S5 getting pregant

Question 1

how is semen derived

Answer 1

seminal plasma from accessory glands of the male reproductive tracts
seminal vesicles - 60%. Alkaline fluid that neutralizes acid. Contains fructose (ATP production), prostaglandins (increase female smooth muscle contraction), clotting factors
Prostate - 25% milky acidic fluid. Contains proteolytic enzymes (break down clotting factors), citric acid (ATP production for sperm)
Bulbourethral glands : 5 %. Alkaline mucus, (lubricates tip of penis)

Question 2

what are the normal values of semen analysis ?

Answer 2

volume of ejaculate - 2-6ml
viscosity - liquifaction in 1 hr
pH - 7-8
count - >_ 20 million/ml

Question 3

describe the human sexual response

Answer 3

excitement phase - psychogenic or somatogenic stimuli
plateau phase - stimulus maitained
orgasm phase - if stimulus reaches the threshold, orgasm occurs
resolution phase - return to haemodynamic norm followed by refractory period

Question 4

what are the requirements of a erection

Answer 4

sinusoidal relaxation
arterial dilation
venous compression - from increased blood flow to the corpus carvenosa, causing sinusoid spaces to expand and push up against the tunica albuginea
parasympathetic innervation. pelvic nerve and pelvic plexus

Question 5

describe the physiological processes involved in erection of the penis

Answer 5

activation of parasympathetic NS and inhibition sympathetic arterial vasoconstrictor nerves
ACh acts on M3 receptors raising Ca 2+, this activates eNOS, more NO produced so vasodilation of arterioles in corpus carvenosa — > increased penile blood flow
testes begin to elevate

Question 6

what is erectile dysfunction

Answer 6

psychological (descending inhibition of spinal reflexes)
tears in fibrous tissue of corpus carvenosa
vascular damage (arterial and venous)
drugs

Question 7

what is the mechanism for viagra ?

Answer 7

inhibits cGMP breakdown in the corpus carvenosa, increasing NO so increasing vasodilation, allowing increased penile blood flow to cause erection

Question 8

describe the physiological processs involved in emission

Answer 8

movement of semen into prostatic urethra. Sympathetic NS causes smooth muscle contractions and contraction of IUS and EUS ( prevention of retrogade ejaculation)

Question 9

describe the mechanism of ejaculation

Answer 9

expulsion of semen. Glands,ducts, bladder internal sphincter and IUS contract, EUS relaxes. Internal urethra fills and stimulates the pudendal nerve causing contraction of penile urethra, causing semen expulsion
erection : symp inhibited (reduction of tone at arterioles ) , parasymp active
ejection : symp active

Question 10

what changes occur in the female tract during the menstrual cycle

Answer 10

in early cycle, lots of oestrogen present so mucus is thin and stretchy (spinnbarkeit mucus) so can facilitate the entry of the male gamete into the female tract
after ovulation oestrogen and progesterone are present, so mucus is thick and sticky so limits access of sperm or bacteria into the female tract
sperm deposits onto the cervix where the semen undergoes coagulation. Site of fertilisation is in the ampulla

Question 11

what is the fern test ?

Answer 11

detection of a fern pattern in cervical mucus when it has been dried on a glass

Question 12

presence of what substance confirms pregnancy ?

Answer 12

HCG presence confirms pregnancy. Speculum placed in the vagina to view cervix

Question 13

describe how sperm is transported through the cervix and uterus

Answer 13

days 14-28 of menstrual cycle is the uterine secretory phase, a hospitable environment for fertilisation and implantation. Oxytocin stimulates uterine contraction following sperm deposition in the vagina

Question 14

what is capacitation ?

Answer 14

sperm glycoprotein coat is removed to allow binding to the zona pellucida of the oocyte, acrosomal enzymes are exposed so can initiate acrosome reaction, tail movement changes from beat to whip like action. This allows sperm to penetrate the corona radiata of follicular cells and the ZP

Question 15

describe the acrosome reaction

Answer 15

sperm contacting the corona radiata push through granulosa cells, sperm surface receptors bind to ZP3 proteins of the zona pellucida triggering the acrosome reaction
acrosomal enzymes digest the path through ZP, one sperm penetrates and fuses with the plasma membrane of the oocyte, sperm moves into the cytoplasm –> zygote. Polyspermy is blocked: cortical reaction

Question 16

what is the fertile window ?

Answer 16

spermatozoa survive 48-72 hr in female tract. Oocytes 6-24 hr (max)
fertile period : sperm deposition up to 3 days prior to ovulation or day of ovulation

Question 17

describe how fertilisation occurs

Answer 17

one sperm penetrates leading to fusion of plasma membrane
cortical reaction block polyspermy : in oocyte , waves of Ca2+ spikes convert the oocyte membrane so no further sperm can fuse, preventing fertilisation of more sperm
cortical reaction also causes resumption of meiosis 2
oocyte completes meiosis II
pronuclei of male and female move together and form a diploid zygote
mitotic spindle forms leading to cleavage

Question 18

what happens after fertilisation

Answer 18

each cell at this stage of development is totipotent i.e has capacity to become any cell type
morula : 16 cell stage, 3-4 days following fertilisation, embryo moves into uterus
blastocyst stage : 5 days post fertilisation, morula develops the fluid - filled blastoceole , loss of totipotency, embryoblast/inner cell mass —> embryo, trophoblast/outer cell mass –> placenta (produces HCG)
hatching : digestion of ZP by enzymes from trophoblast, blastocyst hatches from ZP, can now interact with uterine surface to implant
implantation : outer cell mass (trophoblast) interacts with endometrium, which controls the degree of invasion. Progesterone primes the endometrium, the conceptus is nourished in uterine fluid, trophoblast adheres to endometrium

