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Questions and Answers
What is the first step of sperm formation called?
What is the first step of sperm formation called?
At which stage does female gametogenesis begin?
At which stage does female gametogenesis begin?
What term is used to describe the male primordial germ cells?
What term is used to describe the male primordial germ cells?
What triggers the beginning of spermatogenesis?
What triggers the beginning of spermatogenesis?
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Which of the following occurs during the second step of sperm formation?
Which of the following occurs during the second step of sperm formation?
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Which process refers to the formation and maturation of male and female gametes?
Which process refers to the formation and maturation of male and female gametes?
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What begins with the formation of the three germ layers: ectoderm, mesoderm, and endoderm?
What begins with the formation of the three germ layers: ectoderm, mesoderm, and endoderm?
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Which type of embryology focuses on general principles of development from zygote to embryo?
Which type of embryology focuses on general principles of development from zygote to embryo?
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In the context of developmental anatomy, which term describes the changes from infancy to old age?
In the context of developmental anatomy, which term describes the changes from infancy to old age?
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Which of the following stages involves the formation of the placenta?
Which of the following stages involves the formation of the placenta?
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What is the primary focus of special embryology?
What is the primary focus of special embryology?
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Which stage of development follows fertilization in somatic cell divisions?
Which stage of development follows fertilization in somatic cell divisions?
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What is the correct order of the developmental stages starting from fertilization?
What is the correct order of the developmental stages starting from fertilization?
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Which type of ovum has a small amount of yolk?
Which type of ovum has a small amount of yolk?
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What defines a mesolecithal ovum?
What defines a mesolecithal ovum?
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In which type of ovum is the yolk located at the vegetal pole?
In which type of ovum is the yolk located at the vegetal pole?
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What is the secondary membrane in mammals formed by?
What is the secondary membrane in mammals formed by?
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Which type of egg has yolk distributed uniformly throughout the cytoplasm?
Which type of egg has yolk distributed uniformly throughout the cytoplasm?
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What is the result of the first meiotic division of primary spermatocytes?
What is the result of the first meiotic division of primary spermatocytes?
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What is the role of spermatogonia type A in spermatogenesis?
What is the role of spermatogonia type A in spermatogenesis?
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What structures form the tail of a spermatozoon during spermiogenesis?
What structures form the tail of a spermatozoon during spermiogenesis?
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How long does it take for sperm to develop from a spermatogonium to a sperm?
How long does it take for sperm to develop from a spermatogonium to a sperm?
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What is the end product of oogenesis?
What is the end product of oogenesis?
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Which cellular structure forms the acrosomal cap during spermiogenesis?
Which cellular structure forms the acrosomal cap during spermiogenesis?
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What period of oogenesis occurs from birth until puberty?
What period of oogenesis occurs from birth until puberty?
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What is lost from the spermatid during spermiogenesis?
What is lost from the spermatid during spermiogenesis?
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What stage follows the formation of primary oocytes in oogenesis?
What stage follows the formation of primary oocytes in oogenesis?
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Which structure surrounds the secondary oocyte during ovulation?
Which structure surrounds the secondary oocyte during ovulation?
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During which process does the mature Graafian follicle release the secondary oocyte?
During which process does the mature Graafian follicle release the secondary oocyte?
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How many polar bodies are produced at the end of oogenesis?
How many polar bodies are produced at the end of oogenesis?
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What is a significant difference between oogenesis and spermatogenesis?
What is a significant difference between oogenesis and spermatogenesis?
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What structure forms after ovulation from the remaining follicle cells?
What structure forms after ovulation from the remaining follicle cells?
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During which phase does the first meiotic division of oocytes occur?
During which phase does the first meiotic division of oocytes occur?
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What hormone is primarily responsible for triggering ovulation?
What hormone is primarily responsible for triggering ovulation?
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Study Notes
Developmental Anatomy (Embryology)
- Developmental anatomy is the study of the origin and development of a mammalian organism from fertilization to the end of life.
- Ontogenesis encompasses all developmental events.
- Intrauterine development includes:
- Embryogenesis
- Fetogenesis
- Extrauterine development includes:
- Infancy
- Childhood
- Adolescence
- Maturity
- Old age (senility)
Classification of Embryology
- General Embryology: Focuses on the general principles of development from zygote to embryo.
- Special Embryology: Examines the differentiation and formation of specific organs and systems.
- Comparative Embryology: Compares the structural features of organisms across various developmental stages in mammals.
- Experimental Embryology: Studies the factors and agents influencing or regulating development, as well as the effects of agents or factors on organism development.
Aim of Thesis Course
- To understand the complexity of anatomical structures.
- To understand comparative anatomy.
- To understand the phylogeny (historical development) of organisms.
- To understand teratology and congenital anomalies.
- To understand the importance of gynecology and obstetrics.
