Human Reproduction Flashcards
Name the two functions of the testes
- to produce millions of male gametes (sex cells) called sperm
- to make male sex hormones, which affect the way a man’s body develops
Where are the testes contained
The scrotum
Where does the sperm pass through
The sperm pass through the sperm ducts
What does the sperm mix with?
The sperm mixes with fluids produced by the glands
What is the function of the fluid in the glands?
The fluids provide the sperm cells with nutrients.
What is the mixture of sperm and fluids called?
Semen
What is the urethra
The urethra is the tube inside the penis that can carry urine or semen.
Name the 5 parts of the female reproductive system
oviducts ovaries uterus cervix vagina
Name the 5 parts of the male reproductive system
glands sperm ducts urethra penis testes
What are gametes?
sex cells
What are female gametes called and where are they stored?
The two ovaries (one of them is called an ovary) contain hundreds of undeveloped female gametes (sex cells).
What is the technical term for egg cells?
Ova
What connects the ovary to the uterus?
Each ovary is connected to the uterus by an oviduct.
What is the uterus?
The uterus, also called the womb, is a muscular bag with a soft lining. The uterus is where a baby develops until its birth.
What is the cervix?
The cervix is a ring of muscle at the lower end of the uterus. It keeps the baby in place while the woman is pregnant.
How long is the typical menstrual cycle?
28 days
Why does bleeding occur on the first day of the menstrual cycle?
This is caused by the loss of the lining of the uterus, with a little blood.
What happens in the menstrual cycle when bleeding stops?
The lining of the uterus begins to re-grow and an egg cell starts to mature in one of the ovaries.
Describe the process of ovulation
At about day 14, the mature egg cell is released from the ovary. This is called ovulation. The egg cell travels through the oviduct towards the uterus.
What happens in the menstrual cycle if fertilisation does not occur?
If the egg cell does not meet with a sperm cell in the oviduct, the lining of the uterus begins to break down and the cycle repeats.
Describe the process of fertilisation
Fertilisation happens if the egg cell meets and joins with a sperm cell in the oviduct. The fertilised egg attaches to the lining of the uterus. The woman becomes pregnant, the lining of the uterus does not break down and menstruation does not happen.
Which way does the following substance pass between the baby and mother: poisons from cigarette smoke
passes from the mother’s blood to the baby’s blood
Which way does the following substance pass between the baby and mother: oxygen
passes from the mother’s blood to the baby’s blood
Which way does the following substance pass between the baby and mother: digested food
passes from the mother’s blood to the baby’s blood
Which way does the following substance pass between the baby and mother: carbon dioxide
passes from the baby’s blood to the mother’s blood
Through which part is food passed from the mother to the baby?
placenta
Name one useful substance, other than food, which passes from the mother to the unborn baby
oxygen
Explain why the mass of the placenta increases as the foetus develops
The foetus needs more blood, oxygen and food as it develops
Why do pregnant women need to have extra iron in their diet?
They have extra red blood cells
When a pregnant woman breathes in cigarette smoke, carbon monoxide gas combines with some of her red blood cells. How could this harm the foetus?
The foetus will not get as much oxygen as it needs.
The testes are outside the main part of the body. Suggest the relationship between temperature and sperm production.
Sperm needs to be at a certain temperature to be created (35 degrees centigrade)
Where are hormones produced in males?
Testis
What changes do hormones cause in males during puberty?
- The voice deepens
- Testes start to make sperm
- Shoulders broaden
- Hair grows on face and chest
- Sex organs get bigger
- A growth spurt occurs
- Pubic hair grows.
How many sperm are typically released during sexual intercourse?
Around 250 million
Why is it necessary that so many sperm are released during sexual intercourse?
It increases the chance of one of them reaching the egg.
Before being released from the body, the sperm are mixed with a fluid containing sugar. Explain how and why the sperm makes use of the sugar.
The sperm needs enough energy from the sugar to win the race to the egg. It uses the sugar by swimming to the egg.
What is inside the head of the sperm?
The nucleus containing DNA
What is meant by the term “gestation period”?
The length of time between fertilisation and birth. In general the larger the animal the longer the gestation period.
What is the typical gestation period in humans?
40 weeks
Where are the mitochondria stored in sperm and what is their function?
Mitochondria are stored in the “middle piece” of the sperm. They contain lots of energy to win the race.
What is the function of cytoplasm in the egg.
The cytoplasm has lots of food to start the growth of the embryo
What changes to hormones cause to females during puberty?
- Breasts develop
- Ovaries start to release egg cells (the menstrual cycle starts)
- hips get wider
- A growth spurt occurs
- Pubic hair grows.
What is a zygote?
A zygote is the union of the sperm cell and the egg cell
What is the term for when the sperm leaves the penis?
Ejaculation
What is adolescence?
The period of life between childhood and adulthood
What is puberty?
The time when sex organs begin to work
How many days does the egg last for after ovulation has occurred?
3 days
What is the name of the hormone produced in the ovary?
Oestrogen
What is the name of the hormone produced in the testes?
Testosterone
What is FSH and what does it do?
FSH is a hormone produced in the pituitary gland which matures the egg in the ovary.
What does Oestrogen do?
It causes the uterus lining to be built and it responds to the pituitary gland
What does the hormone LH do and where is it released from?
It is released from the pituitary gland and causes the egg to be released
What is progesterone and where is it released from?
It is a hormone released from the ovary which maintains the uterus lining.
What happens after the egg is fertilised?
The fertilised egg implants to the thick lining of the uterus. It divides and the cells start to specialise.
What position should the baby be in before birth?
Before birth, the baby usually turns itself round so that his/her head lies above the cervix.
What water breaks before the baby is born?
The amniotic sac breaks and the amniotic fluid escapes before the baby is born.
What does the mother feel which signals that the baby is due to be born?
Contractions. The muscles of the uterus wall contracts to push the baby out.
What is the placenta and what happens to it after birth?
The placenta connects the developing foetus via the umbilical cord to the uterine wall. After the baby is born the placenta comes away from the uterus wall, this is pushed out as “afterbirth”.
