MH12th| Biology| Chapter 2 Reproduction in Lower & Higher Animals

 

Topics to be Learn:

• Reproduction
• Asexual Reproduction in animals
• Sexual Reproduction in animals
• Menstrual cycle (Ovarian cycle)
• Gametogenesis
• Fertilization / Syngamy
• Embryonic development
• Pregnancy / Gestation
• Placenta
• Parturition
• Lactation
• Reproductive Health
• Birth control
• Sexually Transmitted Diseases (STDs)
• Infertility
  

Reproduction:

• Definition: Biological process forming new life from similar existing life.
• Ensures species survival over time.
• Methods: Asexual and sexual.

Asexual Reproduction in Animals:

• Characteristics:
  
  • Common and primitive.
  • No meiosis or gamete formation/fertilization.
  • Involves single parent.
  • Offspring identical to parent (clone).
• Examples: Gemmule formation and Budding.
  Gemmule Formation in Sponges:
• Definition: Internal bud exclusive to sponges for asexual reproduction during unfavorable conditions.
• Characteristics:
  
  • Gemmule: Mass of dormant archaeocytes.
  • Archaeocytes develop into new organism.
  • Amoebocytes secrete thick membrane around archaeocytes.
  •  
• Process:
  
  • Gemmules remain dormant until favorable conditions return.
  • Hatch and develop into new individuals.
• Example: Spongilla. 
• Budding in Coelenterates and Colonial Ascidians:
•   

• Definition: Simple asexual reproduction method observed in coelenterates (Hydra and corals) and some colonial ascidians.
• Formation: Small outgrowth (bud) develops towards basal end of body.
• Development: Bud grows, forms tentacles, and transforms into new individual. Young Hydra detaches from parent to become separate organism. 

• Sexual Reproduction in Animals:

• Definition: Offspring produced by fusion of gametes (amphimixes).
• Gamete Formation: Both male and female parents undergo meiosis in gonads.
• Phases in Life: 
• a) Juvenile Phase/Pro-reproductive Phase: Growth.
• b) Reproductive/Maturity Phase: Sex organ maturation.
• Breeding Patterns:
• Seasonal Breeders: Breed only in particular season (e.g., goat, sheep, donkey).
• Continuous Breeders: Breed throughout the year (e.g., human, apes).

•  Human Reproduction:
  • Steps:
    
    1. Gametogenesis
    2. Insemination
    3. Internal Fertilization
    4. Zygote Formation and Embryogenesis
    5. Gestation and Parturition
    6. Lactation
  • Primary Sex Organs:
    
    • Male: Testes (singular: testis)
    • Female: Ovaries (singular: ovary)
  • Secondary or Accessory Sex Organs:
    
    • Male: Organs other than testis.
    • Female: Organs other than ovaries.
  • Secondary Sexual Characteristics:
    
    • Males: Beard, mustache, chest hair, muscular body, enlarged larynx, etc.
    • Females: Developed breasts, broader pelvis, high-pitched voice, etc.
  • Sexual Dimorphism:Phenomena identifying sexes externally.
  Male Reproductive System:
  • 
  • Parts:
    
    1. Testes
    2. Accessory Ducts
    3. Glands
    4. External Genitalia

  Testes:

  • Position: Located in scrotum.
  • Structure:
  • Male gonads.
  • Dimensions: Approximately 4.5 cm length, 2.5 cm width, 3 cm thickness.
  • Contains 200 to 300 lobules with seminiferous tubules.
  • Functions:
  • Produce sperm.
  • Secrete male sex hormone, androgen or testosterone.

Accessory Ducts:

• Components:
  
  1. Rete Testis
  2. Vasa Efferentia
  3. Epididymis
  4. Vas Deferentia
  5. Ejaculatory Duct
  6. Urethra

1. Rete Testis:

• Position: Posterior side of testis.
• Structure: Formed by convergence of Seminiferous tubules.
• Functions: Carry sperms to vasa efferentia.

2. Vasa Efferentia:

• Position: Arise from rete testis and end into epididymis.
• Structure: 12-20 fine tubules.
• Functions: Carry sperms to epididymis.

3. Epididymis:

• Position: Located on posterior border of each testis.
• Structure: Long, coiled tubes with caput, corpus, and cauda regions.
• Functions: Sperm maturation occurs.

