Lecture 38 Flashcards
What is coitus / copulation?
Sexual intercourse
What are the stages of the male sexual act?
Erection of penis, mucus secreted into urethra, ejaculation and resolution
What is erection of the penis controlled by?
The parasympathetic nervous system
Why is mucus secreted into the urethra?
For protection and lubrication
What is ejaculation controlled by?
The sympathetic nervous system
What are the two phases of ejaculation?
Emission and expulsion
What is the erectile tissue of the penis surrounded by?
Different layers of fascia
What do the structures of the clitoris and penis share?
Developmental origins and erectile tissue
What is the blood supply to the penis?
Abdominal artery -> common iliac artery -> internal iliac artery -> internal pudendal artery
What is the gonadal artery?
In females the ovarian artery and in males the testicular artery
Where does the gonadal artery develope?
With the gonads which develops around the kidneys, they then descend bringing the vasculature with them
What does the internal pudendal artery feed?
The peritoneum and external genitalia, including penis
What are the different vasculature branches to the penis?
Artery to bulb, urethral artery, dorsal artery and deep cavernosal artery
What allows an erection to be sustained?
Pressure against the veins and facia
What is the main innervation of nerve supply to the penis?
Sensory and motor nerves
What are sensory fibres responsive to?
Touch, pressure and temperature
What is the pudendal nerve?
The nerve supplying sensory and somatic motor innervation to the perineum and external genitalia
What is autonomic innervation to the penis derived from?
The pelvic plexus
What is the parasympathetic nervous system related to in the male sexual act?
Erection
How does an erection occur?
Production of nitric oxide by deep arteries of the penis which fill lacunae in corpora cavernosa
What is the sympathetic nervous system related to in the male sexual act?
Ejaculation
How does ejaculation occur?
SNS simulates contraction of smooth muscle, reproductive glands and accessory glands
What does the somatic motor complex stimulate?
Ejaculation through the contraction of skeletal muscles around the bulb of the penis
How does an erection occur?
Parasympathetic response to stimuli cause arteries in erectile tissue to dilate, erect tissue becomes engorged with blood and intromission can occur
How does emission occur?
Sympathetic response to smooth muscle of ductus deferens contracts to move sperm into ampulla which contracts, along with seminal vesicles and prostate gland to move sperm and seminal fluid into urethra
What happens when sperm and seminal fluid move to urethra
It becomes activated
How does expulsion occur?
Semen in urethra activates somatic and sympathetic reflexes causing contractions of urethral smooth muscles and pelvic floor contraction to eject semen
What is resolution?
When blood flow to the penis is reduced and it becomes flaccid
What are the stages of the female sexual response?
Engorgement of clitoris, labia and vagina in response to autonomic stimulation. Lubricating fluid is secreted through vaginal wall into vestibules. Vagina increases in width and length. Uterus elevates upwards and rhythmic contraction of vaginal, uterine and perineal muscles
Where is semen released into the vagina?
The upper part
Where does semen travel once it has entered the vagina?
To the uterine tube for fertilisation
What does sperm fuse with?
Secondary oocytes
What happens to the secondary oocyte once the sperm has fused?
It completes meiosis II and becomes a zygote
What happens to the zygote?
It initiates cleavage and travels towards the uterus for implantation
How long does it take between fertilisation and implantation?
About 7 days
What is contraception?
Any method used to prevent pregnancies
What are the methods of contraception?
Natural and artificial
What is natural contraception?
Relys on timing of coitus or behaviour during coitus - has a high failure rate
What are the three types of natural method?
Rhythm method (ovulation timing), withdrawal method and lactational infertility
What are the types of artificial contraception methods?
Barrier methods, intrauterine devices, hormonal contraceptives and sterilisation
What are barrier methods?
Caps, diaphragms and condoms
What is a cap or diaphragm?
An imperfect barrier which should be used in conjunction with spermicidal foams, jellies, creams or sponges. Needs to remain in place at least 6 hours after
What are the pros of condoms?
Cheap, readily available, easy to use and protect against STI
What is the non-hormonal intrauterine device?
Copper IUD - causes low grade inflammation and reduces sperm transport. Is toxic to oocytes and zygotes and impairs implantation
What is hormonal contraception?
Steroidal contraceptives, delivers progestin with or without an estrogen which suppresses ovulation and affects mucus produces by cervix
What is the combined oral pill?
Steroidal contraception with estrogen and progestin which suppresses ovulation and affects mucus
What are forms of progestin only contraception?
The progestin only pill which affects only cervical mucus, the subdermal implant which acts primary by disrupting follicular growth and ovulation and the hormonal IUD
What is the hormonal IUD?
Progestin only which affects mucus and also locally affects endometrium. May prevent ovulation
What is sterilisation?
In females - tubal ligation or salpingectomy (cut/cauterise or remove uterine tubes)
In males - vasectomy (cut ductus deferens)
