1. IV) Female Reproductive System B) Oogenesis

2. IV) Female Reproductive System B) Oogenesis
where as the sperm is small the ovum is much larger because it is packed full of nutrients so it can divide rapidly after fertilization.
like a sperm cell an ovum oocyte undergoes a type of cell division that halves the number of chromosomes (called meiosis).

3. IV) Female Reproductive System B) Oogenesis
like a sperm cell an ovum oocyte undergoes a type of cell division that halves the number of chromosomes (called meiosis).
Oogenesis
is the formation of an ovum
occurs in specialized cells in the ovaries called follicles.
a follicle contains two types of cells
a primary oocyte
cells of the granulosa
~ the granulosa is the layer of cells that form the follicle wall. They provide nutrients for the developing oocytes.

4. IV) Female Reproductive System B) Oogenesis
a primary oocyte
cells of the granulosa
~ the granulosa is the layer of cells that form the follicle wall. They provide nutrients for the developing oocytes.
begins when the nutrient follicle cells which ARE surrounding the primary oocyte begin to divide.
the primary oocyte undergoes cell division and while this occurs the majority of cytoplasmic nutrients move to one of the poles and form a secondary oocyte.
the secondary oocyte contains 23 chromosomes.
the remaining cell, called the first polar body, receives little cytoplasm and dies.

5. IV) Female Reproductive System B) Oogenesis
as the follicle cells surrounding the secondary oocyte start to proliferate a fluid filled cavity forms.
the dominant follicle begins to push outwards trying to escape the ovary.
constriction of blood vessels weaken the ovarian wall.
enzymes weaken the follicle wall from the inside.
the seconday oocyte (with the first polar body) is released, this is called ovulation.

6. IV) Female Reproductive System B) Oogenesis
enzymes weaken the follicle wall from the inside.
the seconday oocyte (with the first polar body) is released, this is called ovulation.
the follicle cells that were surrounding the secondary oocyte stay in the ovary and transform into the corpus luteum.
the corpus luteum secretes hormones essential for pregnancy.
if no pregnancy occurs, the corpus luteum degenerates.
after its release from the ovary the secondary oocyte is swept into the end of the Fallopian tube by the fimbriae.
the secondary ooctye is moved along the Fallopian tube by cilia
if healthy sperm is present fertilization will occur.

7. IV) Female Reproductive System B) Oogenesis

8. IV) Female Reproductive System B) Oogenesis

9. IV) Female Reproductive System B) Oogenesis

10. IV) Female Reproductive System B) Oogenesis
after its release from the ovary the secondary oocyte is swept into the end of the Fallopian tube by the fimbriae.
the secondary ooctye is moved along the Fallopian tube by cilia
if healthy sperm is present fertilization will occur.
after fertilization in the Fallopian tube
the secondary oocyte undergoes an uneven division again.
the cells that retain most of the cytoplasm (nutrients) becomes the ovum.
the other cell becomes the second polar body, which deteriorates.
if no fertilization occurs, the secondary oocyte will deteriorate within 24 hours and die.
the women will then undergo a menstrual cycle.

11. IV) Female Reproductive System
if no fertilization occurs, the secondary oocyte will deteriorate with 24 hours and die.
the women will then undergo a menstrual cycle.
along with the development of the secondary sexual characteristics puberty also initiates the menstrual cycle.
secondary sexual characteristics in females include:
enlarged breasts
hair growth in armpits and pubic area
wider hips
fat deposits around buttocks and hips
angle from thigh to ankle is slightly bent

12. IV) Female Reproductive System C) Menstrual Cycle

13. IV) Female Reproductive System C) Menstrual Cycle
the menstrual cycle includes:
oogenesis, ovulation, thickening and shedding of the endometrium
it can be divided into four distinct phases
Flow phase
Follicular phase
Ovulatory phase
Luteal phase

14. IV) Female Reproductive System C) Menstrual Cycle
Flow phase
Follicular phase
Ovulatory phase
Luteal phase
marked by shedding of the endometrium, or menstruation.
the only phase of female reproductive cycle that can be determined externally.
this is why the flow phase is used to mark the beginning of the cycle.
on average five days are required for the uterus to completely shed the endometrium.

15. IV) Female Reproductive System C) Menstrual Cycle
this is why the flow phase is used to mark the beginning of the cycle.
on average five days are required for the uterus to completely shed the endometrium.
Follicular Phase
characterized by the development of the follicles within the ovary.
as the follicle develops the hormone estrogen is secreted.
estrogen activates the development of secondary sexual characteristics and causes thickening of the endometrium.
takes place between days 6 and 13 of the female menstrual cycle.

16. IV) Female Reproductive System C) Menstrual Cycle
estrogen activates the development of secondary sexual characteristics and causes thickening of the endometrium.
takes place between days 6 and 13 of the female menstrual cycle.
Ovulatory Phase
the secondary oocyte bursts from the ovary and follicular cells differentiate into the corpus luteum.
Day 14 of the menstrual cycle (on average)

17. IV) Female Reproductive System C) Menstrual Cycle
the secondary oocyte bursts from the ovary and follicular cells differentiate into the corpus luteum.
Day 14 of the menstrual cycle.
Luteal Phase
begins when the corpus luteum starts to develop.
occurs between days 15 and 28
estrogen levels begin to decline when the oocyte leaves but are restored when the corpus luteum forms.
corpus luteum secretes both estrogen and progesterone.
progesterone hormone:
stimulates the endometrium and prepares the uterus for an embryo
inhibits further ovulation
inhibits uterine contraction
firms the cervix to prevent expulsion of the fetus

18. IV) Female Reproductive System C) Menstrual Cycle
progesterone hormone:
stimulates the endometrium and prepares the uterus for an embryo
inhibits further ovulation
inhibits uterine contraction
firms the cervix to prevent expulsion of the fetus
if fertilization does not occur the concentrations of estrogen and progesterone will decrease.
the uterus will start to contract (cramps)
contraction makes the endometrium pull away from the uterus wall.
shedding of the endometrium marks the next flow phase.

19. IV) Female Reproductive System C) Menstrual Cycle