Sexual Reproduction

sexual reproduction involves the fusion of teh nucleus of

an ovum(female sex cell)

with the nucleus of a sperm(male sex cell) in the fallopian tube

sperm

- elongated shape -> tail which allows sperm to swim

- little cytoplasm

- nucleus contains 23 chromosomes

-acrosome contains enzymes

ovum

- circular shape

- abundant cytoplasm

-- nucleus contains 23 chromosomes

FEMALE REPRODUCTIVE SYSTEM

- ovary -> releases an ovum every month during ovulation.

: releases sex hormones

(oestrogen & progesterone)

- fallopian tube: oviduct -> site of fertilization:

when the ovary releases an ovum, the

ovum is swept along the F.T by action of the cilia and rhythmic contractions of the muscle walls

uterus(womb) :

site where foetus develops during pregnancy: inner lining is

broken down and discharged once every 28 days during menstruation.

- cervix -> neck of the uterus

- vagina -> site where sperm are deposited during sexual intercourse

- vulva -> opening of the vagina

MALE REPRODUCTIVE SYSTEM

testis : produces spems continuously throughout life: produces sex hormone (testosterone)

scrotum: sac which holds testis outside body cavity as production of sperm requires

a temperature lower than body temperature

epididymis : stores sperm

sperm duct: transport sperm frm the coiled tube to teh urethra

sex glands (prostrate gland, cowper's gland, seminal vesicle) : releases fluid containing

nutrients needed for sperm; sperm + nutrient fluid = semen

urethra : transport semen or urine out of the body

penis: deposit sperm in the vagina during sexual intercourse.

a cycle of 4 stages occuring in a female once she reaches puberty

occurs generally over a period of 28 days

events are controlled by the actions of sex hormones

length of cycle varies frm female to female and it may be affected by stress, illness and diet

Stage 1: menstruation occurs ( day 0-5)

--breakdown and discharge of the uterine lining, blood and dead ovum tru vagina

stage 2: thickening of uterine lining (day 6-11)

stage 3: ovulation occurs during this period (day 12-16)

ovulation is the release of an ovum frm the ovary. therefore this is also

considered the fertile period (fertilization is most likely to be successful if sex occurs)

stage