3-11 (1)

Page 1: Human Reproduction and Development

Overview of Human Reproduction

• Focuses on biological features essential for the continuation of generations.

Page 2: Importance of Reproduction

Biological Significance

• Reproduction is a vital biological process.

• Enables living organisms to persist over generations.

Page 3: Development Post-Reproduction

Developmental Processes

• Human reproduction is followed by developmental processes during gestation.

• These processes lead to the formation of a fully functional individual.

Page 4: Human Life Cycle

Fertilization and Meiosis

• The life cycle alternates between fertilization and meiosis.

• Meiosis produces haploid gametes (n = 23).

• Multicellular diploid adults have a diploid number of chromosomes (2n = 46).

• Key stages:

  • Ovum (female gamete)

  • Sperm (male gamete)

  • Fertilization leads to the diploid zygote.

Page 5: Role of Gametes in Life Cycle

Gametes as Genetic Vectors

• Gametes are crucial for delivering and combining parental DNA.

• They are involved in the alternation of fertilization and meiosis.

Page 6: Restoration of Chromosome Number

Zygote Formation

• The zygote's chromosome number is restored after fertilization.

• Gametes continuously alternate between meiosis and fertilization in the life cycle.

Page 7: Development of Zygote

Stages of Development

• The zygote develops into an embryo and eventually grows into an adult.

• Reinforces the cycle of meiosis and fertilization.

Page 8: Human Life Stages

Overview of Developmental Stages

• Life stages are categorized and described.

Page 9-12: Detailed Life Stages

Life Stages

• Infancy: Ages 0-2; characterized by continuous physical development.

• Childhood: Ages 1-12; focuses on locomotor and cognitive skills.

• Adolescence: Ages 13-19; marked by physical and hormonal changes due to puberty.

• Adulthood: Ages 20 and onwards; individuals reach sexual maturity physically and behaviorally.

Page 13: Changes During Puberty

Physical Changes in Males and Females

• Male Changes:

  • Increased facial and body hair, wider shoulders, oilier skin.

  • Changes in genitalia size and muscle development.

• Female Changes:

  • Development of breasts, wider hips, and growth of hair under arms and pubic areas.

  • General physical maturation and curvier body shapes.

• These changes prepare individuals for adulthood on physical, physiological, and behavioral levels.

Page 14: Human Reproduction Overview

Reproductive Method

• Mode of reproduction is exclusively sexual.

Page 15-17: Sexual Reproduction

Characteristics

• Only sexual reproduction is viable; no asexual means.

• Involves genetic material from two parents, preventing mutations.

Page 18: Reproductive Anomaly Prevention

Genetic Variability

• Genetic recombination helps maintain species diversity while minimizing mutation rates.

Page 19-20: Male Reproductive Anatomy

Components

• Key Organs/Structures:

  • Testes (produce and nourish sperm)

  • Epididymis (sperm storage)

  • Vas deferens (sperm transport)

  • Seminal vesicle, prostate and bulbourethral glands (fluid contributions to semen).

  • Urethra (common duct for urine and sperm).

Page 21: Factors Affecting Spermatogenesis

Conditions for Optimal Reproductive Health

1. Optimal temperature range (34.5 °C).

2. High enzymatic activity; excess heat disrupts enzymes.

3. Hormonal balance and blood flow is essential.

4. Cellular health and oxidative stress management.

Page 22-24: Functionality of Male Reproductive Organs

Functional Roles

• Scrotum: Regulates temperature for testis.

• Epididymis: Transports and stores sperm.

• Urethra: Exit duct for both urine and semen.

Page 25-29: Glandular Contributions to Semen

Gland Functions

• Seminal Vesicle: Provides alkaline fluid for nourishment.

• Prostate Gland: Adds fluid to neutralize acidity in the female reproductive tract.

• Bulbourethral Gland: Supplies lubrication fluid.

• Penis: Functions as the copulatory organ to deliver sperm.

