SUGER: Genitourinary Anatomy Flashcards
What two structures is the right adrenal gland posterior to?
Liver and inferior vena cava.
What two structures is the left adrenal gland posterior to?
Stomach and pancreas.
Which adrenal artery is a branch of the inferior phrenic artery?
Superior adrenal artery
Which adrenal artery is a direct branch of the abdominal aorta?
Middle adrenal artery
Which adrenal artery is a branch of the renal artery?
Inferior adrenal artery
What does the right adrenal vein drain into?
Directly into the inferior vena cava
What does the left adrenal vein drain into?
The left renal vein, then the inferior vena cava
What part of the adrenal gland produces steroid hormones (e.g. cortisol, aldosterone, testosterone)?
Cortex
What part of the adrenal gland produces adrenaline?
Medulla
Which ribs help protect the kidneys by partially covering them?
11th and 12th ribs
What three layers are the kidneys embedded in?
Perinephric fat
Renal fascia
Paranephric fat
What do the left and right renal arteries branch from?
Abdominal aorta
What do the left and right renal veins drain into?
Inferior vena cava
What is the renal medulla composed of?
Renal pyramids
The majority of the nephron is situated in the cortex. Which parts of the nephron are situated in the renal pyramids?
Loop of Henle and part of the collecting ducts.
Urine travels from the collecting ducts in the pyramids into what structure?
Minor calyx
Minor calyces in the kidneys merge to form a major calyx. What does the merger of the major calyces form?
Renal pelvis
What is the renal pelvis continuous with?
Ureter
What are the renal papillae?
The pointed, funnel-shaped tips of the renal pyramids.
Why do the renal papillae have a sieve-like appearance?
They have numerous small papillary ducts where collecting tubules converge.
What mechanism moves urine from the kidneys to bladder via the ureter?
Peristalsis
The bladder is an infra-peritoneal organ (below the peritoneum). What smooth muscle in the bladder wall contracts to forcibly expel urine?
Detrusor muscle
Where do the ureters join the bladder?
Near the base, on the posterior aspect.
What is the triangular-shaped smooth area of the bladder interior wall?
Trigone
What are the folds of mucosa on the interior wall of the bladder called, which allow it to stretch without tearing when full?
Rugae
What arteries supply the bladder, and what are they branches of?
Vesical arteries; branches of the internal iliac artery
What veins drain the bladder, and what larger vein do they drain into?
Vesical veins; drain into the internal iliac vein
Where is the internal urethral sphincter?
Base of the bladder where it opens into the urethra
Is the internal urethral sphincter composed of smooth (involuntary) or skeletal (voluntary)?
Smooth muscle; involuntary control
Where is the external urethral sphincter?
In the deep perineal pouch in females, or just inferior to the prostate in males.
Is the external urethral sphincter composed of smooth (involuntary) or skeletal (voluntary)?
Skeletal muscle; voluntary control
Is urination caused by sympathetic or parasympathetic stimulation?
Parasympathetic
Branches of what nerve allow conscious control of the external urethral sphincter?
Pudendal nerve (S2-S4)
Branches of what sympathetic nerve cause relaxation of the detrusor and contraction of the internal urethral sphincter, to allow storage of urine?
Hypogastric nerve (sympathetic chain T12-L2)
What parasympathetic nerves cause contraction of the detrusor and relaxation of the internal urethral sphincter, resulting in urination?
The pelvic splanchnic nerves (S2-S4)
What are the four subdivisions of the male urethra?
Pre-prostatic, prostatic, membranous, and penile
What muscles form the posterior abdominal wall?
Psoas, quadratus lumborum, and iliacus muscles
What spinal nerves form the plexus that supplies the nerves that innervate the skin and muscles of the abdominal wall and thigh?
L1-L4; form the lumbar plexus
What nerve branch of the lumbar plexus supplies the muscles and skin of the medial thigh?
Obturator nerve
What nerve branch of the lumbar plexus supplies the skin of the external genitalia?
