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115 Cards in this Set
- Front
- Back
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What is gametogenesis?
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The production of human reproductive cells (gametes)
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What is the production of spermatozoa called
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spermatogenesis
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What is the production of ovum called?
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oogenesis
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What are primordial germ cells called?
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gonocytes
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What are primordial germ cells called in female embryo:
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oogonia
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Where do primordial germ cells called arise + what do they do?
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Outside the gonads in the wall of yolk sac -> They migrate through the dorsal mesentery until they reach the primordial of the gonads.
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What happens once the gonocytes reach the gonads + becomes?
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They begin a phase of rapid mitotic proliferation – becomes spermatogonia or oogonia
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When does the proliferation and migration of PGC happen?
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Between 3rd to 6th week
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What type is spermatocytogenesis?
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Meiosis
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When does spermatocytogenesis take place?
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32 days
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How many types spermatogonium are they?
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Two types, A & B
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What does the spermatogonium B become?
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Spermatid 23, 1c DNA after miosis 2
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What does the spermatogonium A become?
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Spermatogonium as the reserve population;stem-cell population
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How many chromosomes do the primary spermatocytes have?
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46, 4c DNA
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How do spermatocytes become secondary spermatocyte?
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By division
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How many chromosomes do the secondary spermatocytes have?
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23, 2c DNA
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What happens to/after secondary spermatocytes:
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They become spermatids
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How many chromosomes do the spermatids have?
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23, 1c DNA
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What is spermiogenesis?
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Spermatids differentiation into spermatozoa
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What happens in the first phase of spermiogenesis?
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Golgi apparatus granules merges and forms Acrosome
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What forms the acrosome?
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Acrosomal granules. Acrosome is an enzyme-filled structure that plays a very important role in the fertilization process.
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What happens in the second phase of spermiogenesis?
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Centriole divides and participates in organizing flagellum of spermatozoa. Mitochindria are arranged in a spiral around the proximal part of the flagellum and forms mitochondrial sheat.
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What forms the head of the spermatozoa – which phase?
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in phase 3- Acrosome + nucleus
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What else happens in phase 3?
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Flagellum growth
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What happens in phase 4 of the spermiogenesis?
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The remains of the cytoplasm (residual body) moves away from the nucleus and is shed along the developing tail of the sperm cell. The residual bodies are phagocitized by Sertoli cells.
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What is the condensation of chromosomal material material associated with?
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Condensation of the chromosomal material, which is associated with the replacement of histones by protamines.
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What is the condition of spermatozoa in seminiferous tubules?
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Morphologically organized. They are nonmotile and incapable of fertilizing an egg.
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How long time does it take for the spermatogenesis to finish?
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64-74 days
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When does spermatogenesis begin?
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Begins at puberty time
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What happens to the spermatozoa on their way to the epididimys?
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Undergo biochemical maturation, becoming covered with a glycoprotein coat
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For how long time is the spermatozoa alive in the female reproductive tract?
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4 days
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When do the oogonia undergo mitotic division?
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Between 8-30 weeks
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What number oogonia after 5-6 months of fetus?
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7 million
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When do the oogonia enter meiosis?
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During fetal period, at 12-13 weeks
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What forms the covering of the primary oocytes?
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Primary oocyte surrounded by follicular cells forms primary follicle.
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What is the difference between oogonia and spermatogonia when talking about entering meiosis?
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Spermatogonia do not enter meiosis at fetal period.
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What is formed by a primary oocyte?
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Primary follicle
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What is formed after the second division?
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Secondary oocyte and polar body
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How is the cytoplasm distribution to the daughter cells?
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Unequal cytoplasm distribution to cells
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When is the meiosis of the oocyte arrested?
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In diplotene stage, at fetal period
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When does the oocyte continue meiosis?
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At puberty, oocyte for years (14-50) is in the diploten stage
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What inhibits meiosis?
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OMI (Oocyte Maturation Inhibitor) secreted by follicular cells.
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How does the OMI block the cell cycle?
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It causes high level of cAMP
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When is the second meiotic division arrested of oocyte?