Stages of Development
- Progenesis: Includes gametogenesis, sexual cycle, and fertilization.
- Blastogenesis: Involves cleavage, morula formation, and blastula formation.
- Gastrulation: The formation of the three germ layers (ectoderm, mesoderm, and endoderm).
- Fetal Membrane: The formation of amnion, chorion, allantois, and yolk sac.
- Placentation: The formation of the placenta.
- Organogenesis: The formation of organs.
Gametogenesis
- Gametogenesis is the process of formation and maturation of male (spermatozoa) and female (ovum) gametes.
- In males, it's called spermatogenesis.
- In females, it's called oogenesis.
Oogenesis & Spermatogenesis
- Involves nuclear and cytoplasmic stages
- Oogenesis has three periods
- Proliferation
- Growth
- Maturation (meiosis)
- Spermatogenesis has three periods
- Proliferation
- Growth
- Maturation (meiosis)
Primordial Germ Cell
- Primordial germ cells (PGCs) migrate from the yolk sac endoderm to the genital ridge (future testis or ovary) during the fourth week of development.
- In males, the PGCs differentiate into spermatogonia.
- In females, they differentiate into oogonia.
Time of Gametogenesis
- Male: Gametogenesis starts at puberty and continues throughout life.
- Female: Gametogenesis begins in fetal ovaries, progressing to primary oocyte formation (proliferation), continues through puberty (growth), and culminates in maturation through ovulation (first meiosis) and fertilization (second meiosis). Oogenesis is completed with menopause.
Spermatogenesis
- Spermatocytogenesis: Spermatogonia transform into spermatids.
- A stage of mitosis (cell divisions to produce more cells).
- A stage of differentiation into primary spermatocytes
- Spermiogenesis: Spermatids differentiate into mature sperm (spermatozoa).
- The structure of a mature sperm including the head, mid-piece, and tail.
Site and Time of Spermatogenesis
- Occurs within the seminiferous tubules of the testes.
- Begins at puberty.
Spermatocytogenesis
- At puberty, primordial germ cells proliferate by mitosis, forming spermatogonia.
- Spermatogonia differentiate into type A and type B.
- Type B spermatogonia develop into primary spermatocytes; type A become stem cells replenishing the supply.
Maturation in Spermatogenesis
- Primary spermatocytes undergo meiosis I, resulting in secondary spermatocytes.
- Secondary spermatocytes undergo meiosis II, forming spermatids.
Spermiogenesis (detailed)
- Is a stage of sperm maturation
- The spermatids transform into mature sperm (spermatozoa)
- The structural changes involved (e.g., acrosome formation, condensation of the nucleus, development of the flagellum, and reorganization of the cytoplasm, loss of excess cytoplasm as a residual body)
Oogenesis
- Oogenesis is the formation and maturation of female gametes (ova).
- It begins during fetal development, with a fixed number of primary oocytes present at birth.
- Stages include proliferation (fetal development), growth (during childhood and into puberty), and maturation (ovulation).
- It is a protracted process compared to spermatogenesis.
Folliculogenesis
- Folliculogenesis is the formation of follicles around oocytes.
- Follicles develop from primordial follicles to primary follicles to secondary follicles to Graafian follicles.
- Ovulation involves the release of a mature secondary oocyte from a Graafian follicle.
- Follicles and oocytes that do not mature degenerate.
Ovulation
- Ovulation is the release of a secondary oocyte from a mature ovarian follicle.
- The oocyte is enveloped by the zona pellucida and corona radiata that facilitate fertilization.
Structure of Ovulated Oocyte
- Structure of the released secondary oocyte:
- Cytoplasm
- Nucleus
- Cytoplasmic membrane/vitelline membrane
- Previtelline space
- First polar body
- Zona pellucida
- Corona radiata
Membranes of Ovum
- Primary membrane (oolemma): The cell membrane of the ovum.
- Secondary membrane (zona pellucida): Glycoprotein layer surrounding the mature ovum.
- Tertiary membrane (additional layers): Albumin, shell membrane, and shell layers in birds.
Type of Ova
- Ovum types categorized by yolk amount and distribution:
- Microlecithal (small amount of yolk): Organisms like amphibians and mammals.
- Mesolecithal (moderate amount of yolk): Organisms like amphibians and fish.
- Macrolecithal/Polylecithal (large amount of yolk): Organisms like birds and reptiles.
Types of Ova (continued)
- Ova classifications based on yolk distribution:
- Isolecithal (uniform distribution of yolk)
- Anisolecithal (non-uniform distribution):
- Telolecithal (yolk concentrated at one pole)
- Centrolecithal (yolk centralized)
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Description
Test your knowledge on the key concepts of gametogenesis and embryology. This quiz covers the stages of sperm formation, female gametogenesis, and the developmental processes involved in creating human life. Ideal for students studying biology or related fields.
