Biology- Reproductive System

what is a zygote?

fertilized egg cell

what is fertilization?

fusion of an oocyte and sperm cell

what is a gamete?

reproductive cell

how many chromosomes do each gamete have?

egg and sperm both have 23 each

Why are gametes haploid?

have half as many chromosomes than somatic

what are somatic cells?

Every cell in the body except for sex cells.

how many chromosomes do somatic cells have?

46

why are somatic cells diploid?

twice as many chromosomes as gametes

when does the ball of cells become a fetus?

past 8 weeks

what is Gametogenesis?

creation of gametes

what are Gonads?

organs where gametogenesis is performed

what is the female gonad?

ovaries

what is the male gonad?

testes

when does spermatogenesis begin in men?

begins at puberty

does spermatogenesis ever end?

no, it is continuous and prolific (200,000,00 a day)

when does Oogenesis begin in women?

before birth (immature/not fertile)

when does Oogenesis stop?

stops at menopause (around 52, eggs stop maturing)

what are hormones?

chemical messengers used to send signals between far away cells

What is the pituitary gland?

releases hormones to the gonads which then secrete their own hormones

what are the 2 pituitary hormones?

leutenizing hormone (LH)

follice-stimulating hormone (FSH)

what are the 3 sex hormones released by the gonads?

testosterone (male)

estrogen (female)

progesterone (female)

what is a androgen?

Male sex hormone (testosterone)

what do sex hormones cause?

the development of secondary sex characteristics

what are some male secondary sex characteristics?

shoulder girdle broadens

increased muscle tissue

body/facial hair

adams apple

deeper voice

what are some female secondary sex characteristics?

pelvic gurdle broadens

stores fat in extremeties

breast tissue develops

where does spermatogenesis occur in the testes?

seminiferous tubules

what are the germ cells used in spermatogenesis?

spermatogonia (line the wall of testes, divide to create sperm)

how many sperm cells can one spermatogonia make?

4 (divides twice)

what is testicular descent?

movement of testes from abdominal cavity into scrotom

when does testicular descent occur?

33 weeks after conception

why does testicular descent occur?

it is too hot in the abdominal and spermatogenesis can only occur in 3 degrees lower than average body temp.

what does the cremaster muscle do?

pulls testes closer to body in colder conditions

what is ejaculation?

movement of sperm out of the body

what is the Ejaculatory Pathway in order? (S.E.V.E.N.U.P)

Seminiferous Tubules

Epididymus

Vas Deferens

Ejaculatory Duct

Nothing

Urethra

Penis

what does the epididymus do?

stores sperm

what does the Bulbourethral gland do?

Secrete bulbourethral fluid (balances out the acid in the urethra) comes before ejactulation

what does prostrate gland/seminal vesticles do?

secretes semen

what does semen do?

allows sperm to live up to 5 days in the female reproductive system

what is penile erection?

corpus cavernosum fills with blood=rigidity in penis