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At metaphase
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Where is the meiosis of the secondary oocyte completed?
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When secondary oocyte ovulates and enters uterine tubes
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What is the corona radiata?
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Follicular cells that surrounds oocyte
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What forms the corona radiata?
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Follicular cells
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How many chromosomes are in primary oocytes
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2n, 4c
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How many chromosomes are in secondary oocytes
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1n, 2c
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How many chromosomes are in fertilized eggs?
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1n, 1c
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How does the number of primary follicles from a 6th moth fetus until puberty changes?
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Decreases from 7 mln to 0.4 mln
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How many follicles enter maturation during ovarian cycle + how many are there in the end?
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20, 1 in the end
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When is meiosis finished?
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Meiosis is finished after fertilization
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How long is the reproductive period assumed to be?
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12-50 years
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How many oocytes ovulate?
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1 oocyte during one cycle
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What happens during cytoplasmic maturation of oocytes?
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Changes in oocyte cytoplasm necessary to fertilization and the rapidly cleaving embryo. During oocyte maturation number of mitochondria increases and formation of cortical granules.
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What does the secondary oocyte have?
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1. Zona pellucida
2. Cortical granules 3. Materials needed for early development |
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What is the function of cortical granules?
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Participate in the block to polysperma
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What is the difference between oogenesis and spermatogenesis when talking about - time:
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Oogenesis – years
Spermatogenesis – about 2 months |
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What is the difference between oogenesis and spermatogenesis when talking about –meiosis:
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Oogenesis – arrested twice
Spermatogenesis – continuous process |
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What is the difference between oogenesis and spermatogenesis when talking about - number of gametes
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Oogenesis – 1
Spermatogenesis – 4 |
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What is the difference between oogenesis and spermatogenesis when talking about - dynamic of gametes production
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Oogenesis – 1 cell/month
Spermatogenesis – 3000cells/s |
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What is the difference between oogenesis and spermatogenesis when talking about - ability to gametes production?
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Oogenesis – cyclic
Spermatogenesis – continuous |
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Describe the structure of a spermatozoon!
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Head, acrosome, nucleus, neck, midpiece, tail, flagellum
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Describe the structure of a secondary oocyte!
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Zona Pellucida, Corona Radiata
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What are the functions of the testis?
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1. Secret male’s hormons
2. Produce sperm cells |
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What cells are found in the testis?
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Leydig and Sertoli cells
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What is the function of Leydig cells?
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Secrete androgens (testosterone)
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What are the functions of Sertoli cells?
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1. Secrete antimullerian hormone (MIS/AMH)
2. Secrete ABP 3. Metabolic and structural support to developing sperm cells. |
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Where is the gonadotropin-releasing hormone (GnRH) secreted?
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In hypothalamus
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How does the GnRH function?
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Influences pituitary gland to secrete gonadotropic hormones.
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What are the gonadotropic hormones in males?
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ICSH, FSH
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What are the male sex hormones?
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Androgens; eg. Testosterone
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Where are the testosterone produced?
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Leydig cells
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What are the functions of the ovary?
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1. Produces females hormones
2. Produces eggs 3. Prepares the endometrium of uterus |
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What are the gonadotropic hormones in females?
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FSH, LH
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How do FSH and LH function in females?
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FSH – stimulates follicles growth, produce estrogen LH – stimulates follicle cells, produce progesterone
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What are the female sex hormones?
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Estrogen, Progesteron
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When are Estrogen and Progesteron produced?
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Estrogen are produced during fetal period. Progesteron are produced from puberty time
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What do the estrogens stimulate?
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Uterus and vagina growth. Cyclic changes
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What are the functions of progesterone?
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Cyclic changes before implantation
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What hormones participate in the ovarian cycle?
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Gonadotropins: FSH, LH
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What is the function of the ovarian cycle?
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Follicle maturation, and corpus luteum differentiation
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What is the name of the cycle in the uterus?
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Menstrual cycle
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What hormones participate in Menstrual cycle:
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Estrogen, Progesteron
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What is the function of this Menstrual cycle?
