UNIT 3 CHAPTER 42-HUMAN REPRODUCTION Flashcards
what is ejaculation ?
it is the release of semen from the penis
what is a gonad ?
it is an organ that produces sex cells in animals
what are secondary sexual characteristics ?
they are those features that distinguish males from females, apart from the sex organs themselves
what is infertility ?
it is the inability to produce offspring
what is ovulation ?
it is the release of an egg from the ovary
what is the menstrual cycle ?
it is a series of events that occurs every 28 days on average in the female if fertilisation has not taken place
what is insemination ?
it is the release of semen into the vagina, just outside the cervix
when does fertilisation occur ?
it occurs when the nucleus of the sperm fuses with the nucleus of the egg, forming a diploid zygote.
what is birth control ?
it refers to methods taken to limit the number of children that are born,
examples:
abortion and contaception.
what is abortion ?
it is the termination of a pregnancy .
what is contraception ?
it is the deliberate prevention of fertilisation or pregnancy . there are 4 types: -natural -mechanical -chemical -surgical
what is implantation ?
it is the embedding of the fertilised egg into the lining of the uterus.
what is a morula ?
it is a solid ball of cells formed from a zygote by mitosis
what is a blastocyst ?
it is a hallow ball of cells formed from a morula.
what are germ layers ?
they are basic layers of cells in the blastocyst from which all adult tissues and organs will form.
what is gestation ?
it is the length of time spent in the uterus from fertilisation to birth.
what is lactation ?
it is the secretion of milk by the mammary glands(breasts) of the female.
what do the testes do ?
the testes produce sperm and testosterone
what do sperm ducts do ?
they carry sperm to the urethra in the penis.
what does testosterone do ?
testosterone causes:
- the primary male characteristics (growth of the penis and descent of the testes from the body cavity),
- the secondary male characteristics (increased body hair, enlargement of the larynx, muscle and bone growth).
what are the average events of the menstrual cycle ?
~Days 1-5= Menstruation (loss of endometrium), meiosis occurs in the ovary, forming a new egg in the Graafian follicle.
~Days 6-14= The endometrium thickens (due to oestrogen).
~Days 14= Ovulation (i.e, an egg is released from the Graafian follicle in the ovary).
~Days 14-28= The endometrium continues to develop; the egg dies by day 16 if it is not fertilised .
what are fibroids ?
they are benign tumours of the uterus.
how are fibroids treated ?
they are not treated if they are small but if they are big then they can be surgically removed.
what does the placenta do ??
it separates the blood of the embryo and the mother.
what are the functions of the placenta ? (in reference to the exchange of materials).
~oxygen, food, antibidies, drugs, some hormones and micro-organisms entering the embryo.
~carbon dioxide, salts, and urea entering the mother.
