Reproduction Flashcards
(187 cards)
Which structures form the ‘walls’ of the pelvic cavity?
Superior - no real wall, continuous with abdominal cavity.
Inferior - pelvic diaphragm
Lateral - hips bones and obturator
Anterior - pubic bones + pubic symphysis
Posterior - sacrum + coccyx + piriformis muscle
What are the 3 pairs of Pelvic apertures and what structures pass through them?
- Obturator foramen - for obturator nerve
- Lesser sciatic foramen - for perineal structures
- Greater sciatic foramen - literally everything else
Which structures pass above the piriformis and which structures pass below?
Superior gluteal nerves and vessels pass through the greater sciatic foramen above the piriformis.
Everything else, including the inferior gluteal and sciatic nerves, passes below piriformis.
What are the muscles of the pelvic wall?
Obturator internus and the piriformis (virtually horizontal). Both joint to greater trochanter of the femur. Obturator internus basically covers obturator foramen.
Functions of the pelvic floor?
- Supports pelvic organs
- lift the floor to release feaces
- resist changes to abdo pressurisation - i.e so you don’t piss yourself when you cough
What is the main muscle group of the pelvic floor, what muscles makeup this group and weakness in these muscles leads to what?
Levator Ani, made up by muscles with either pubo- or coccygeus in them. Weakness in this area can lead to incontinence.
Which muscle of the levator ani is most important for me to know and what does it split into?
Pubococcygeus muscle - becomes the muscle that holds onto all the structures that pierce the pelvic floor and others. Puboanalis, pubovaginalis, puboprostatatis. Puborectalis is most important runoff as it controls fecal continence - like a sling.
What are the two holes of the pelvic floor?
Urogenital hiatus and anal aperture.
Where does the peritoneum end? What pelvic structures are covered in peritoneum?
The peritoneum does not cover the pelvic floor, it rests on the superior part of it. The only organ totally covered in peritoneum are the uterine tubes.
The draped nature of the peritoneum over the pelvic floor forms what structures in females and males?
2 pouches in females: vescio-uterine pouch and recto-uterine pouch.
In males: recto-vesical pouch.
The peritoneum is loose over which structure?
Bladder, to allow for expansion.
Name the pelvic floor ligament I must know:
hypogastric sheath - all important structures must pass through.
What unrelated structure could a hysterectomy damage?
The uterine vessels lie next to the ureters, so could damage them.
Describe the blood supply of the pelvis.
The abdominal aorta turns into the common iliac artery which turns into the internal iliac which does pelvis and the external iliac which becomes the femoral artery.
The internal iliac then splits into posterior and anterior trunks.
Posterior - iliolumbar, lateral sacral, superior gluteal
Anterior - umbilical, internal pudendal (perineum) and middle rectal.
Where do most perineal structures attach?
To the perineal body (gooch).
List the layers of the anterior perineal triangle in order.
Skin, superficial fascia, deep fascia, superficial perineal pouch, perineal membrane, deep perineal pouch, muscles.
Describe the erectile bodies in males and females.
Both of Corpus cavernosa.
Females then have clitoris and males have corpus spongiosim (continues as head of penis).
Where are the external urethral sphincters?
These voluntary sphincters for voiding are present in the deep perineal pouch.
Males also have an involuntary internal urethral sphincter.
What nerves supply the perineum?
The nerve is the pudendal nerve (S2-S4) which splits into all the rectal, perineal, penis nerves etc. Pudendal nerve exits greater sciatic foramen and renters pelvis through the pudendal canal - really interesting course.
What arteries/veins supply the perineum?
Pudendal artery off the internal iliac, just follows the pudendal nerve.
Most empty into internal iliac vein.
Exception is penis dorsum which is the deep dorsal vein for.
Where do testes empty their lymph?
Unlike other perineal structures which tend to do inguinal nodes, the testes empty into the para-aortic and lumbar nodes, so any pain (often not present) will present with abdo pain.
What are the broad steps of oocyte/zygote growth.
- Ovulation
- Fertilisation
- Cleavage
- Morula - ball
- Blastocyst - hollow ball
- Implantation - after a week
- Gastrulation - germ layers
What are the two divisions of the blastocyst before implantation?
Trophoblast (will become placenta) and inner cell mass (will become embyro)
Explain Gastrulation
Starts with primitive streak.
Invaginates one end of the epiblast. Cells migrate through the invaginated groove between the epiblast and hypoblast (yolk) to form endoderm and then mesoderm. Remaining epiblast cells become ectoderm.
All cells will come from these layers except germ cells.