Untitled Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the initial stage of embryogenesis following fertilization?

Cleavage (correct)

Blastula Formation

Gastrulation

Histogenesis

During which stage of embryogenesis does the formation of germ layers occur?

Organogenesis

System Genesis

Embryo Formation

Gastrulation (correct)

Which term refers to the fertilized egg before it undergoes cleavage?

Conceptus

Morula

Zygote (correct)

Oocyte

What is the primary outcome of spermatogenesis?

Mature Sperm Signup and view all the answers

What best describes meiosis in terms of chromosome number?

Diploid to Haploid Signup and view all the answers

Which term describes the developing embryo along with its associated membranes?

Conceptus Signup and view all the answers

What is the primary function of oogenesis?

Formation of mature oocytes Signup and view all the answers

What is the term for the stage known as the morula?

A mulberry-like cluster of cells Signup and view all the answers

What is the role of the inner cell mass during embryonic development?

It generates embryonic tissues. Signup and view all the answers

How do blastomeres behave during the cleavage process?

They remain equivalent and do not diverge. Signup and view all the answers

What initiates the first differentiation of embryonic lineages after the 8-cell stage?

Increased cell-cell adhesion. Signup and view all the answers

What happens during the 'hatching' of the blastocyst?

The blastocyst prepares for implantation by escaping the zona pellucida. Signup and view all the answers

What is the significance of sodium channels in the development of the blastocyst?

They facilitate the influx of sodium and water into the blastocoele. Signup and view all the answers

What is the role of the cytotrophoblast during implantation?

It serves as a stem cell population. Signup and view all the answers

Which structure is formed from the epiblast during implantation?

Amniotic membrane Signup and view all the answers

What is the function of syncytiotrophoblasts?

To invade maternal tissues and break capillaries. Signup and view all the answers

During which days does the process of implantation occur?

Days 6-12 Signup and view all the answers

How does the inner cell mass during implantation differentiate?

Into epiblast and hypoblast. Signup and view all the answers

What percentage of the total semen volume is contributed by the seminal vesicles?

60% Signup and view all the answers

What is the primary function of the mitochondria in the midpiece of sperm?

To produce ATP for energy Signup and view all the answers

Which of the following fluids is primarily secreted by the prostate gland?

Citric acid Signup and view all the answers

What does the oocyte specifically contain within its cytoplasm?

Yolk granules and ribosomes Signup and view all the answers

What is the role of the enzyme acrosin during fertilization?

Promotes membrane fusion Signup and view all the answers

How does oogenesis differ from spermatogenesis regarding the timing of differentiation?

Spermatogenesis starts at puberty, while oogenesis starts in utero. Signup and view all the answers

What mechanism does the 'fast block' to polyspermy utilize?

Membrane depolarization Signup and view all the answers

How many types of spermatozoa are produced during spermatogenesis?

Two types: 23X and 23Y Signup and view all the answers

What cellular change follows the binding of sperm to the zona pellucida?

Release of hydrolytic enzymes Signup and view all the answers

What does the zona pellucida primarily consist of?

Glycoproteins and glycosaminoglycans Signup and view all the answers

What reaction prevents other sperm from fertilizing the egg after the first sperm binds?

Cortical reaction Signup and view all the answers

Where does fertilization typically occur following ovulation?

Ampulla of the oviduct Signup and view all the answers

Which of the following components is NOT found in the cytoplasm of an ovocyte?

Vesicles from the prostate gland Signup and view all the answers

When does a single egg typically get ovulated during the menstrual cycle?

Day 14 Signup and view all the answers

What is the outcome of cytokinesis during oogenesis?

Formation of one main cell and two polar bodies Signup and view all the answers

What essential contribution does sperm make to the oocyte during fertilization?

The paternal genome Signup and view all the answers

What is the function of the cytotrophoblast during implantation?

It serves as a stem cell population. Signup and view all the answers

Which structure forms from the inner cell mass during implantation?

Epiblast and hypoblast Signup and view all the answers

Which of the following describes the mesoderm layer during gastrulation?

It is involved in generating muscle and blood tissues. Signup and view all the answers

What occurs during the process of neural induction?

Establishment of left-right asymmetry. Signup and view all the answers

What is the primary origin of the endoderm layer?

It becomes the epithelial lining of internal organs. Signup and view all the answers

Study Notes

Embryology Overview

Embryology is the study of the development of an organism from fertilization to birth.
It involves the formation of tissues, organs, and systems from a single fertilized cell (zygote).
The process involves intricate and miraculous cellular differentiation.

General Embryology

A single-celled zygote develops into a complex multicellular human being.
The process is continuous, with the zygote differentiating into definitive organ systems and their early functional stages.

Common Terms in Embryology

Oocyte (Ovum): A mature secondary oocyte, ready for fertilization.
Sperm (Spermatozoa): Male gamete.
Zygote: A diploid fertilized cell, with potential to form an embryo.
Cleavage: Rapid mitotic cell divisions immediately following fertilization.
Morula: A solid ball of cells formed by cleavage, resembling a mulberry.
Conceptus: The developing embryo or fetus along with its associated membranes.
Embryo: The developing human from the first eight weeks, with primordia of all organs and systems formed.

