I. Oogenesis: Formation of the female gametes (eggs or ova) Between birth and puberty A female is born with a set number of eggs and ovarian follicles - usually anywhere from 1 to 2 million- and the total declines over time. At and after puberty - approximately 25% or 300,000 follicles are present. Oogonia (oogonium- singular) are the diploid stem cells that produce oocytes. Oogonia each contains 46 chromosomes. In the female fetus, the oogonia divide by mitosis. Each oogonium then enlarges to form a primary oocyte. The primary oocyte is surrounded by a follicle, which becomes rich with nutrients. Primary oocytes then remain dormant in the ovaries until puberty begins. 2n Oogonium Mitosis Primary oocyte 2n Before birth (arrests in prophase I) After puberty Polar body in 10 In Meiosis continues Secondary oocyte (arrests in metaphase II) Ovulation, sperm entry Meiosis, fertilization Polar body in 2n Fertilized Egg A Membrane fusion Penetration of the corona radiata B Zona pellucida Corona radiata Penetration of the zona pellucida Acrosome reaction Zona pellucida Fusion of nuclei C D
I. Oogenesis: Formation of the female gametes (eggs or ova) Between birth and puberty A female is born with a set number of eggs and ovarian follicles - usually anywhere from 1 to 2 million- and the total declines over time. At and after puberty - approximately 25% or 300,000 follicles are present. Oogonia (oogonium- singular) are the diploid stem cells that produce oocytes. Oogonia each contains 46 chromosomes. In the female fetus, the oogonia divide by mitosis. Each oogonium then enlarges to form a primary oocyte. The primary oocyte is surrounded by a follicle, which becomes rich with nutrients. Primary oocytes then remain dormant in the ovaries until puberty begins. 2n Oogonium Mitosis Primary oocyte 2n Before birth (arrests in prophase I) After puberty Polar body in 10 In Meiosis continues Secondary oocyte (arrests in metaphase II) Ovulation, sperm entry Meiosis, fertilization Polar body in 2n Fertilized Egg A Membrane fusion Penetration of the corona radiata B Zona pellucida Corona radiata Penetration of the zona pellucida Acrosome reaction Zona pellucida Fusion of nuclei C D
Human Anatomy & Physiology (11th Edition)
11th Edition
ISBN:9780134580999
Author:Elaine N. Marieb, Katja N. Hoehn
Publisher:Elaine N. Marieb, Katja N. Hoehn
Chapter1: The Human Body: An Orientation
Section: Chapter Questions
Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...
Related questions
Question
Check all the answers and answe the question that isn't answered.
Which step triggers release of enzymes by the head of a sperm cell which help
dissolve the zona pellucida? Step C involving the Acrosome reaction.
Which step forms the fertilization membrane which disallows multiple sperm cells
from entering the ovum? Step A including the membrane fusion as cortical
granules are released.
In what step are pronuclei formed? Step D where the sperm's head contains the
nucleus and must meet the pronucleus.
At what step does the ovum complete meiosis??
Which step is the "official formation of a zygote? Step D (fusion of a nuclei).
Transcribed Image Text:I. Oogenesis: Formation of the female gametes (eggs or ova)
Between birth and puberty
A female is born with a set number of eggs and
ovarian follicles - usually anywhere from 1 to 2
million- and the total declines over time.
At and after puberty - approximately 25% or
300,000 follicles are present.
Oogonia (oogonium- singular) are the diploid stem
cells that produce oocytes.
Oogonia each contains 46 chromosomes.
In the female fetus, the oogonia divide by mitosis.
Each oogonium then enlarges to form a primary
oocyte. The primary oocyte is surrounded by a
follicle, which becomes rich with nutrients.
Primary oocytes then remain dormant in the
ovaries until puberty begins.
2n Oogonium
Mitosis
Primary oocyte
2n
Before birth
(arrests in prophase I)
After puberty
Polar body in
10
In
Meiosis continues
Secondary oocyte
(arrests in metaphase II)
Ovulation, sperm entry
Meiosis, fertilization
Polar body in
2n Fertilized Egg
Transcribed Image Text:A
Membrane
fusion
Penetration of
the corona radiata
B
Zona
pellucida
Corona radiata
Penetration of
the zona pellucida
Acrosome
reaction
Zona pellucida
Fusion of
nuclei
C
D
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