Genitourinary Anatomy Flashcards
Where do the adrenal glands lie?
- Close to the upper pole of each kidney.
- Right lies behind liver and IVC.
- Left lies behind stomach and pancreas.
How many arteries is each adrenal gland supplied by? Name these, and what they are branches of?
3 arteries:
- Superior adrenal artery (branch of the inferior phrenic artery).
- Middle adrenal artery (branch of the abdominal aorta).
- Inferior adrenal artery (branch of the renal artery).
Describe the veinous drainage of the adrenal glands.
- Both drained by a single vein on each side (L + R adrenal veins).
- Right adrenal vein drains directly into IVC.
- Left adrenal vein drains into left renal vein, which then joins the IVC.
Describe the composition of the adrenal gland.
Composed of a cortex (outer part) and medulla (inner part).
What does the cortex of the adrenal gland produce?
Steroid hormones such as cortisol, aldosterone, and testosterone.
What does the medulla of the adrenal gland produce?
Adrenaline.
Describe the rough shape and size of the kidneys.
- Bean-shaped.
- Approx 11 x 7 x 3cm.
What is the relationship between the kidneys and the periotneum?
- Located outside the peritoneum = extra-peritoneal.
- Behind the peritoneum = retro-peritoneal.
Where are the kidneys located?
One on either side of the upper lumbar vertebrae.
Describe what the kidney is embedded in/its coverings.
- Embedded in perinephric fat.
- This is covered by renal fascia.
- Further layer of paranephric fat over this.
What can be found on the medial border of the kidney? What is found in this structure?
- Renal hilum.
- Where renal vessels, nerves, lymphatics, and the ureter enter/leave the kidney.
Describe the blood supply of the kidneys.
Left and right renal arteries (branches of the abdominal aorta).
Describe the venous drainage of the kidneys.
Left and right renal veins (both drain directly into IVC).
What is the kidney composed of?
The cortex, medulla and the calyces.
What is the medulla of the kidneys arranged into?
Renal pyramids.
What are the functional units of the kidneys called, and what are they responsible for?
- Nephrons.
- Filtering blood, reabsorbing water and solutes, and secreting and excreting waste products as urine.
Name 4 structures that can be found in the cortex of the kidneys.
- Glomeruli.
- Glomerular capsules.
- Proximal and distal tubules.
- Parts of the collecting ducts.
Name 2 structures that can be found in the renal pyramids.
- Nephron loop (of Henle).
- Rest of the collecting ducts.
From the collecting ducts, where does urine travel down the renal pyramids towards?
The renal papilla (apex of the pyramid).
What structure does urine enter from the renal papilla? Which structures does it then pass through?
- A minor calyx.
- Minor calyces merge to form a major calyx.
- Major calyces merge to form the renal pelvis.
- The renal pelvis is continuous with the ureter.
Where do the ureters carry urine to?
The urinary bladder.
Describe the ureters’ structure.
Narrow tubes with muscular walls.
How do the ureters transport urine?
By peristalsis.
Where do the ureters run?
Anterior to psoas major on the posterior abdominal wall, cross the pelvic brim to enter the pelvis.
Describe the urinary bladder’s structure.
A hollow, muscular organ.
Where is the urinary bladder found?
- Located in the pelvis.
- Posterior to the pubic symphysis, and anterior to the vagina and rectum.
What is the relationship between the urinary bladder and the peritoneum?
Below the peritoneum = infra-peritoneal.
What type of muscle is found in the bladder wall? What is it called? What does it do?
- Smooth muscle.
- Detrusor.
- Contracts to forcibly expel urine.
How much urine can a bladder accommodate in an adult?
~ 400-600ml.
Where do the ureters join the bladder? What is special about this?
- Posterior aspect of the bladder, near the base.
- Triangular area called the trigone, which has a smooth internal wall.
- Form a rudimentary valve by entering at an angle, prevents reflux of urine into ureters when the bladder is full.
Describe the rest of the inside wall of the urinary bladder, other than the trigone.
Corrugated with folds of mucosa called rugae.
What does rugae allow in the urinary bladder?
The bladder can stretch without tearing when it fills.
Describe the blood supply of the bladder.
