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Procreation, Genetics, and Nursing Care - Vocabulary Flashcards

Theories of Procreation

  • Procreation defined as the biological process of producing offspring; essential for continuation of the human species. Involves union of sperm (male) + egg (female) → zygote.
  • Theories of Procreation:
    • Preformation Theory (outdated): a tiny human (homunculus) preformed in the sperm/egg.
    • Epigenesis Theory: development occurs gradually from the fertilized egg.
    • Modern Genetic Theory: DNA and genes carry traits from both parents.

Process of Human Reproduction

  • Gamete Formation: sperm (male) and eggs (female).
  • Fertilization: union of gametes in the fallopian tube → zygote.
  • Cell Division: zygote → blastocyst → implantation.
  • Embryonic & Fetal Development: organs form; fetus grows.

Genetic Disorders and Types

  • Definition: A genetic disorder is a disease or condition caused by an abnormality in a person’s DNA. Abnormality may be:

    • A mutation (change) in a single gene,
    • An extra or missing chromosome, or
    • A combination of genetic and environmental factors.

  • Types of Genetic Disorders (with Examples):

    • Single-Gene Disorders (changes in one gene)
    • Sickle Cell Anemia: red blood cells crescent-shaped; pain and poor oxygen transport.
    • Cystic Fibrosis: thick mucus affects lungs and digestion.
    • Chromosomal Disorders (number/structure of chromosomes)
    • Down Syndrome: extra copy of chromosome 21 → intellectual disability, facial features.
    • Turner Syndrome: missing one X chromosome in females → short stature, infertility.
    • Multifactorial Disorders (genes + lifestyle/environment)
    • Diabetes, Heart Disease, Cleft Lip/Palate.

Teratogenic Problems

  • Teratogens: substances or environmental exposures that cause abnormal development of the embryo/fetus, leading to birth defects or pregnancy complications.

  • Examples & Effects:

    • Drugs/Medications: Thalidomide → limb deformities; Isotretinoin (Accutane) → facial, heart, brain defects.
    • Alcohol: Fetal Alcohol Syndrome (FAS) → small head, facial abnormalities, learning difficulties.
    • Infections (TORCH):
    • Toxoplasmosis → brain damage, blindness
    • Rubella → deafness, heart defects, cataracts
    • Cytomegalovirus (CMV) → developmental delays, microcephaly
    • Herpes Simplex Virus (HSV) → neurologic damage, stillbirth
    • Environmental Exposures: Radiation → growth retardation, microcephaly; Lead & Mercury → brain damage; industrial solvents → miscarriage, limb malformations.
    • Lifestyle Factors: Smoking → low birth weight, cleft lip/palate, preterm birth; Illicit drugs (e.g., cocaine) → small head size, placental abruption.

  • Critical Period of Risk:

    • Most dangerous time: First trimester (3–8 weeks) when organs form (organogenesis).
    • Teratogenic exposure during this period has greatest chance of structural defects.
    • Later exposure may cause growth restriction, functional or behavioral problems.

Genetic Inheritance Patterns

  • When parents have a genetic disease, their child may inherit the condition depending on the pattern of inheritance.

  • Patterns:

    • Autosomal Dominant: one copy of the mutated gene is enough to cause disease.
    • Examples: Huntington’s disease, Marfan syndrome, Polycystic Kidney Disease.
    • Risk: Each child has a P{ ext{affected}} = 0.5 (50%) chance of inheriting the disorder. P{ ext{affected}} = 0.5 ext{ per pregnancy}
    • Autosomal Recessive: both parents must carry the defective gene.
    • If both parents are carriers: child probabilities: 25% affected, 50% carrier, 25% healthy.
      P( ext{affected}) = 0.25,\, P( ext{carrier}) = 0.50,\, P( ext{healthy}) = 0.25
    • Examples: Sickle cell anemia, Cystic fibrosis, Thalassemia.
    • X-Linked Disorders: gene on X chromosome; mothers often carriers; sons more affected.
    • Examples: Hemophilia, Duchenne Muscular Dystrophy.
    • Risk: A mother who is a carrier has a 50% chance to pass the mutation to sons (affected) and a 50% chance to daughters (carriers).
    • Multifactorial Inheritance: caused by genetics + environment.
    • Examples: Diabetes, heart disease, cleft lip/palate.

  • Illustrative Notes:

    • Autosomal dominant patterns often appear in every generation if penetrance is high.
    • Autosomal recessive disorders may skip generations; parents are often carriers.
    • X-linked disorders disproportionately affect males; females may be carriers.

