Week 2- physiology of the reproductive system Flashcards
what are the two stages of sperm production?
spermatocytogenesis- diploid spermatogonia undergo meiosi forming 4 haploid spermatids
spermiogenesis- each haploid spermatid undergoes differentiation to become spermatozoa
what are the functions of Sertoli cells?
- guide sperm towards lumen
- form a blood testes barrier by forming tight junctions- immunologically safe
- secretes fluid to move immobile sperm
- aids in transfer of nutrients
- phagocytosis of any dead cells
- prodcues androgen binding protein to maintain a high concentration of testosterone
- produces hormones and responds to FSH
what are the steps of spermiogenesis?
- Golgi apparatus pieces assemble together to form the acrosome
- mitochondria arrange themselves in a parallel position next to where the tail starts to form
- the centriole lines up between the nucleus and tail
- mitochondria line up in the first part of the tail and excess cytoplasm is removed by sertoli cells
what happens to the sperm in the epididymis?
binding sites on head of sperm are closed to stabilise the cell membrane until capacitation occurs. sperm become motile
what is the function of the components of the seminal fluid?
alkaline- protects sperm from acidic environment
fructose- energy
coagulation factors- sperm coagulates into ball of fluid for delivery into vagina
prostaglandins- decrease female immune response to semen
what is the composition and function of the prostatic fluid in semen?
thin milky fluid with citrate and zinc
prostate specific antigen- liquifies coagulated ejaculate15 minutes after ejaculation so sperm can be motile.
what is the function of the bulbourethral glands?
secrete mucus to help the transport of sperm
what are the characteristics assessed on a sperm count?
quantity- volume, sperm concentration, total sperm count
morphology
motility
vitality- how many live
what hormone do Leydig cells respond to
LH
how is dihydrotestosterone formed?
testosterone is converted to DHT by 5-alpha reductase
which enzyme converts testosterone to oestrogen?
aromatase
how is testosterone produced in leydig cells?
cholesterol is converted to pregenolone which is either converted to DHEA then to androstenediol which is converted to testosterone by 3-beta-HSD or progesterone is converted to progesterone by 3-beta-HSD which is then converted to androstenedione which is converted to testosterone by 17beta3-HSD.
at any stage 3-beta-HSD can first pathway to change to the second pathways
what are the function of androgens?
- differentiation of male genitals
- sperm and semen production
- secondary sexual characteristics- puberty
what is the function of inhibin and where is it produced?
inhibits FSH production
produced by Sertoli cells
what causes respiratory distress syndrome in preterm newborns?
surfactant deficiency
what circulation problems are common in preterm newborns?
hypotension, anaemia, patent ductus arteriosus
why do some preterm newborns require NG tube feeding?
feeding intolerances, difficulty latching
what are common brain complications in preterm newborns?
haemorrhage, post hemorrhagic hydrocephalus (ventricularmegoly due to disturbances in CSF flow or abdorption)
what are common metabolic complications in preterm newborns?
hypoglycaemia, electrolyte disturbances, osteopenia- cause by calciumand phosphate deficiency
what is the babkin reflex?
applying pressure to the palm and dorsum of hand causes the infant to open their mouth and drop their tongue
what is the rooting reflex?
stroking an infants cheek will cause them to turn their head and open their mouth
what is the moro reflex?
when head falls backwards, the infant will symmetrically extend and abduct their arms and open their hands
what is the menstrual cycle?
cyclical changes whereby the ovum develops for ovulation and fertilisation and the uterus prepares for implantation
what is the ovarian cycle?
the cycle of follicle growth resulting in ovulation and corpus lute formation
what is the reproductive cycle?
the reproductive cycle is the cycle of physiological changes in the reproductive organs, from the time of fertilisation of the ovum through gestation and childbirth
where is the GnRH pulsatile generator found?
in the arcuate nucleus pf the hypothalamus
describe the follicular and ovulation stages of the ovarian cycle
GnRH acts on anterior pituitary causing FSH to be released. FSH stimulates follicular development. follicles produce oestrogen which has a negative feedback effect on FSH. rising levels of oestrogen causes an LH surge which triggers ovulation
describe the luteal phase of the ovarian cycle
the follicle becomes lutenised forming the corpus lute which releases oestrogen and progesterone. if fertilisation does not occur the CL regresses and stops producing hormones forming the corpus albicans. if fertilisation does occur hCG released from the developing placenta maintains the corpus luteum until the placenta can take over hormone release
what are the layers of the endometrium?
stratum compactum and stratum spongiosum (functional zone)
stratum basalis - not shed q
what happens during the proliferative phase of the menstrual cycle?
increased oestrogen imitates proliferation of the functional zone of the endometrium, storm proliferates becoming thicker and richly vascularised
what happens during the secretory phase of the menstrual cycle?
increased progesterone and oestrogen. glands produce thick glycogen and glycoprotein-rich secretions
what happens during the mestrual phase?
progesterone withdrawal induces shedding of the functional layer of endometrium
what are the effects of hormones on the cervix?
increased oestrogen- thin watery cervical mucus, highly spinnbarkeit (stretchable), sperm can get through
increased progesterone- thick, viscous, low spinnbarkeit, sperm can’t get through
what are the effects of hormones Fallopian tubes?
increased oestrogen- increased transport speed
increased progesterone- decreased transport speed
what are the effects of oestrogen and progesterone on on lactation?
oestrogen- stimulation of duct growth, inhibition of milk let down
progesterone- stimulation of lobuloavleolar development, inhibition of milk let down
what is primary and secondary amenorrhoea?
primary- failure to establish mestruation by 15 years of age in girls with secondary sexual characteristics or 13 in girls with no secondary sexual characteristics
secondary- cessation of menstruation for 3-6 months in women with previously regular menses or 6- 12 months in women with previous oligomenorrhoea
how does polycystic ovary syndrome cause amenorrhoea?
increased GnRH causes increased LH levels and hyperandrogegism and decreased FSH. this causes impaired folliculogenesis and an ovulation and polycytic ovarian morphology.
how do thyroid disorders disrupt menstruation?
changes in thyroid function can impact the pituitary, metabolism or availability of steroid hormones.
hyper thyroid- periods become light and infrequent
hypothryoid- irregular bleeding
how do eating disorders affect menstruation?
low BMI (anorexia)- loss of GnRH secretion, no FSH high BMI- increased oestrogen- negative feedback on anterior pituitary