Genitofemoral nerve
What two nerve branches of the lumbar plexus supply the anterior abdominal wall muscles and skin of the external genitalia?
Iliohypogastric and ilioinguinal nerves
At what vertebral level does the abdominal aorta bifurcate into the left and right common iliac arteries?
L4
At what vertebral level do the left and right common iliac veins join to form the inferior vena cava?
L5
Where in the spinal cord does the bladder stretch reflex that controls urination occur?
Sacral spinal cord
What three bones compose the pelvis?
Sacrum and left & right hip bones
What three bones fuse together to form the hip bone?
Ilium, ischium, pubis
What are the five articulations in the pelvis?
Hip joint
Sacroiliac joint
Pubic symphysis
Lumbosacral joint
Sacrococcygeal joint
In the hip joint, the head of the femur sits inside the acetabulum (socket). What three bones fuse together to form the acetabulum?
Ilium, ischium, and pubis
What vertebral level can be found by using the iliac crests (intercristal line) as a landmark?
L4/L5 disc space
What is the most anterior point of the ilium, palpable in almost all patients?
Anterior superior iliac spine (ASIS)
What is the most lateral point of the ilium?
Iliac tubercle
Why are the iliac tubercles are useful anatomical surface landmark?
A line drawn between the iliac tubercles (intertubercular line) marks the division of the lower third of the abdomen from the middle third.
What is the most medial point of the pubic bone, palpable in most people?
Pubic tubercle
What ligament runs from the anterior superior iliac spine to the pubic tubercle?
Inguinal ligament
Where is the femoral artery palpable?
Mid-inguinal point = mid-point of line drawn from the anterior superior iliac spine to the pubic symphysis.
The female pelvis is wide and circular, whereas the male pelvis is narrow and heart-shaped.
What is the difference between the male and female pelvis in reference to the angle of the inferior pubic rami?
In females = more obtuse angle
In males = more acute angle
Does the male or female pelvis have a longer, narrower sacrum?
Male
What separates the pelvis from the perineum?
The muscles of the pelvic floor
What two muscles compose the pelvic floor?
Levator ani and coccygeus
What three paired muscles compose the levator ani muscle of the pelvic floor?
Puborectalis
Pubococcygeus
Iliococcygeus
The puborectalis is the most anterior levator ani muscle and attaches to the pubic bones. What key function does the puborectalis muscle provide, and how does it provide this function?
Controls defecation:
U-shaped, forming a sling around the rectum.
When contracted, pulls on rectum to form a sharp angle between rectum and anal canal, preventing defecation.
(Also contributes towards micturition in the same way)
What innervates the levator ani muscle group in the pelvic floor?
Branch of S4 and some branches of pudendal nerve (S2-S4).
What arteries supply the pelvis and pelvic viscera?
Internal iliac arteries
What branches of the internal iliac arteries supply the bladder (and the prostate and seminal vesicles in males)?
Vesical arteries
What branch of the internal iliac artery supplies the rectum?
Middle rectal artery
What branches of the internal iliac arteries exit the pelvis to supply the gluteal region?
Superior and inferior gluteal arteries
What branch of the internal iliac artery exits the pelvis to supply the perineum?
Internal pudendal artery
What branch of the internal iliac artery exits the pelvis to supply the lower limb?
Obturator artery
The pelvis contains several venous plexuses which drain the pelvic organs. These venous plexuses then unite and mostly drain into what larger veins?
Internal iliac veins
What five key nerves arise from the sacral plexus?
Sciatic nerve
Pudendal nerve
Superior gluteal nerve
Inferior gluteal nerve
Pelvic splanchnic nerves
The sciatic nerve arises from the sacral plexus. What spinal nerves is the sciatic nerve derived from?
L4-S3
The pudendal nerve arises from the sacral plexus. What spinal nerves is the pudendal nerve derived from?
S2-S4
What is the major nerve of the perineum?
Pudendal nerve
What nerves carry parasympathetic fibres to the pelvic viscera?
Pelvic splanchnic nerves
The pelvic splanchnic nerves arise from the sacral plexus. What spinal nerves are the pelvic splanchnic nerves derived from?