4. Vas Deferentia:

• Position: Enter abdominal cavity through inguinal canal, ascend as spermatic cord.
• Structure: Pair of 40 cm long tubular structures.
• Function: Carry sperm from epididymis to ejaculatory ducts.

5. Ejaculatory Duct:

• Position: About 2 cm long, formed by joining vas deferens and ducts of seminal vesicles.
• Structure: Tube-like structure passing through prostate gland, opening into urethra.
• Functions: Carry seminal fluid containing spermatozoa to urethra.

6. Urethra:

• Position: Extends through penis.
• Structure: About 18-20 cm long tube with urethral orifice.
• Functions: Provides passage for urine and semen.

Accessory Glands:

• Components: Seminal Vesicles, Prostate Gland, Cowper’s or Bulbourethral Glands.
• Functions: Secrete fluids aiding reproductive functions.

    External Genitalia:

• Components: Penis, Scrotum.
• Functions: Copulatory organ (penis), thermoregulator (scrotum).

Terms Associated with External Genitalia of Male:

1. Inguinal Canal: Passage for testes descent into scrotum.
2. Gubernaculum: Fibro-muscular band in scrotum.
3. Cryptorchidism: Failure of testis descent into scrotum causing sterility.
4. Erectile Tissues in Penis: Paired Corpora Cavernosa, Median Corpus Spongiosum.

Semen:

• Composition: Viscous, alkaline, milky fluid containing sperm and secretions from epididymis, prostate gland, and Cowper’s glands.
• Rich in: Fructose, Ca++, bicarbonates, prostaglandins.

Histology of Testis:

 

• External Coverings (L.S.):
• Outer to inner: Tunica Vaginalis, Tunica Albuginea, Tunica Vasculosa.
• Testicular Structure:

• Divided into 200-300 testicular lobules by Tunica Albuginea.
• Each lobule contains 1-4 seminiferous tubules.

• Cellular Components:

• Interstitial Cells of Leydig (Leydig's Cells):

• Found between seminiferous tubules.
• Secrete male hormone androgen or testosterone.

• Germinal Epithelial Cells: Cuboidal cells lining seminiferous tubules.
• Sertoli Cells (Sub-tentacular Cells or Nurse Cells):

• Large pyramidal cells.
• Provide nutrition to developing sperm.

• Stages of Sperm Development: Spermatogonia, Primary Spermatocyte, Secondary Spermatocyte, Spermatids, Sperms.
   

  Female Reproductive System:

   

• Parts:
  
  1. Ovaries
  2. Fallopian Tubes (Oviducts)
  3. Uterus (Womb)
  4. Vagina
  5. External Genitalia (Vulva)
  6. Vestibular Glands
  7. Mammary Glands

Ovaries:

• Situated in upper lateral part of pelvis near kidneys.
• Dimensions: About 3 cm length, 1.5 cm breadth, 1.0 cm thickness.
• Solid, oval or almond-shaped.
• Produce ova and hormones (estrogen, progesterone, relaxin, activin, inhibin).
• Control secondary sexual characteristics, menstrual cycle, pregnancy, and parturition.

Fallopian Tubes (Oviducts):

• Horizontal over peritoneal cavity.
• Length: 10 to 12 cm.
• Lined by ciliated epithelium.
• Transport ovum from ovary to uterus.
• Subdivisions:

• Infundibulum: With finger-like processes (fimbria).
• Ampulla: Site of fertilization.
• Cornua or Isthmus: Opens into uterus.

Uterus (Womb):

• Pear-shaped, highly muscular, thick-walled, hollow organ.
• Dimensions: About 8 cm length, 5 cm width, 2 cm thickness.
• Three Parts: Fundus, Body (Corpus), Cervix.
• Layers:

• Perimetrium: Outer serous layer.
• Myometrium: Middle thick muscular layer.
• Endometrium: Inner highly vascular mucosa with uterine glands.

• Functions: Receive ovum, develop placenta during pregnancy, expel young at birth.

Vagina:

• Highly distensible fibro-muscular tube between cervix and vestibule.
• Length: 7 to 9 cm.
• Internally lined by stratified, non-keratinized epithelium.
• Functions: Birth canal, copulatory passage, passage of menstrual flow.
• Opens into vestibule with vaginal orifice, may be covered with hymen.

