Week 2- physiology of the reproductive system

Question 1

what are the two stages of sperm production?

Answer 1

spermatocytogenesis- diploid spermatogonia undergo meiosi forming 4 haploid spermatids
spermiogenesis- each haploid spermatid undergoes differentiation to become spermatozoa

Question 2

what are the functions of Sertoli cells?

Answer 2

1. guide sperm towards lumen
2. form a blood testes barrier by forming tight junctions- immunologically safe
3. secretes fluid to move immobile sperm
4. aids in transfer of nutrients
5. phagocytosis of any dead cells
6. prodcues androgen binding protein to maintain a high concentration of testosterone
7. produces hormones and responds to FSH

Question 3

what are the steps of spermiogenesis?

Answer 3

1. Golgi apparatus pieces assemble together to form the acrosome
2. mitochondria arrange themselves in a parallel position next to where the tail starts to form
3. the centriole lines up between the nucleus and tail
4. mitochondria line up in the first part of the tail and excess cytoplasm is removed by sertoli cells

Question 4

what happens to the sperm in the epididymis?

Answer 4

binding sites on head of sperm are closed to stabilise the cell membrane until capacitation occurs. sperm become motile

Question 5

what is the function of the components of the seminal fluid?

Answer 5

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

Question 6

what is the composition and function of the prostatic fluid in semen?

Answer 6

thin milky fluid with citrate and zinc

prostate specific antigen- liquifies coagulated ejaculate15 minutes after ejaculation so sperm can be motile.

Question 7

what is the function of the bulbourethral glands?

Answer 7

secrete mucus to help the transport of sperm

Question 8

what are the characteristics assessed on a sperm count?

Answer 8

quantity- volume, sperm concentration, total sperm count
morphology
motility
vitality- how many live

Question 9

what hormone do Leydig cells respond to

Answer 9

LH

Question 10

how is dihydrotestosterone formed?

Answer 10

testosterone is converted to DHT by 5-alpha reductase

Question 11

which enzyme converts testosterone to oestrogen?

Answer 11

aromatase

Question 12

how is testosterone produced in leydig cells?

Answer 12

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

Question 13

what are the function of androgens?

Answer 13

1. differentiation of male genitals
2. sperm and semen production
3. secondary sexual characteristics- puberty

Question 14

what is the function of inhibin and where is it produced?

Answer 14

inhibits FSH production

produced by Sertoli cells

Question 15

what causes respiratory distress syndrome in preterm newborns?

Answer 15

surfactant deficiency

Question 16

what circulation problems are common in preterm newborns?

Answer 16

hypotension, anaemia, patent ductus arteriosus

Question 17

why do some preterm newborns require NG tube feeding?

Answer 17

feeding intolerances, difficulty latching

Question 18

what are common brain complications in preterm newborns?

Answer 18

haemorrhage, post hemorrhagic hydrocephalus (ventricularmegoly due to disturbances in CSF flow or abdorption)

Question 19

what are common metabolic complications in preterm newborns?

Answer 19

hypoglycaemia, electrolyte disturbances, osteopenia- cause by calciumand phosphate deficiency

Question 20

what is the babkin reflex?

Answer 20

applying pressure to the palm and dorsum of hand causes the infant to open their mouth and drop their tongue

Question 21

what is the rooting reflex?

Answer 21

stroking an infants cheek will cause them to turn their head and open their mouth

Question 22

what is the moro reflex?

Answer 22

when head falls backwards, the infant will symmetrically extend and abduct their arms and open their hands

Question 23

what is the menstrual cycle?

Answer 23

cyclical changes whereby the ovum develops for ovulation and fertilisation and the uterus prepares for implantation

Question 24

what is the ovarian cycle?

Answer 24

the cycle of follicle growth resulting in ovulation and corpus lute formation

Question 25

what is the reproductive cycle?

Answer 25

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

Question 26

where is the GnRH pulsatile generator found?

Answer 26

in the arcuate nucleus pf the hypothalamus

Question 27

describe the follicular and ovulation stages of the ovarian cycle

Answer 27

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

Question 28

describe the luteal phase of the ovarian cycle

Answer 28

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

Question 29

what are the layers of the endometrium?

Answer 29

stratum compactum and stratum spongiosum (functional zone) | stratum basalis - not shed q

Question 30

what happens during the proliferative phase of the menstrual cycle?

Answer 30

increased oestrogen imitates proliferation of the functional zone of the endometrium, storm proliferates becoming thicker and richly vascularised

Question 31

what happens during the secretory phase of the menstrual cycle?

Answer 31

increased progesterone and oestrogen. glands produce thick glycogen and glycoprotein-rich secretions

Question 32

what happens during the mestrual phase?

Answer 32

progesterone withdrawal induces shedding of the functional layer of endometrium

Question 33

what are the effects of hormones on the cervix?

Answer 33

increased oestrogen- thin watery cervical mucus, highly spinnbarkeit (stretchable), sperm can get through increased progesterone- thick, viscous, low spinnbarkeit, sperm can't get through

Question 34

what are the effects of hormones Fallopian tubes?

Answer 34

increased oestrogen- increased transport speed | increased progesterone- decreased transport speed

Question 35

what are the effects of oestrogen and progesterone on on lactation?

Answer 35

oestrogen- stimulation of duct growth, inhibition of milk let down progesterone- stimulation of lobuloavleolar development, inhibition of milk let down

Question 36

what is primary and secondary amenorrhoea?

Answer 36

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

Question 37

how does polycystic ovary syndrome cause amenorrhoea?

Answer 37

increased GnRH causes increased LH levels and hyperandrogegism and decreased FSH. this causes impaired folliculogenesis and an ovulation and polycytic ovarian morphology.

Question 38

how do thyroid disorders disrupt menstruation?

Answer 38

changes in thyroid function can impact the pituitary, metabolism or availability of steroid hormones. hyper thyroid- periods become light and infrequent hypothryoid- irregular bleeding

Question 39

how do eating disorders affect menstruation?

Answer 39

``` low BMI (anorexia)- loss of GnRH secretion, no FSH high BMI- increased oestrogen- negative feedback on anterior pituitary ```