Chapter #15 - Reproduction In Humans Flashcards
Uterus
womb - the organ in which a fetes develops before birth.
What are the charectaristics of the uterus
- It has thick walls made of muscle
- It is small (about the size of a clenched fist) but it stretches during pregnancy
Cervix
A narrow opening leading from the uterus to the vagina
Vagina
opening from the uterus to the outside of the body where sperm is deposited
Ovaries
organs that produce female gametes (eggs)
Oviducts
Fallopian tubes – lead from the ovaries to the uterus. (They don’t connect directly but they are very close).
Where are the urethra and rectum located?
The urethra is a tube that is in front of the vagina, while the rectum is just behind it.
Are the urethar and rectum part of the reproductive system?
NOOOOO!!!!!!!!!!!!!!
X = testes
W = scrotum
V = sperm duct
Y = penis
T = prostate gland
Z = urethra
S bladder
Testes (singlular = testis)
organs in which the male gametes (sperm) are created. The testes are outside the body inside the scrotum.
Srotum
the sac that contains the testes.
Sperm duct
a tube that transports sperm from the testis to the urethra.
Penis
organ containing the urethra, through which urine and sperm are carried outside of the body (at different times).
Prostate gland
organ that produces fluid called semen that is filled with nutrients for the sperm. The fluid also transports the sperm.
Where and when are eggs formed?
Eggs begin to be formed inside a girl’s ovaries before she is born.
What is the state of a female’s eggs at birth?
At birth, a female has thousands of partially developed eggs in her ovaries.
What happens to a female’s eggs at puberty?
At puberty, some eggs mature, usually one at a time.
What is the diameter of an egg cell?
0.1mm
What happens when the egg is fully developed?
When the egg is fully developed, it bursts out of the ovary and into the funnel at the end of the oviduct.
Ovulation
When thee egg is fully developed and it bursts out of the ovary and into the funnel at the end of the oviduct. Takes place once a month.
What are the stages of the menstrual cycle?
- Menstruation (day 1 -5)
- Most fertile days (day 11 - 13)
- Ovulation (day 14)
- Could still be fertile after ovulation (day 15 -16)
- repeate
Lable this diagram of the male gamete
Where are the sperm made within the male gamete?
Inside the testis, in many coled tubes & tubules. Sperm are created from cells in the walls of these tubules.
Where are sperm stored one they are made?
The epididymis
Epididymis
Where sperm are stored
How oftem are sperm made?
They are made continually from puberty onwards.
Draw a labled diagram of a sperm
Acrosome
A vesicle containig enzymes, to dissolve a way through the jelly surroundidn the egg cell
Why are the testes positioned outside the body?
Sperm production is very sensitive to heat.
If the sperm get too hot, cells in the tubules will not develop into sperm.
What adaption ensures the production of sperm?
The testes are positioned outside the body to ensure sperm do not get too hot.
Semen
The fluid containing sperm
What is the fluid containing sperm called?
Semen
How is semen produced?
By the prostate gland
Where is semen deposited after ejaculation?
At the top of the vagina, near the cervix.
What happens during sexual intercourse in terms of sperm release?
During sexual intercourse, sperm is ejaculated (released from the penis) into the vagina.
What occures during ejaculation?
During ejaculation, muscles contract rhythmically, starting from the testes, along the sperm ducts and through thepenis. This wave pushes the sperm out of the male’surethra.
What is the process of fertilisation in eggs?
- After egg is released in oviduct, it slowly starts to travle towards the uterus
- Cilia lining oviduct help it move
- For fertilisation to take place, a sperm must swim up to reach the egg in the oviduct.
- If the egg is not fertilised between 8-24 hours after ovulation, it dies.
How does the cilia help the egg move towards the uterus?
The cilia, lining the oviduct helps move the egg cell by producing ripple movements.
How does sperm move?
It swims using flagellum and energy released in the mitochondria
What are the steps leading to a sperm fertilising an egg ?
1.Sperm are left in the top of the vagina
2.Sperm swim htough the uterus and into the oviduct
3.If there is an egg in the oviduct, it will be fertilised
How many sperm are deposited in the vagina?
