Reproduction Flashcards
What are the male gonads and what do they produce?
- Testis and they produce testosterone, and sperm.
What are the female gonads and what do they produce?
- Ovaries and produce oestrogen and eggs.
What does the reproductive tract do?
- Provides passage and supportive secretions for gametes - consists of ducts and glands.
What kind of function do the glands in the reproductive tract have?
- Endocrine.
Can women function without functional gonads?
- Yes: menopause, function of ovaries ceases - no longer producing sufficient hormones therefore reproductive function of women ceases.
What are the two major parts of gonads?
- primordial germ cell (PGC), these cells produce gametes, gametes carry important information.
- mesenchymal tissue, this firms a matrix around the gonads.
Which cells “nurse” and “foster” the primordial cell line and assist maturation and movement through reproductive tract?
- In males: sertoli.
- In females: granulosa.
In males what is the PGC and what are the cells present in mesenchymal tissue?
- PGC = spermatozoa and the cells present in mesenchymal tissue are: Sertoli cells (close to spermatozoa) and leydig cells (further removed).
In females what is the PGC and what are the cells present in mesenchymal tissue?
- PGC = oocyte (egg) and the cells present in the mesenchymal tissue are theca cells (more peripheral) and granulosa (surrounding oocytes).
What kind off cell division takes place in primordial germ cell?
- Meiosis.
When is the gender of offspring determined and when can it be seen?
- At point of fertilisation and if you look at structure between 3 and 7 weeks following fertilisation cannot determine gender based on structure.
What are the names of the male and female genital ducts that develop on either side of gonads?
- Male: wolffian.
- Female: mullerian.
When are the wolffian and Müllerian ducts fully developed?
- Male: wolffian.
- Female: mullerian.
- Both developed fully within 18-20 weeks following fertilisation.
What is an important difference between male and female genitalia in fetus?
- You do not require a positive hormonal influence to get female pattern of reproductive hormones.
For both sexes the steroid sex hormones (testosterone and oestrogen) are regulated by which hormones and where are these hormones produced?
- LH = lutenising hormone.
- FSH = follicle stimulating hormone.
- both are produced in the anterior pituitary.
What do LH and FSH do?
- Act by activating cell membrane receptors.
- LH stimulates leydig (male) and theca (female) cells to lead to production of steroid based hormones.
- LH activates an enzyme known as 20,22 desmolase enzyme.
- FSH activates ovarian granulosa cells and testicular cells to increase activity of aromatase enzyme. It converts testosterone -> oestrogen.
Anterior pituitary gonadotropins are regulated by what?
- Hypothalamus.
What regulates gonadotrophin hormones?
GnRH - gonadotrophin hormone releasing hormone - decapeptide which is released phasically by neurones
What are the male gonads?
Testis - oval, about 4-5cm long and are suspended external to individual in scrotal sac, this sac is made up of cremaster muscle - has ability to contract when temp cold and relax when temp high
Why are testis external?
Sperm tissue is unable to develop at body temp, spermatogensis most efficient at 2-3 degrees lower than body temp
Where is sperm produced and stored?
Spermatozoa is produced in testis, stored in epididymis and delivered by penis
What are the ducts of the testis called?
Seminiferous vesicles/tubules
Which cells are inside and which are outside the seminiferous tubule?
Inside - sertoli and sperm
Outside - leydig
Function of vas deferens?
Connects testis to rest of the body, joins the urethra and prostate glands and then to a set of other organs referred to as seminal vesicles
How can sterility arise?
Either by abnormal sperm or low sperm found (
What are the three components of sperm?
- head: contains 23 chromosomes and enzymes in acrosomal cap, aids penetration of ovum
- mid piece: contains mitochondrial sheath to power cell movement
- tail: flagellations provide motive force (44mm/min in vagina - 2 days survival time)
What do the gonads do?
They produce gametes and provide sex hormones
How many sperm are produced daily by cell division?
Estimated 100-200 million within seminiferous tubules
Function of Fallopian tube (oviduct)
To collect released ova which then moves from ovary down the Fallopian tube into next structure known as the uterus (Fallopian tube is site of fertilisation)
What is the uterus?
Thick walled hollow structure consisting of the endometrium and myometrium (under endometrium these are smooth muscle cells) . Responsible for maintain developing fetus during pregnancy
What is oogenesis?
Process whereby primary oocytes (primordial germ cell - oogonia) are converted into the mature ovum with associated replication of genetic material
What happens during process of ovulation?
Graffian follicle migrates to surface of ovary and ruptures to release secondary oocyte into Fallopian tube under the influence of LH - this has 23 chromo ready to meet with sperm in Fallopian tube and fertilisation to occur
What is menstrual cycle?
Governed by ovaries. Cycle in terms of the level of hormones within the body of a woman. Lasts 24-32 days and involves changes in hormones, the ovary and womb. About 14 days into cycle - ovulation occurs