External Genitalia (Vulva):

• Components:
  
  1. Labia Majora
  2. Labia Minora
  3. Mons Veneris
  4. Clitoris
  5. Vestibule.

Vestibular Glands (Bartholin’s Glands): Release lubricating fluid into vestibule.

Mammary Glands (Breasts): Accessory organs for production and release of milk after parturition.

Puberty / Sexual Maturity in Females:

• Initiation of Puberty:
  
  • Gonadotropins (FSH and LH) secreted by anterior pituitary stimulate ovaries.
  • Ovaries produce estrogen and progesterone.
  • Hormonal changes bring about secondary sexual characters.
• Reproductive Age of Female:
  
  • Period from menarche to menopause.
  • Menarche: Beginning of menstrual cycle at 10 to 14 years.
  • Menopause: Cessation of reproductive cycles around 45 to 50 years due to hormonal imbalance.
• Structure and Development of Ovary:
  • Histological Structure:
    
    • Central part: Medulla.
    • Outer part: Cortex.
    • Cortex covered by germinal epithelium, medulla contains stroma with blood vessels, lymph vessels, and nerve fibers.
  • Ovarian Follicle Development:
    
    • Primordial follicles mature into multilayered primary, secondary, and Graafian follicles during menstrual cycle.
    • Graafian follicle: Outer layers - theca externa, theca interna, membrane granulosa, filled with antrum containing liquor folliculi.
    • Cumulus oophorus or discus proligerus: Small hillock of cells over which ovum is lodged.
    • Layers covering ovum: Vitelline membrane, zona pellucida, corona radiata.
  • Corpus Luteum:
    
    • Formed from empty Graafian follicle after ovulation.
    • Converts into corpus albicans (white body) in absence of conception.
  Menstrual Cycle (Ovarian Cycle)
  • Overview:
    
    • Series of cyclic changes in ovary and uterus.
    • Regulated by gonadotropins from pituitary and hormones from ovary.
    • Cycles repeated approximately every 28 days.

  Phases of Menstrual Cycle and Their Hormonal Control:

  1. Menstrual Phase (Day 1-5):

• Occurs in absence of fertilization.
• Uterine endometrium sloughed off.
• Decrease in progesterone and estrogen levels.
• Release of prostaglandins causing endometrial rupture.
• Discharge of blood, tissue fluid, mucus, cellular debris through vagina.
• FSH secretion from pituitary stimulates follicle development.

2. Follicular Phase (Day 5-14):

• Follicles develop in ovary, endometrium proliferates.
• 6 to 12 secondary follicles develop, one becomes Graafian follicle.
• Developing follicles secrete estrogen.
• Estrogen stimulates endometrial regeneration, proliferation.
• Endometrial thickness: 3-5 mm.

3. Ovulatory Phase (Day 14-15):

• Ovulation occurs.
• Mature Graafian follicle ruptures, secondary oocyte released.
• Surge of LH from pituitary triggers ovulation.

4. Luteal Phase (Day 16 to 28):

• Empty Graafian follicle becomes corpus luteum under LH influence.
• Uterine endometrium thickens, becomes more secretory (secretory phase).
• Corpus luteum secretes progesterone, estrogen, inhibin.
• Stimulates growth of endometrial glands, uterine secretions.
• Endometrium becomes more vascularized, 8-10 mm thick.
• Corpus luteum survives for two weeks, then degenerates into corpus albicans if no fertilization.
• If fertilization occurs, hCG secreted by embryo maintains corpus luteum.
• Presence of hCG in blood and urine indicates pregnancy.
• If no fertilization, corpus luteum regresses, new menstrual cycle begins.

Gametogenesis:

• Definition: Formation of gametes in sexually reproducing animals.
• Types of Gametes: Sperm: Male gamete andOvum (Egg): Female gamete.
• Formation of Gametes: From primordial germ cells of gonads.