About one million sperm
How fast do sperm generally swim?
about 5mm per minute (it takes a while to get to the oviduct)
What happens when the sperm comes into contact with the jelly coat around an egg?
- The acrosome is activated
- Acrosome releases digestive enzymes that digest the jelly coat
- Then, the head of the sperm can push through the cytoplasm(only the headgoes in, not the flagellum).
- The nucleus of the sperm fuses with the nucleus of the egg. This is fertilisation.
- After one sperm has entered the egg, the egg’s membrane and jelly coat become impenetrable.
- Unsuccessful sperm will die
What do a fused sperm and egg nucleus form?
A zygote
What are the stages leading to implantation?
- Ovulation.
- Fertilisation
- The zygote divides
- A ball of cells is formed
- Cells in ball keep dividing snd forms an emryo
- Implantation
What happens during ovulation?
A mature follocle bursts, and releases an egg in the oviduct.
Implantation
When the embryo sinks into the spongy, thick lining of the uterus.
How is an embryo formed?
After several hours that the egg has been fertilised and the zygote is dividing.
What are the stages between the formation of an embryo and implantation?
- After a few hours the zygote is a ball of cells =embryo.
- The embryo gets nutrients from theyolk of the egg.
- After several hours the embryo reaches the uterus. By then it consists of 16 or 32 cells.
- The embryo sinks into the spongy, thick lining of the uterus. This is implantation
Placenta
An organ that connects the growing fetus to its mother, in which the blood of the fetus and mother are brought close together so that materials can be exchanged between them.
What are the fetures of the placenta?
- soft
- red
- has villi that fit closley into the uterus wall
Label the digram of the placenta
When is a human fetus formed?
After 11 weeks
What does the umbilical chord do?
It joins the placenta to the fetus
Inside the umbilical chord are:
Two arterise and one vein
The arteries take blood from the fetus into the placenta, and the vein returns blood to the fetus
Fetus
an unborn mammal in which all organs have been formed
What is the structure of the placenta in terms of blood supply?
The placenta contains capillaries filled with the fetus’ blood, and the lining of the uterus has large spaces filled with the mother’s blood. The fetus’ blood and mothers’ blood do not mix.
How are nutrients exchanged from the mother to the fetus?
- Oxygen and other dissolved nutrients move across the placenta from mother to fetus.
- They are carried along the umbilical cord to thefetus.
- Carbon dioxide and other excretory productsmove across the placenta from fetus to mother’s blood.
What unwanted toxins could pass through the placenta?
- alcohol
- carbon monoxide
- pathogens
Amniotic sac
A strong membrane which surrounds the the fetus
Amneotic fluid
A liquid created by the mother that helps to support the embryo abd protect from mechanical injury (mother originally makes fluid but after 20 weks the fluid is mainly urine from the fetus).
What is a sighn that a women is a about to give birth?
Contractions, causing the amniotic sac to break, releasing the fluid
Lable this diagram
Adolescence
when a person is approaching sexual maturity.
What chages take place in males due to hormones?
Quantity of testosterone secreted in testis increases which causes seconday sexual charectaristics such as:
* facial hair
* pubic hair
* growth
* broadening shoulders
* deeper voice
* muscle developement
* etc.
What changes in females take place due to hormones?
Oestrogen is secreted by ovaries causing:
* breasts to grow larger
* pubic hair growth
* hips become wider
Puberty
The point at which sexual maturity is reached
I an individual an adult after puberty?
No, there are still changes and developments happening in the brain.
Where do eggs develop?
Eggs develop in small structures called follicles – inside the ovaries.
What changes occur in the uterus before the egg is released?
- Before the egg is released, the lining of the uterus becomes thick and spongy – ready to receive a zygote.
- The lining becomes more vascular
What happens if an egg is not fertilised?
= the spongey lining is not needed. It is broken down and slowly lost through the vagina = menstruation / period.
A period usually lasts about 5 days. Then the cycle repeats.
What is a corpus luteum?
What the follicle turns into after ovulation if it is not fertilised.