Question 19

what is contraception

Answer 19

any method to prevent pregnancy

• blocking transport of sperm to avoid fertilisation of oocyte
• disrupting the HPG axis to interfere with ovulation
• inhibiting implantation of the conceptus into the endometrium

Question 20

what are examples of natural contraception

Answer 20

fertility awareness - indicators like cervical secretions , basal body temperature (prog from CL increases temp), length of cycle
lactational amenorrhoea - breastfeeding suppresses GnRH release so delays ovulation up to 6M after birth

Question 21

what are the advantages or disadvantages of natural contraception

Answer 21

adv - no hormones , no contraindications

dis adv - not as effective, unreliable, No STI protection

Question 22

what are examples of barrier contraception

Answer 22

male/female condom

female diaphragm

Question 23

what is the mechanism, adv and dis adv of condoms

Answer 23

physical barrier prevents sperm entry into cervix
protects against STIs
male latex sensitivity

Question 24

what is the mechanism, adv and dis adv of female diaphragm

Answer 24

used with spermicide making an additional chemical barrier
insert any time before intercourse
spermicide can cause a local reaction

Question 25

what are examples of hormonal control preventing ovulation

Answer 25

combined oral contraceptive pill (oes + pro)
progesterone depot (high dose)
progesterone implant (high dose)

Question 26

what is the mechanism, adv and dis adv of combined oral contraceptive pill (oes + pro)

Answer 26

prevents ovulation
decreases endometrial receptivity so inhibits implantantion
thickens cervical mucus (inhibits sperm penetration)
can relive menstrual disorders, decreased risk of ovarian cysts and cancer
user dependant - many contraindications due to its side effects including increased risk of VTE and MI . Can cause breast tenderness and mood disturbance

Question 27

what is the mechanism, adv and dis adv of progesterone depot ?

Answer 27

inhibits ovulation
thickens cervical mucus
makes endometrium unsuitable for implantation
can relieve menstrual disorders
irregular bleeding, not quickly reversible so delayed return of fertility up to 1 year after stopping

Question 28

what is the mechanism, adv and dis adv of progesterone implant

Answer 28

4cm flexible rod subdermal implant , can last 3 Y , same mechanism as progesterone depot
long duration , convenient, can relieve menstrual disorders
small procedure, required to fit and remove, can cause bleeding changes

Question 29

what are examples of contraception inhibiting sperm transport

Answer 29

progesterone only pill (low dose)

Question 30

what is the mechanism, adv and dis adv of progesterone only pill (low dose)

Answer 30

lower dose of progesterone taken daily. thicken cervical mucus so impenetrable to sperm, usually ovulation continues
used when COCP contraindicated
menstrual problems common, must be taken at same time of day

Question 31

what are examples of contraception inhibiting implantation

Answer 31

intrauterine system

intrauterine device

Question 32

what is the mechanism, adv and dis adv of intrauterine system

Answer 32

small plastic device in uterus with slow release progesterone last 3-5years , progesterone decreses endometrial proliferation and prevents implantation secondarily thickens cervical mucus
convenient, long duration, can relieve menstrual disorders
insertion may be unpleasant, risk of uterine perforation

Question 33

what is the mechanism, adv and dis adv of intrauterine device ?

Answer 33

contains copper so toxic to sperm and ovum, preventing fertilisation
secondary effect of copper is endometrial proliferation, and decreases sperm penetration due to the
effect on cervical mucus
convenient, long duration of 5-10 Y can be used for emergency contraception up to 5 D after unprotected sexual intercourse
insertion may be unpleasant, periods may be heavier/ more painful risk of uterine perforation

Question 34

what are examples of sterilisation

Answer 34

vasectomy

tubal ligation

Question 35

what is the mechanism, adv and dis adv of vasectomy and tubal ligation

Answer 35

vas deferens interrupted to prevent sperm entering ejaculate
fallopian tubes cut/ blocked to stop ovum travelling from ovaries into uterus
permanent, no hormonal side effects
should not be chosen if there are doubts about future children, can fail

Question 36

what are examples of emergency contraception

Answer 36

levonorgestrel (72H after sex), Ulipristal acetate ( 120 H after sex)

Question 37

what is subfertility defined as ?

Answer 37

failure of conception in a couple having regular, unprotected coitus for one year
primary infertility : when someones whos never conceived a child has difficulty conceiving
secondary infertility : when someone has had one or more pregnancies in the past but is difficulty conceiving again (includes abortion and ectopic pregnancy )

Question 38

what factors can cause subfertility

Answer 38

male factors 30% - idiopathic , oligospermia most common. other cause include varicocele, abnormal sperm production (e.g trauma to testicles)
ovulatory disorders 25% - hypothalamic - pituitary failure ( common can treat e.g with GnRH). Hypothalamic-pituitary - ovarian dysfunction (most common e.g polycystic ovary syndrome). ovarian failure (least common)
- tubal damage 20% - past pelvic infection e.g chlamydia, ectopic pregnancies
- uterine/peritoneal disease (<10%) e.g endometriosis, give NSAID and the contraceptive pill. others include uterine fibroids, pelvic inflammatory disease

Question 39

what are the investigations of subfertility

Answer 39

female : thyroid functions tests, cervical smear, FSH/LH levels , pelvic USS
male : sperm analysis (sperm count, motility, Ph), anti sperm antibodies, USS, FSH/LH/testosterone levels

Question 40

what is the management for subfertility

Answer 40

ovulation induction : GnRH agonists, weight loss/gain, dopamine agonists
tubal occlusion : assisted conception
male factors : artificial insemination, GnRH agonists, dopamine agonists