Reproduction (Humans) Flashcards
What is the prostate gland and its function?
- It is the circular gland under the bladder, attached to the sperm ducts
- It produces a fluid called semen providing sperm cells with nutrients
They perform this function alongside the seminal vesicles
What are the seminal vesicles and their function?
- They are the two small circular glands attached to the sperm ducts
- They produce a fluid called semen providing sperm cells with nutrients
They perform this function alongside the prostate gland
What is the function of the sperm duct?
It is for sperm to pass through from the testes and mix with the fluids produced by the glands before passing into the urethra
In men, what is the urethra and its function?
- It runs down the centre of the penis, and is connected to the bladder and the sperm duct
- It carrys and releases either semen or urine
- A ring of muscle in the urethra prevents the two from mixing
What are the functions of the testes?
- Produces sperm (the male gametes)
- Produces testosterone
What is the function of the scrotum
The sac supports the testes, keeping them outside the body as sperm production prefers a temperature of roughly 34 not 37
What are the functions of the penis?
- To pass urine out of the body
- To allow semen to be released inside of a womens vagina
What is the oviduct and its function?
- It is a tube connecting each ovary to the uterus
- It is lined with ciliated cells to push the ovum down
- Fertilisation occurs in the oviduct
What are the functions of the ovaries?
There are two ovaries
- They produce and contain ova
- They mature and release eggs when hormones are released
Ova is plural of ovum (the female gamete)
In women, what is the urethra and its function?
It connects the bladder and the hole, allowing urine to be released
The hole where urine comes out is seperate from the vagina
What is the uterus and its function?
It is a muscular bag, where the zygote (fertilised egg) implants itself to develop into a foetus
What is the cervix and its function?
- It is a ring of muscle at the lower end of the uterus, in between the vagina and the uterus
- It keeps the foetus in place during pregnancy
What is the vagina and its function?
- It is a muscular tube with an opening which leads to the uterus
- It is where the penis enters during sexual intercourse and deposits sperm
How long is the average menstrual cycle?
28 days
What happens on the first 5-7 days on the menstrual cycle if fertilisation of the oviduct did not happen?
Menstruation occurs, where the lining of the uterus is broken down in preperation for the next cycle which lasts 5-7 days
What happens between day 7 and day 14 of the menstrual cycle?
The uterine lining begins to thicken and is built up in preparation for possible zygote implantation
What happens on day 14 of the menstrual cycle?
Ovulation occurs
Ovulation is the release of the egg
What happens from day 14 to day 28?
The lining continues to build up and is maintained
If implantation occurs, the lining will stay, if not the cycle starts over again at day 28 with menstruation
How do oestrogen levels change during the menstrual cycle?
- Levels rise from day one (stimulated by FSH), and peak shortly before day 14 to stimulate LH (ovulation)
- They drop after ovulation, rise slightly to maintain the lining and then drop for menstruation
How do progestrone levels change during the menstrual cycle?
- Levels stay low from day 1-14
- They rise signifigantly once ovulation has occured, stimulated by LH, to maintain and thicken the lining, and then drop, causing menstruation
How do LH levels change during the menstrual cycle?
- Levels are low from day 1-12
- They rise at day 13, stimulated by oestrogen, and peak at day 14 for ovulation
- They then drop, and are low for the rest of the cycle as progestrone inhibits it
How do FSH levels change during the menstrual cycle?
- Levels are high between day 1-12 to mature the egg and stimulate oestrogen production
- Levels drop shortly before ovulation as oestrogen peaks
- They are low for the rest of the cycle as progestrone + oestrogen inhibit it to ensure only one egg is fully matured
What are the roles of oestrogen in the menstrual cycle?
- Stimulates the uterus to begin to build up a lining
- Stimulates the production of LH at its peak
- Inhibits FSH production to stop the maturation of another follicle
Oestrogen is produced in the ovaries
What are the roles of progesterone in the menstrual cycle?
- Maintains the lining of the uterus
- Inhibits the production of LH and FSH to stop the maturation and release of another egg past day 14
Progesterone is produced by the corpus leutem, which is a dead follice left behind after ovulation
What are the roles of FSH in the menstrual cycle?
- Causes an egg to mature inside a follicle in the ovaries
- Stimulates oestrogen production in the follice
FSH is produced in the pituitary glands
What are the roles of LH in the menstrual cycle?
- Causes ovulation to occur
- Stimulates progestrone production by causing the formation of a corpus leutum
LH is produced in the pituitary glands
What is the placenta?
- The placenta is an organ in the uterus which forms after implantation
- It connects the mothers blood to the umbilical chord which is connected to the foetuses blood
What are the roles of the placenta?
- It transmits nutrients and other important substances like oxygen and vitamins to the foetus by diffusion or active transport
- It absorbs waste products like urea and carbon dioxide by diffusion or active transport
- It acts as a barrier for toxins and pathogens, although it does not stop everything from getting through
What is the amniotic fluid and its role?
- It is a fluid in the uterus made from the mothers blood plasma held in by the amniotic sac
- It protects the fetus by cushioning it from bumps to the mothers abdomen
Which hormones control secondary sexual characteristics for each sex (changes which occur during puberty)?
Primary sexual characteristics are characteristics that are present at birth, like reproductive organs
- Testosterone for males
- Oestrogen for females
What are the secondary sexual characteristic changes for females which develop during puberty?
- Breasts develop
- Body hair grows
- Menstrual cycle begins
- Hips get wider
What are the secondary sexual characteristic changes for males which develop during puberty?
- Growth of penis and testes
- Growth of facial and body hair
- Muscles develop
- Voice breaks
- Testes start to produce sperm
