Urogenital System Anatomy Flashcards
Urinary System - Components
Kidney: paired
Urinary tract: paired ureters, urinary bladder and urethra
Kidneys - Components and Location
Retroperitoneal
In posterior body wall. Superior portion protected by 11th and 12th rib.
Left: extends from T12 to L3.
Right: lower because of liver.
11 cm long, 6 cm wide, 150g.
Adrenal glands on top for endocrine functions.
External Anatomy of the Kidneys - External layers
Kidneys are protected by 3 external layers of connective tissue:
- Renal fascia
- Adipose capsule
- Renal capsule
Renal Fascia - Kidney
Attaches each kidney to the peritoneum and to the fascia covering the muscles of the posterior abdominal wall.
Adipose Capsule - Kidney
Adipose tissue to protect from shock, layer of fat.
Renal Capsule - Kidney
Covers the exterior of each kidney to protect from infection and physical trauma.
Renal Hilum
Medial surface where: - Renal artery - Renal vein - Renal nerves - Ureter enter and exit. Opens to the Central cavity: renal sinus
Renal Sinus
Central cavity lined by renal capsule, filled with urine-draining structures and adipose tissue.
anchors the ureter, blood vessels, and nerves in place.
Internal Anatomy of the Kidneys
3 distinct regions:
- Outermost renal cortex
- Middle renal medulla
- Inner renal pelvis
Renal Cortex and Renal Medulla
Form urine
Cone-shaped renal pyramids within the medulla.
Contain 1 million nephrons.
Renal Pelvis and Associated Structures - function
Drain urine that cortex and medulla have formed.
Renal Column
Extension of renal cortex. Includes Blood vessels that branch from renal artery that travel in the cortex.
Nephron
Functional unit of the kidneys.
Filters blood and produces urine.
- Globe shaped renal corpuscle.
- Long renal tube
Papilla - Kidney
Borders with Minor calyx, that is the first draining structure.
Minor and major calyx drain urine into renal pelvis leading to ureter.
Blood Supply - Kidneys
Receive 1/4 of cardiac output.
Right and left renal arteries (from abdominal aorta).
1. Renal artery → 2. Segmental artery → 3. Interlobar artery → 4. Arcuate artery → 5. Interlobular artery → 6. afferent arteriole → 7. Glomerulus → 8. Efferent arteriole
9. Peritubular capillaries → 10. Interlobular vein → 11. Arcuate vein → 12. Interlobar vein → 13. Renal vein.
Renal vein exits through hilum and empties into inferior vena cava.
Anatomical Relations - Right Kidney
Anterior: Suprarenal gland, liver, duodenum, right colic flexure.
Posterior: Diaphragm, 12th rib, psoas major, quadratus lumborum, transversus abdominis.
Anatomical Relations - Left Kidney
Anterior: Suprarenal gland, spleen, stomach, pancreas, left colic flexure, jejunum.
Posterior: Diaphragm, 11 & 12 rib, psoas major, quadratus lumborum, transversus abdominis.
Urinary Tract
- Ureters: Tubes running posteriorly connected to the urinary bladder. Pathway for urine to bladder.
- Urinary Bladder: Stores urine
- Urethra: Tube connecting bladder to the outside of the body to expel urine. (longer in men).
Ureters - Size, Location, mechanism to prevent back flow
25-30 cm long, 3-4 mm diameter.
From renal pelvis (L2 level), behind peritoneum and empty into bladder.
Mechanism to prevent backflow: increasing pressure with increasing urine, compresses tunnel in bladder, pinching ureter closed.
Anatomical Relations - Ureters
Right ureter:
- Posterior: psoas major, genitofemoral nerve.
- Anterior: duodenum, branches of superior mesenteric vessels.
- Inferior: bladder.
Left ureter:
- Posterior: psoas major, genitofemoral nerve.
- Anterior: branches of inferior mesenteric vessels.
- Inferior: bladder.
Urinary Bladder - Composition, Location
Mostly smooth muscle. Non-voluntary.
Sits on floor of pelvic cavity, suspended by fold of parietal peritoneum. Collapses when empty.
700-800 ml of urine (male), less in female (uterus pressing on top).
Trigone
Triangular area on floor of bladder (important for infection). Prevent backflow during eliminiation.
Internal Urethral Orifice
Opening to the urethra from the bladder.
Anatomical Relations - Bladder Female vs. Male
Male: anterior to the rectum and prostate.
Female: anterior to vagina. Inferior to uterus.
Urethra - Function and Sphincters
Drains urine from bladder to outside of body.
From internal urethral orifice, surrounded by internal urethral sphincter: remains closed until peeing.
External urethral sphincter: skeletal muscle, voluntary.
Urethra - Female vs. Male
Female: short (4 cm). Opens at external urethral orifice between vagina and clitoris.
Male: long (20 cm). 3 regions:
- Prostatic urethra: passes through prostate gland.
- Membranous urethra: passes through levator ani muscle.
- Spongy urethra: passes through penis to external urethral orifice and erectile body of penis.
Transport urine and semsen.
Female Reproductive System - External Genital Organs
Held by female perineum.
- Mons pubis
- Labia majora
- Labia minora
- Clitoris
- Vestibule
- Vestibular bulb
- Vestibular gland
Female Reproductive System - Internal Genital Organs
Duct system.
- Vagina
- Cervix
- Uterus
- Uterine tubes (Fallopian)
- Ovaries (primary reproductive organs)
Mons Pubis - External Genitals
Superior external part.
Subcutaneous adipose tissue anterior to pubic symphysis.
Covered with pubic hair.