  • Visual cues from slides (simplified):

    • Autosomal Dominant: affected parent → every affected child, with 50% risk per child.
    • Autosomal Recessive: carrier × carrier → 25% affected, 50% carrier, 25% healthy.
    • X-Linked: affected sons from carrier mother; carrier daughters possible from carrier mother.

  • Note on terminology: Carrier = a person who has one copy of a gene mutation but is phenotypically normal.

Genetic Testing and Counseling (Common Tests)

  • Newborn Screening: simple procedure to detect congenital metabolic disorders that may lead to mental retardation or death if untreated.
  • Diagnostic Testing: identifies or rules out a specific genetic or chromosomal condition; often confirms a suspected diagnosis.
  • Carrier Testing: identifies people who carry one copy of a gene mutation; informs couple’s risk when both partners are tested.
  • Prenatal Testing: detects changes in a fetus’s genes or chromosomes before birth.
    • Amniocentesis: sampling of amniotic fluid; detects chromosomal disorders.
    • CVS (Chorionic Villus Sampling): early placental tissue sampling.
  • Preimplantation Testing (PGD): testing embryos created via IVF; only embryos without specific genetic changes are implanted.
  • Predictive and Presymptomatic Testing: detects gene mutations associated with adult-onset disorders (e.g., certain cancers) in asymptomatic individuals.
  • Forensic Testing: uses DNA to identify individuals for legal purposes (not disease-focused).
  • Screening Tests (non-diagnostic):
    • Ultrasound: detects physical defects.
    • Maternal serum screening: measures hormone/protein levels.
    • NIPT (Non-invasive Prenatal Testing): analyzes fetal DNA in maternal blood.

Nursing Process in Genetic Care

  • Assessment: gather family and medical history; assess lifestyle factors.

  • Diagnosis: anxiety, risk for altered family processes, knowledge deficit.

  • Planning: refer to genetic counselor; set goals for healthy pregnancy.

  • Implementation: educate about risks; encourage folic acid intake; provide emotional support.

  • Evaluation: assess client understanding, coping, and informed decision-making.

  • Nursing Considerations:

    • Assessment: obtain detailed family and health history.
    • Education: explain inheritance risks in simple terms.
    • Support: offer genetic counseling referrals.
    • Prevention: advise on prenatal testing, folic acid, and lifestyle modification.
    • Care: provide emotional support; acknowledge guilt or fear in parents.

Obstetrics: Broad Perspective and Aims

  • Obstetrics: branch of medicine dealing with childbirth and care before/after birth; includes labor, pregnancy, puerperium.
  • Pregnancy: period from conception to start of labor; normal duration ≈ 280 days / 40 weeks / 10 lunar months, with ~±2 weeks allowance.
  • Fertilization: union of sperm and ovum.
  • Labor: expulsion of products of conception from the uterus once viability is reached.
  • Stage of Viability: ≈ 20 weeks, 500 g, 25 cm.
  • Abortion: fetal expulsion before 20 weeks.
  • Puerperium: postpartum period 4–6 weeks; genital organs return to pregravid state.
  • Physiological Obstetrics: normal pregnancy, labor, puerperium.
  • Pathological Obstetrics: complications of pregnancy (dystocia, puerperal abnormalities).
  • Gynecology: diseases of the nonpregnant woman.
  • Obstetrician: physician specializing in obstetrics.

Aims of Obstetrics

  • Primary aim: every pregnancy culminates in a healthy mother and a healthy baby.
  • Reduce maternal and infant mortality and morbidity associated with pregnancy, labor, and puerperium.
  • Minimize discomforts and safeguard the physical and mental health of both mother and child.

Maternal Mortality: Causes and Risk Factors

  • Common causes of death in childbearing: hemorrhage, pregnancy-induced hypertension, infection. Heart disease also a significant contributor.
  • Specific obstetric hemorrhage causes include postpartum hemorrhage, abortion-related bleeding, ectopic pregnancy bleeding, placenta previa, placental abruption, uterine rupture.
  • Pregnancy-induced hypertension features: hypertension, edema, proteinuria; severe cases may involve convulsions/coma.
  • Puerperal infection: infection of birth canal; can extend to peritonitis, thrombophlebitis, bacteremia.
  • Other major causes: pulmonary embolism, heart disease.
  • Perinatal mortality as a quality index; higher risk with extreme maternal ages and parity patterns.

Risk Factors in Pregnancy

  • Age: high risk under 20 and over 40; safest between 20–30.
  • Parity: highest risk in first and sixth pregnancies; safest around the 2nd pregnancy.
  • Interpregnancy interval: 10 years or more is high risk.
  • Height: <155 cm (less than 5 feet) is high risk.
  • Smoking and alcohol use: associated with adverse outcomes such as low birthweight.
  • Socioeconomic/educational level.