Vesical arteries (branches of the internal iliac artery).
Describe the venous drainage of the bladder.
Vesical veins (drain into the internal iliac vein).
How many sphincters control the release of urine? What are these called?
2:
- Internal urethral sphincter.
- External urethral sphincter.
Describe the location, composition and control of the internal urethral sphincter.
- At the base of the bladder, where it opens into the urethra.
- Composed of smooth muscle.
- Under involuntary control.
Describe the location, composition and control of the external urethral sphincter.
- Just inferior to the prostate in males, and in the deep perineal pouch in females.
- Composed of skeletal muscle.
- Under voluntary control.
Describe the somatic innervation of the urinary bladder and urethral sphincters.
- Via branches of the pudendal nerve (S2-S4).
- Allows conscious control of the external urethral sphincter.
Describe the sympathetic innervation of the urinary bladder and urethral sphincters.
- Via branches of the hypogastric nerve (sympathetic chain, T12-L2).
- Causes relaxation of the detrusor, and contraction of the internal urethral sphincter: allowing storage of urine.
Describe the parasympathetic innervation of the urinary bladder and urethral sphincters.
- Via the pelvis splanchnic nerves (S2-S4).
- Causes contraction of the detrusor, and relaxation of the internal urethral sphincter: allowing initiation of micturition (urination).
Where does the urethra carry urine from and to?
- From the internal urethral orifice.
- To the external urethral orifice.
Where is the external urethral orifice located in males and females?
- Males: tip of the penis.
- Females: in the vestibule.
Roughly how long is the female urethra?
~ 3-4cm.
What are the 4 conventional subdivisions of the longer male urethra?
- Pre-prostatic.
- Prostatic.
- Membranous.
- Penile.
What else does the male urethra carry, other than urine?
Semen.
Where does the posterior abdominal wall extend from and to?
- From the attachments of the diaphragm superiorly.
- To the pelvis brim inferiorly.
What does the posterior abdominal wall consist of?
- Lumbar spine.
- Psoas and quadratus lumborum muscles.
Give 5 structures associated with the posterior abdominal wall.
- Aorta.
- IVC.
- Sympathetic trunks.
- Ureters (on the surface of the psoas muscles).
- Gonadal vessels (over the ureters).
What forms the lumbar plexus>
Lumbar spinal nerves L1-L4, with a contribution from teh T12 nerve.
What do the branches that the lumbar plexus give rise to innervate?
Skin and muscles of the abdominal wall and thigh.
Name 6 notable branches of the lumbar plexus that can be located in the posterior abdominal wall.
- Iliohypogastric nerves.
- Ilioinguinal nerves.
- Genitofemoral nerve.
- Lateral femoral cutaneous nerve.
- Femoral nerve.
- Obturator nerve
What do the iliohypogastric and ilioinguinal nerves supply?
The anterior abdominal wall muscles, and skin of the external genitalia.
What does the genitofemoral nerve supply?
The skin of the external genitalia.
What does the lateral femoral cutaneous nerve supply?
The skin over the lateral thigh.
What does the femoral nerve supply?
The muscles and skin of the anterior thigh.
What does the obturator nerve supply?
The muscles and skin of the medial thigh.
Where does the abdominal aorta begin, descend and terminate?
- Begins at level of T12.
- On the posterior abdominal wall, just to the left of the midline.
- Terminates by bifurcating at approx the level of L4.
What does the abdominal aorta bifurcate into at the level of ~L4?
Left and right common iliac arteries.
What are the 3 unpaired branches of the abdominal aorta?
- Coeliac trunk.
- SMA.
- IMA.
Name 4 paired branches of the abdominal aorta.
- Renal arteries.
- Adrenal arteries.
- Gonadal arteries.
- Lumbar arteries.
How is the IVC formed? Where?
- Union of the left and right common iliac veins.
- Approx level of L5.
Where does the IVC ascend, and pass through the diaphragm?
- On the posterior abdominal wall, just to the right of the midline.
- Passes at level of T8.
Which veins drain into the IVC?
- Those which correspond to the paired arteries branches of the abdominal aorta.
- Left gonadal and adrenal veins typically drains into left renal vein.
- Also receives hepatic veins.