Labia Majora
Most lateral part of vulva, extending from mons pubis to perineum. 2 skin folds covered with pubic hair.
Pudendal cleft: between the two, containing labia minora and vestibule.
Homologous to scrotum of male.
Labia Minora
Hairless skin folds between labia majora.
Surrounds vaginal vestibule, its urethral and vaginal orifice.
Contributes to clitoris.
Clitoris
Analogous to male penis.
Most superior part of vulvar vestibule, surrounded by anterior part of labia minora (has two attachment points (crura) within the labia minora).
Three parts: root, body and glans.
Vestibule
Between labia minora.
Contains vaginal orifice, opening of urethra, opening of excretory ducts of vestibular glands.
Vestibular Glands
Greater vestibular (Bartholin's gland) on each side, bulbourethral gland in male. Lubrication during intercourse. Lesser vestibular (Skene's or paraurethral gland): between urethral and vaginal orifices. Prostate in male.
Vestibular Bulb
Pair of subcutaneous erectile tissue.
Blood Supply - External Genitals
Internal pudendal arteries.
Innervation:
- Anterior labial nerves: mons pubis and anterior labia.
- Pudenal nerve and posterior cutaneous nerve of thigh: Posterior aspect of vulva.
- Dorsal nerve of clitoris: clitoris.
Vagina
Fibromuscular tube, extends postero-superiorly from the vulva to the uterus.
Standing: 45° angle with uterus
Lying: 60° angle
Upper ending surrounds cervix, two domes anterior and posterior.
Roles: intercourse, childbirth, menstruation.
Anatomical Relations - Vagina
Anterior: Bladder and urethra.
Posterior: Rectouterine pouch, rectum and anal canal.
Lateral: Ureters and levator ani muscles.
Blood Supply - Vagina
Arterial: uterine and vaginal arteries.
Venous: vaginal venous plexus drains into internal iliac veins.
Innervation: Autonomic nervous system. Parasympathetic and sympathetic nerves from uterovaginal nerve plexus.
Cervix
Lower portion of uterus. Connects vagina with uterus.
2 regions:
- Ectocervix: projects into vagina.
- Endocervical canal: inner part of cervix.
Facilitates passage of sperm into uterine cavity.
Maintains sterility of upper reproductive tract.
Blood Supply - Cervix
Arterial: uterine artery
Venous: plexus in broad ligament that drains into uterine veins.
Innervation: uterovaginal plexus.
Uterus
Womb 8 cm muscular organ, expands for a growing fetus. Connects distally to vagina and laterally to fallopian tubes. 4 parts: - Fundus: top of uterus. - Body: implantation of blastocyst - Isthmus: connects body and cervix. - Cervix: lower part of uterus
Anatomical Position - Uterus
Varies with distension of bladder.
Anteverted (most common): in respects to vagina: rotated forward, towards anterior surface of body.
Anteflexed: in respects to cervix, flexed, towards anterior surface of body. (fertility problems)
Normally posterosuperior to bladder, anterior to rectum.
Ligaments of the Uterus
Keep uterus in place.
- Broad ligament
- Round ligament
- Ovarian ligament
- Cardinal ligament
- Uterosacral ligament
Broad Ligament
Double layer of peritoneum attaching the sides of uterus to pelvis.
Round Ligament
Extending from uterine horns to labia majora to maintain anteverted position of uterus.
Ovarian Ligament
Joins ovaries to uterus.
Cardinal Ligament
At the base of broad ligament, extends from cervix to lateral pelvic walls. Contains uterine artery as well as supporting uterus.
Uterosacral Ligament
Extends from cervix to sacrum. Provides support.
Blood Supply - Uterus
Arterial: uterine artery
Venous: via a plexus in the broad ligament that drains into uterine veins.
Innervation - Uterus
Sympathetic nerve: uterovaginal plexus.
Parasympathetic: pelvic splanchnic nerves (S2-S4).
Afferent fibers: inferior hypogastric plexus.
Fallopian Tubes
In upper border of broad ligament, from uterus to near ovaries.
transport of ovum from the ovary, to uterus.
4 parts:
- Fimbriae: ciliated projections that capture ovum from surface of ovary.
- Infundibulum:
- Ampulla: Fertilization happens here.
- Isthmus:
Blood Supply - Fallopian Tubes
Arterial: uterine and ovarian arteries.
Venous: uterine and ovarian veins.
Innervation - Fallopian Tubes
Sympathetic and parasympathetic innervation: ovarian and uterine plexuses.
Sensory afferent fibers run from T11-L1.
Ovaries
Female gonads, attached to posterior surface of broad ligament.
Functions:
- Produce oocytes in preparation for fertilization.
- Produce estrogen and progesterone, in response to LH and FSH.
Ovaries - Ligaments
Suspensory ligament of ovary: fold of peritoneum extending from mesovarium to the pelvic wall.
Ligament of ovary: Extends from ovary to fundus of uterus and continues to the connective tissue of labium majus as the round ligament of uterus.
Ovarian cycle
Follicular phase
Ovulation phase
Luteal phase
Ovaries - Blood Supply
Arterial: paired ovarian arteries, uterine arteries.
Venous: Paired ovarian veins. Left drains into left renal vein, right drains into inferior vena cava.
Ovaries - Innervation
Sympathetic and parasympathetic: ovarian and uterine plexuses.
Nerves reach ovaries via suspensory ligament of the ovary.
Ovaries - Innervation
Sympathetic and parasympathetic: ovarian and uterine plexuses.
Nerves reach ovaries via suspensory ligament of the ovary.