• Spermatogenesis:
  
  • Process of sperm formation.
  • Occurs in testis (male gonads) in seminiferous tubules lined by germinal epithelium.
  • Nurse cells (or Sertoli cells) provide nourishment to developing sperms.
•  
• Phases of Spermatogenesis:
  
  • Multiplication Phase
  • Growth Phase
  • Maturation Phase
• Multiplication Phase: Repeated mitotic divisions produce spermatogonia (diploid).
• Growth Phase: Spermatogonium grows in size, becomes primary spermatocyte.
• Maturation Phase:
  
  • Primary spermatocyte undergoes first meiotic division, forming two haploid secondary spermatocytes.
  • Secondary spermatocyte undergoes second meiotic division, forming spermatids.
• Spermiogenesis: Spermatids undergo metamorphosis to form mature, motile sperms.
• Changes During Spermiogenesis:
  
  • Increase in sperm length.
  • Distinction of centrioles into proximal and distal.
  • Formation of axial filament, spirally coiled mitochondria, and acrosome from Golgi complex.

 Structure of Sperm (Spermatozoa):

 

• Description:
  
  • Microscopic, elongated haploid motile male gamete.
  • Measures about 0.055 mm in length.
  • Produced by spermatogenesis.
  • Viability: 72 hours, fertilization potential: 12 to 14 hours.
• Parts of Sperm: Head, Neck, Middle Piece, Tail.

Head:

• Main part, flat and oval.
• Contains large nucleus and acrosome.
• Acrosome: Derived from Golgi complex, secretes hyaluronidase for egg penetration.
• Covered by a fibrillar sheath.

Neck:

• Short region with two centrioles.
• Proximal centriole aids in first cleavage of zygote.
• Axial filament formed by distal centriole.

Middle Piece:

• Functions as powerhouse for sperm.
• Contains many spirally coiled mitochondria.
• Mitochondria supply energy for sperm's movement (1.5 to 3 mm per minute).
• Covered by a sheath along with posterior half of nucleus and neck.

Tail:

• Long, slender, tapering structure.
• Formed of cytoplasm.
• Contains axial filament and nine accessory fibers surrounding two central longitudinal axial filaments.
• Tail lashes, aiding spermatozoa's swimming.

• Oogenesis: Process in the ovary leading to the formation of the secondary oocyte.

  Phases of Oogenesis:

  • Phase of Multiplication: Oogonia formation in large numbers.
  • Phase of Growth: One oogonium enlarges, becoming a primary oocyte.
  • Phase of Maturation:
  • Primary oocyte undergoes meiosis I, forming a large haploid secondary oocyte.
  • Unequal cytoplasmic division: secondary oocyte and polar bodies.

1. •  

Structure of Ovum (Secondary Oocyte):

 

• Rounded, haploid, non-motile, largest cell in the body (0.1 mm diameter).
• Microlecithal, almost yolk-free.
• Abundant cytoplasm with a large eccentric nucleus surrounded by a vitelline membrane.
• Centriole absent.
• Exhibits polarity: animal pole (with polar body and nucleus) and vegetal pole.
• Enclosed by zona pellucida (inner, thin, non-cellular) and corona radiata (outer, thick, cellular).
• Perivitelline space between vitelline membrane and zona pellucida.
• Zona pellucida secreted by the ovum, corona radiata formed by follicular cells.

• Fertilization / Syngamy
  
  • Fertilization: Fusion of haploid male and female gametes into a diploid zygote.
  • Location: Internal, occurs in the ampulla of the fallopian tube.
  • Sequence of Events:

1. Capacitation of Sperms:
2. Sperms move towards the secondary oocyte.
3. Release of Acrosomal Enzymes:
4. Sperm head releases enzymes upon contact with the secondary oocyte.
5. Separation of Corona Radiata Cells:
6. Acrosomal enzymes like hyaluronidase dissolve cells of the corona radiata.
7. Compatibility Reaction:
8. Fertilizin (egg) binds with antifertilizin (sperm).
9. Zona pellucida of the egg has fertilizin receptor proteins (ZP3, ZP2).
10. Acrosome ruptures, releasing acrosin / zona lysin.
11. Acrosome Reaction:
12. Acrosin dissolves zona pellucida and vitelline membrane at the contact point of the sperm head.
13. Entry of Sperm Nucleus into Ovum:
14. Sperm nucleus and centriole enter the ovum.
15. Formation of Fertilization Membrane / Cortical Reaction:
16. Vitelline membrane of the ovum converts into a fertilization membrane, preventing polyspermy.
17. Activation of Ovum:
18. Completion of meiosis-II of the secondary oocyte occurs.
19. Ovum receives the centriole from the sperm, completing meiosis-II and releasing the second polar body.
20. Syngamy / Karyogamy:
21. Fusion of male pronucleus and female pronucleus.
22. Synkaryon formed after fusion of male and female nuclei.
23. Formation of Diploid Zygote:Concludes the process of fertilization.