Infant Mortality and Perinatal Mortality

  • Major causes of infant mortality: preterm birth, brain injury from hypoxia or delivery trauma, congenital anomalies, SIDS.
  • Perinatal mortality correlates with maternal age and parity; highest for
  • About half of neonatal deaths occur on the first day of life.

Reproductive Anatomy: Male System (Andrology)

  • Primary reproductive function: production and transport of sperm through the genital tract into the female.

  • Key Structures: Scrotum, Testes, Penis, Epididymis, Vas deferens, Seminal vesicles, Ejaculatory ducts, Prostate gland, Bulbourethral (Cowper’s) glands, Urethra.

  • The Penis:

    • Three erectile tissue columns: two corpora cavernosa and one corpus spongiosum which contains the urethra.
    • Glands: glans penises; prepuce (foreskin).
    • Erection: vascular engorgement; parasympathetic control.
    • Ejaculation: sympathetic control with contraction of pelvic floor muscles and accessory glands.

  • Blood Supply & Nerve Supply:

    • Internal and external pudendal arteries/veins; pudendal nerve provides innervation.

  • Sperm Statistics (ejaculate):

    • 2–4 mL of semen per ejaculation; about 10^8 sperm/mL; roughly 20–25% abnormal sperm.
    • Total sperm per ejaculation: about 2 imes 10^8 ext{ to } 4 imes 10^8.
    • A successful sperm can fertilize an ovum in about 5 ext{ to }30 ext{ minutes} after ejaculation.

  • Ductus Deferens & Seminal Vesicles:

    • Ductus deferens travels from the epididymis to the ampulla; merges with seminal vesicle; form ejaculatory duct.
    • Vasectomy: cutting and tying off the ductus deferens; nearly 100% effective contraception.
    • Seminal vesicles contribute ~60% of semen volume; secretes fructose, prostaglandins, ascorbic acid.

  • Accessory Glands:

    • Prostate: activates sperm; contributes about one-third of semen; secretes citrate, enzymes, PSA; anticoagulant for sperm.
    • Bulbourethral glands (Cowper’s): produce mucus to neutralize residual urine in urethra.

  • Hormonal Regulation (Male):

    • FSH stimulates spermatogenesis via Sertoli cells and androgen-binding protein (ABP) and inhibin.
    • Interstitial Cell Stimulating Hormone (ICSH, aka LH) stimulates testosterone production by Leydig cells.
    • Testosterone supports spermatogenesis and secondary sexual characteristics; ABP increases testosterone bioavailability in seminiferous tubules.

  • Testosterone Production & Dynamics:

    • Testosterone stimulates development of male secondary sex characteristics; are involved in prostate function and spermatogenesis.
    • Testosterone can be converted to DHT (via 5-alpha-reductase) in the prostate and other tissues; high DHT can contribute to prostate growth and male pattern baldness.

  • Additional Effects of Testosterone:

    • Gynecomastia can result from elevated estrogenic activity (xenoestrogens such as certain pesticides or BPA);
    • Symptoms of testosterone deficiency include insulin resistance risk, increased visceral obesity, sleep apnea, and decreased libido.

  • Spermatogenesis (overview):

    • Spermatogenic stem cells in the seminiferous tubules produce sperm via a sequence:
    • Mitosis of spermatogonia → spermatocytes
    • Meiosis → spermatids
    • Spermiogenesis → spermatozoa

Reproductive Anatomy: Female System

  • External Genitalia (Vulva):

    • Perineum: space between vagina and anus; mons pubis; labia majora/minora; clitoris; Bartholin’s glands (lubrication via mucoid secretions).

  • Clitoris: erectile tissue; highly sensitive; primary center for sexual stimulation.

  • Urethral Orifice (meatus): opening of the urethra in the vestibule; Skene’s glands drain near the urethra.

  • Vaginal Opening & Hymen:

    • Hymen varies in shape; hymen may partially cover vaginal opening in virgins.

  • Perineum & Pelvic Floor:

    • Perineum includes urogenital/ pelvic diaphragms; pelvic floor muscles (levator ani) support pelvic organs; perineal body structures can be injured during delivery.
    • Innervation by pudendal nerve (S2–S4).

  • Vagina:

    • Anatomical features: anterior/posterior walls normally in contact; fornices (anterior and posterior) allow palpation of internal organs; posterior fornix provides surgical access.
    • Vagina’s pH varies by life stage:
    • Prepuberty: pH ext{ approximately } 6.8 ext{–}7.2
    • Adult: pH ext{ approximately } 4.0 ext{–}5.0 due to Lactobacillus (Lactobacillus acidophilus / Doderlein bacilli) converting glycogen to lactic acid.
    • Vaginal columns and rugae; levator ani closes the vagina.