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Prepare endometrium of the uterus to the embryo implantation
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Name all the phases of the ovarian cycle and when they take place!
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1. Follicle growth phase (1-14 days).
2. Ovulation (14 day) 3. Corpus luteum phase (14-27 days) |
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Name all the phases of the menstrual cycle and when they take place!
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1. Menstrual phase (1-5 days)
2. Proliferative phase (5-14 days) 3. Secretory phase (14-27) 4. Ischemic phase (27-28) |
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Where do sperm cells maturate?
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In epididymis
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What happens in the maturation process of sperm cells?
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Changes in the glycoproteins of the plasmamembrane in sperm head. Ability to move.
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What happens in the capacitation process?
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Plasma membrane changes. Changes at Ca2+ level. Removing the glycoprotein coat to expose receptors necessary to interaction with zona pellucid.
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What do the follicular cells of the corona radiate contain?
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Hyaluronic acid in the intracellular matrix
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which receptor have sperm cells in the plasma membrane?
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PH-20
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What is PH-20?
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A hyaluronidase
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What glycoproteins is the zona pellucida composed of?
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ZP1, ZP2, ZP3
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What is the function of the receptor reaction?
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Allows only sperm of the same species access to the egg and induce acrosomal reaction
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Name the receptor recognizing proteins of ZP of the plasma membrane of sperm cells?
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Lectin, Receptor ZRK, spermadhesine.
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What is the most important enzyme in Acrosomal reaction and where is it found?
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Acrosin – serine proteinase. Is bound to the inner acrosomal membrane of the sperm
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How does the spermatozoon get through the zona pellucida?
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Enzymes digest zona pellucida and sperm tail movement mechanically helps in sperm penetration of the zona pellucida.
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What are the reactions that prevent polyspermy
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Cortical reaction, Zona reaction.
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What is a fertilized egg called?
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Zygote
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What happens after the egg is fertilized?
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Cleavage begins
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What are the embryological periods and when do they take place?
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Early development (0-3 weeks).
Embryonic period (4-8 weeks). Fetal period (9-38 weeks). |
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Which male hormons stimulate/inhibit hypothalamus:
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Inhibin from sertoli cells and testosterone from ledyig cells
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ICSH do what:
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more Testosterone production ->
initiates spermatogenesis and multiple effects on male phenotype changes e.g. hair growth, voice changes and other tertiary sexual characteristic |
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FSH do what:
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more testosterone ->
induces spermatogenesis; stimulates Sertoli cells to start Androgen Binding Protein production |
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Which part of the OOGENESIS takes place in the foetus:
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Oogonium(Mitosis - 8-30weeks)
-> Primary Oocyte (Meiosis - 12 weeks – 7 month) |
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Which female sex hormone is produced from puberty time:
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progesterone
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ESTROGENS do what:
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- cyclic changes at endometrium
- uterus and vagina growth, - more estrogens initiates female phenotype changes e.g. pelvis, breast, hair growth and other tertiary sexual characteristic |
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1 important thing that happens before diplotene stage:
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crossing over aka parental genetic material recombination
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Second stop of meiotsis happens when + what stage:
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puberty - second meiotic division which is arrested at metaphase – now called Secondary oocyte
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Sertoli cells do what(3):
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1.metabolic and structruralsupport to developing sperm cells
2.secrete ABP Androgen Binding Protein -influences testosterone level 3. phagocytosis of residual bodies of sperm cells |
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FUSION OF EGG AND SPERM – which proteins interact?
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integrin in the plasma membrane of egg and fertiline in the plasma membrane of sperma
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Prevention of polyspermy is done by 2 ways:
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Cortical reaction – (exocytosis of cortical granules (acid hydrolases)
Zona reaction – changes of glycoproteins in zona pellucida (ZP-2, ZP-3) caused by the secretory products of the pellucida (ZP-2, ZP-3) caused by the secretory products of the cortical granules |
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The sex of the future embryo is determined by:
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the chromosomal complement of the spermatozoon: X female, Y male
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