Gametogenesis Flashcards
The female genital system consists of?
Ovaries, uterine tubes and uterus
What are the functions of ovaries ?
Produce ova
Secrete estrogen and progestrone
What are estrogen and progestrone responsible for?
They are responsible for the development of the secondary sexual characters and regulation of pregnancy
What are the parts of the uterine tubes?
Fimbriae
Ampulla
Isthmus
Interstitial part
The uterus consists of 3 layers in the uterine wall which are?
Endometrium : the internal lining mucosal layer ( Blue )
Mymoetrium : a thick smooth muscle layer ( green )
Perimetrium : external covering layer of peritoneum ( purple)
The endometrium is split into 2 layers which are ?
Basal layer ( lower layer ) and a functional layer ( upper layer )
Functions of the basal layer ?
Basal layer : contains the ends of uterine glands
Doesn’t shed off during mestruation
Regenerates the functional layer
Functions of the functional layer :
Disintegrates and sheds at menstruation and after delivery
Male reproductive system consists of?
Testis
Epididymis
Vas defernes
Seminal vesicle and prostate
Ejaculatory duct
Bulbourtheral glands
Function of the testis
Produce sperms and secretes hormones
Function of epididymis
Stores the sperms
Vas deferens
Transports the sperms before ejaculation
Seminal vesicake and prostate
Secrete seminal alkaline fluid that nourishes the sperms
Ejaculatory duct
Transfer the sperms into urethra
What is Gametogenesis
Is the process of formation of sperms ( spermatogenesis) in males or ova ( oogenesis ) in females
What is speematogemesis ?
It is the transformation of spermatogonia into sperms
How many days the spermatogensis cycle take and where ?
Takes 60 days in the seminiferous tubules of the testis
How many stages does spermatogensis have?
4 stages
Proliferation
Growth
Maturation
Transformation
proliferation
increases the number of spermatogonia
Spermatogonia which contain (44 XY)
Growth
Increases the size of spermatogonia
The daughter spermatogonia enlarge to form
primary spermatocytes, which have (44 XY )
Maturation
what happens during the first maturation division ?
Each primary spermatocyte produces 2
secondary spermatocytes, each
contains (22 + X OR 22 + Y) of double
stranded chromosomes.
Primary spermatocytes: contain 46
double stranded chromosomes
Secondary
Maturation
Second maturation division
(meiosis II )
Each secondary spermatocyte
produces 2 spermatids , each
contains (22 + X OR 22 + Y) of
single stranded chromosomes.
What is Transformation : spermiogenesis?
It is the process by which, the 4 spermatids are transformed into 4 mature
sperms
* The nucleus condenses
* The acrosome (sac of enzymes) appears, covers the nucleus
* Most of the cytoplasm is shed.
* Flagellum appears.
The mature sperm
Head :
Has Nucleus
Acrosomal cap which contains enzymes that
facilitate penetration of secondary oocyte
The mature sperm
Neck:
the junction between the head and the tail
The mature sperm
Tail
is responsible for sperm motility
what are the three segments of the mature sperm?
The middle piece contains, mitochondria which
provides energy for sperm motility (sometimes it is
called body).
* The principal piece.
* The end piece.
what is Azoospermia?
Absence of living sperms in the semen.
what is oligospermia?
Less than 10 million sperms per milliliter of semen is likely to be sterile, especially when the specimen contains immotile & abnormal shaped sperms.
what is vesectomy?
This means excision of a segment of the
vas deferens (trans –scrotal incision).
It is the most effective method of male
contraception.
after vasectomy, are there sperms in ejaculation?
After vasectomy ,there are no sperms in
the ejaculate , but the amount of seminal
fluid is the same as before the procedure
what is oogenesis?
transformation of oogonia to oocytes
where dies oogenesis occur?
site : ovary
Prenatal events of Oogenesis
proliferation:
During early fetal life, oogonia
proliferate by mitosis to form many
daughter oogonia (44+ XX).
Prenatal events of Oogenesis
Growth:
The daughter oogonia undergoes
meiosis I (arrested at prophase) to
form primary oocytes (44+ XX).
at birth the ovary only contains primary oocytes that are arrested in the prophase 1
True or false ?
True
is there oogonia after the growth phase?
No more oogonia
First maturation (meiotic) division
Primary oocyte go through interphase & prophase.
* At birth, all primary oocytes have completed preparation for first meiotic
division.
* They remain in prophase 1 this stage until puberty
completion of the first maturation meiotic division occurs at puberty every month?
yes
Second maturation division (meiosis 2):
where does it occur?
the uterine tube ( only if the fertilization occurs )
The 2ry oocyte released at ovulation is
surrounded by:
A non cellular covering of glycoprotein
coat known as the zona pellucida.
A layer of follicular cells called the
corona radiata.
The space between zona pellucida &
oocyte cell membrane is called peri –
vitelline space
