Lecture 38: Reproductive System V Flashcards
What is coitus?
Sexual intercourse / copulation
During coitus what happens to the erect penis?
It is introduced into the vagina (intromission)
During coitus what happens to semen?
It is released into the upper part of the vagina (insemination) so that sperm can travel to the appropriate site for fertilisation (ampulla of the uterine tube)
What are the 4 stages of the male sexual act?
- Erection of penis (parasympathetic)
- Emission
- Expulsion
- Resolution
What are the 2 phases of ejaculation?
- Emission
- Expulsion
What are the erectile tissues of the penis surrounded by?
Different layers of fascia
What happens to lacunae in the penis?
They fill with blood during an erection
What is the function of trabeculae in the penis?
They seperate out lacunae
What are the layers of fascia in the penis form deepest to most superficial?
(3)
- Tunica albuginea
- Deep (buck’s fascia)
- Superficial fascia
What do the structure of the penis and the clitoris share?
Developmental origins
What is specific about the tissues of the clitoris?
They are erectile such as in the penis
What are the branches off the abdominal aorta that supply the penis with blood?
(4)
- Abdominal aorta
- Common iliac artery
- Internal iliac artery
- Internal pudendal artery
What does the internal pudendal artery feed?
The perineum and external genitalia including the penis
What do the branches of the internal pudendal artery include?
(4)
- Artery to bulb
- Urethral artery
- Dorsal artery
- Deep (cavernosal) artery
What happens to blood supply to the penis during an erection?
It increases
What is the penis richly innervation by?
Sensory and motor nerves
The penis includes sensory fibres that respond to what?
3
- Touch
- Pressure
- Temperature
What do pudendal nerve supply sensory and somatic motor innervation to?
(2)
- Perineum
- External genitalia (including penis)
Via the dorsal nerve
What is autonomic innervation to the penis derived from?
Pelvic plexus (parasympathetic & sympathetic)
What parasympathetic stimulation is there in an erection?
- Production of nitric oxide (NO, vasodilator) by deep arteries of the penis)
- Deep arteries dilate and fill lacunae in corpora cavernosa
What sympathetic stimulation is there during ejaculation?
3
- Stimulation for the contraction of smooth muscle
- reproductive glands
- Accessory glands
What somatic motor stimulation is there during ejaculation?
Stimulation for the contraction of skeletal muscles around the bulb of the penis
Is the erection of a penis parasympathetic or sympathetic?
Parasympathetic
What are the 2 phases of ejection?
- Emission
- Expulsion
Erection involves parasympathetic response to what?
Stimuli
During erection arteries in erectile tissue do what?
Dilate
During erection what happens to erectile tissue?
It becomes engorged with blood
During an erection an erect penis can be inserted where?
Into a vagina (intromission)
What type of response is emission?
Sympathetic
What does the smooth muscle of ductus deferens contract to do during emission?
Move sperm into the ampulla (peristaltic contractions)
What do the muscle of the ampulla, seminal vesicles and prostate gland contract to do during emission?
Move sperm and seminal fluid into the urethra
What happens to semen in the urethra during expulsion?
It activates somatic and sympathetic reflexes
During expulsion what smooth muscles contract?
Urethral smooth muscle
During expulsion what happens to the pelvic floor muscles?
They contract and semen is ejected
What happens during resolution?
2
- Blood flow to the penis is reduced
- Penis becomes flaccid
What enlarges in response to autonomic stimulation for females during the female sexual response?
Enlargement of the clitoris, labia and vagina
During the female sexual response what is their secretion of?
(2)
- Fluid through the vaginal wall
- Secretion of mucus into the vestibule (greater vestibular glands)
During the female sexual response there are rhythmic contractions of what?
(3)
- Vaginal
- Uterine
- Perineal (pelvic floor) muscles
Where do sperm released into the upper part of the vagina during insemination travel?
Into the uterine tube to the ampulla for fertilisation
During fertilisation what do sperm fuse with?
Secondary oocyte
What is a fertilised oocyte/ovum known as?
A zygote
A zygote initiates cleavage and does what?
Travels towards the uterus for implantation
What is contraception?
Any method used to prevent pregnancy
What are the 2 types of contraception method?
- Natural
- Artificial
What are examples of the artificial method of contraception?
4
- Barrier methods
- Hormonal contraceptives
- Intrauterine devices
- Sterilisation
What are 2 common features of natural methods of contraception?
- Relies on timing of coitus or behaviour during coitus
- High failure rate
What are the features of caps/diaphragm barrier method of contraception?
(3)
- Imperfect barrier
- Needs to remain at least 6 hours after intercourse
- Not commonly used anymore
What are common characteristics about condoms?
4
- Cheap
- Readily available
- Easy to use
- Reduce risk of sexually transmitted infections (STI’s)
What do combined oral contraceptive pills contain?
2
- Estrogen
- Progestin
What do combined oral contraceptive pills suppress?
Ovulation (affect feedback loops to hypothalamus and pituitary)
What do combined oral contraceptive pills affect the mucus production by?
By the cervix
What does progestin-only contraception pill affect?
Cervical mucus
What do subnormal implant/injectable progestins act primarily by?
Disrupting follicular growth and ovulation
What are 4 features of copper IUD?
- Causes low grade inflammation
- Reduces sperm transport
- Toxic to oocytes/zygote
- Impairs implantation
What are 4 features of hormonal IUD?
- Contains progestins
- Affects cervial mucus, reducing sperm transport
- Local affects on endometrium
- May prevent ovulation
What is tubal ligation?
When the uterine tubes are cut
What is a vasectomy?
When vas (ductus) defers are cut?