Give 6 clinical relevancies of the adrenal glands, urinary tract and posterior abdominal wall.
- Urinary tract infection (UTIs).
- Renal cancer.
- Abdominal aortic aneurysm (AAA/triple A).
- Kidney stones (calculi).
- Phaeochromocytoma.
- Bladder stretch reflex and spinal cord injury.
What causes UTIs?
Almost always caused by bacteria (most common = E. Coli) entering the urinary bladder via the urethra.
Which gender are UTIs more common in? Why?
- Females.
- Shorter urethra.
What is infection of the urinary bladder called? Give 2 symptoms of this infection.
- Cystitis.
- Burning pain on passing urine (dysuria), and sensation of needing to pass urine much more frequently.
What is is called is cystitis spreads superiorly to the kidneys?
Pyelonephritis.
Give 4 symptoms of pyelonephritis.
- Fever.
- Flank pain.
- Nausea/vomiting.
- Cystitis symptoms.
What are the 3 main types of renal cancer?
- Renal cell carcinomas (RCC).
- Transitional cell carcinomas (TCC).
- Wilms’ tumours.
Describe the histological origins of the 3 main types of renal cancer.
RCC - lining of the nephron.
TCC - epithelial lining inside the kidney.
Wilm’s - renal stem cells.
What is the triad of symptoms which may present with renal cancer?
- Flank pain.
- Palpable abdominal mass.
- Haematuria (blood in the urine).
What is an aneurysm?
The bulging of a blood vessel, caused by a weak point in the blood vessel wall.
Give 4 risk factors for development of an AAA.
- Smoking.
- Alcohol.
- Hypertension.
- Atherosclerosis.
When are AAAs diagnosed?
If the diameter of the aorta is wider than 3cm.
What happens if an AAA ruptures?
Significant intra-abdominal bleeding occurs rapidly, mortality is high.
What are kidney stones most often composed of?
Calcium oxalate.
Give 4 risk factors for developing kidney stones.
- High urine-calcium levels.
- Dehydration.
- Obesity.
- Certain medications.
What can kidney stones obstruct if they are too large?
The ureter.
Describe the typical presentation of an obstructing kidney stone.
Excruciating, pulsatile pain felt from ‘loin to groin’.
What will happen if the flow of urine from the kidney is obstructed? What are some possible risks of this happening?
- Kidney will fill with urine and swell (hydronephrosis).
- Can injure the kidney and may lead to infection.
What are the 3 regions of which the ureter narrows, meaning stones are most likely to get stuck at these points?
- Pelvi-ureteric junction (PUJ): between renal pelvis and ureter.
- Pelvic brim: where ureter runs over the pelvis brim, anterior to the iliac artery.
- Vesico-ureteric junction (VUJ): where ureter joins the bladder.
What is phaeochromocytoma?
A rare hormone-producing tumour of the adrenal medulla.
What symptoms may phaeochromocytoma produce and why?
- Hypertension, tachycardia, and excessive sweating.
- Because secretion of excess adrenaline causes symptoms and signs related to hyperactivity of the sympathetic NS.
What happens to bladder function if there is an injury to the spinal cord above the sacral level?
Patient does not realise they need to pass urine, and the bladder automatically empties as it fills = patient is incontinent of urine.
What happens to bladder function if there is an injury to the spinal cord at/below the sacral level?
The bladder fills with urine without emptying = overflow incontinence OR urinary retention.
Which centres control urination?
Those in the cerebral cortex, brainstem and sacral spinal cord (contains the sacral micturition centre).
Describe the bladder stretch reflex.
- Bladder fills, stretch of bladder wall detected, relayed to sacral spinal cord via visceral afferent fibres, these synapse directly onto motor neurons.
- Motor neurons (via parasympathetic fibres in pelvis splanchnic nerves) stimulate bladder contraction.
- This system = a reflex arc.
- Older children and adults can inhibit via descending pathways when it is not convenient to urinate.
What do ascending pathways do in relation to bladder function?
Convey sensation of bladder filling.
What do descending pathways do in relation to bladder function?
Exert voluntary, inhibitory control over the external urethral sphincter.
Give 3 functions of the bony pelvis.
