Sperm Transport and Maturation in the Female Reproductive Tract Flashcards
Characteristics of the phallus in birds
- mechanism of erection is lymphatic rather than vascular
2. semen is transfered via a groove along the outside of the phallus rather than a tube in the middle
What are the two types of penises in mammals?
musculocavernous
fibro-elastic
Describe the musculocavernous penis
- large amount of erectile tissue
- found in horse, dog, cat, and human
Describe the fibro-elastic penis
- fibroelastic tissue with smaller amounts of erectile tissue
- tends to have a sigmoid flexure
- found mostly in artiodactyls (ruminants, pigs)
What other components are found within the penis?
- paired corpora cavernosa enclosed in tunica albuginea
- os penis in some species (dogs, raccoons, seals)
- barbs on the glans in some species (rabbit, cat, ferret)
- corpus spongiosum (surrounds urethra)
What is the purpose of the retractor penis muscle? (not in all species)
keeping the non-erect penis within the prepuce
What are the 4 phases of erection?
flaccid
tumescence
stable erection
detumescence
Describe the flaccid state
maintained by tonic contraction of s.m. in the corpora and arteries supplying them under the influence of sympathetic adrenergic input
Describe erection
- psychic stimuli acting on the brain and tactile stimuli on the penis result in decreased sympathetic tone and increased parasympathetic tone causing relaxation of penile arterioles and smooth muscle of the cavernous sinuses
- NO and cGMP mediate relaxation and blood flows into the erectile corpora
- venous drainage is then compressed
Describe detumescence
- sympathetic tone increases and parasympathetic tone decreases
- synthesis of NO and cGMP ceases
- venous outflow is re-established and blood expelled from the cavernous sinuses returns the penis to a flaccid state
Ejaculation consists of what 2 components?
emission
expulsion
What is the function of the spinal ejaculation generator?
integrate sensory inputs from the genitalia that will trigger ejaculation with the autonomic and motor outputs required to generate the ejaculatory response
Where are sensory receptors located on the penis?
penile skin
glans
urethra
within the corpus cavernosum
What is involved in emission?
getting all the components of ejaculation into the pelvic urethra
What happens during emission?
- secretion of fluids from the accessory glands
- contraction of the cauda epididymis and vas deferens containing the sperm
- closure of the sphincter at the bladder neck and the external urethral sphincter