S2-S4
What nerves are sympathetic fibres that innervate the pelvic viscera derived from?
Lumbar splanchnic nerves
The rectum is supplied by the superior, middle, and inferior rectal arteries. The superior rectal artery is a branch of the inferior mesenteric artery. What are the middle and inferior rectal arteries branches of?
Middle rectal artery is a branch of the internal iliac artery
Inferior rectal artery is a branch of the internal pudendal artery (which is a branch of internal iliac artery)
The perineum is a diamond-shaped area which can be split into two triangles by drawing an imaginary line between the ischial tuberosities. What two structures are found in the anal triangle (posterior)?
Anus and external anal sphincter.
The perineum is a diamond-shaped area which can be split into two triangles by drawing an imaginary line between the ischial tuberosities. What are the four layers of the urogenital triangle (anterior), from most superficial to most deep?
Skin
Perineal fascia
Superficial perineal pouch (containing muscles and erectile tissue)
Perineal membrane
What divides the anal canal into superior and inferior parts?
Pectinate line (AKA dentate line)
What are the differences between the embryological origin of the superior anal canal, above the pectinate line, and the inferior anal canal?
Superior = hindgut
Inferior = ectoderm
What are the differences between the epithelium of the superior anal canal, above the pectinate line, and the inferior anal canal?
Superior = columnar
Inferior = stratified squamous
What are the differences between the blood supply and drainage of the superior anal canal, above the pectinate line, and the inferior anal canal?
Superior = superior rectal artery, portal venous drainage
Inferior = middle & inferior rectal arteries, systemic venous drainage
Is the inferior anal canal encircled by the external or internal anal sphincter?
External (internal anal sphincter encircles the superior anal canal)
The perineal body is a dense mass of fibrous tissue and muscles which sits between the anal and urogenital triangles. What is the main function of the perineal body?
Provides attachment for almost all the perineal and pelvic floor muscles, including both anal sphincters, and levator ani.
What length is the inguinal canal in adults?
Roughly 5cm
Which two apertures does the inguinal canal travel between?
Deep inguinal ring and the superficial inguinal ring.
What is the deep inguinal ring?
Aperture in the transversalis fascia
What is the superficial inguinal ring?
Aperture in the external oblique aponeurosis
Name the three structures in the female inguinal canal.
- Round ligament of the uterus
- Ilioinguinal nerve
- Genital branch of the genitofemoral nerve
What two nerves are found in the male inguinal canal?
Genital branch of the genitofemoral nerve
Sympathetic nerve fibres
What three arteries are found in the male inguinal canal?
Testicular artery
Cremasteric artery
Vas deferens artery
What three fascial layers are found in the male inguinal canal?
External spermatic fascia (derived from external oblique aponeurosis)
Cremaster muscle & fascia (derived from internal oblique muscle)
Internal spermatic fascia (derived from transversalis fascia)
The male inguinal canal contains two nerves, three arteries, three fascial layers, and what other four structures?
Pampiniform venous plexus
Lymphatics
Vas deferens
Processus vaginalis
What thin involuntary muscle is found beneath the skin and thin superficial fascia of the scrotum?
Dartos muscle
What extends between the testes to form a septum dividing the scrotum into right and left halves?
The superficial fascia of the scrotum.
Where are spermatozoa stored?
In the epididymis
Where do the testicular arteries originate from?
The abdominal aorta
What drains venous blood from the testes and epididymis?
Pampiniform venous plexus (which then forms the testicular vein)
What larger veins do the right and left testicular veins join?
Right = inferior vena cava
Left = left renal vein
What is the glans (the end of the penis/clitoris) an expansion of?
The corpus spongiosum
What is the term for the circular base of the glans (end of the penis)?
Corona
In males and females, what do the ‘legs’ or crura of the corpora cavernosa attach to (crura of penis or crura of clitoris)?
The ischial rami
In males and females, what does the ‘bulb’ of the corpus spongiosum attach to?
