Getting Pregnant

Question 1

What is normal sperm count?

Answer 1

> 20 x10^6

Question 2

What is the normal ejaculate volume?

Answer 2

2-6ml

Question 3

What are the phases of the human sexual response?

Answer 3

Excitement phase
Plateau phase
Orgasm phase
Resolution phase

Question 4

What happens in the excitement phase?

Answer 4

Arousal in response to psychogenic and/or somatogenic stimuli

Question 5

What happens in the plateau phase?

Answer 5

Period of sexual excitement before orgasm

Increased sexual pleasure with increased stimulation

Question 6

What happens in the orgasm phase?

Answer 6

Quick successions of muscular contractions with pleasure

Ejaculation in males

Question 7

What happens in the resolution phase?

Answer 7

Return to haemodynamic norm

Followed by a refractory period in males

Question 8

What is the first stage of the male sexual response?

Answer 8

Erection

Question 9

How is an erection produced?

Answer 9

Stimulants

• psychogenic
• tactile

Spinal reflex to somatic/autonomic efferents

• pelvic nerve
• pudendal nerve

Haemodynamic changes

Question 10

What autonomic system maintains the erection?

Answer 10

Parasympathetic

Question 11

What is the parasympathetic innervation to the penis?

Answer 11

Pelvic nerve + pelvic plexus

Cavernous nerve to corpora + vasculature

Question 12

What is the neurophysiology of an erection?

Answer 12

Inhibition of sympathetic arterial vasoconstrictor nerves
Activation of PNS
Activation of autonomic nerves = release nitric oxide

Question 13

What is the role of nitric oxide in an erection?

Answer 13

Nitric oxide diffuses into vascular smoth muscles + causes vasodilation

Question 14

What can cause erectile dysfunction?

Answer 14

Psychological
Tears in fibrous tissues of corpora cavernosa
Vascular
Drugs

Question 15

What can be used to help erectile dysfunction?

Answer 15

Viagra

Question 16

How does Viagra work?

Answer 16

Slows rate of cGMP degradation

Question 17

What is the second stage of the male sexual response?

Answer 17

Emission + ejaculation

Question 18

What autonomic system is involved in ejaculation?

Answer 18

Sympathetic

Question 19

How does emission occur?

Answer 19

Movement of semen into prostatic urethra

Contraction of smooth muscle in prostate, vas deferens + seminal vesicles

Question 20

What is ejaculation?

Answer 20

Expulsion of sperm

Question 21

What happens during ejaculation?

Answer 21

Contraction of glands and ducts

Bladder internal sphincter contracts

Question 22

Why does the bladder internal sphincter contract?

Answer 22

Prevent semen entering bladder

Question 23

What is the effect of oestrogen on cervical mucus?

Answer 23

Thin, stretchy mucus - supports transport of male gamete

Question 24

What is the effect of progesterone + oestrogen on cervical mucus?

Answer 24

Thick, sticky mucus - forms a plug

Question 25

Where is the site of semen deposition?

Answer 25

External os of cervix

Question 26

What happens to the sperm once in female reproductive tract?

Answer 26

Capacitation - sperm cell membrane changes to allow fusion with oocyte - tale movement changes to more whip like action

Question 27

How long are sperm fertile for?

Answer 27

48-72 hr

Question 28

How long are oocytes fertile for?

Answer 28

6-24 hr

Question 29

What is the acrosome?

Answer 29

Head of sperm - containing enzymes Derived from golgi region in spermatid

Question 30

What happens in the acrosome reaction?

Answer 30

Sperm pushes through corona radiata Binding of sperm to ZP3 glycoprotein of zona pellucida Triggers acrosome reaction Enzymes digest zona pellucida

Question 31

How is polyspermy prevented?

Answer 31

Cortical reaction | - release of cortical granules

Question 32

What happens when fertilisation occurs?

Answer 32

Calcium waves activated following fusion of oocyte + sperm membranes Oocyte continues meiosis 2 Pronuclei move together Mitotic spindle forms - cleavage of cells Formation of morula