- Supporting the spine, torso, and upper body.
- Locomotion.
- Housing and protecting the pelvis viscera.
What is the bony pelvis made up of?
3 bones:
- The sacrum.
- The left and right hip bones.
What are the hip bones made up of?
3 smaller bones that fuse together:
- The ilium.
- The ischium.
- The pubis.
Name the 5 articulations of the bony pelvis.
- Hip joint.
- Sacroiliac joint.
- Pubic symphysis.
- Lumbosacral joint.
- Sacrococcygeal joint.
Describe the hip joint.
- Between the head of the femur and the acetabulum (socket) of the pelvis.
- The 3 parts of the hip bone fuse at the acetabulum.
Describe the sacroiliac joint.
- Between the sacrum and the ileum of the hip bone.
- Very stable and strong, supported by many ligaments.
Describe the pubic symphysis.
- Between the two pubic bones at the front of the pelvis.
- Very little movement permitted.
Describe the lumbosacral joint.
- Between the 5th lumbar vertebra and the sacrum.
- An intervertebral disc lies between the two.
Describe the sacrococcygeal joint.
- Between the sacrum and the coccyx.
Give 6 surface landmarks of the bony pelvis.
- Iliac crest.
- Anterior superior iliac spine (ASIS).
- Iliac tubercle.
- Pubic tubercle.
- Inguinal ligament.
- Mid-inguinal point.
Give the 3 differences between male and female bony pelves.
- Wider, circular pelvic inlet in females (for childbirth); narrower, heart-shaped inlet in males.
- Obtuse angle formed by inferior pubic rami in females; acute angle in males.
- Wider and shorter sacrum in females; narrower, longer sacrum in males.
What does the pelvis contain?
- Bladder and rectum.
- Uterus, ovaries and vagina (females).
- Prostate and seminal vesicles (males).
- Arteries, veins and nerves.
What is the pelvic floor? Describe its shape.
- The collective name for several muscles that support the pelvic organs from below.
- Like a bowl or funnel.
What do the muscles of the pelvic floor separate?
The pelvis from the perineum.
What are the 3 primary functions of the pelvic floor muscles?
- Prevent herniation of the pelvic organs inferiorly, out of the pelvis.
- Control continence of urine and faeces by providing a sphincter action on the urethra and rectum.
- Aid in increasing intra-abdominal pressure.
Give the names of the muscles of the pelvic floor.
- The levator ani (composed of 3 smaller muscles: puborectalis, pubococcygeus, and iliococcygeus).
- The coccygeus.
Describe the innervation of the levator ani.
By a branch of the S4 nerve, and by some branches of the pudendal nerve (from S2-S4).
Describe the arterial supply of the pelvis.
- Left and right internal iliac arteries.
- Give rise to several branches that supply pelvis viscera as well as branches to supply the perineum and gluteal region.
Give 6 key branches of the internal iliac arteries, and what they supply.
- Vesical arteries (bladder in both, and prostate and seminal vesicles in males).
- Uterine and vaginal arteries (females).
- Middle rectal artery (rectum).
- Internal pudendal artery (perineum).
- Superior and inferior gluteal arteries (gluteal region).
- Obturator artery (lower limb).
Describe the venous drainage of the pelvis.
- Contains several venous plexuses which drain the pelvic organs.
- Plexuses unite and mostly drain into the internal iliac veins.
Give 4 key nerves arising from the sacral plexus.
- Sciatic nerve.
- Pudendal nerve.
- Superior and inferior gluteal nerves.
- Pelvic splanchnic nerves.
Describe the sciatic nerve.
- Formed by L4-S3 nerves.
- Exits pelvis and supplies lower limb.
Describe the pudendal nerve.
- Somatic nerve.
- Derived from spinal nerves S2-S4.
- Exits pelvis and supplies perineum.
Describe the superior and inferior gluteal nerves.
- Exit pelvis and innervate the gluteal region.
Describe the pelvic splanchnic nerves.
- Carry parasympathetic fibres from S2-S4 spinal cord segments, to pelvic viscera.
Where are sympathetic fibres that innervate the pelvic viscera derived from?
The lumbar splanchnic nerves.
How long is the rectum approximately?
~12cm in an adult.