Flashcards in Reproductive System Deck (392)
What are the benefits of sexual reproduction?
Production of new individuals and mixing of genotypes to create genetic diversity.
Why is infertility becoming more common?
Cigarette smoking (can cause erectile dysfunction and poor sperm)
Increasing age at childbearing
How many couples does infertility affect?
1 in 7
Name two assisted reproductive techniques (ART). What percentage of babies born in most Western countries are by ART?
In vitro fertilisation (IVF)
Intracytoplasmic sperm injection (ICSI)
Describe the production of spermatozoon and the fertility in males over life.
Describe the fertility of females over their lifetime.
Constant production at ~300 million per day from puberty.
Constant fertility. Gradual decline with age.
Cyclical fertility from puberty, 3-5 days per month.
Compare the number of follicles in utero and the number that will be ovulated.
In utero, 7 million follicles, declining to near zero at menopause, only ~400 follicles will be ovulated.
Compare the sizes of sperm and eggs.
Sperm: smallest cell in the body
Egg: largest cell in the body
What is the rate of production of sperm per testicle? Compare the weights of sperm and eggs.
1500 per second per testicle
175,000 sperm weigh as much as one female egg.
How far must sperm swim to reach the egg?
List the endocrine glands controlling the reproductive processes. What happens with regard to the endocrine system when puberty starts?
- Hypothalamus, pituitary, adrenal glands, testes and ovaries
- Activation of the hypothalamic-pituitary axis and production of hormones.
What are the two main functions of the gonads?
Produce reproductive hormones
What does testosterone bind to in the body?
Cells with an androgen receptor
List the main water soluble reproductive hormones.
Gonadotrophin releasing hormone (GnRH)
Follicle stimulating hormone
Water soluble hormones are usually _______ and ________
What is the site of secretion of GnRH?
What is the site of secretion of FSH and LH?
What is the site of production and secretion of oxytocin?
Secretion: Posterior pituitary
List the main lipid soluble reproductive hormones.
Lipid soluble hormones are _______ _________
What are the two main types of androgens?
5 alpha dihydrotestosterone (more active form)
What are the three types of oestragen?
What is the one type of progestagen?
Oestradiol (most potent)
What are steroid hormones made from? What percentage of steroid hormones are free?
Cholesterol - obtained from diet
2-3% free (able to diffuse into cells whilst bound hormones cannot)
Which is faster out of action due to water soluble hormones vs lipid soluble hormones?
Action due to water soluble hormones
If a person were to lose their pituitary gland, what would be the result?
They would be castrate: loss of all reproductive function
Compare the sizes of the posterior and anterior lobes of the pituitary
The posterior lobe is much smaller
Out of the hypothalamus and pituitary, which is part of the central nervous system?
What kind of arrangement is the hypothalamic/pituitary/gonadal axis? What is beneficial about this?
Hierarchical arrangement: allows signal amplification
What is the main function of the hypothalamus?
To act as a homeostatic regulator for reproduction, stress, body temperature, hunger, thirst, and sleep.
Why is the hypothalamus called a neuroendocrine organ?
It processes both neural and hormonal information.
What is another name for the posterior pituitary?