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46 Cards in this Set

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Embryonic development of inguinal canal

Gubernaculum descends through ant. ab. wall from inferior pole of gonad

Attaches to labioscrotal swelling


Peritoneal herniation (processus vaginalis) occurs along path of gubernaculum


In male, testis descends along gubernaculum, ventral to processus vaginalis



Contents of inguinal canal

Ilioinguinal nerve


Males - vas deferens, gonadal vessels and gonadal nerve


Females - round ligament of uterus

Course of pudendal nerve


+branches x3

Passes out of greater sacral foramen


Back into perineum via lesser sacral foramen




Inferior rectal nerve


Posterior scrotal/labial nerve


Dorsal nerve of clitoris/penis

Ovarian and uterine ligaments

Broad ligament - peritoneal fold covering uterus and ovaries anteriorly


Round ligament of uterus - from uterus to labium majorum via inguinal canal


Ovarian ligament - from ovary to lateral margin of uterus


Suspensory ligament of ovary -from ovary to lateral pelvic wall, with ovarian neurovasculature

Normal orientation of uterus

Anteversion (right angle to vagina)


Anteflexion (Pointed inferiorly at anterior extent)

Blood supply of:


Uterus


Vagina


Ovary

Uterus+vagina: uterine artery (from internal iliac artery)


Ovary: ovarian artery (from abdominal aorta distal to renal arteries)

Sections of oviduct


lateral to medial, x4

Fimbria - communicates with ovary


Infundibulum


Ampulla


Isthmus

Epithelium of:


Uterus and endocervix


Ectocervix and vagina

Uterus and endocervix - Simple columnar


Ectocervix and vagina - Stratified squamous

Temperature regulation of testis

Cremaster (over testis) and dartos (in scrotum) contract in response to cold etc. to hoist testes


Pampiniform venous plexus acts as a countercurrent hear exchanger to cool blood in gonadal arteries

Tributaries of male spongey urethra (+what supplied)

Bladder - urine


Vas deferens - spermatozoa


Seminal vesicle (vas deferens outcrop posterior to bladder) - sugars and prostaglandins


Prostate - hydrolytic enzymes

Erectile tissue of penis

2x (dorsal) corpora cavernosa


1x (ventral) corpus spondiosum, surrounding penile urethra

Mechanism of male erection and ejactulation

Parasympathetic activation


Internal pudendal arteries dilate


Pudendal veins compressed against fascia


Ischiocavernosus and bulbospongiosus compress bulb of penis


Sympathetic activation


Contraction of smooth muscle of epididymis, vas deferens etc.

1' oocyte


2' oocyte


ovum

1' oocytes - arrested in meiosis i at birth, in primary follicle


2' oocyte - recruited in follicular phase of menstrual cycle, meiosis i complete, meiosis ii arrested


ovum - haploid, following meiosis ii

Spermatogenesis vs. spermiogenesis

Spermatogenesis - production of spermatids in seminiferous tubule


Spermiogenesis - development of spermatids into motile spermatozoa, in epididymis

Oestrogens

Oestrone - produced in adipose tissue. Triggers menarche


Oestradiol - most important and potent oestrogen, converted from testosterone by aromatase in granulosa cells


Oestriol - metabolite of other oestrogens

Androgens

DHEA - weak androgen produced in adrenal medulla and Leydig cells


Testosterone - produced in Leydig cells (Theca cells in women)


DHT - Sertoli cell metabolite (by 5-α reductase) of testosterone twice as potent. Bound to ABP and carried to seminiferous tubule.

FSH and LH actions in males

FSH activates ABP production by Sertoli cells


LH induces Leydig cell testosterone production

Capacitation and fertilisation

Spermatozoa reach the ovum by chemotaxis


Capacitation occurs, exposing the acrosome and intensifying sperm motility behaviour


Membrane, ECM of zona pellucida hydrolysed


Acrosome reaction leads to Ca2+ influx into ovum, causing degranulation of factors preventing polyspermy. 2' oocyte completes meiosis ii.


Sperm contents exocytosed into peri-vitelline space and taken into fertilisation cone.

Pre-implantation conceptus stages

Zygote (fertilised ovum)


Morula (16-32 cells, polarised)


Blastocyst (32-64 cells, differentiation of inner cell mass and trophoblast, cavity formation)

Pearl index

For contraceptive efficacy evaluation


Unintended pregnancies per 100 woman-years of use

CoCP mechanism


+risks

Oestrogen+progesterone


Inhibits LH/FSH release, preventing follicular development and ovulation




Increased risk of VTE, CV events, temporary breast cancer risk

POCP mechanism

indicated eg. in breast cancer, breastfeeding

Alters cervical mucus to prevent sperm penetration and implantation, often prevents ovulation

Intrauterine contraceptive devices

Copper - induces inflammatory response which reduces sperm and ova viability




Hormonal - slow release of levonorgestrel, acts similarly to the POCP (alters cervical mucus to prevent penetration, implantation, and often ovulation)

Emergency contraceptive methods


x3

Levonorgestrel (<72 hours)


Ulipristal acetate - progesterone receptor modulator (<120 hours)


Copper IUD, prevents implantation

Stem cell classes

Pluripotent - can differentiate into any cell from any of the three germ layers. eg. embryonic


Multipotent - can give rise to several specialised cells or tissues.