1. Significance of Fertilization:

• Forms Zygote: Fertilization creates the zygote, which develops into new offspring.
• Restores Diploid Chromosomes: Two haploid gametes merge during fertilization, restoring the diploid number of chromosomes in the zygote.
• Completion of Oogenesis: Fertilization passes on centrioles to the ovum, allowing the secondary Oocyte to complete meiosis-II, concluding the process of oogenesis.
• Genetic Variation: Fertilization mixes the genetic characters of two parents, leading to variation and playing a role in evolution.
• Determines Sex: Fertilization determines the sex of the offspring.

1. 
   

   Embryonic Development:

2. Cleavage:
   
   • Rapid mitotic divisions of the zygote to form a hollow spherical multicellular blastula.
   • Begins as the zygote passes through the fallopian tube.
   • Holoblastic, equal, and indeterminate in humans.
   • Daughter cells are called blastomeres.

    Cleavage Stages: 

Cleavage	Direction	Time	Results
First	Vertical (animal pole - vegetal pole)	32 hours after fertilization	Two blastomeres
Second	Vertical (perpendicular to first)	60 hours after fertilization	Four blastomeres
Third	Horizontal (at right angles to first two)	32 hours after fertilization	Eight-celled stage (morula)

 

 Blastulation:

• Formation of a hollow, multicellular blastocyst from the 16-32 celled morula stage.
• Blastocyst reaches the uterus and absorbs glycogen-rich uterine milk.
• Outer layer forms trophoblast, inner cells form inner cell mass or embryoblast.
• Blastocyst size doubles from 0.15 mm to 0.30 mm.
• Trophoblast cells flatten, forming a blastocyst cavity.
• Rauber's cells are trophoblast cells in contact with the embryonal knob.

• Implantation:

  • Embedding of the blastocyst in the uterine endometrium for further gestation.
  • Occurs on the 7th to 10th day after fertilization.
  • Trophoblast divides into cytotrophoblast and syncytiotrophoblast, aiding in burying the blastocyst in the endometrium.

   

  Gastrulation:

• Definition: Formation of gastrula from the blastocyst, starting around 8 days after fertilization.
• Events during Gastrulation:

• Differentiation of blastomeres: Rearrangement of blastomeres forms three germinal layers.
• Morphogenetic movements: Cells move to their destined areas of differentiation.

Sequential Changes in Gastrulation:

1. Formation of endoderm
2. Formation of embryonic disc
3. Formation of amniotic cavity
4. Formation of ectoderm
5. Formation of mesoderm
6. Formation of extra-embryonic coelom
7. Formation of chorion and amnion

Organogenesis:

• Definition: Process of forming organs after gastrulation.
• Fate of Germinal Layers (Histogenesis):
• Ectoderm: Epidermis, sweat glands, lens, nervous system, etc.
• Mesoderm: Muscles, connective tissue, circulatory system, kidney, etc.
• Endoderm: Epithelium of gut, glands of stomach, lungs, liver, pancreas, etc.

• Pregnancy / Gestation:

• Definition: Condition of developing foetus in the uterus.
• Duration: About 280 days in humans, divided into three trimesters of three months each.

Three Trimesters:

    First Trimester: (From fertilization to 12th week)

• Radical changes in mother's body and embryo.
• Organogenesis occurs.
• Embryo becomes a rudimentary foetus (~3 cm long) by eight weeks.
• Major organs, limbs, CNS, and circulatory system develop.
• Maternal progesterone levels rise, suspending menstrual cycle.
• Foetus reaches ~7-10 cm by trimester end.
• Mother may experience morning sickness.

    Second Trimester: (From 13th to 26th week)

• Foetus grows to ~30 cm.
• Pregnancy becomes visually apparent.
• Hormone levels stabilize, placenta takes over progesterone production.
• Foetus develops hair, eyebrows, eyelashes, pinnae.
• Baby's movements felt by mother.
• Foetus reaches half the size of a newborn.

