Urinary System

What are the 4 major functions of the urinary system?

• Removal of metabolic waste

• Regulation of fluid & electrolyte balance

• Regulation of blood pressure

• Production, transport, storage & excretion of urine

What are the 4 major components of the urinary system?

• Kidneys

• Ureters

• Urinary bladder

• Urethra

Label the following diagram

For the kidneys, state:

• Which vertebra they correspond to

• Where they are wedged

• Which kidney is lower

• Whether they are intraperitoneal or retroperitoneal

• T12-L3

• Wedged lateral to vertebrae in paravertebral gutter (‘either side’ of the vertebrae)

• Right kidney slightly lower (but both are the same size)

• Retroperitoneal

What are the kidneys surrounded by & what are the implications if this structure is removed?

• Surrounded by fat

  • Keeps kidneys in position

  • Pathway for blood vessels supplying the kidneys

• Kidney stripped away → kidneys start to drop → problems

Name the medial anatomical relationships of the kidneys

• T12 - L3

• Psoas major (but is not directly attached due to the fat)

Name the posterior anatomical relationships of the kidneys

• Quadratus lumborum

• Thoracic diaphragm

• Ribs 11-12

Name the anterior anatomical relationships of the kidneys

• Peritoneum + abdominal viscera

  • Urinary viscera are retroperitoneal

Label the following diagram

Label the following diagram of the attachments of the kidneys

Label the following diagram of the external anatomy of the kidney

What structures make up the hilum of the kidney?

• Renal artery

• Renal vein

• ANS nerves

• Lymphatic vessels

Label the following diagram of the internal anatomy of the kidney

What are the 2 solid tissues in the kidneys, and what do each of these tissues comprise?

• Renal cortex

  • Renal columns

  • Renal cortex

• Renal medulla

  • Medullary pyramid

  • Medullary papilla (apex of renal pyramids)

What are the 3 components of the tubular system of the kidneys? For each component, state how many there are of each

• Minor calyx: many

  • Where waste (after blood has been filtered) initially drains into

  • Direct contact w/ medulla

• Major calyx: few

• Renal pelvis: singular

Label the following diagram of the kidney

Describe the movement of blood into, throughout, and out of the kidneys

1. Blood enters via renal artery through hilum & progressively divides w/n kidney

2. Filtration occurs in glomeruli located in renal cortex

3. Filtrate passes through the nephron and collecting ducts w/n renal pyramids

4. Urine drains from minor calyx → major calyx → renal pelvis → ureter

5. Filtered blood returns to systemic circulation via renal vein

What is an implication of the kidneys’ location to the ribs?

Kidneys are extremely vascular; cracked rib in the back → kidney bleed (rapid blood loss)

Label the following diagram

Order the following from most anterior → posterior:

• renal artery

• renal vein

• renal pelvis

• Anterior: renal vein

• Middle: renal artery

• Posterior: renal pelvis

Label the following image

Name the gonadal veins in females vs males

• Female: ovarian veins

• Male: testicular veins

Where does the right gonadal vein drain into?

Inferior vena cava

Where does the left gonadal vein drain into?

left renal vein → across aorta → inferior vena cava

For the renal artery, state:

• How many there are

• What it branches off

• How it supplies the kidneys & the relevance of this

• 2 renal arteries; 1 R & 1 L

• Branches off abdominal aorta

• Provides segmental branching of kidney; segments are surgically resectable

  • Artery ruptures → cannot be preserved (b/c they are too small) → ligate artery

For the ureters, state:

• What they are

• What type of action they perform & what this facilitates

• Intraperitoneal or retroperitoneal

• Structure during relaxed vs functioning state

• Paired smooth muscle tubes

• Perform peristaltic contractions → urine transport from kidney to urinary bladder

• Retroperitoneal course

• Relaxed state has folds, distends during urine passage

Label the following diagram

Name the 3 sites of constriction along the ureter & where they are found

1. Ureteropelvic junction: renal pelvis:

   • wide renal pelvis → narrow true ureter

   • ‘loin-to-groin’ pain; common symptom of kidney stones

2. Pelvic brim: crossing pelvic inlet

   • Where the ureter bends as it crosses over the pelvic brim

3. Vesicoureteric junction: posterior entry into bladder

Label the following diagram of the constrictions along the ureters

What type of sphincter is the urinary bladder wall?

Functional

Label the following diagram of the urinary bladder

Where do the ureters enter the urinary bladder?

Ureteric opening on posterior superior surface

Describe the 3 key landmarks of the urinary bladder

• Ureteric orifices: where ureters enter bladder

• Trigone: smooth triangular region formed by

  • 2 ureteric openings

  • internal urethral orifice

  • Taute; don’t want opening to be compromised as bladder fills

• Rugae: mucosal folds when the bladder is empty

  • Allows bladder to fill & stretch

For the urinary bladder, state:

• What type of organ it is

• How it changes shape & why

• Where it is located

• Where it moves as it fills

• Hollow (muscular) viscus

• Highly distensible to store urine; changes shape from empty → expanded

• Located anteriorly in pelvis

• Moves into false pelvis area as it fills

Label the following surfaces of the urinary bladder

Describe the position and shape of the bladder when it is empty

• Lies within pelvis, posterior to pubis

• Internal surface with prominent rugae (folded mucosa)

• Muscular wall contracted

Describe the position and shape of the bladder when it is filling

• Expands superiorly into abdominal cavity

• Bladder neck remains relatively fixed

• Rugae flatten as wall stretches

• Shape becomes more rounded/expanded

Describe the process of urine outflow

• Bladder stores urine until micturition

• Bladder contracts → expel urine

• Urine exits via internal urethral orifice

  • Transition from storage → excretion

Label the following image of the urinary bladder in its empty state

Label the following diagram

What is the urethra?

Muscular tube that carries urine from the bladder to the exterior

• Terminal part of the urinary system

Where does the urethra begin?

at the internal urethral orifice of the bladder

How does the structure of the urethra differ in females to males, & what are 2 clinical implications of this?

Urethra is a lot shorter in females

• Easier to get UTIs + for infections to get into bladder & spread to vag!na

• Easier to insert catheters in females; no bending (which may be painful in men, also requires more skill)

Where is the external urethral orifice of the female urethra located?

• Between labia minora

• Anterior to vaginal opening

Where does the male urethra pass, & how is it distinctly different to the female urethra?

• Passes through prostate & pen!s

• Common pathway for urinary & reproductive systems (only urinary in females)

Name the 4 regions of the male urethra

1. Preprostatic (intramural) urethra

2. Prostatic urethra

3. Membranous urethra

4. Spongy (penile) urethra

Label the following diagram of the male urethra

Where does the preprostatic (intramural) urethra pass?

Through the bladder wall

Describe the surrounding structures of the prostatic urethra, & the clinical relevance of this

• Widest part of urethra

• Surrounded by soft tissue, but this tissue is not stuck to the urethra

• Prostatic enlargement may obstruct urine flow

Describe the structure of the membranous urethra & an implication of this

• Surrounded by external urethral sphincter

• Important for voluntary control of urination

Describe the location, structure, & surrounding tissue of the spongy (penile) urethra

• Located within corpus spongiosum

• Structure: remains patent (open) for urination + ejaculat!on

• Surrounding tissue prevents urethral collapse