US Lecture 1 - The Kidney and Urinary Tract Flashcards
What does the kidney and urinary tract comprise?
Kidneys, ureters, urinary bladder and urethra
Where are the kidneys located?
In upper abdomen - RETROPERITONEAL, surrounded by dense fibrous capsule, which has renal fascia containing the peri-renal adipose tissue
What overlaps the kidneys?
The diaphragm posteriorly and the pleural cavity superiorly
What is the difference between the location of the right and the left kidney?
Right kidney is slightly lower than the left - superior pole of RK lies at 11th intercostal space and LK at 11th rib
Where are the hilums of the kidneys located?
Around L1
Fill in the blanks of the urinary system
What are the anterior relations of the kidney?
Right: liver, hepatic flexure and hilus lies behind 2nd part of duodenum Left: stomach, pancreas, spleen and splenic flexure
How are the kidneys supplied with blood?
Via renal arteries (short direct branches from abdominal aorta), BP drives ultrafiltration Renal vein drains into IVC
What does the abdomen vasculature look like in relation to the kidneys? - Fill in the blanks
What is the basic structure of the kidney? - FITB
Why does the cortex look granular?
Due to random organisation
Why is the medulla of the kidney striated?
Due to radial arrangement of tubules and micro-vessels
What is the kidney split into and why is that important?
It is multilobar, so each lobe drains through its own papilla and calyx
What does the structure of the inside of the kidney look like? FITB
Where are the ureters located?
Run vertically down posterior abdominal wall in the plane of the tips of the transverse processes of the lumbar vertebrae Crosses pelvic brim anterior to sacro-iliac joint and bifurcation of common iliac arteries
How do the ureters descend down the abdominal cavity?
Anteromedially to enter bladder at the level of ischial spine - need to go around the rectum (and vagina in females) to reach the bladder
How does urine travel down the ureter?
By peristalsis in the smooth muscle walls of the ureters - open diagonally through bladder wall
What are the 3 sites of ureteric constriction?
Pelviureteric junction, where ureter crosses pelvic brim and where ureter traverses bladder wall
Why does renal colic occur and where are they most likely to occur?
Due to kidney stones attempting to pass - in the first constriction of the ureter in the pelviuteric junction
What is the bladder’s structure?
Pelvic organ - triangular pyramid with apex pointing anteriorly and base posteriorly Lined by urothelium (transitional epithelium), 3-layered epithelium with very slow cell turnover, large luminal cells present
What do luminal cells do?
Highly specialised low permeability luminal membrane which prevents dissipation of urine-plasma gradients
What is the structure of the bladder? - FITB
What are the 2 urinary sphincters?
Sphincter vesicae and sphincter urethrae
What is the sphincter vesicae?
Internal sphincter, smooth muscle, neck of bladder, reflex opening in response to wall tension
Which nervous system is the sphincter vesicae controlled by?
Parasympathetic
What is the sphincter urethrae?
External sphincter, striated muscle, in perineum - opened by voluntary inhibition of nerves
How is tone maintained?
By somatic nerves in Pudendal nerve (S2-4)
How does the activation of the reflex control of the internal sphincter urethrae work?
Bladder fills, stimulates stretch receptors which stimulate parasympathetic nerves and inhibit motor neurons, the PS nerve stimulate the bladder to contract, causing internal urethral sphincter to open mechanically
How does the activation of the voluntary control of the external sphincter urethrae work?
Cerebral cortex stimulates motor neurons and stretch receptors inhibit them - so motor neurons either cause, external US to open when motor neuron inhibited OR external US remains closed when motor neuron is stimulated
How is the urethra different in males than females?
Females: Paraurethral gland Males: Preprostatic/ prostatic/membranous/ spongy part of urethra
Fill in the blanks on the differences between male and female urethra differences
What is the male urethra comprised of?
Internal urethral orifice (bladder neck/outlet), prostatic urethra, membranous urethra, bulbar urethra, penile urethra, navicular fossa, external urethral meatus
What is the lymph drainage of the urinary system?
x
Under which ribs does the spleen lie?
Ribs 9-10
What are the posterior relations of the kidneys?
Abdominal wall: psoas major nearest to the medial side of kidney, then quadratus lumborum, and Transversus abdominis Above: diaphragm is present
How are the aorta and IVC arranged in the abdomen?
Aorta is to the left and IVC is to the right in the abdomen, so left renal vein is longer and passes in front of aorta, underneath IMA Renal artery passes underneath the IVC
What is the renal pelvis?
Each renal papilla is surrounded by a branch of the renal pelvis called a calyx. The major function of the renal pelvis is to act as a funnel for urine flowing to the ureter.
What is the arrangement of the urinary system in the abdomen?
How is the renal blood supply organised in the abdomen? FITB
X
How does the urine drain from the kidney?
Urine drains into the minor calyx, then major calyx which then all drains into the renal pelvis
From where does the ureter get its blood supply from and why does it need a blood supply?
Upper: from renal arteries Middle: common iliac arteries, some branches of abdominal aorta and gonadal arteries Lower: internal iliac arteries (and some others) Need it as it is a muscular tube and needs a continuous blood supply
Where is the bladder located?
Usually in the true pelvis but can be in the abdomen in children and when full in adults
What is the trigone?
It is a straight, not corrugated triangle shape in the bladder