    Third Trimester: (From 27th week till parturition)

• Foetus grows to ~50 cm and 3-4 kg.
• Uterus expands, compressing maternal organs.
• Mother experiences frequent urination, digestive issues, back strain.
• Foetus fully developed and ready for parturition.

Placenta:

• Definition: Flattened, discoidal organ attached to uterine wall and baby's umbilical cord.
• Functions: Facilitates nutrient and oxygen exchange, removes waste.
• Formation: Combination of foetal chorionic villi and maternal uterine wall.
• Type: Human placenta is haemochorial (foetal villi and maternal tissue).
• Endocrine Function: Produces hormones like hCG, progesterone, estrogen, and relaxin.

•  
•  

  Parturition:

• Definition: Birth process accompanied by labour pains.
• Neuro-endocrine Mechanism:
  
  • Rise in estrogen:progesterone ratio.
  • Increase in oxytocin receptors in uterine wall.
• Stages:
  • Dilation Stage: (~12 hours)
    
    • Uterine contractions start, moving baby toward cervix.
    • Oxytocin secretion causes severe uterine contractions.
    • Cervix and vagina dilate, amniotic sac ruptures.
    •  
  • Expulsion Stage: (20 to 60 minutes)
    
    • Stronger uterine and abdominal contractions.
    • Foetus moves head down through cervix and vagina.
    • Umbilical cord tied and cut.
    •  
  • After Birth/Placental Stage: (10 to 45 minutes)
    
    • Placenta separates from uterine wall and expelled.
    • Uterine contractions continue.
    •  

Lactation:

• Definition: Nourishment of newborn through milk.
• Process:
  
  • Mammary glands become functional.
  • First milk called colostrum, rich in proteins and antibodies.
  • Neuroendocrine process involving various maternal glands.

Distinguish between Asexual and Sexual Reproduction:

Asexual Reproduction	Sexual Reproduction
Requires single parent.	Needs two different parents.
Only mitosis occurs.	Involves meiosis and mitosis.
No gamete formation or fertilization.	Gamete formation and fertilization occur.
Progeny and parent genetically identical.	Progeny and parents genetically dissimilar.
Produces large number of progeny.	Produces limited number of progeny.

 

Reproductive Health:

• Definition: Total wellbeing of emotional, behavioural, physical, and social aspects related to reproduction.
• Initiatives in India:
  
  • Reproductive and Child Health Care (RCH) programmes.
  • National-level action plans for improving reproductive health.
• Objectives:
  
  • Control population growth.
  • Improve awareness and facilities for reproductive health.
  • Reduce infertility, infant mortality, and maternal mortality rates.

Goals of RCH Programmes:

• Create awareness about reproduction.
• Provide reproductive health facilities.
• Support for a reproductively healthy society.
• Reduce infertility, infant, and maternal mortality rates.

Achieving RCH Goals:

1. Sex Education: Introduce in schools covering safe practices, STDs, adolescent issues.
2. Media Awareness: Use audio-visual and print media for dissemination.
3. Birth Control Education: Educate youth about contraception, prenatal, and postnatal care.
4. Population Control Awareness: Highlight problems of uncontrolled growth, sex crimes prevention.
5. Ban Awareness: Educate on statutory bans like amniocentesis for sex determination.
6. Immunization Awareness: Promote child immunization programmes.

• Birth Control:

• Definition: Methods to control family size through contraceptive measures.

Types of Contraceptive Methods:

1. Temporary Methods:

   • Natural Method/Safe Period/Rhythm Method: Avoiding intercourse around ovulation (14th day of menstrual cycle).
   • Coitus Interruptus or Withdrawal: Withdrawal of penis before ejaculation.
   • Lactational Amenorrhoea: Intense lactation post-parturition inhibits ovulation.
   • Chemical Means (Spermicides): Foam, tablets, jellies, or creams immobilize and kill sperm.

2. Mechanical Means/Barrier Methods:

   • Condom: Thin rubber sheath covering the penis; prevents STDs and AIDS.
   • Diaphragm, Cervical Caps, and Vaults: Rubber devices inserted into the vagina to cover the cervix.
   • Intra-uterine Devices (IUDs): Plastic or metal objects placed in the uterus; prevent fertilization or embryo implantation.
   • Oral Contraceptive Pills: Inhibit ovulation by suppressing FSH and LH secretion.
   • Birth Control Implant: Implanted under the skin of the upper arm; similar to oral contraceptives.

