sexual reproduction in humans Flashcards
male gametes
sperm cells
female gametes
egg cells
during ovulation
an egg moves into the oviduct
sperm cells are adapted by
- flagellum (a tail)
- contains enzymes in the head
egg cells are adapted by
- cytoplasm contains energy
- jelly like coating that changes after fertilisation
disadvantages of sexual reproduction
- takes energy and time to find a mate
- difficult for isolated members of the species to reproduce
advantages of sexual reproduction
- increases genetic variation
—> disease is less likely to affect the population
what is sexual reproduction?
- type of reproduction involving two parents
- involves the production of gametes by meiosis
- a gamete from each parents fuses to form a zygote
- genetic information mixes so each zygote is unique
What does haploid mean
Half the number of chromosomes as a normal cell - a gamete has this
name the four hormones involved in the menstrual cycle
- FSH (follicle stimulating hormone)
- Oestrogen
- LH (luteinising hormone)
- Progesterone
What is the role of follicle stimulating hormone
Where is it produced?
Produced in the pituitary gland
Causes an egg to mature in an ovary - stimulates the ovaries to release estrogen
Estrogen - produced where? The role
of it in the menstrual cycle?
Produced in the ovaries
Stops FSH from being produced (so that only one egg matures per cycle)
Repairs, thickens and maintains the uterus lining
Stimulates that pituitary gland to release LH
luteinising hormone - produced where? What is it’s function?
- produced in the pituitary gland
- triggers ovulation
Progesterone - function? Made where?
- produced in the ovaries
- maintains the lining of the uterus during the middle part of the menstrual cycle and during pregnancy
Where is testosterone produced (tip: look at the name)
Testes
What is puberty?
When secondary sex characteristic begin to develop
Secondary sex characteristic in boys only
- voice breaks and begins to deepen
- body becomes more muscular
- tested begin to produce sperm cells
- hair grows on face and body
Secondary sexual characteristics - boys and girls
- pubic hair grows
- underarm hair grows
- sexual organs grow and develop
Secondary sexual characteristics - girls
- Voice deepens gradually
- hips get wider
- breast develop
- ovaries start to release egg cells - menstruation starts
timeline of the menstrual cycle
DAYS 0-4 / MENSTRUATION = break down of uterus lining tissue
DAYS 4-14 / LINING BUILT BACK UP AGAIN = prepares the uterus lining for fertilisation as it implants there
DAY 14 / OVULATION OCCURS = egg released from the ovaries
DAY 14 - 28 / LINING MAINTAINED = fertilisation is able to occur
…with no egg, it starts over again; it breaks down again (stage 1)
…with an egg, pregnancy starts instead
Sperm duct
Sperm passes through this
Sex gland
Produced semen that contains sperm cells
Testis
Contained in scrotum - bag of skin
Produces sperm and testosterone
Penis definition
Passes urine and semen out of the body
Urethra
Tube inside the penis to carry urine or semen
A ring of muscle inside stops the two mixing
Vagina meaning
Muscular tube that leads to the inside of the body
