Principles - The Renal System Flashcards
What is the urinary tract?
Upper Kidney: produces urine Ureter: drains urine from kidney to bladder Lower Bladder: stores/voids urine Urethra: Excretion of urine
What is the distal urethra lined by?
Protective stratified squamous mucosa
Where is the urinary tract?
In the retroperitoneum
In which region/quadrant of the abdomen are the kidneys in?
In the right or left flank
or
Right or left upper quadrant
What protects the kidneys?
- being in the retroperitoneum
- vertebral column (transverse processes)
- floating ribs
- skeletal muscles (guarding)
- renal (deep) fascia
- paranephric and perinephric fat
- renal capsule
How do the kindeys move with respiration?
They move inferiorly on inspiration then superiorly on expiration
Why does the right kidney lie at a slightly inferior level?
Due to the size of the liver
What are the structures of the renal hilum?
Right or left renal artery
Right or left renal vein
Right or left ureter
What is the blood supply to the kidneys?
Renal artery (right or left) This is a paired branch of the abdominal aorta
What is the venous drainage of the kidney?
renal veins
These drain into the IVC for return to the RA
What veins drain into the left renal vein?
left gonadal vein and left suprarenal vein
On the right side these veins drain straight into the IVC
How many renal segments are there?
5
What is the blood supply to the renal segments?
5 segmental branches arise from each renal artery
What does the kidney consist of?
Outer cortex and inner medulla mainly
How many pyramids does the inner kidney medulla contain and how many nephrons are in each?
27
Each contains about 50000 nephrons
What is the structure of a nephron? (proximal to distal)
glomerulus proximal convoluted tubule loop of Henle distal convoluted tubule collecting duct (passes into minor calyx)
What happens at the glomerulus of the nephron?
Ultrafiltration of the blood arriving via branches of the renal artery
How does urine drain from the kidney?
Nephrons collecting duct Minor calyx Major calyx Renal pelvis Ureter
Diameter of the tubes is increasing until a constriction at the pelviureteric junction
Where are the anatomical sites of ureteric constriction?
- Pelviureteric junction
- ureter crossing the anterior aspect of the common iliac artery
- ureteric orifice opening into the posterior surface of the bladder
What are renal calculi?
Stones that can form from urine calcium salts
How can ureteric obstruction occur?
- internal obstruction: renal calculus or blood clot
- external compassion e.g. expanding tumour
Tends to be felt as renal colic - peristaltic waves, pain that comes and goes
What can be stretched to allow the bladder to fill?
The urothelium
Where is the trigone located in the bladder?
On the floor of the bladder between the bilateral ureteric and midline urethral orifices
What happens on filling of the bladder?
The apex rises but the trigone doesn’t stretch or move which helps to prevent the obstruction of the orifices
What contracts to void during micturition (urination)?
The detrusor
smooth muscle within the bladder wall
Where are the bladder sphincters?
At the ureteric orifices (detrusor muscle fibres encircle) - prevents reflux of urine into the ureters during micturition
At the bladder neck - internal urethral sphincter - preventing ejaculatory reflux - only present in MALES
Describe the journey of sperm through the male reproductive system.
right testis (travels inferior to superior)
right epididymis (travels superior to inferior)
right vas deferens (travels from inferior to superior)
right seminal gland
right ejaculatory duct
prostatic urethra
spongy urethra
external urethral orifice
Describe the movement of urine through the male lower urinary tract.
Bladder Through the internal urethral orifice and internal urethral sphincter Prostatic urethra External urethral sphincter Spongy urethra External urethral orifice
What can benign (BPH) or malignant enlargement of the prostate gland cause?
Urinary retention - inability to void completed due to obstruction of the prostatic urethra
Describe the movement of urine through the female lower urinary tract.
Bladder Internal urethral orifice (females do not have an internal urethral sphincter) Urethra External urethral sphincter External urethral orifice