Permanent Methods:

• Sterilization: Surgical procedures for permanent contraception.
• Male Sterilization (Vasectomy): Cutting and sealing the vas deferens.
• Female Sterilization (Tubectomy): Blocking or sealing the fallopian tubes.

•  

  Medical Termination of Pregnancy (MTP):

• Definition: Intentional termination of pregnancy before full term.

• MTP is induced abortion.
• Indirectly controls population.
• Legalized in India since 1971.
• Performed for discontinuing unwanted pregnancies or due to foetal defects.
• Aborting healthy female embryos is illegal.
• Safely done only during the first trimester.

Amniocentesis:

• Process of collecting amniotic fluid containing foetal cells for chromosome analysis.
• Done to check for foetal abnormalities.
• Sex determination by amniocentesis is legally banned in India.

PC-PNDT Act (2003):

• Mandates:
  
  • Prohibition of sex selection before or after conception.
  • Regulation of pre-natal diagnostic techniques.
  • Prevention of misuse for sex determination leading to female foeticide.

• Aimed at banning sex selection techniques and preventing misuse of pre-natal techniques for sex-selective abortions.
• Essential for preventing female foeticides and improving the sex ratio in India.

• Sexually Transmitted Diseases (STDs):

• Definition: Infections transmitted through sexual intercourse.
• Also known as Venereal Diseases (VDs) or Reproductive Tract Infections (RTIs).
• Major diseases include syphilis and gonorrhoea.

Syphilis:

• Caused by: Spirochaete bacterium Treponema pallidum.
• Transmission Modes:

• Sexual intercourse, kissing, close body contact.
• Mothers can transmit to newborns (Congenital syphilis).

• Symptoms:

• Primary lesion called chancre at infection site.
• Skin rashes, fever, inflamed joints, hair loss.
• Paralysis, degenerative changes in heart and brain.

• Preventive Measures:

• Sex education, hygiene, avoiding sex with unknown partners.
• Condom use during intercourse.

• Treatment: Prompt treatment with Penicillin.

Gonorrhoea:

• Caused by: Diplococcus bacterium, Neisseria gonorrhoeae.
• Transmission Modes:

• Sexual contacts, infested clothes.
• Incubation period: 2-14 days in males, 7-21 days in females.

• Symptoms (Males): Partial urethral blockage, pus from penis, pain during urination, arthritis.
• Symptoms (Females): Pelvic inflammation, urinary tract issues, sterility, arthritis.
• Preventive Measures:

• Sexual hygiene, condom use.
• Avoiding sex with unknown or multiple partners.

• Treatment: Cefixime antibiotic.

• Infertility:

• Definition: Inability to conceive naturally after one year of regular unprotected intercourse.
• Options for infertile couples:
  
  • Fertility drugs
  • Test tube babies
  • Artificial insemination
  • Intrauterine insemination (IUI)
  • Surrogate motherhood
•  
• Assisted Reproductive Technologies (ART):
  
  • In Vitro Fertilization (IVF): Fertilization outside the body, with the embryo later transferred to the mother's body (test-tube baby).
  • Zygote Intra Fallopian Transfer (ZIFT): Transfer of the embryo into the fallopian tubes.
  • Gamete Intra Fallopian Transfer (GIFT): Transferring donor ovum to another female's fallopian tube acting as a surrogate mother.
  • Intra Cytoplasmic Sperm Injection (ICSI): Injection of single sperm directly into an ovum's cytoplasm in the laboratory.
  • Artificial Insemination (AI): Introduction of collected sperms into the female cervix for in vivo fertilization.
  • Intra Uterine Insemination (IUI): Similar to AI, but sperms are introduced into the uterine cavity.
  • Sperm/Semen Bank: Collection and storage of sperms for needy couples via cryopreservation.
  • Adoption: Legal adoption of a child by a couple or single parent.
  • Surrogate Mother: Implantation of embryo in a woman who acts as a surrogate, not the biological mother.
•  
• Impact of Substance Use on Infertility:
  
  • Tobacco/Nicotine: Blocks sperm production, reduces testicle size.
  • Alcoholism: Interferes with testosterone synthesis, impacts sperm count.
  • Cocaine/Marijuana: Reduces sperm count and quality temporarily.
   
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