The perineal membrane
In the penis, what structure does the urethra run within?
The corpus spongiosum
What muscles cover the corpora cavernosa, to force blood into the body of the penis/clitoris from the crura?
Ischiocavernosus muscles
The bulbospongiosus muscle covers the corpus spongiosum. What three main functions does the bulbospongiosus muscle provide?
- To force blood into the glans penis/clitoris
- Assist in maintaining erection by compressing the veins that drain erectile tissues
- Contracts around the vaginal orifice to help express fluid from the greater vestibular (Bartholin’s) glands in females/urethra in males.
What arteries supply blood to the clitoris/penis, and branch into the deep artery of the clitoris/penis and the artery of the bulb of the clitoris/penis?
Internal pudendal arteries (branches of the internal iliac arteries)
What nerve innervates the ischiocavernosus and bulbospongiosus muscles in males and females, and also has a branch (the dorsal nerve of the penis) which supplies general sensation and sympathetic innervation?
Pudendal nerve
Parasympathetic nerve fibres supplying the penis arise from the peri-prostatic nerve plexus. What function do these fibres provide?
Cause erection by dilating the arteries of the corpora cavernosa.
What part of the penis is mainly responsible for the increase in size and rigidity of the penis during erection?
Corpora cavernosa
What is the main role of the corpus spongiosum during erection?
To prevent the urethra from becoming compressed (which would prevent ejaculation)
Branches of what artery supply blood to the vas deferens, seminal vesicle, and prostate?
Internal iliac artery
In females, what forms the boundaries of the vestibule?
Labia minora
What erectile tissue is the clitoris composed of?
Corpora cavernosa and corpus spongiosum
Where are the greater vestibular glands (Bartholin’s glands) located and what is their purpose?
Just posterior to the vaginal opening.
Secrete lubricant into the vagina during sexual arousal.
Where are the lesser vestibular glands (Skene’s glands) located and what is their purpose?
Near the urethral opening (in females).
Secrete fluid; function of this fluid is debated, may lubricate vaginal opening/urethra, or have antimicrobial effect.
How does the corpus spongiosum vary in females compared to males?
In females, corpus spongiosum splits into two parts, the bulbs of the clitoris, that flank the vaginal opening.
(In both males and females, the corpus spongiosum attaches to the perineal membrane)
What is the body of the clitoris composed of?
Distal part of the corpora cavernosa
What four nerves innervate the vulva?
Ilioinguinal nerve
Genital branch of the genitofemoral nerve
Pudendal nerve
Posterior cutaneous nerve of the thigh
A short mesentery, the mesovarium, attaches what female pelvic organs to the broad ligament?
Ovaries
The broad ligament is a mesentery (fold of peritoneum). Where is the broad ligament?
Lateral to the uterus, connects the sides of the uterus to the pelvic floor.
What is the name for the space posterior to the uterus but anterior to the rectum, which is lined with peritoneum? What is significant about this area?
Rectouterine pouch (pouch of Douglas)
Deepest point in the peritoneal cavity; therefore it is a common site for the accumulation of intraperitoneal fluid/pus.
Where do the uterine (fallopian) tubes run?
In the upper border of the broad ligament
What is the funnel-shaped area near the ovary-end of the uterine (fallopian) tube?
Infundibulum
What are the finger-like projections at the end of the infundibulum that drape over the ovary?
Fimbriae
Through what openings does the cervix communicate with the uterine cavity and the vagina?
Uterine cavity: internal os
Vagina: external os
(os = mouth-like opening)
What is the name for the recess created by the lower part of the cervix inside the vagina?
Vaginal fornices
What is the introitus?
The vaginal opening, where the vagina opens into the vestibule (the space between the labia minora).
What proportion of the vagina is in the pelvic cavity (superior to the pelvic floor)?
Two thirds (lower third is in the perineum).
What arteries supply the female pelvic organs (ovary, uterus, uterine/fallopian tubes, cervix, vagina)?
Internal iliac artery, except the ovary which is supplied by the ovarian artery (direct branch of the abdominal aorta).
