Intro to Urinary System Flashcards
What four structures are part of the urinary system?
- Kidneys
- Ureters
- Urinary bladder
- Urethra
Why is the urinary system important?
- Removes metabolic waste via filtration and excretion
- Regulates plasma electrolytes and blood pressure
- Stabilises the pH
- Resorption of small molecules - AA, Glc
- Produces erythropoietin (stimulant of RBC production)
How are the kidneys peritonised?
Retroperitonised, but partially because organs lie across it
What are the important structures within the kidney?
Interior arranged into outer cortex layer and inner medulla.
- Medulla
- Pyramid
- Papilla
- Minor calyx
- Major calyx
- Pelvis
- Ureter
What are the different constrictions of the ureter?
- Ureter passes over inferior renal pole (abdominal)
- Ureter cross over external iliac vessels (pelvic)
- Ureter traverses the bladder wall (intramural)
How are vessels arranged at the hilum of the kidneys?
Front to back:
Vein -> artery -> renal pelvis
How do you renal arteries branch after they enter the hilum of the kidneys?
- Segmental branches (x5)
- Interlobar
- Arcuate branches pass around the circumference
- Intralobular branches which ultimately supply each nephron
What is the lymphatic drainage of the kidneys?
Lateral aortic lymph nodes
What is the nerve supply to the kidneys?
Renal plexus:
o Sympathetic: T10-L1 and coeliac plexus
o Sensory afferent: T11-L2
What is the epithelium of the bladder?
Transitional epithelium
What is the peritonisation of bladder?
Only superior surface is covered
What is the epithelium of the urethra?
Stratified columnar epithelium
What is the nerve supply of the urethra?
- Somatic supply to pelvic organs – pudenal nerve (S2, 3, 4)
- Sympathetic nerves control neck of bladder to allow urine flow – hypogastric nerve (T12-L2)
- Pelvis splanchnic nerve (S2, 3, 4 ) to the muscle around bladder, contracts to squeeze urine out
- Bladder full -> sympathetic neck and parasympathetic contracts
As the urethra is also an exit route for semen in males, how does it not end up mixing with urine?
Parasympathetic nerves constrict internal sphincter
What are the four parts of the male urethra?
- Pre-prostatic (intramural) - internal urethral orifice
- Prostatic - passes through prostate gland + contains opening of vas deferens
- Membranous
- Spongy
What is the widest part of the male urethra?
Prosthatic part
What is the narrowest part of the male urethra?
Membranous part
What is the longest part of the male urethra?
Spongy part of urethra
What vessels supply the urinary bladder?
- Branches of the internal iliac artery
* Drains into the internal iliac veins
What is the lymphatic drainage of the urinary bladder?
- External iliac lymph nodes: suprapubic part
* Internal iliac lymph nodes: infrapubic part
What is the nerve supply of the urinary bladder?
- Sympathetic T11-L2 – constricts internal urethral sphincter
- Parasympathetic S2-4 – motor to detrusor muscle and also to internal urethral sphincter
- Afferent/sensory: pain/distention of bladder goes via parasympathetic fibres
- Somatic: pudendal nerve (external urethral sphincter) – voluntary control
What is the nephron?
Renal corpuscles + renal tubules
What is the renal corpuscle?
Glomerulus + bowmen’s capsule
Describe the histology of the cortex
- Renal corpuscles
- Prox and distal convoluted tubules
- Collecting tubule
Describe the histology of the medulla
- Prox and distal convoluted tubules
- Loop of Henle (thin, squamous epithelium)
- Collecting tubule
Describe the histology of the ureter
- Transitional epithelium
- Star shaped lumen
- Inner longitudinal smooth muscle
- Outer circular SM
Describe the histology of the bladder
- Transitional epithelium
- Inner longitudinal SM
- Middle circular SM
- Outer longitudinal SM
What are five pathologies of the urinary system
- Urinary tract infection (UTI)
- Glomerulonephritis
- Kidney stone/renal calculi
- Kidney failure and dialysis
- Urinary incontinence (common after child birth, old age and in females)
What are the important markers of kidney disease?
- High protein (albumin) level in the urine – proteinuria
- Glomerular filtration rate (GFR)
- Increased level of serum creatinine/urea in the blood