Chapter 16.4 Sexual Reproduction in Humans Flashcards
Name the parts of the male reproductive system and their functions
Testes: It is a male gland which produces sperm and testosterone
Scrotum: the sac which contains the testicles
Sperm Ducts: They are two muscular tubes, each connected to a testis. They carry the sperms from the testis to the urethra.
Prostate gland: It secretes a nutritive fluid to the sperm to form a mixture called semen
Urethra: A tube inside the penis which is the pathway of sperm and urine out of the body.
Penis: It’s the male sex organ which ejaculates semen into the vagina during sexual intercourse
Epididymis: Coiled tubes in which sperms are stored
Seminal vesicle: Another gland like the prostate gland. Also secretes nutritive fluid for sperms to feed from and swim in forming semen.
Name the parts of the female reproductive system and their functions
Ovary: contain follicles where eggs are produced
Oviduct: They are two tubes, one on each side connected to the ovary. They are where fertilisation occurs and they provide a passageway for the egg to reach the uterus by sweeping them by cilia on its walls.
Uterus: Where foetus develops
Cervix: Muscular tissue which separates the vagina from the uterus
Vagina: Receives the male penis during sexual intercourse
Name the gametes differences
Sperms are much smaller than eggs and are produced in much larger numbers
The tip of the cell carries an acrosome, which secretes enzymes capable of digesting a path into an egg cell, through the jelly coat, so the sperm nucleus can fuse with the egg nucleus.
The cytoplasm of the mid-piece contains a lot of mitochondria. They carry out respiration, which provides energy to make the tail move and propel the sperm forward.
Egg cell is much larger than sperms and only one egg cell is released each month while the woman is fertile.
It is surrounded by a jelly coat, which protects the contents of the cell and prevents more than one sperm from entering and fertilising the eggs.
The egg contains a large amount of cytoplasm, which is rich in fats and proteins. Fats act as an energy store, proteins are available for growth if the egg is fertilised.
What happens when the sperm nucleus enters egg?
When the sperm nucleus enters the egg, a chain reaction occurs. The cortical granules fuse together and release a chemical onto the jelly coat.
It forms a fertilisation membrane that hardens that cannot be penetrated by other sperms.
The sperm nucleus then fuses with the egg cell and fertilisation occurs. Zygote is formed.
Describe fertilisation in humans
The fusion of the nucleus of the male gamete with the nucleus of the female gamete, producing a new cell called the zygote. This then matures into the embryo.
What is the function of the umbilical cord?
connects placenta to embryo, in which nutrients and oxygen pass from placenta to foetus and waste products and carbon dioxide move the other way.
What are the functions of the amniotic sac and amniotic fluid?
Amniotic sac produces amniotic fluid.
Amniotic fluid surrounds and protects the developing embryo
What is the function of the placenta?
The placenta, connected by the umbilical cord, develops from the embryo.
It anchors embryo in uterus and allows:
-nutrients and oxygen to move from mother to embryo.
-waste materials and carbon dioxide to move the other way.
The mother and embryo’s blood doesn’t mix. Materials pass through diffusion/active transport depending on the nutrient.
- placenta can prevent some harmful substances from mother reaching embryo (except alcohol, nicotine, pathogens like HIV and rubella virus)
- placenta produces hormones (progesterone and oestrogen) which keep uterus in good condition and simulate milk producing hormones.
Describe the antenatal care of pregnant women
Antenatal care is the way a woman should take care of herself during pregnancy so the birth is safe and her baby healthy.
- Eat properly, intake of more iron and folic acid (a vitamin) to prevent anaemia
- Refraining from drinking and smoking because it can cause low birth weights of the baby. Babies with low birth weights tend to be more prone to disease.
Describe the process of labour and birth
- amniotic sac breaks
- amniotic fluid is released
- contractions of uterus
- cervix dilates
- baby passes out of the vagina
- tying and cutting of the umbilical cord
- delivery of placenta
Pros and cons of breast feeding
pros: no cost/preparation no preservatives/additives no allergy risk has antibodies; no bacteria builds mother-child bond correct proportion of food correct temperature breastfeeding stimulates reduction of uterus size cons: may be painful damage beauty mother always has to be present
Pros and cons of formula milk
Pros:
Less painful
Anyone can feed the child
May contain supplement vitamins, minerals
Cons:
Expensive
Risk of wrong formula
More likely to develop illness
Describe the role of testosterone in developing 2ndary sexual characteristics
Testosterone is produced by the testes
These control the development of male secondary sexual characteristics
The pituitary gland releases hormones that stimulate the adrenal glands and testes to release hormones that stimulate:
- Facial and underarm hair growth
- Pubic hair growth
- Larynx enlargement
- growth of penis and testes
- beginning of ejaculation
Describe the role of oestrogen in developing 2ndary sexual characteristics
Oestrogen is produced by the ovaries
It controls the development of the female secondary sexual characteristics
The pituitary gland releases hormones that stimulate adrenal glands and ovaries to release hormones that stimulate
- underarm growth
- development of breasts
- enlargement of uterus
- beginning of menstruation
- Pubic hair growth
Describe the menstrual cycle in simple terms
ovaries release an ovum once every approximate four weeks
uterus lining builds up for embryo implantation
if no implantation occurs, the uterus lining breaks down (cells and blood is passed out) this is the menstrual period.
