ANA124 ABDOMINAL MIDTERM: A6 + A7

what is the pelvic diaphragm

group of muscles that form the floor of the pelvis (muscular hammock)

what is the pelvic diaphragm made of

levator ani + coccygeus

function of the pelvic diaphragm

supports pelvic organs and maintains continence

• helps control urination + defecation

what is the levator ani

broad, thin sheet of muscle across the pelvic floor

• forms the pelvic diaphragm

function of the levator ani

• lifts the pelvic organs (supports bladder, uterus, rectum)

  • maintains pelvic floor stability 

• aids in continence

• maintains closure of the urethra + anal canal during rest → prevents leaks

what is the anal triangle

region of the perineum..

• located posterior to the urogenital triangle

boundaries of the anal triangle 

1. anteriorly - line between the ischial tuberosities

2. laterally - sacro-tuberous ligaments

3. posteriorly - coccyx

what does the anal triangle contain

contains the anus and its associated muscles + structures

• muscles - internal/external anal sphincter 

function of the anal triangle

• houses the anal canal + muscles that control defecation 

  • work together to maintain continence

• supports the pelvic diaphragm

  • keeps abdominal + pelvic organs in place

what is the urogenital triangle

the anterior half of the peritoneum

• forms the front part of the diamond-shaped area

boundaries of the urogenital triangle

1. anteriorly - pubic symphysis

2. laterally - ischiopubic rami

3. posteriorly - line between the ischial tuberosities

what does the urogenital triangle contain

• in men → base of penis, scrotum + uretheral opening

• in women → vaginal opening, urethral opening, clitoris + labia

• in both → external urethral sphincter

function of the urogenital triangle

• houses important muscles of the pelvic floor → stabilizes pelvic organs 

• supports urethral openings

what is the perineal membrane

thin layer of fibrous tissue 

location of the perineal membrae

• spans across the urogenital triangle

• stretches between the right + left ischiopubic rami

• borders.. (from the inside to outside) 

  • superior to skin + external genitalia

  • inferior to the pelvic diaphragm

function of the perineal membrane

• supportive floor for the pelvic organs

• attachment point for muscles of the urogenital region

• pierced by openings

  • urethra in males

  • urethra + vagina in females

location of the apex of the bladder

located at the anterior part of the bladder

• just behind the pubic symphysis

• superior to the urethra (in females) 

function of the apex of the bladder

anchors the bladder in place 

location of the base of the bladder

posterior part of the bladder

• downward + backwards 

  • towards rectum in males

  • towards vagina in females

• inferior to the uterus

• superior to the prostate

function of the base of the bladder

• reservoir for urine storage

• attachment point for the ureters

structure of the base of the bladder (+ what it contains)

• ureters enter the bladder at the upper corners of the base

• urethra exits from the lower part

• contains the trigone

what is the trigone

triangular region on the inner surface of the bladder’s base

what is the trigone formed by

1. 2 internal urethral openings (where ureters enter the bladder)

2. internal urethral orifice (where the urethra begins) 

function of the trigone

funnel that directs urine from the ureters → urethra

location of the ureters

extends from the kidney’s renal pelvis → base of the bladde

function of the ureters

• carries urine from the kidneys → bladder

  • through peristalsis 

• ensures one-way flow of urine (because it’s angled)

what is the urethra

muscular tube 

location of the urethra

from the bladder → outside of the body

• males: longer, passes through the prostate + penis

• females: shorter, between clitoris + vaginal opening 

function of the urethra

drains urine from the bladder to the outside of the body

• males: transports their semen 

location of the urethral openings

located at the upper corners of the bladder’s trigone

• on either side of the trigone

function of the urethral openings

openings where urine enters the bladder from the ureters

• prevents back-flow of urine

location of the internal urethral orifice

at the bottom of the trigone 

• where the bladder connects to the urethra 

function of the internal urethral orifice

serves as the opening where urine exits the bladder → urethra

• males: closes during ejaculation 

what is the internal urethral orifice controlled by

the internal urethral sphincter

what is the internal urethral sphincter

the ring of smooth muscle

location of the internal urethral sphincter

around the internal urethral orifice

function of the internal urethral sphincter

• keeps the bladder closed until it’s time to urinate 

  • stays contracted 

  • provides involuntary control

• prevents urine leakage 

• males: prevents semen from entering the bladder during ejaculation

location of the external urethral orifice

opening where urine leaves the body

• males: tip of penis

• females: below clitoris, above vaginal opening (in the vulva) 

function of the external urethral orifice

exit point for uren (and semen in males)

what is the external urethral sphincter

ring of skeletal muscle

location of the external urethral sphincter

 in the urogenital diaphragm 

function of the external urethral sphincter

allows you to consciously control urination

• voluntary control 

• weakening = incontinence (lack of control over urination) 

what is the bladder

hollow, muscular organ

location of the bladder

in the pelvic cavity → behind the pubic symphysis

• males: above the prostate gland

function of the bladder

stores urine (that comes from ureters)

• bladder fills → stretch receptors signal brain → triggers urination

• expands + contracts to hold urine 

location of the prostate gland

located inferior to the bladder

• surrounds the urethra (the prostatic urethra)

• in front of the rectum 

function of the prostate gland

produces seminal fluid to contribute to motility + viability of the sperm 

portions of the urethra (in men)

