Biology π | Human Reproduction | 16.2 Flashcards
I PROMISE YOU THE REPRODUCTION DECK HAVIGN EXACTLY 69 FLASHCARDS WAS AN ACCIDENT
What is the testes?
The organ containing many coiled tubes which produce sperm, the cells inbetween producing testosterone.
What is the scrotum?
The protective bag around the testes
What are the sperm ducts?
The tubes through which sperm cells travel out of the testes, into the urethra
What is the prostrate gland?
The gland close to the bladder which secretes seminal fluid which sperm swim in
What is the urethra?
The tube leading from the bladder to the outside
What is the ovary in humans?
The organ containing follicles containing egg cells, and producing progesterone, and oestrogen
Where is progesterone produced?
In the ovaries
What is the oviduct / fallopian tube?
The tube from the ovaries to the uterus, which carries an ovum
What is the uterus?
The organ where the embryo develops (and fetus)
What is the cervix?
The lower neck of the uterus, a strong rigid muscle, covered in mucus, which has a small opening
What is the penis?
The male sex organ which transfers semen
What is the vagina?
The female sex organ which recieves the penis during intercourse and is a way out for a baby during birth.
What are the adaptive features of a sperm cell?
- A flagellum for swimming
- Many mitochondria for energy
- Has enzymes in the acrosome
What is the acrosome?
The head of a sperm containing enzymes used for the digestion of outer layers of the egg cell
What are the adaptive features of an egg cell?
- Yolk: A cytoplasm containing an energy store
- Jelly-like coating that changes after fertilisation
How is an egg cellβs changing jelly-like coating important?
It forms an impenetrable barrier after fertilisation to prevent other sperm enterring the egg cell
How large are sperm cells?
Very small (45 um)
How large are egg cells?
Large (0.2mm)
How does motility vary between egg and sperm cells?
Sperm are capable of locomotion, egg cells are not capable of locomotion
How high in number are sperm cells?
Very high, produced every day in huge numbers
(100 million)
How high in number are ovaries?
Thousands of immature eggs in ovaries, only one released a month
How does a zygote form into an embryo?
Cells multiply, until a ball of cells called an embryo is created and it implants into the uterus lining
What is the function of the umbilical cord?
Joins fetusβs blood supply to the placenta for exchange of nutrients and removal of waste products
What is the function of the placenta?
- Anchoring the embryo to the uterus wall
- Allowing nutrients and oxygen to travel from mother to embryo
- Allowing waste materials and carbon dioxide to travel from embryo to mother
What is the function of amniotic fluid?
Protects fetus against mechanical shock, drying out and temperature fluctuations.
What is the function of the amniotic sac?
The membrane which encloses amniotic fluid, broken at birth
How can the fetus be negatively affected?
Sometimes, pathogens and toxins can pass across the placenta and affect the fetus
What are secondary sex characteristics?
The changes that occur during puberty as children become adolescents
What are primary sexual characteristics?
Characteristics present at birth and required for reproduction
What hormone causes the development of secondary sex characteristics in males?
Testosterone
What hormone causes the development of secondary sex characteristics in females?
Estrogen
What are the female secondary sex characteristics?
- Breasts develop
- Body hair grows
- Menstural cycle begins
- Wider hips
What are the male secondary sex characteristics?
- Growth of penis and testes
- Growth of facial and body hair
- Muscle development
- Voice breaking
- Production of sperm begins
Define menstrual cycle
The monthly series of changes a womanβs body goes through in preparation for the possibility of pregnancy, involving an ovulation each month
How long is the menstrual cycle?
28 days long
When does ovulation happen in the menstrual cycle?
Halfway through - on day 14
What does failure for the egg to be fertilised cause?
Menstruation
What is menstruation?
The breakdown of the thickened uterus line to get rid of an egg cell
What happens between days 1-5 of the menstrual cycle?
Menstruation:
- If the egg isnβt fertilised, the uterus lining is shed as it isnβt needed
What happens between days 6-10 of the menstrual cycle?
Regrowth:
- The uterus lining regrows, readying for a potential pregnancy
What happens between days 11-14 of the menstrual cycle?
Ovulation:
- The most mature folicle bursts. An egg is released and the woman is fertile for a few days
What happens between days 15-28 of the menstrual cycle?
Thickening:
- Uterus remains thick and ready for a potential pregnancy
What is the function of oestrogen in the menstrual cycle?
- Repairs endometrium
- Inhibits LH and FSH (after ovulation)
Where is oestrogen produced?
Ovaries
What is the function of progesterone in the menstrual cycle?
- Keeps endometrium thick
- Prevents follicular stimulation and ovulation
Where is progesterone released in the menstrual cycle?
In the ovaries, by the corpus lutenum after bursting
What does LH stand for?
Lutenising Hormone
What does FSH stand for?
Follicle stimulating hormone
What is the function of LH in the menstrual cycle?
When LH levels are at their peak, it causes ovulation of the most mature ovum, and the formation of a corpus lutenum in its place
Where is LH released?
Pituitary gland
What is the function of FSH in the menstrual cycle?
- Stimulates egg maturation in ovaryβs follicles
- Stimulates follicles in the ovary to secrete oestrogen
Where is FSH released?
Pituitary gland
During days 1-13 of the menstrual cycle, what is happening in the ovaries?
Eggs are developing in growing follicles
On day 14 of the menstrual cycle, what happens in the ovaries?
The most mature folicle releases an egg
During days 15-28 of the menstrual cycle, what happens in the ovaries?
The empty folicle turns into a corpus lutenum. Continued growth
How do levels of FSH change in the menstrual cycles?
It stys fairly constant, but peaks around day 14 at ovulation
How do levels of LH change in the menstrual cycle?
It peaks around day 14 at ovulation
How do levels of oestrogen change in the menstrual cycle?
It continually increases from day 1-14, peaking at day 14 (ovulation), then dropping and returning to a fairly average level.
How do levels of progesterone change in the menstrual cycle?
It increases slowly from days 1-14, until it reaches a plateau between days 14-24, until dropping.
Define STI
An infection that is transmitted through sexual contact
What does STI stand for?
Sexually Transmitted Infection
What does HIV stand for?
Human Immunodeficiency Virus
What is HIV?
An pathogen that causes an STI, infecting lymphocytes
What type of white blood cell does HIV target?
Lymphocytes
How does HIV avoid being recognised by lymphocytes?
It repeatedly changes its protein coat
What condition can HIV lead to?
AIDS
What is AIDS?
When our body doesnβt have enough lymphocytes and thus cannot produce many antibodies to protect against infection.
What are the methods of transmission of HIV?
Sexual intercourse, Sharing needles with an infected person, Blood transfusions with infected people, From mother to fetus by placenta, From mother to baby by breastfeeding
How can we control the spread of STIs such as HIV?
- Limiting the number of sexual partners an individual has
- Not having unprotected sex, but making sure to always use a condom
- Getting tested if unprotected sex or sex with multiple partners has occurred
- Raising awareness by education programmes