  • Uterus, Cervix, and Supporting Ligaments:

    • Uterus: hollow, thick-walled; fundus; body; cervix; dimensions ~7.5 cm long, 5 cm wide, 2.5 cm depth; wall thickness ~1.25 cm.
    • Fallopian Tubes: receive ovulated oocyte; fertilization site in distal tube; ampulla ends in infundibulum with fimbriae.
    • Ligaments:
    • Broad ligaments (uterine support)
    • Round ligaments (keep uterus in place)
    • Ovarian ligaments (to ovaries)
    • Cardinal ligaments (transverse cervical/Mackenrodt’s ligaments; chief support)
    • Uterosacral ligaments (support uterus/cervix at ischial spines)
    • Pubocervical ligaments (to pubic bones)

  • Ovaries:

    • Paired endocrine and reproductive organs; contain primordial follicles (oocytes + follicular cells).
    • Stimulated by FSH and LH from the pituitary.
    • Estrogen triggers secondary sex characteristics; progesterone triggers uterine changes during the menstrual cycle.

  • Hormonal Control (Female Reproduction):

    • Hypothalamus secretes GnRH; stimulates anterior pituitary to secrete FSH and LH.
    • FSH → stimulates ovaries to produce estrogens; stimulates follicle development; stimulates production of ABP and inhibin from Sertoli-like (sustentacular) cells in the ovary context.
    • LH → stimulates theca/interstitial cells to produce androgens/estrogens; stimulates ovulation in the cycle.

  • The Female Breast and Lactation:

    • Breast anatomy: 15–25 lobes radiating around the nipple; areola; lobes contain alveoli that produce milk; lactiferous ducts open at the nipple.
    • Prolactin release during lactation stimulates milk production; regulation involves hypothalamic releasing hormones (PRH) stimulating anterior pituitary to produce prolactin.

  • Menstrual Cycle and Puberty (Hormonal Overview):

    • At ≈10 years of age, GnRH increases, stimulating LH/FSH production.
    • At puberty, ovaries synthesize estrogens in response to FSH.
    • Ovaries also secrete progesterone, triggering uterine changes during the menstrual cycle.

Practical and Ethical Implications in Genetic Care

  • Genetic testing decisions involve informed consent, risk communication, and consideration of the psychosocial impact on individuals and families.
  • Nurses play a critical role in: education about inheritance risks, referrals to genetic counseling, and supporting informed decisions about testing and pregnancy management.
  • Prenatal and preimplantation options raise ethical considerations about pregnancy decisions, potential discrimination, and access to services.

Key takeaways for exam-style review

  • Procreation integrates classical theories with modern genetics to explain inheritance and offspring traits.
  • Human reproduction progresses from gamete formation to zygote, to blastocyst, to implantation, culminating in embryonic/fetal development.
  • Genetic disorders are categorized as single-gene, chromosomal, or multifactorial; teratogens can cause developmental defects especially during the first trimester.
  • Inheritance patterns (autosomal dominant, autosomal recessive, X-linked, multifactorial) dictate offspring risk; probabilities can be expressed numerically as shown above.
  • A broad array of genetic testing exists (newborn, diagnostic, carrier, prenatal, PGD, predictive, forensic, and screening), each with specific indications and implications.
  • The nursing process in genetic care emphasizes assessment, planning, education, emotional support, and ethical considerations.
  • Obstetrics aims to optimize outcomes for both mother and baby through surveillance and management of physiological and pathological conditions across pregnancy, labor, and puerperium.
  • Maternal and perinatal mortality are influenced by clinical factors (hemorrhage, hypertensive disorders, infection) and demographic risk factors (age, parity, interpregnancy interval, height, lifestyle).
  • The male and female reproductive systems have complex anatomical and hormonal regulation that supports fertility, sexual function, and lactation.
  • Lactation is hormonally driven, with prolactin as the milk-producing hormone and oxytocin facilitating milk ejection (not detailed in slides but commonly taught alongside prolactin).

Study prompts and activity ideas

  • Explain the differences between preformation, epigenesis, and modern genetic theory with examples.
  • Outline the steps from fertilization to implantation and identify key time points where teratogens have the greatest impact.
  • Draw and label the major male reproductive structures and describe the sequence of spermatogenesis (mitosis → meiosis → spermiogenesis).
  • Compare autosomal dominant and autosomal recessive inheritance with a Punnett square example and interpret probabilities.
  • List the primary tests in prenatal genetic screening and diagnostic pathways, describing when each is appropriate.
  • Describe the key risk factors for adverse pregnancy outcomes and how nursing interventions can mitigate risk.