What hromones are involved in the menstrual cycle and what are they secrete by?
Describe the steps of the menstrual cycle regarding the hormones.
- FSH causes a follicle to develop in the ovary, with a developing egg cell inside it.
- The developing follicle secretes oestrogen, which causes the thickening of the uterus lining.
- When the follicle is fully developed there is a surge of LH. This causes ovulation.
- After ovulation, oestrogen levels fall.
- The follicle develops into
acorpusluteum. This secretes progesterone,which keeps the uterus lining thick andspongy. - Increase in progesterone inhibits the pituitary gland, decreasing LH and FSH.
-
If egg is not fertilised →corpus luteum breaks down →progesterone levels decrease→menstruation.
(Then FSH and LH can increase again and restart the cycle)
If egg is fertilised →progesterone levels stay high, because the corpus luteum remains in the ovary.
* Uterus lining stays thick and healthy for implantation
* Once placenta has developed,it takes over the role of secreting progesterone. (This continues throughout pregnancy).
So, while pregnant, no FSH and LH are produced… hence no other follicles develop.
Draw diagram to show the development of an ovary
Draw a graph to compare the conc of LH and FSH over a month.
Draw a graph to represent the levels of oestrogen and prgesterone levels over a month.
Draw a diagram to represent the uterus wall over the period of a month
What is the difference between infectiona and disease?
Wether the person has any symptoms. Even without symptom, the infection can be passed on to another person.
What does AIDS stand for?
Acquired Immune Deficiency Syndrome
What are AIDS caused by?
They are caused by HIV
What does HIV attack?
HIV infects specific white blood cells called Tcells
T Cells
They are white blood cells which are normally our strongest defence against viruses.
How does HIV affect our immune system?
- Overtime, HIV slowly destroys T cells.
- After several years of havingHIV, levels of T cellsare so low that they are unable to fight offpathogens effectively (including HIV).
How long does a person have HIV before they develop symptoms of AIDS
About 10 years
What are the affects of AIDs?
- become very vulnerable to other infections, like pneumonia
- maydevelop cancer,because the body can’t protectitself properly
- brain cells can become damaged
- usually dies from a collection of several illnesses
What are the different treatment methods for HIV?
- antiretrovirals
- vaccines (in development)
How do antiretrovirals help treat HIV?
The stop the virus from multiplying inside a person’s cells
Where can HIV not survive?
HIV cannot survive outside the human body. It is a fragile virus (more so than the flu or COVID).
How can HIV not be transmitted?
- talking
- normal contact
- drinking from the same cup
- etc.
How and why is HIV transmitted through sexual contact?
- HIV can survive in the fluid in the vagina, rectum and urethra.
- These fluids come into contact during sexual intercourse.
- The more sexual partners a person has = the greater chance of HIV.
What are the best ways to avoid getting HIV through sexual contact?
- Not having more than 1 sexual contact (if all did this, it would stop the spread completely)
- Use a condom (although not complete protection)
- Getting testedfor STIs to know if one is contracted, then doctors will try to trace whoit come from / where it could have been passed on to.
What are the best ways to avoid getting HIV through blood contact
- Making sure people who donate blood are tested fro HIV
- If a mother is known to have HIV and is giving birth, there is a risk of the child getting HIV when it comes in contact with the mother’s blood during childbirth. To reduce this risk antiretrovirals can be taken)
- Any hyperdoodermic nedle should be sterilised.
- If helping someone who is bleeding, protective clothing or barrier should be used.
What are examples of how HIV be transmitted through blood?
- In the 70’s and 80’s, before knowing this, blood transfusions may have contained HIV. Now, all blood is screened/tested.
- During childbirth when the blood of mother comes into contact with the baby, HIV can be passed on.
- Through shared use of a hypodermic needle.
How can HIV be tranmitted through breast feeding?
If a mother is HIV positive, the virus can get into her milk and be passed on to her baby.
How can you prevent HIV being transmitted through breast feeding?
The risk is reduced if the mother takes antiretroviralsduringpregnancy and breast feeding.
