41 Questions
Which of the following best describes the characteristics of the rectum?
It is the terminal part of the sigmoid colon and is mainly located in the pelvic cavity.
Which of the differences between internal and external anal sphincters is false?
Both sphincters are composed of smooth muscle and are innervated by autonomic nerves.
What are the differences between internal and external hemorrhoids?
Internal hemorrhoids originate above the pectinate line and are painless, while external hemorrhoids originate below the pectinate line and may be painful.
Where are the ureters located and what are their relationships?
The ureters are located in the pelvic cavity anterior to the bifurcation of the common iliac artery
What is the shape of the base of the bladder?
Inverted triangle
What is the remnant of the embryological urachus that contributes to the formation of the bladder?
Median umbilical ligament
In women, what are the tough fibromuscular bands that connect the neck and pelvic part of the urethra to the pubic bone called?
Pubovesical ligaments
In men, what are the tough fibromuscular bands that connect the neck and pelvic part of the urethra to the pubic bone called?
Puboprostatic ligaments
Where does the urethra end in both men and women?
In the perineum
How long is the urethra in women?
4 cm
How long is the urethra in men?
20 cm
What prevents retrograde movement of semen into the bladder during ejaculation in men?
Internal urethral sphincter
Where is the prostatic part of the male urethra surrounded by the prostate?
On each side of the prostatic utricle
What type of tissue surrounds the spongy urethra in men?
Erectile tissue (corpus spongiosum)
What are the two small para-urethral mucous glands associated with the lower end of the urethra in women called?
Skene's glands
Where does the urethral opening lie in relation to the vaginal opening in women?
Anterior to the vaginal opening
Which structure is the rectum continuous with above and below?
Sigmoid colon and anal canal
What is the shape of the empty bladder?
Three-sided pyramid
Which part of the large intestine lacks distinct taeniae coli muscles, omental appendices, and sacculations?
Rectum
Where do internal hemorrhoids occur?
Above the pectinate line
What allows for the expansion of the anal canal?
Ischioanal fossae
Which part of the anal canal is derived from ectoderm?
Inferior third
Which veins are part of the blood supply of the anal canal?
Superior rectal vein, middle rectal vein, inferior rectal vein
Where do external hemorrhoids occur?
Below the pectinate line
Which nerves innervate the anal canal?
Visceral and somatic nerves
Which part of the anal canal is derived from hindgut?
Superior two-thirds
What is the shape of the bladder when it is full?
Expands into the abdominal cavity
Where do the ureters join the base of the bladder?
Pelvic wall and floor
What pulls the anorectal junction forward?
Puborectalis
The curvatures of the rectum include the:
- Upper curvature to the right 2)Lower curvature to the right
- Middle curvature to the left
True
What does the lower part of the rectum expand to form?
Rectal ampulla
The superior two-thirds of the anal canal has anal columns (vertical folds created by tributaries to the superior rectal vein) that are joined together by anal valves (semilunar folds)
True
In men, the ureter is crossed by --- as it enters the pelvis
In women, the ureter is crossed by the --- as it enters the pelvis
What is the most anterior element of the pelvic viscera?
The bladder
The mucosal lining at the base of the bladder is folded and loosely attached to the wall
False
The trigone refers to the smooth triangular area on the inside of the bladder between the openings of the ureters and the urethra.
True
What is the most "fixed" part of the bladder?
Neck
Match each aspect of the urethra in men to its corresponding characteristic.
Preprostatic = Associated with the circular cuff of smooth muscle fibers (internal urethral sphincter)(1 cm) Prostatic = The opening of the ejaculatory duct is located here. The connection between the urinary and reproductive tracts occurs here. Membranous = Narrow and passes through the deep perineal pouch. During its transit through the deep pouch, the urethra is surrounded by skeletal muscle of the external urethral sphincter. Spongy urethra = Surrounded by erectile tissue (corpus spongiosum)
The two bulbourethral glands in the deep perineal pouch are part of the female reproductive system and open into the bulb of the spongy urethra
False
The external urethral orifice is the sagittal slit at the end of the penis
True
Study Notes
Anatomy of the Rectum, Anal Canal, and Bladder
- The rectum is continuous with the sigmoid colon above and the anal canal below, located immediately anterior to the sacrum and having three lateral curvatures.
- The lower part of the rectum forms the rectal ampulla and lacks distinct taeniae coli muscles, omental appendices, and sacculations.
- The anal canal is an inferior continuation of the rectum, surrounded by the ischioanal fossae, allowing for expansion, and contains the internal and external anal sphincters.
- The superior two-thirds of the anal canal is derived from hindgut, while the inferior third is derived from ectoderm, and it is innervated by both visceral and somatic nerves.
- The blood supply of the anal canal includes the superior rectal vein and artery, middle rectal artery and vein, and inferior rectal artery and vein.
- Internal hemorrhoids occur above the pectinate line and are painless, while external hemorrhoids occur below the pectinate line and are painful.
- The ureters enter the pelvic cavity from the abdomen, cross the pelvic inlet, and continue along the pelvic wall and floor to join the base of the bladder.
- The bladder, when empty, is shaped like a three-sided pyramid and expands into the abdominal cavity when full, with an apex, base, superior surface, and two inferolateral surfaces.
Test your knowledge of the anatomy of the rectum, anal canal, and bladder with this quiz. Explore the structure, blood supply, and innervation of these important pelvic organs, as well as common conditions like hemorrhoids.
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