Q4-Animal-Rep-System

ANIMAL REPRODUCTIVE SYSTEM & ANIMAL DEVELOPMENT

General Overview

  • General Biology 2 course, aimed at STEM 12 students.

Learning Competency

  • Compare and Contrast Processes:

    • Reproduction

    • Development

    • Nutrition

    • Gas Exchange

    • Transport/Circulation

    • Regulation of Body Fluids

    • Chemical and Nervous Control

    • Immune Systems

    • Sensory and Motor Mechanisms

Learning Objective

  • At the end of the lesson, students should be able to:

    1. Describe human reproductive organ systems.

    2. Value the importance of knowing human reproductive organ systems.

    3. List the advantages and disadvantages of sexual and asexual reproduction in animals.

Mechanisms of Sexual Reproduction

Types of Fertilization

  • Internal Fertilization:

    • Male delivers sperm cells directly into female body.

    • Example: Most terrestrial animals, few fish, and some aquatic animals.

  • External Fertilization:

    • Mating partners release eggs and sperm simultaneously into the water.

    • Example: Many aquatic animals like fish and amphibians.

    • Note: Exceptions include aquatic mammals and certain fish.

Reproductive System Overview

  • Variation in reproductive processes among organisms.

  • Generalizations help understand the variations in animal reproductive systems.

Human Reproduction

Male Reproductive System Components

  • Key Structures:

    • Bladder, Pubic Symphysis, Prostate, Corpus Spongiosum, Urethra, Foreskin, Penis, Glans, Urethral Opening (Meatus).

    • Vas Deferens, Anus, Epididymis, Testicle (Testis), Scrotum, Seminal Vesicle, Ejaculatory Duct.

Female Reproductive System Components

  • Key Structures:

    • Ovarian Ligament, Fimbriae, Uterus, Uterine Fundus, Fallopian Tube, Ovary, Cervical Canal, Cervix, Vagina.

Female Reproductive System Details

  • Ovaries:

    • Produce egg cells and sex hormones.

    • Contain follicles; ovulation expels egg cells.

  • Oviducts and Uterus:

    • Egg cell released near fallopian tube; uterus expands during pregnancy.

    • Endometrium has rich blood supply; cervix opens to vagina.

  • Vagina and Vulva:

    • Repository for sperm; serves as birth canal.

    • Vulva is external female genitalia.

  • Mammary Glands:

    • Present in both sexes but primarily functional in women for milk secretion.

    • Not part of the reproductive system but plays a significant role in reproduction.

Male Reproductive System Details

  • Testes:

    • Composed of coiled tubes; interstitial cells produce testosterone.

  • Ducts:

    • Sperm travel from seminiferous tubules to epididymis; ejaculatory duct formed by vas deferens and seminal vesicle ducts.

  • Glands:

    • Accessory glands contribute secretions to semen (seminal vesicles, prostate gland, bulbourethral glands).

  • Penis Structure:

    • Composed of spongy erectile tissue which engorges with blood during arousal.

Physiological Reactions

  1. Vasocongestion:

    • Tissue filling with blood due to increased blood flow.

  2. Myotonia:

    • Increased muscle tension in skeletal and smooth muscles.

Contraception and Its Types

  • Types of Methods:

    • Ovulation-suppressing methods (e.g., oral contraceptives).

    • Barrier methods (e.g., condom, diaphragm).

    • Chemical methods (e.g., spermicides).

    • Surgical methods (e.g., vasectomy, tubal ligation).

    • Implantation-suppressing methods (e.g., IUD).

    • Others (e.g., abstinence).

Stages of Animal Development

  • Key Stages:

    • Gametogenesis

    • Fertilization

    • Cleavage

    • Organogenesis

    • Differentiation and Growth

Gametogenesis

  • Production of specialized reproductive cells (gametes); haploid.

  • Types of Gametogenesis:

    • Oogenesis: Production of egg cells in ovaries.

    • Spermatogenesis: Production of sperm cells in testes.

Fertilization Process

  • Union of sperm and egg; restores diploid chromosome number.

  • Takes place in oviduct (fallopian tube).

  • Key Events:

    • Sperm penetration initiates biochemical events.

    • Nuclear fusion forms diploid zygote.

Cleavage Process

  • Rapid series of mitotic cell divisions post-fertilization.

  • No significant growth; creates multicellular embryo (blastula).

  • Components:

    • Blastomeres: Individual cells formed during cleavage.

    • Blastocoel: Fluid-filled cavity within the blastula.

Organogenesis

  • Formation of organs from three germ layers during gastrulation:

    • Ectoderm: Outermost layer (skin, nervous system).

    • Mesoderm: Middle layer (muscles, bones, circulatory system).

    • Endoderm: Innermost layer (digestive and respiratory systems).

Differentiation and Growth

  • Cells become specialized and perform specific functions.

  • Growth involves cell division, enlargement, and extracellular material production.

Human Development Stages

  • Key Events:

    1. Fertilization

    2. Cleavage

    3. Blastocyst formation

    4. Implantation

    5. Gestation

  • Fertilization: Merging of sperm and egg forms diploid zygote.

  • Cleavage: Zygote travels down fallopian tube.

  • Morula and Blastocyst: Morula forms after 3-4 days; transforms into blastocyst by day 5-6.

  • Implantation: Blastocyst attaches to uterine lining after 6-7 days.

  • Gestation: Lasts approximately 40 weeks; divided into embryonic stage (first 8 weeks) and fetal stage (from ninth week to birth).