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34 Cards in this Set
- Front
- Back
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Cell Division |
The process by which a cell reproduces itself that consists of nuclear division ( mitosis or meiosis) and cytoplasmic division (cytokinesis). |
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Two types of cell division |
Mitosis and Meiosis |
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Mitosis is... |
Somatic nuclear division. 46 chromosomes replicate, line up on the equatorial plane, centromeres split, and 46 chromosomes move to opposite poles to produce 2 identical daughter cells with 46. Diploid |
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Meiosis is... |
Reproductive nuclear division. It only occurs in the Gonads (testes and ovaries) to produce gametes (sperm and eggs). It involves two nuclear divisions. |
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Two nuclear divisions |
Meiosis I Meiosis II |
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Meiosis I |
Reduction division. The 46 chromosomes replicate and the 23 homologues pair up, each of the 23 homologues pairs line up on the equatorial plane, the homologues pairs seperate the move to opposite poles (Centromeres do not split). This produces two cells with 23 chromosomes. Haploid |
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Meiosis II |
Increases the number of haploid cells Each cells 23 chromosomes line up on the equatorial plane, centromeres now split, produce 4 cells with 23 chromosomes. Haploid |
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Diploid |
A cell having 2 complete sets of chromosomes, the full normal amount for somatic cells. 2n=46 |
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Haploid |
A cell having half the normal number of chromosomes (one set), only found in the gametes (sperm and egg). n=23 |
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Primary Male sex organs |
Testes |
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Characteristics of Testes |
Paired oval structures Heterocrine gland Produces sex hormones- testosterone produces haploid sperm |
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Each testes is divided into... |
250 compartments called lobules. Each lobule contains 2 highly coiled seminiferous tubules. |
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Each seminiferous tubule is lined with... |
Spermatogenic cells that undergo spermatogenesis to produce sperm. |
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Spermatogenesis- Male meiosis is... |
The development of the sperm. |
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5 stages of spermatogenesis |
1. Spermatagonia 2. Primary spermatocyte 3. Secondary spermatocyte 4. Spermatids 5. Spertmatazoa |
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Spermatagonia |
2n undifferentiated stem cells that line the basement membrane of the seminiferous tubules. At puberty under the influence of FSH they differentiate into primary spermatocytes. They constantly undergo mitosis to maintain the population. |
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Primary Spermatocytes |
2n Undergo meiosis I to produce two secondary spermatocytes. |
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Secondary Spermatocytes |
n Undergo meiosis II to produce four spermatids. |
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Spermatids |
n Develop a flagellum to become a spermatazoa. |
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Spermatazoa |
n Mature sperm divided into 3 areas. |
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3 areas of sperm |
1. Head 2. Midpiece 3. Tail |
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Head of Sperm |
Contains the nucleus (DNA) and the Acrosome (contains an enzyme to penetrate the ovum). |
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Midpiece |
Contain many mitochondria to produce ATP energy for movement. |
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Tail |
Flagellum that propels the sperm. |
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How many haploid spermatazoa for every primary spermatocyte? |
4 (2X and 2Y chromosome sperm) |
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Primary Female Sex Organs |
Ovaries |
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Characteristics of the Ovaries |
Paired oval structures (size and shape of almond) suspended by ligament in the upper pelvic cavity. They are homologues to the testes. They consist of four tissue layers. Heterocrine gland Produces sex hormones- estrogen Produces haploid ova |
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4 Tissues of the ovaries from outside to inside |
1. Serosa- simple cuboidal e.t. 2. Tunica Albuginea- dense c.t. 3. Cortex- Contains many developing follicles surrounded by dense c.t. 4. Medulla- areolar c.t. with many blood vessels and nerves. |
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Oogenesis- Female Meiosis |
Starts before birth and takes years to complete, stimulated by FSH. Has 4 stages. |
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4 stages of Oogenesis |
1. Oogonia 2. Primary Oocyte 3. Secondary Oocyte 4. Ovum |
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Oogonia |
2n undifferentiated stem cells that develop before birth into primary Oocytes Only in fetus. |
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Primary Oocyte |
2n Undergo meiosis I each month starting at puberty under the influence of FSH to produce one large haploid secondary Oocyte and a 1st polar body (n) that dies off. |
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Secondary Oocyte |
n undergoes meiosis II to produce one large ovum and a 2nd polar body (n) that dies off. |
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Ovum |
n Mature egg |
