Physiology of Coitus and Histology of the penis and vagina

Question 1

what regulates sexual behaviours?

Answer 1

the brain and spinal cord

Question 2

what is coitus?

Answer 2

sexual intercourse that results in the deposition of semen in the vagina at the level of the cervis

Question 3

what mediates an erection?

Answer 3

the parasympathetic plexus at the level of S2 and S3

Question 4

what happens during n erection?

Answer 4

-penis becomes engorged
-testis and penis increase in size
-increased skeletal muscle tension
-increased HR
-ventilation

Question 5

what happens during sexual stimulation of the vagina?

Answer 5

-vagina and clitoris engorge with blood
-circumference of the vagina at the level of the pelvis as well as the length of the vagina increases
-labia minora deepen in colour
-more secretions in the vagina provide lubrication
-the uterus elevates
-rep rate, HR and BP increase

Question 6

what is the physiology of ejaculation?

Answer 6

-reflex contractions of the bulbocavernosus and ischiocavernosus muscles
-spinal reflex under sympathetic control
-requires contraction of ductus deferens, seminal vesicles and prostate
-filling of urethra stimulates nerves in the genital region which contracts the muscle of the penis resulting in forcible expulsion of semen

Question 7

what is the physiology of an orgasm (vaginally)?

Answer 7

-stimulation of the clitoris and the labia result in progression towards an orgasm
-vaginal lubrication increases and the labia become more engorged due to blood flow
-during orgasm the clitoris retracts and a succession of contractions occur in the vaginal walls and the pelvic floor

Question 8

what are the 2 types of erectile tissue?

Answer 8

corpus cavernous
corpus spongiosum

Question 9

what is the corpus cavernous?

Answer 9

course erectile tissue with lots of white spaces which is bound by a tough fibrous coat

Question 10

what is erectile tissue?

Answer 10

interconnecting vascular space which is empty when the penis is placid
when erection is achieved they will with blood

Question 11

what is the tunica albuginea?

Answer 11

tough fibrous capsule around the erectile tissue that holds the tissue together
not as thick or coarse with not as much vascular spaces

Question 12

what happens during arousal of penis?

Answer 12

parasympathetic stimulation causes relaxation of the smooth muscle and the artery and then the erectile tissue which leads to vasodilation and allows the blood to flow into these cavernous spaces

Question 13

what kind of epithelium is found on the vaginal cavity?

Answer 13

stratified squamous and non keratinised

Question 14

which vein drains the penis?

Answer 14

dorsal vein

Question 15

why do the cells become more cuboidal in the vagina?

Answer 15

allows the top layer of the epithelia to be removed as there’s lots of activity inside the vagina
we also need the basal cells to be able to divide and replace the upper epithelia

Question 16

what kind of muscle makes up the vagina?

Answer 16

mainly smooth muscle (bulbospongiosis) but some skeletal muscle can also be seen

Question 17

what is responsible for making the vagina acidic?

Answer 17

glycogen

Question 18

where is vaginal mucus produced?

Answer 18

greater vestibular glands and the cervix which lubricates the cervical walls

Question 19

what is viagra?

Answer 19

sildenafil protects cGMP from degradation by cGMP-specific phosphodiesterase type 5 in the corpus cavernosum of the penis. Nitric oxide in the corpus cavernosum of the penis binds to guanylate cyclase receptors, which results in increased levels of cGMP, leading to vasodilation and increased inflow of blood into the penis, causing an erection.