1. pre-prostatic

2. prostatic

3. membranous

4. spongy 

where is the pre-prostatic urethra

before the prostate

• connects the bladder → prostatic urethra 

• surrounds by the internal urethral sphincter 

where is the prostatic urethra

runs through the prostate gland

• passage for urine + semen 

• contains site (where the ejaculatory duct opens) 

where is the membranous urethra

through the UG diaphragm + external urethral sphincter

• passage for urine + semen

• allows for voluntary control over urination 

where is the spongy urethrea

runs through the corpus spongiosum → external urethral orifice

• passage for urine + semen

• final exit from the body

what is the corpora cavernosa

2 cylindrical columns of erectile tissue

• lay side-by-side 

location of the corpora cavernosa

runs along the dorsal side (top side) of the penis

function of the corpora cavernosa

engorges w/ blood for erection

• arteries dilate = more blood comes in

• veins close = traps blood 

what is the corpus spongiosum

single column of erectile tissue

location of the corpus spongiosum

runs along the ventral side (bottom side) of the penis

• surrounds the spongy urethra

function of the corpus spongiosum

prevents the urethra from closing during erection

• because it fills with blood but not too much

location of the testes

• located in the scrotum

• outside the body

function of the testes

produces sperm + hormones (specifically testosterone) 

• contains seminiferous tubules where sperm is made

location of the epididymis

located on the back of each teste

function of the epididymis

stores + matures sperm 

• sperm gain motility + fertilizing ability here

location of the ductus (vas) deferens

extends from the epididymis → ejaculatory duct

function of the ductus (vas) deferens

• joins the seminal vesicle → ejaculatory duct 

• transports sperm from epididymis → ejaculatory duct 

location of the seminal vesicle

• posterior to the bladder

• above the prostate gland 

function of the seminal vesicle

produces..

• seminal fluid - nourishes sperm

• alkaline (basic) fluid - protects sperm from acidic environments (urethra + female reproductive system) 

forms the ejaculatory duct

function of the penis

external genitalia

• lets urine + sperm out of the body

function of the ejaculatory duct

transports sperm + seminal fluid → prostatic urethra (gland)

pathway of semen

1. produced in seminiferous tubules (in the testes) → epididymis → ductus deferens

2. ampulla → seminal vesicle 

3. ductus deferens + seminal vesicle = ejaculatory duct 

location of the rectum

• males: behind the prostate, bladder + external genitalia

• female: behind the uterus, vagina

what is the uterus

hollow, muscular organ

location of the uterus

between the bladder and rectum

function of the uterus

• site of fetal development

• contracts during labour

what is the vagina

muscular canal

• walls are highly elastic → allows for expansion

location of the vagina

from the cervix → genital opening

function of the vagina

• serves as a birth canal

• menstrual passageway 

what is the cervical canal (+ location)

the narrow passage

• runs through the cervix 

• into the uterine cavity → vagina 

function of the cervical canal

allows flow of menstrual blood out + entry of sperm into the uterus

location of the ovaries

attached to the lateral pelvic wall + uterus

• via the suspensory ligament (pelvic wall)

• via the ovarian ligament (uterus)

function of the ovaries

produces eggs + hormones (estrogen)

location of the uterine tube

extends from the superior corners of the uterus → ovaries

function of the uterine tube

transports eggs from the ovary → uterus

• site of fertilization 

parts of the uterine tube

1. isthmus

2. ampulla

3. infundibulum

4. fimbrae

location + function of the isthmus

located closest to the uterus

• most narrow portion

• connects the uterine tube → uterine wall

location + function of the ampulla

located between the isthmus + infundibulum

• widest, longest part

• where fertilization happens 

location + function of the infundibulum

located at the open end of the uterine tube

• funnel-shaped end

• near the ovary

location + function of the fimbrae

located at the end of the infundibulum

• finger-like projections

• sweeps the egg into the tube (after ovulation) 

parts of the uterus

1. fundus

2. body

3. isthmus 

4. cervix

location + function of the fundus of the uterus

dome-shaped top

• above the uterine tubes 

• helps identify pregnancy growth

location + function of the body of the uterus

main portion of the uterus

• where the embryo is implanted + grows 

location + function of the isthmus of the uterus

area where it begins to narrow 

• above the cervix

• connects the body → cervix

location + function of the cervix

neck-like, lower part

• part of the uterus that opens into the vagina

• allows passage of..

  • sperm

  • menstrual blood

  • baby during birth 

what is the broad ligament

double-layer of visceral peritoneum

function of the broad ligament

drapes over the uterus, uterine tubes + ovaries

• supports + stabilizes reproductive organs

• carries blood vessels + nerves

what is the ovarian ligament

fibrous band

function of the ovarian ligament

to anchor the ovary in place → keeps it close to the uterus

• keeps it close so that the fallopian (uterine) tube can easily catch the ovulated egg 

location of the suspensory ligament

extends from the ovary → lateral pelvic wall

function of the suspensory ligament

anchors the ovaries

• carries ovarian artery, ovarian vein, nerves + lymphatic vessels 

location of the round ligament

extends from the uterine wall → inguinal canal → labia majora

function of the round ligament

helps maintain the forward position of the uterus