[BIO] Chapter 16 - Reproduction in Humans

© Hee Xin Wei (Copyrighted) Topic 16: Reproduction in humans

Chapter Analysis FOCUS EXAM WEIGHTAGE •Constitute to around 6.5% in Paper 2 in the past 5 years •commonly tested in MCQ and structured questions •tested once in section B in the past 5 years •straightforward chapter •linked to homeostasis & hormones

male reproduction system female reproduction system Key Concept

Testes •Produces sperms (male gametes) •Produce male sex hormones e.g. testosterone. Male sex hormones are responsible for development and maintenance of secondary sexual characteristics. Epididymis Where sperms are stored Scrotum •Testes are held in the scrotum, which are pouch-like sac outside the body •This allows the scrotum to be at a lower temperature than body temperature, which is essential for sperm production. Sperm ducts / Vas deferens Transport sperm from the epididymis to the urethra. Prostate gland •Together with Seminal vesicle and Cowper’s gland/Bulbourethral gland, these 3 glands secrete fluid that is mixed with sperms to make semen •The fluids contain nutrients and enzymes which nourish and activate the sperm, allowing them to swim actively. Urethra •Urethra is a tube which passes from the bladder •passage for urine and semen to pass out of the body Penis •Penis is an erectile organ, containing erectile tissue, which allows the spaces within the tissue to be filled up with blood. •When filled with blood, the penis becomes erect and hard, allowing it to enter the vagina of a woman during sexual intercourse to deposit semen. male reproductive system

sperm cell Head •The head is about 2.5 μm wide. •It contains a large nucleus with small amounts of cytoplasm. The nucleus carries a haploid number of chromosomes. •Acrosome is a vesicle containing enzymes. The enzymes break down part of the egg membranes so that the sperm can penetrate the egg during fertilisation. Middle piece •The middle piece contains numerous mitochondria, which provides energy for the sperm to swim towards the egg. Tail (flagellum) •It carries out beating movement to swim towards the egg

female reproductive system Ovaries •Produces ova (S:ovum), female gamete •Produce female sex hormones e.g. estrogen and progesterone. Female sex hormones are responsible for development and maintenance of secondary sexual characteristics. Oviducts / Fallopian tubes •Narrow muscular tube where ovary releases the ovum into and leads to uterus •Cilia on the inner lining help move the ovum to the uterus. •Where fertilisation happens Uterus •The uterus is a thick muscular organ. •The uterus is lined by uterine lining or endometrium •The endometrium is richly supplied with blood vessels. -It is broken down every month and flows out of the body in the process called menstruation. -It is the site of implantation of the embryo post-fertilisation. •Uterus is where foetus develops during pregnancy Cervix •The cervix is a circular ring of muscle that open