Sexual Reproduction - Humans

Question 1

testes function

Answer 1

contain seminiferous tubules for sperm production

testerone production

Question 2

scrotum function

Answer 2

holds testes outside body for temp regulation

Question 3

penis function

Answer 3

removes waste

delivers sperm in reproduction

Question 4

urethra function

Answer 4

passage of urine/semen through penis

Question 5

vas deferens function

Answer 5

muscular tube transport sperm from epididymis to top of urethra

Question 6

seminal vesicles function

Answer 6

secrete mucus into vas deferens - 70% of semens liquid content

Question 7

prostate gland function

Answer 7

30% of semens liquid content

alkaline to maintain sperm mobility, provide nutrients, neutralise acidity of urine/vaginal tract

Question 8

epididymis function

Answer 8

sperm complete development

stores sperm until ejaculation

Question 9

ovary function

Answer 9

egg production

oestrogen + progesterone production

Question 10

uterus function

Answer 10

embryo/foetal development

3 layers = perimetrium (thin, around outside), myometrium (muscle), endometrium (inner mucous membrane)

Question 11

endometrium function

Answer 11

varying thickness

highly vascularised - supplies foetus

Question 12

oviduct (Fallopian tubes) function

Answer 12

carrues egg from ovary to uterus by muscular contractions and cilia
site of fertilisation

Question 13

cervix function

Answer 13

ring of muscle that supporta embryo/foetus

Question 14

vagina function

Answer 14

muscular Ru where penis is placed during intercourse

Question 15

where does spermatogenesis take place

Answer 15

seminiferous tubules (testes)

Question 16

spermatogenesis

Answer 16

germinal epithelial tissue (lines seminiferous tubules) (2n)
mitosis
spermatogonium (2n) (+1 stays as germinal epithelial cell)
mitosis
primary spermatocytes (2n)
meiosis 1
secondary spermatocytes (n)
meiosis 2
spermatids (n)
spermatozoan

Question 17

what protects sperm

Answer 17

cells of Sertoli

Question 18

where does oogenesis take place

Answer 18

ovary

Question 19

oogenesis

Answer 19

germinal epithelial tissue (2n) (also divides to form primary follicles that surround primary oocytes)
mitosis
oogonia (2n)
growth
primary oocytes (2n)
meiosis 1 (ends at prophase 1) to produce first polar body (n) + secondary oocyte (n)
ovulation - primary follicles develop into secondary then Graafian follicles which migrate to ovary, burst and release secondary oocyte
meiosis 2 (ends at metaphase 2)
secondary oocyte moves along fallopian tubes…

Question 20

oogenesis if no intercourse/sperm

Answer 20

secondary oocyte passes along fallopian tubes, reaches uterus, lost in menstruation

Question 21

oogenesis if intercourse takes place

Answer 21

sperm + secondary oocyte in fallopian tubes, sperm ‘capacitated’ bursts in contact with corona radiata enters secondary oo cute triggering meiosis 2
meiosis 2 completes making ovum + second polar body
Graafian follicle becomes corpus luteum - produces hormones

Question 22

sexual intercourse

Answer 22

penis erect, enters vagina, sperm ejaculated through cervix into uterus

Question 23

fertilisation

Answer 23

capacitation - cholesterol + glycoproteins removed from acrosome on sperm head making membrane permeable to calcium ions
acrosome reaction - acrosome releases proteases digesting corona radiata, acrosome membrane ruptures releasing acrosin hydrolysing zona pellucida around secondary oocyte
sperm + secondary oo cute cytoplasm fuse - ovum
cortical reaction - calcium ions into cytoplasm, cortical granules fuse with cell membrane releasing enzymes by exocytosis, zona pellucida forms fertilisation membrane, prevent polyspermy
meiosis 2 completes, ovum nucleus divides an expels second polar body
mitosis combine genetic material produces 2 cells (embryo)

Question 24

implantation

Answer 24

embryo down oviduct, divides my mitosis many times (cleavage)
ball of cells hollow - blastocysts (with trophoblast cells) divide making inner cell mass on one side
blastocyst moves from oviduct to uterus
endometrium thickens, increased blood supply for embryo
trophoblastic villi penetrate endometrium increasing surface area for nutrient absorption
blastocyst into endometrium = implantation

Question 25

menstrual cycle | day 0

Answer 25

endometrium break down, gonadotrophic releasing hormone secreted by hypothalamus stimulates anterior pituitary gland to secrete FSH + LH FSH stimulates primary follicles in ovary, 1 matures forms theca + secretes fluid into antrum = Graafian follicle FSH thecal cells make oestrogen (+feedback) lots of LH, Graafian follicle to ovary surface releasing secondary oocyte +feedback effect on FSH Graafian follicle into corpus luteum, secretes oestrogen + progesterone inhibit FSH + LH

Question 26

menstrual cycle | day 6-7

Answer 26

oestrogen levels rise - endometrium rebuilds, FSH inhibited (-feedback), stimulates LH (+feedback)

Question 27

menstrual cycle | day 12

Answer 27

progesterone increase - maintains endometrium so if secondary oocyte is fertilised there'll be suitable tissue for embryo to implant no implantation - fall in FSH + LH causes progesterone decrease, endometrium sheds

Question 28

menstrual cycle | day 14

Answer 28

LH peak causes ovulation | Graafian follicle becomes corpus luteum, secretes I estrogen + progesterone

Question 29

menstrual cycle | day 21

Answer 29

oestrogen + progesterone levels drop | oestrogen falls, FSH not inhibited, increases, next follicle develops

Question 30

menstrual cycle | day 28

Answer 30

progesterone levels not high enough to maintain endometrium - menstruate FSH levels rise - cycle restarts

Question 31

if fertilisation occurs...

Answer 31

progesterone + oestrogen levels remain high | embryo produces HCG, maintains corpus luteum for progesterone + oestrogen

Question 32

hormones + birth

Answer 32

more oestrogen than progesterone in last 3 months of pregnancy, oxytocin + prolactin no longer inhibited posterior pituitary gland secretes oxytocin causing myometrium to contract, +feedback more oxytocin, myometrium contracts top down to push foetus through cervix anterior pituitary gland secretes prolactin stimulates glandular tissue in mammary glands to synthesise, milk released when oxytocin causes muscles around milk ducts to contract

Question 33

placenta function

Answer 33

connects embryo and foetus to uterus wall produces hormones in pregnancy exchange between mother + foetus blood (nutrients, waste, gases) stops blood mixing (different pressures) passive immunity to foetus protects mothers immune system

Question 34

placental hormones

Answer 34

embryo secretes HCG after fertilisation made by chorion (inner layers of placenta) after implantation, maintains corpus luteum (secretes progesterone maintains endometrium) corpus luteum secretes oestrogen + progesterone, placenta increases, FSH, LH, prolactin, oxytocin inhibited by progesterone, oestrogen stimulates uterus growth accommodating foetus + mammary gland growth