sexual reproduction

PUBERTY

Changes in female

CHANGES IN MALE

• shoulders widen
• facial hair develops
• breasts develop slightly
• muscles get bigger and stronger
• penis gets longer and wider
• testes enlarges
• gets erections
• adams apple gets more prominent

Changes in both sexes

• acne for some
• growth spurt
• gain weight
• armpit hair growth
• pubic hair growth
• emotional changes

reproduction

female gametes

• size: diameter = 120 micrometers
• number: 1
• motility: non-motile, moved through fallopian tube by cilia and peristalsis

male gametes

• size: 2.5 micrometers (head of sperm)
• number: millions (40 million)
• motility: motile, has tail/flagellum to swim towards egg for fertilisation

Female reproductive system

pregnancy

amnion

• consists of the amniotic cavity, amniotic sac (membraneous sac) and amniotic fluid
• functions:
• allows fetus to move freely
• lubrication so that fetus' fingers and toes don't grow together
• support and cushions fetus against mechanical shock
• allow fetus to practice using digestive and urinary systems (when fetus swallows amniotic fluid)

amniocentesis

• process:
• hypodermic needle is inserted into womb to collect amniotic fluid
• function:
• amniotic fluid contains cells of fetus
• thus can observe pairs of chromosomes to test for genetic diseases
• eg. if have one extra chromosome, trisomy 21, will have down syndrome
• can also check for gender, if have x and y chromosomes, boy, if have two x chromosomes, girl

amniocentesis

• precautions:
• needle must be sterile and preferably new, never used before
• room must be sterile
• doctor must have washed hands, wear surgical gown, hat, gloves
• skin at site of entry of needle must be swabbed with iodine
• insert needle carefully

menstruation

menstruation days

• days 1-5 >> menstrual flow stage
• days 6-13 >> follicle stage
• day 14 >> ovulation
• oestrogen levels highest >> day 10
• progesterone levels highest >> day 16
• fertile period >> day 11-16
• corpus luteum stage >> 15-28

menstruation process

• endometrium is shed
• pituitary gland produces follicle-stimulating hormone (FSH) causing primary follicle to develop and grow into secondary and Graafian follicle
• secondary and Graafian follicle produces oestrogen which feedbacks to pituitary gland to stop producing FSH so that no other follicles grow and mature
• oestrogen also repairs and thickens uterine lining to prepare it for pregnancy
• oestrogen also stimulates pituitary gland to produce luteinising hormone (LH)
• luteinising hormone triggers ovulation, which is the release of the ovum from ovary at around day 14.
• luteinising hormone also causes whats left of Graafian follicle to develop into corpus luteum
• corpus luteum produces progesterone and a little oestrogen
• progesterone inhibits the production of LH, which causes corpus luteum to break down and levels of progesterone and oestrogen in blood to