Urinary System 1 - The kidney and urinary tract Flashcards
What are the contents of the urinary tract?
- Kidneys
- Ureters
- Urinary bladder
- Urethra
Describe the position of the kidneys
- Retroperitoneal in the upper abdomen
- Covered with a dense fibrous capsule and fascial pouch containing peri-renal adipose tissue
- Overlapped posterosuperiorly by the diaphragm and pleural cavity
- Right kidney is lower than the left
Describe the spinal level of the kidney
- Superior pole of the right kidney is at the level of the 11th intercostal space
- Left kidney superior pole is at the 11th rib
- Hilum is at the level of L1
List the layers around the kidney
- Perinephric fat
- Renal fascia
- Paranephric fat
- Transversalis fascia
List the posterior relations of the kidney
- Transversus abdominis muscle (lateral under rib 12)
- Quadratus lumborum muscle (between transversus and psoas major muscles)
- Psoas major muscle (under rib 12, medially)
- Diaphragm covers the kidneys down to rib 12
List the anterior relations of the kidney
- Right - liver, hepatic flexure (hilus behind 2nd part of duodenum)
- Left - stomach, pancreas, spleen and splenic flexure
What is the hepatic flexure?
The sharp bend between the ascending colon and the transverse colon
Describe the blood supply of the kidney
- Rich supply via renal arteries
- Short direct branches from the abdominal aorta
- Blood pressure drives ultrafiltation
- Renal veins drain into the IVC
What is attached to the superior pole of the kidney?
Adrenal/supradrenal glands
Describe the structure of the kidney
- Cortex is granular-looking due to random organisation
- Medulla striated because of radial arrangement of tubules and micro-vessels
- Human kidney is multilobar – like a lot of simple kidneys stuck together
- Each lobe drains through its own papilla and calyx via the renal medulla
Describe the position of the ureters
- Run vertically down the posterior abdominal wall in the vertical plane of the tips of the transverse process of the lumbar vertebrae
- Cross the pelvic brim anterior to the sacro-iliac joint & bifurcation of the common iliac arteries
- Descend anteromedially to enter bladder at the level of the ischial spine
How do the ureters transport urine?
By peristalsis of the smooth muscle walls
List the sites of ureteric constriction
- Pelviureteric junction
- Where the ureter crosses the pelvic brim
- Where the ureter transverses bladder wall
Describe the shape of the bladder
Triangular pyramid with apex pointing anteriorly and base posteriorly
Describe the anatomy of the bladder and its location
- Pelvic organ
- Lined with urothelium
- 3-layered epithelium with slow cell turn over
- Large luminal cells have highly specialised low-permiability luminal membrane
- Prevents dissipation of urine-plasma gradients
Where is the pubovesical ligament?
Attaches the neck of the bladder to the inferior aspect of the pubis bones
Where is the puboprostatic ligament?
Extends laterally from the prostate to the tendinous arch of the pelvic fascia and continues forward and medially from the tendinous arch to the pubis.
What are the two urinary sphincters?
- Sphincter vesicae (internal sphincter - smooth muscle)
- Sphincter urethrae (external sphincter - striated muscle)
Describe the control of the sphincter vesicae
- Smooth muscle, internal
- At the neck of the bladder
- Reflex opening in response to bladder wall tension
- Relaxed by PNS, contracts by SNS
Describe control of the sphincter urethrae
- In the perineum (external)
- Tone maintained by somatic nerves in pudenal nerve (S2, 3, 4)
- Opened by voluntary inhibition of nerves
Summarise the nervous control of the bladder
- Bladder fills stimulating stretch receptors
- This stimulates parasympathetic nerves to make the bladder contracts, opening the internal urethral sphincter
- Stretch receptors inhibit motor neurons, which opens the external urethral sphincter. Cerebral cortex stimulation causes the sphincter to become closed
How is the urethra different in males and females?
- Shorter in females, 2 inches compared to 8 inches in males
- In males there are multiple parts of the urethra
List the parts of the urethra in males
- Preprostatic part of urethra
- Prostatic part
- Membranous part
- Spongy part
Describe lymphatic drainage of the urinary system
- Vessels from the superiolateral region drain into external iliac lymph nodes
- Vessels from the neck and fundus draining into the internal iliac lymph nodes and some into the sacral or common iliac lymph nodes.