 8

• pair of muscular tubes that extend from kidneys to urinary bladder
• ~ 25 cm long, 3-5 mm wide
• begin at renal pelvis
• run along the posterior abdominal wall
• penetrate posterior wall of the urinary bladder

Backflow of urine into the ureter is prevented by:

• the oblique angle that the ureter enter the bladder wall, and the ureter travels in the wall for ~ 1 cm.
• the ureteral openings are slit-like rather than rounded so that they close off during bladder contraction

Three points where the ureters narrow:

• uretero-pelvic junction
• pelvic brim
• ureto-vesical junction

Peristaltic contractions begin at renal pelvis and sweep along ureter every 30 s forcing urine toward urinary bladder

Question 9

The urinary bladder

Answer 9

• Hollow, muscular organ that functions as temporary reservoir for urine storage
• can hold up to ~1 L of urine (desire to void starts at ~250-300 ml)
• Made up of smooth muscle (detrusor muscle)
• Inner surface of bladder has folds called rugae that disappear as bladder fills
• Inner lining of bladder is transitional epithelium
• 3 openings (2 ureters and urethra) form Trigone
• 2 urethral sphincters: internal urethral sphincter (smooth muscle), external urethral sphincter (skeletal muscle)

Question 10

pelvic floor muscles definition + role

Answer 10

• the pelvic floor muscles: sling of muscles that run b/w your legs, from pubic bone anteriorly to the tailbone (coccyx) posteriorly
• support the pelvic organs including the bladder, bowel + vagina + include the external urethral sphincter and anal sphincter
• damage to these muscles = major cause of incontinence

Question 11

Comparison of male and female urethra

Answer 11

• The urethra extends from neck of urinary bladder to the exterior of the body
• The Male Urethra is 18–20 cm long and comprises
  
  • pre-prostatic (through bladder neck, surrounded by internal sphincter),
  • prostatic urethra (3cm) passes through centre of prostate gland,
  • membranous urethra (1 cm) passes through the urogenital (or pelvic) diaphragm
  • Spongy urethra (penile urethra) (15 cm) extends from urogenital diaphragm to external urethral orifice
• The Female Urethra is very short (3–5 cm) and extends from bladder to vestibule
  
  • external urethral orifice is near anterior wall of vagina