2.3 - sexual reproduction in humans Flashcards
list parts of female reproductive system + explain function
ovaries - produce egg cells in follicles
fallopian tubes - transports egg cell from ovary to uterus
uterus - where embryo develops
cervix - separates uterus from vagina, protects fetus
vagina - leads from cervix to outside of body
list parts of male reproductive system + explain function
testes - production of sperm cells + testosterone
vas deferens - carry sperm from testes to urethra
prostate gland - secretes alkaline fluid to counteract vaginal acidity
urethra - allows excretion of urine + semen from body
seminal vesicle - secretes fluid (proteins + fructose) to nourish sperm
penis - penetrates vagina, releases sperm
epididymis - stores sperm
scrotum - holds + maintains optimum temperature for testes
how does human body produce gametes
via gametogenesis
name 2 types of gametogenesis
- spermatogenesis
- oogenesis
what is spermatogenesis
gametogenesis in males resulting in production of spermatozoa
where does spermatogenesis take place
seminiferous tubules
outline stages of spermatogenesis
primordial germ cells → spermatogonia → primary spermatocytes → secondary spermatocytes → spermatic → 4 spermatozoa
what’s the germinal epithelium
surface layer of cells surrounding ovaries in females + testicles in males that’s involved in gametogenesis
how do primary spermatocytes form
- primordial germ cells divide by mitosis, forming spermatogonia
- growth period of spermatogonia w/out further division forms primary spermatocytes
how are spermatids formed
- primary spermatocytes divide in meiosis I to form haploid secondary spermatocytes
- secondary spermatocytes divide in meiosis II to form 4 haploid spermatids
how do spermatozoa form
spermatids differentiate to gain flagellum, acrosome, + many mitochondria
the 3 types of cells within testes
- spermatogonia
- sertoli cells
- interstitial cells (cells of leydig)
what are leydig cells
- cells located adjacent to seminiferous tubules in testes that secrete testosterone
- also called interstitial cells of leydig
what are sertoli cells
cells located within seminiferous tubules in testes that provide nourishment + protection to cells produced in spermatogenesis
describe structure of mature sperm cell
acrosome - contains digestive enzymes which break down zona pellucida of egg
flagellum - propulsion
mitochondria - energy
what’s oogenesis
gametogenesis in females that results in production of secondary oocytes
where does oogenesis take place
ovaries
outline stages of oogenesis
primordial germ cell → oogonia → primary oocyte → secondary oocyte + polar body → ootid + polar bodies → ovum
how do primary oocytes form
- primordial germ line cells in ovaries (+ oviduct) divide by mitosis, forming oogonia
- growth period of oogonia w/out further division forms primary oocytes
- meiosis begins but pauses in prophase I until puberty
what happens during first meiotic division of oogenesis
- primary oocytes divide in meiosis I to form secondary oocyte
- polar body buds off + sticks to oocyte
what’s a polar body
haploid cell produced during meiosis in females that doesn’t have ability to be fertilised
when is second meiotic division of oogenesis completed
meiosis II initiated but pauses in metaphase II unless fertilisation takes place
what happens during second meiotic division
secondary oocyte develops into fertilised ovum + second polar body
describe structure of secondary oocyte
corona radiata - outer layer of follicle cells
zona pellucida - coating above cytoplasm that prevents polyspermy + hardens when cortical granules release chemicals
haploid nucleus - fertilisation restores diploid chromosome number