life sciences - human reproduction

SEXUAL REPRODUVTION

production of a new individual from the fusion of two gametes 

COPULATION

male depositing sperm into the female vagina

ROLE OF TESTOSTERONE

• encourages sperm maturation

• develops male sex organs

• causes voice to become deeper

• enhances muscle development

• promotes development of body and facial hair

TESTES

Male gonad that produces sperm and sex hormones

EPIDIDYMIS

stores sperm and allows them to mature

VAS DEFERENS

sperm duct that propels sperm to urethra by peristalsis

PROSTATE  GLAND

produces fluid which activates sperm and secretes alkaline fluid which neutralizes the acidity in vagina

COWPERS GLAND

protects sperm by neutralizing acidity of urethra and secrets pre ejaculation fluid

PENIS

transfers semen into vagina

URETHRA MALE

tube through which semen and urine pass out the body

SECONDARY SEXUAL CHARACTERISTICS OF FEMALES 

• pubic and underarm hair 

• breast development 

• widening of pelvic girdle 

• accumulation of fat around hips abdomen and breast 

OVARY

produces ova 

FALLOPIAN TUBE 

carries egg from ovary to uterus 

UTERUS

muscular structure in which fetes developes

CERVIX

forms the neck of the uterus which is tightly closed to protect it

VAGINA

canal where sperm is deposited and serves as a birthing canal

VULVA

external genitalia

PUBERTY

stage where boys and girls mature sexually

during this period eggs are released from the ovaries and sperm matures

GAMETOGENESIS

process of game formation which commences at puberty

SPERMATOGENESIS

 diploid cells in tubules undergo meiosis to form haploid cells under the hormone testosterone 

SERTOLI CELLS

support and nourish spermatozoa in the walls of the seminiferous tubules

LEYDIG CELLS

secrete male hormone testosterone

FUNCTION OF SPERM TAIL

for swimming

FUNCTION OF ACROSOME

produces enzymes to dissolve surface of egg

FUNCTION OF MIDDLE PIECE

has mitochondria to supply energy for swimming

OOGENESIS

in ovary diploid cells undergo mitosis to form many primary follicles then at puberty FSH is secreted causing one follicle to enlarge and divide by meiosis to produce haploid cells where only 1 of 4 survive 

MENTRUAL CYCLE

series of changes that occur within a woman’s body every month to prepare for pregnancy and lasts about 28 days

OVARIAN CYCLE 

it involves the development of the graafian follicle, ovulation, and formation of the corpus luteum 

UTERINE CYCLE

it involves changing in the thickness of endometrium and menstruation  

MENSTRUATION

day 1 to 5 where uterus sheds endometrium

DEVELOPMENT OF GRAAFIAN FOLLICLE

day 1 to 13 where the pituitary gland secretes a hormone called FSH to stimulate the development of the primary follicle into graafian follicle

GRAAFIAN FOLLICLE

secretes a hormone oestrogen that stimulates the uterus to develop a lining of blood vessels called endometrium

OVULATION PROCESS

around day 14 rising levels of oestrogen stimulate the pituitary gland to secrete LH which causes follicle to burst and release mature egg into fallopian tube

OVULATION

the release off an egg by the graafian follicle

FORMATION OF CORPUS LUTEUM

day 15 to 28 where the corpus luteum releases a large amount of progesterone and some oestrogen which thicken the endometrium 

IN CASE OF NON FERTILISATION

corpus luteum slowly dies and progesterone levels levels decrease which causes the lining to fall away starting the new menstrual cycle 

ROLE OF OESTROGEN

• responsible for secondary characteristics in females

• repairs and builds endometrium 

• increases cilia movement which propels ovum towards tubes 

• high levels stimulate secretions of LH 

ROLE OF PROGESTERONE

promotes further thickening of endometrium

prepares endometrium for implantation of blastula 

maintains thickening of endometrium through gestation 

EMBRYONIC DEVELOPMENT

zygote - morula - blastula - embryo

IMPLANTATION

when the blastocyst reaches the uterus it becomes it becomes embedded into the wall of the uterus 

FUNCTION OF PLACENTA

• umbilical cord and placenta form a link

• placenta serves as an organ for gaseous exchange, excretion and nutrient supply 

• placenta serves as microfilter that prevents pathogens from  mother to child 

• placenta produces antibodies that provide passive immunity 

• placenta secrets hormone progesterone that helps maintain uterine wall while pregnant