Reproductive Physiology Flashcards
Where does LH act in the males and what does this produce?
Leydig cells - testosterone
Where does FSH act in the males and what does this produce?
Sertoli cells - androgen binding protein (ABP)
In males, what are the two mechanisms of negative feedback? State where these are produced
Inhibin (Sertoli cells)
Testosterone (Leydig cells)
Where are the two hormones secreted into?
The seminiferous tubule
List the names of the sperm in the stages of spermatogenesis
Primordial germ cell Spermatogonium Primary spermatocyte Secondary spermatocyte Spermatids Mature sperm
What do you call the sperm which undergoes mitotic division, and what does it become?
Spermatogonium -> primary spermatocyte (diploid, 44+XY)
What do you call the sperm which undergoes first meiotic division, and what does it become?
Primary spermatocyte -> secondary spermatocyte
What do you call the sperm which undergoes second meiotic division, and what does it become?
Secondary spermatocyte -> spermatid
What is a spermatid?
The product of second meiotic division, just before maturing to become sperm
What happens to sperm as men age?
Sperm quantity and quality decreases
In females, besides ovarian follicle development, what is the role of FSH?
Stimulation of 17beta-oestradiol synthesis
Which hormone does LH stimulate in females?
Progesterone production
Give another name for GnRH and describe the release of this hormone
LHRH
Pulsatile
Describe the effect of oestradiol on the HPA during the follicular cycle
Follicular phase - negative feedback
Midcycle (ovulation) - positive feedback
Describe the effect of progesterone on the HPA during the follicular cycle
Luteal phase - negative feedback
What do you call days 0 to 14 of the ovarian cycle?
Follicular phase
What do you call days 14 to 28 of the ovarian cycle?
Luteal phase
Describe the peaks and troughs of hormones from the HPA during the ovarian cycle
Follicular phase: LH and FSH levels rise minimally Midcycle: Both peak Luteal phase: Both fall
Describe the peaks and troughs of hormones from the ovaries during the ovarian cycle
Follicular phase:
Progesterone levels stay low
17b oestradiol levels rise and peak just before midcycle
Luteal phase:
Progesterone levels rise greater than oestradiol
Oestradiol levels rise but not so much as in the follicular phase
What causes endometrial shedding?
Declining progesterone levels
What initially causes thickening of the endometrium during the menstrual cycle?
Oestrogen
What causes further thickening of the endometrium during the luteal phase?
Oestrogen and progesterone from corpus luteum
Describe folliculogenesis in the baby
Primordia follicle grows to become antrum, which undergoes meiosis 1, producing a diploid primary oocyte.
At which stage has the oocyte released during ovulation been arrested?
Metaphase 2
Is the oocyte diploid or haploid?
Diploid 2n
What happens to the primary oocyte after fertilisation?
It continues with meiosis to produce a PRONUCLEUS ovum and a second polar body
How long does it take to move a resting oocyte into ovulation?
3 cycles i.e. 3 months
What happens to the sperm following fertilisation?
Sperm chromosomes condense to form pronucleus
Is the pronucleus haploid or diploid?
23 chromatids (haploid)
What happens to the male and female pronucleus once they’ve formed following fertilisation?
They bind together, duplicate, align on mitotic spindles and separate to form two identical cells
What do you call the creation of the first two identical cells following fertilisation?
1st cleavage division
What do you call the death of developing follicles?
Atresia
Which cells of the developing follicle are responsible for production of oestrogens?
Thecal cells
Which cells of the developing follicle take over hormone production during the second stage of the cycle, and what do they produce?
Granulosa-luteal cells produce oestrogens and progesterone
Which nerve takes afferent tactile info from the penis?
Pudendal nerve
What initiates the changes during erection?
Increased PNS activity to SM of pudendal artery
What induces dilatation of the arterial smooth muscle?
Increased nitric oxide synthase activity, therefore increased nitric oxide and downstream cGMP
What other changes occur during erection?
Increased blood flow to corpus cavernosum (cave of blood)
Compression of dorsal vein (restricting blood outflow)
What protects the urethra from increased pressure during erection?
Corpus spongiosum (protective sponge)
What is the target of Viagra?
Phosphodiesterase inhibitor; therefore prevents deactivation of cGMP
Which pathways regulate fertility and planning?
Neuroendocrine pathways
Which pathways in the brain regulate sexual movements?
Nigrostriatal tract