Page 30-31: Female Reproductive Anatomy

Key Structures

• Ovary: Produces and nourishes egg cells.

• Fallopian Tubes: Site of fertilization and pathway to the uterus.

• Uterus: Nourishes the developing embryo.

• Vagina: Serves as the birth canal and organ for receiving sperm.

Page 32-38: Reproductive Anatomy Overview

Detailed Female Structures

• Cervix: Prevents entry of foreign materials.

• Bartholin's Gland: Produces lubricating fluid.

• Fimbriæ: Aid in egg capture during ovulation.

Page 39: Gametogenesis Overview

Process of Gametogenesis

• Purpose is to reduce chromosome number via spermatogenesis (males) and oogenesis (females).

• Reduction of the chromosome number

• Makes sperm cells sufficiently motile

• Produces egg cells with enough nutrients

  

Page 40-46: Spermatogenesis

Stages of Sperm Development

-Occurs in the seminiferous tubules of male testis, Nourishing cells include the Sertoli cells, and Starts during puberty and continuous throughout life.

1. Proliferation: Initial stages involving mitosis of spermatogonia.

2. Growth: Spermatogonia develop into primary spermatocytes.

3. Maturation involves the meiotic division of the primary spermatocyte

   • Meiosis I a primary spermatocyte produces two secondary spermatocytes.

   • Meiosis II of each secondary spermatocyte produces two spermatids.

4. Differentiation- Each spermatid differentiates to become functional and motile spermatozoon.

Page 47-50: Oogenesis

Stages of Oocyte Development

It occurs in the ovaries and fallopian tubes.The follicles of the ovary exert hormonal influence.It starts during the pregnancy  of the mother

• Proliferation: Oogonia undergo mitotic division.

• Growth: Development into primary oocytes.

• Maturation: involves the meiotic division of the primary oocyte to reduce chromosome number.

  • Meiosis I of the primary oocyte produces a secondary oocyte and a polar body.

  • Meiosis II of the secondary oocyte produces an ootid and another polar body.

• Differentiation: The ootid is a very transient stage. Eventually, it becomes the ovum, but with very minimal differentiation.

Page 51-53: Hormonal Influence in Oogenesis

Ovarian Follicles Interaction

• Follicles provide hormones influencing maturation and readiness for fertilization.

Page 54-60: Final Stages of Oogenesis

Completion and Significance

• The final stages produce the ovum, capable of being fertilized by sperm, and discuss the role of polar bodies.

Page 61-64: Human Fertilization Process

Stages of Fertilization

• Sperm penetrates layers granulosa and jelly coat layerssurrounding the egg.- With slow-block and fast-block mechanisms against polyspermy

  

• Fusion of gamete membranes occurs, followed by mechanisms to prevent polyspermy.

• Produces the zygote with normal or restored chromosome number

  

Page 65-67: Pre-implantation and Implantation

Stages of Embryo Development

• From zygote to blastocyst; implantation occurs as the embryo develops layers.

• Gastrulation forms the trilaminar embryo.

Page 68-70: Extraembryonic Membranes

Functionality

• Amnion, yolk sac, allantois, and chorion support development and nutrient exchange in the embryo.

Page 71-73: Fetal Development

Organogenesis

• Distinct period for organ development from embryonic through fetal stages.

• Specific milestones in growth and development over timeline.

Page 74: Crucial Development Periods

Question

• Discussion of the most critical stages in human development.

Page 75-76: Statement Verification and Comparisons

True/False Statements

• Activities to gauge understanding and compare embryonic and fetal development.

Page 77-79: Summary of Human Life Cycle

Cycle Highlights

• Overview of fertilization, development, and pre-implantation.

Page 80-82: Teratogenic Risks and Developmental Phases

Awareness

• Acknowledgment of sensitive stages and teratogens' impacts on development during pre-embryonic, embryonic, and fetal time frames.