Oligopotent - can give rise to a few specialised cells or tissues


Unipotent - can produce only one cell type, but is capable of self-renewal

Cavities in developing placenta

Primary yolk sac - First formed, lined with hypoblast


Amniotic cavity - Forms at implantation pole, surrounded by ectoderm


Chorionic cavity - forms within layer of extraembryonic mesoderm, surrounds yolk sac, amniotic cavity, and embryo

Features of maternal and foetal surfaces of placenta at term

Foetal: smooth, amnion-covered


Maternal: grey, divided into ~15 cotyledons, each supplying one main stem villus

Umbilical cord contents




+gas transfer in mature placenta

2 umbilical arteries


1 umbilical vein




Maternal spiral arteries open directly into intervillous spaces


Foetal capillary networks, covered by a thin layer of syncytium, exchange gas with maternal blood in which they are bathed

Week 2 events in embryonic development

Trophoblast -> cytotrophoblast, syncytiotrophoblast


Inner cell mass -> dorsal epiblast, ventral hypoblast (lines yolk sac)


Amniotic cavity and 1' yolk sac develop

Neurulation

Week 4


Neural plate forms from ectoderm over notochord


Neural plate folds, forming neural tube (embedded within mesoderm)


Endoderm-derived neural crests develop adjacent to neural tube


Neuropores close at rostral and caudal ends

End-tissues from components of neurulation:


Neural tube


Lumen


Rostral neural crest cells


Caudal neural crest cells

Neural tube: brain and spinal cord


Lumen of neural tube: ventricular system


Rostral neural crest cells: cranial bones, pia and arachnoid mater, cranial nerves


Caudal neural crest cells: spinal ganglia, Schwann cells

Development of septa in embryonic heart

Endocardial cushions give rise to AV septum


Incomplete IA septum develops from atrial roof from septum primum


Second IA structure develops from septum secondum, forming valved foramen ovale


IV septum develops from base of common ventricle


Helical septum develops from walls of ventricular outflow tract (aorta, pul. trunk)

Shunt functions in foetal circulation

Foramen ovale channels oxygenated blood from the inferior vena cava into the left atrium to supply the major aortic arch branches




Deoxygenated blood from the SVC passes to the right ventricle, and is shunted via ductus arteriosus into the aortic arch distal to the carotid artery branches

Neonatal fontanelles

Anterior


Posterior (anterior to occipital, in midline)


Sphenoid (pterion)


Mastoid (between occipital and temporal)

Milk constituents

x4 nutrients


x3 immune



Triacylglycerides, Proteins, Lactose, Trace elements, IgA, lysozyme, Complement

Colostrum special characteristics

More IgA and protein


Less lactose

Definitions:

miscarriage


stillbirth


early/late neonatal death

Miscarriage: pregnancy loss <24 weeks


stillbirth: born >24 weeks dead


Early neonatal death: death <1/52


Late neonatal death: death 8-28 days

Events in puberty

Adrenarche - increased production of adrenal steroids


Gonadarche - enlargement of testes/ovaries


Thelarche - onset of pubertal breast tissue growth


Pubarche - first appearance of pubic hair growth


Menarche - first menstruation. Mean age ~13 (8-16 may be normal)



Factors underlying menarche

Attainment of ~17% body fat, and consequent secretion of sufficient levels of adipose oestrone to trigger gonadarche.


Establishment of the HPG axis and secretion of ovarian oestrogens, stimulating uterine and endometrial growth

Pregnancy test mechanism


when effective

detection of β subunit of hCG


Most tests effective from a few days after implantation



Calculation of due date


approximation


+ investigation

From date of last menstrual period


Add 7 to date


Subtract 3 from month


Add a year if necessary




foetal crown rump length at USS 11-14 weeks

Intrauterine insemination


+use x2

The male partner provides a semen sample, fast-moving sperm are ‘washed’ (by centrifugation, to remove prostaglandins which can induce cervical cramping), and this is introduced into the uterine cavity.




Technique used in eg. IVF, ICSI. Used standalone for mild male factor infertility, endometriosis.

In vitro fertilisation


+2 indications

GnRH agonists suppress spontaneous ovulation (by upsetting the HPG axis) and then human menopausal gonadotrophin (containing FSH and LH) elicit ovulation.


Oocytes then harvested, fertilised in vitro, and transferred to uterine cavity.


- Indicated for tubal infertility, pre-implantation genetic screening w/ history of disorders

Intracytoplasmic sperm injection

A single sperm is directly injected into the egg which has been aspirated from the ovary. The fertilised egg is transferred to the uterine cavity.




Used in severe male factor infertility (very low sperm count, tetarozoospermia)

Physical milestones at 3, 6, 12, 18 months

3: head up prone


6: sits unsupported


12: stands


18: walks decently

Law of Laplace

P=2T/r


Surfactant reduces tension T in alveolar wall by forcing water to spread more uniformly