Embryogenesis Stages

Fertilization: Formation of a zygote.
Fragmentation: Formation of a blastula.
Gastrulation: Formation of germ layers and axial organs.
Histogenesis: Tissue formation.
Organogenesis: Organ formation.
System genesis: System formation.

Progenesis

Period of germ cell (egg and sperm) development.
Closely related to embryogenesis and the early postembryonic period.

Gametogenesis (Gamete Formation)

The production of mature male (sperm) and female (ova) gametes.
Spermatogenesis: Process of sperm formation from primordial germ cells (spermatogonia).
Oogenesis: Process of ova (egg) formation from primordial germ cells (oogonia).

Meiosis

A type of cell division that reduces the chromosome number from diploid (46) to haploid (23).
Essential for the production of gametes.
Consists of two divisions: meiosis I and meiosis II.

First Meiotic Division (Prophase I)

DNA replication occurs.
Each chromosome replicates into sister chromatids.

Mitosis vs. Meiosis

Mitosis is a form of cell division for growth and repair.
Meiosis is a specialized type of cell division for gamete formation.

Spermatogenesis details

Total time taken: 64 days.
Starts after puberty (13-16 years).
Comprises: Spermatocytogenesis (mitosis), Meiosis, and Spermiogenesis.

Spermiogenesis

Transformation of spermatids into mature sperms.
Changes in shape and structure of spermatids.

Male Reproductive Cells

Formed in the convoluted seminiferous tubules of the male reproductive gland.
The sperm has a head, midpiece (containing mitochondria) and tail (for movement).

Sperm Tail

Several parts contribute to its shape and structure.
The tail aids in movement.

Female Reproductive Cells

Ovum is a large, immobile cell.
Number of oocytes is significantly less than sperm.
Oocyte has a single X chromosome in its nucleus.
Cytoplasm contains SER, CG, ribosomes, mitochondria, cortical granules and vitelline layers.

Oogenesis/Ovulation/Ovarian Cycle

Stages of follicle development, ovulation, and the formation of the corpus luteum.

Yolk Granules in Oogenesis

Contains proteins, phospholipids and carbohydrates.
Forms oocyte membranes (oolemma).
Forms extracellular glycoprotein layer (zona pellucida).

The Egg (and Corona Radiata) at Ovulation

Structure at the time of ovulation.

Oogenesis vs. Spermatogenesis Similarities

PGCs originate from the same source and at the same time.
Occur in sex cells.
Both undergo two reduction divisions—meiosis.
Cells from columnar epithelium contribute to form supportive cells—Sertoli cells in males and follicular cells in females.

Oogenesis and Spermatogenesis Differences

Spermatogenesis begins at puberty, oogenesis begins in prenatal life.
Meiosis is completed in oogenesis only if fertilization occurs.
Spermatogenesis has a duration of 64 days, in oogenesis cells may remain dormant for years.
Cytokinesis is unequal in oogenesis, leading to a single mature ovum and polar bodies.
Spermatocytes produce two types of cells (23x & 23y), oocytes produce one type (23x).

Fertilization Overview

Sperm penetrates corona radiata and zona pellucida.
Acrosomal reaction releases enzymes for penetration.
Fusion of sperm and egg membranes occurs.
Prevention of polyspermy (multiple sperm fertilizations).

Fertilization: Generalized Acrosomal Process

Stages involved in sperm interaction with the egg.
Membrane fusion, entry of sperm nucleus, fusion of pronuclei.

Cortical Reaction

Prevents polyspermy after fertilization by changing egg surface.
Preventing multiple sperm entrance, maintaining genetic integrity.

Fertilization: Formation of male and female pronuclei

Stages of forming male and female pronuclei after fertilization.

Transport through the Oviduct

Process of the zygote travels through various stages of the oviduct to the uterus.
Cleavage (early cell divisions), development into morula, blastocyst, and implantation.

Cleavage Overview

Series of rapid mitotic divisions in a fertilized ovum, without significant cell growth.
Forms blastomeres.

Cleavage Types

Complete and incomplete
Uniform and uneven
Synchronous and asynchronous

Embryo Development After 8-cell stage: Compaction

Embryo undergoes compaction after the 8-cell stage
Increased cell adhesion leads to compaction.
Differentiation of trophoblast and inner cell mass.

Formation of the Blastocyst

Fluid-filled cavity (blastocoele) forms inside the embryo.
Outer layer of cells (trophoblast) and inner cell mass (ICM) are established.
Embryo is still enclosed within the zona pellucida.

Inner Cell Mass (ICM)

Inner cell mass will form the embryo proper.
It contains the cells destined for becoming the body proper of the embryo.

Hatching of the Blastocyst

Trophoblast secretes proteases that digest the zona pellucida.
Allows the embryo to escape and prepare for implantation.

Implantation

Processes and stages in which the blastocyst adheres to the endometrium of the uterus.
Several days of adhesion, proliferation and formation of the embryo's structure.

Implantation and Placentation (days 8-13)

Further differentiation and invasion of maternal tissues.
Formation of the placenta and the early stages of the embryo
Key parts such as trophoblast, epiblast, hypoblast are formed.

Gastrulation (Week 3, Days 14-21)

Transformation of the two-layered epiblast into three primary embryonic germ layers (ectoderm, mesoderm, endoderm).
Forming the rudimentary structures for organs.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.