Topography of the Urinary System Flashcards
List 6 functions of the urinary system.
1 - To maintain an optimal hydration status.
2 - To maintain optimal electrolyte levels.
3 - To control blood pressure.
4 - To clear the aqueous phase of products of metabolism.
5 - To clear drugs / exogenous molecules.
6 - To promote haemopoesis via haemopoetin.
List the components of the urinary system.
1 - Systemic blood vessels.
2 - Renal arteries and veins.
3 - 2 kidneys.
4 - 2 ureters.
5 - The urinary bladder.
6 - The urethra.
7 - Continence and micturition centres of the CNS.
In which anatomical region is the urinary system kept?
The abdominopelvic region.
How are the viscera of the urinary system divided?
Into upper and lower urinary tracts:
- The upper urinary tract is composed of the kidneys and ureters.
- The lower urinary tract is composed of the urinary bladder and urethra.
How does the urinary system differ between males and females?
The male urethra is also the passageway for semen from the gonads.
Are the kidneys, ureters and urinary bladder intraperitoneal or retroperitoneal?
- The kidneys and proximal half of the ureters are retroperitoneal.
- The urinary bladder and distal half of the ureters are intraperitoneal.
Is the urinary bladder in the true or false pelvis?
- When empty, it is only in the true pelvis.
- When full, it is in both the true and the false pelvis.
Through which surface does the urethra pass?
The perineum.
How does the upper urinary tract differ functionally from the lower urinary tract?
- The upper urinary tract is concerned with the production of urine.
- The lower urinary tract is concerned with the storage and excretion of urine.
List the main muscles of the posterior abdominal wall.
1 - Quadratus lumborum.
2 - Psoas major and minor.
3 - Left and right crura of the diaphragm.
What are the crura of the diaphragm?
A tendinous structure of the diaphragm that extends to the vertebral column.
What are paravertebral gutters?
Spaces formed by medial and lateral lumbosacral arches that house the kidneys.
What forms lumbosacral arches?
Thickenings of fasciae of quadratus lumborum, psoas major and psoas minor.
On which sides of the vertebral column are the abdominal aorta and inferior vena cava?
- The abdominal aorta lies to the left of the vertebral column.
- The inferior vena cava lies to the right of the vertebral column.
At which vertebral level does the abdominal aorta give rise to the renal arteries?
L1/2.
Which veins form the renal veins?
The interlobular veins.
Into which vein does the renal vein empty?
The inferior vena cava.
List the ways in which the left renal vein differs from the right renal vein.
- The left renal vein is longer (as the inferior vena cava is on the right side of the body).
- The left renal vein also drains blood from the left suprarenal, left gonadal and left ascending lumbar veins.
Which organs lie superior to the kidneys?
The adrenal / suprarenal glands.
Describe the anterior relations of the right kidney.
- The duodenum lies anterior to the medial border.
- The right lobe of the liver lies anterior to the superior 2/3.
- The jejunum and right colic flexure lie anterior to the inferior 1/3.
What are colic flexures?
The bends between the ascending, descending and transverse colon.
What is the hilum of the kidney?
The recessed central fissure where its vessels, nerves and ureter pass.
Describe the anterior relations of the left kidney.
- The spleen lies anterior to the lateral border.
- The pancreas and stomach lie anterior to the superior portion.
- The jejunum and left colic flexure lie anterior to the inferior portion.
List the posterior relations of the right kidney.
1 - The diaphragm.
2 - The costodiaphragmatic recess of the pleura.
3 - The 12th rib.
4 - Quadratus lumborum.
5 - Psoas major and minor.
6 - Transversus abdominis.
7 - The subcostal nerve.
8 - The iliohypogastric nerve.
9 - The ilioinguinal nerve.
What are the spinal nerve roots of the subcostal nerve?
T12.
What are the spinal nerve roots of the iliohypogastric nerve?
L1.
What are the spinal nerve roots of the ilioinguinal nerve?
L1.
What is horseshoe kidney?
A congenital disorder whereby the kidneys fuse during development to form a horseshoe shape.
List the coverings of the kidneys from deep to superficial.
1 - Fibrous capsule.
2 - Perirenal fat.
3 - Renal fascia (Gerota’s fascia).
4 - Pararenal fat (forms the retroperitoneal fat).
Of which tissue is the renal fascia (Gerota’s fascia) a continuation?
Transversalis fascia.
What are the outer and inner zones of the kidneys known as?
- The outer zone is the cortex.
- The inner zone is the medulla.
Why does the renal cortex appear granular in appearance?
Due to its high content of glomeruli.
Why does the renal medulla appear striated in appearance?
Due to its straight tubules and collecting ducts.
What is the functional unit of the kidney?
The nephron.
How many nephrons are contained within a kidney?
~ 1 million.
List the segments of a nephron.
- The proximal convoluted tubule.
- The loop of Henle.
- The distal convoluted tubule.
Describe the path taken by renal arteries.
What is different about the path taken by the right renal artery?
- From the aorta, they course anterior to the crura of the diaphragm and psoas muscles to reach the hilum of the kidneys.
- The right renal artery is longer and lower than the left renal artery.
- The right renal artery also passes behind the vena cava, head of the pancreas and second part of the duodenum.
What is the difference between the preperitoneal, retroperitoneal and extraperitoneal spaces?
- The extraperitoneal space includes the preperitoneal and retroperitoneal spaces.
- The preperitoneal space is the space anterior to the peritoneum whereas the retroperitoneal space is the space posterior to the peritoneum.
In which tissue are the ureters contained?
Extraperitoneal connective tissue.
Describe the path taken by the ureters.
They descend anterior to the psoas major / minor muscles until crossing the bifurcation of the common iliac arteries (into the internal and external iliac arteries) where they enter the pelvis.
List the structures that cross the ureters.
- Each ureter is crossed by the testicular / ovarian vessels.
- The right ureter is also crossed by the ileocolic and right colic vessels.
- The left ureter is also crossed by the left colic vessels.
List the divisions of the urinary bladder.
Describe the function of each division.
1 - Body (temporary store of urine).
2 - Trigone (triangular region of the urinary bladder formed by the two ureteric orifices and the urethral orifice).
3 - Neck (connects bladder to urethra.
List the muscular components of the urinary bladder.
1 - Detrusor urinae muscle.
2 - Internal urethral sphincter.
3 - External urethral sphincter.
What forms the external urethral sphincter?
Pelvic floor muscles.
Describe the histology of the detrusor urinae muscle.
- It is a mesh of smooth muscle fibres.
- In cross section, the muscle fibres run in all orientations.
- The muscle fibres are arranged in layers.
What is the advantage of the way in which the muscle fibres of the detrusor urinae muscle are oriented?
It confers strength to the urinary bladder irrespective of direction of stretch.
