A&P_CH26_REPRODUCTION__FETAL_DEVELOPMENT_AND_HEREDITY_FINAL abridged sc
Chapter 26: Reproduction, Fetal Development, and Heredity
Page 1: Overview
Title: Reproduction, Fetal Development and Heredity Anatomy and Physiology in Context
Chapter 26 Abridged Version
Page 2: Objectives
Learning Levels:
Level 1: Know the steps involved in fertilization.
Level 2: Comprehend embryonic tissue origins.
Level 3: Demonstrate roles of placental hormones in regulating metabolic changes during pregnancy.
Level 4: Analyze components of semen and their contribution to reproductive success.
Level 5: Connect the menstrual cycle to pregnancy.
Level 6: Evaluate the difference between phenotypes and genotypes.
Page 3: The Sexual Response Cycle
Overview of the sexual response cycle as it relates to reproduction and development.
Page 4: Sexual Arousal
Stages of Sexual Arousal:
Excitement
Plateau
Orgasm
Resolution
Arousal can be reflexogenic or psychogenic, incorporating all senses.
Physiological changes include:
Urethra widens
Scrotum skin thickens
Elevation of testes due to cremaster muscle
Increased heart rate, blood pressure, depth of breathing, erect nipples, and sexual flushing.
Page 5: Male Sexual Response Cycle
Originates in the erection reflex center of the sacral spinal cord.
Erection may be reflexogenic or psychogenic, requiring continuous erotic stimulation.
Involves loss of voluntary muscle control, emission, expulsion, followed by a refractory period.
Page 6: Female Sexual Response Cycle
Physiological changes include vaginal lubrication and uterine contractions.
External indicators of sexual arousal increase, with strong muscle contractions that apply pressure on the penis.
Vaginal dilation occurs to receive ejaculate, and there is no refractory period for females.
Page 7: Components of the Male Ejaculate
Key Components and Functions:
Seminogelin: Coagulant that holds sperm against vaginal wall.
Motility Inhibitor: Prevents sperm from wasting energy.
PSA: Breaks down seminogelin, freeing sperm.
Prostaglandins: Induce peristalsis in uterus to facilitate sperm movement, reduce mucus viscosity.
hCAP-18: Anti-microbial protein that prevents bacterial growth.
Factor III: Aids in coagulation and abrasion healing.
Page 8: The Pre-Embryonic Period
Introduction to the events following fertilization, leading to the early stages of embryonic development.
Page 9: Fertilization Process
Steps Involved: A video detailing embryology and the fertilization process lasting 30 minutes to 2 hours.
Page 10: Capacitation
Final Step in Sperm Maturation:
Insemination: Introduction of sperm.
Capacitation: Last maturation step.
Sperm reservoir formation.
Hyperactivation of sperm.
Sperm penetration through cumulus mass.
Zona penetration.
Page 11: Fertilization Details
Fusion of sperm with oocyte.
Zona Pellucida (ZP): Species-specific barrier.
Acrosome Reaction: Sperm releases proteases to digest the ZP for penetration.
Hyperactive sperm rearranges its plasma membrane to access perivitelline space (PVS).
Page 12: Egg and Sperm Fusion
Oocyte features microvilli for optimal sperm docking.
Oocyte activation occurs post-fusion, prompted by PLCz in sperm membrane, triggering Ca2+ release from oocyte ER.
Page 13: Blocking Polyspermy
Post-Oocyte Activation Events:
Cortical reaction to prevent additional sperm fusion by forming a barrier.
Meiosis II completes, resulting in a diploid zygote due to pronuclei fusion and maternal mitochondrial activation.
Page 14: Early Embryogenesis
Overview of early stages of embryonic development post-fertilization.
Page 15: Stages of Early Embryogenesis
Stages:
Day 1: Fertilized zygote.
Days 2-3: Cleavage stages (2-cell, 4-cell, 8-cell).
Days 4-5: Morula and compaction.
Days 6-7: Blastulation with formation of the inner cell mass and trophoblasts.
Page 16: Uterine Receptivity and Implantation
Introduction to the process of implantation in the uterine lining.
Page 17: Three Stages of Uterine Implantation
Apposition: Uterine walls come into close proximity with incoming blastocyst.
Attachment: Polarity required (inner cell mass must touch uterine lining).
Penetration: Blastocyst burrows into stroma for nutrient access.
Page 18: Embryogenesis and Tissue Origin
Insights into how the embryo develops and the origins of embryonic tissues.
Page 19: Origins of Extraembryonic Tissues
Key Layers:
Hypoblast: Forms extraembryonic endoderm.
Epiblast: Develops into the embryo proper.
Together, they form the blastodisc leading to significant structures such as yolk sac, amnion, and chorion.
Page 20: Formation of Germ Layers
Gastrulation Process: Involves primitive pit and streak, leading to ectoderm, mesoderm, and endoderm formation.
Page 21: Embryonic Folding
Video on embryonic folding and its significance in development.
Page 22: Developing Embryo
Embryo simultaneously folds along two axes, creating distinct regions and layers.
Page 23: Fate of the Mesoderm
Various derivatives of mesoderm including notochord, somites, and lateral plate mesoderm associated with organ systems.
Page 24: Fates of Ectoderm and Endoderm
ECTODERM:
Forms nervous tissue and epidermis, sense organs, etc.
ENDODERM:
Forms internal linings and organs such as glands, pancreas, and portions of the GI tract.
Page 25: Placenta Structure and Function
Structure: Chimeric organ with uterine and embryonic tissue.
Functions: Nutrient exchange and hormone production essential for pregnancy.
Page 26: Pregnancy Overview
Introduction to the dynamics of pregnancy and fetal development.
Page 27: Pregnancy Complications
Focus on Disease: Common complications such as ectopic pregnancy, placenta previa, preeclampsia, dystocia, and issues with physiological immaturity at birth.
Page 28: Uterus Growth During Pregnancy
Uterus undergoes hypertrophic and hyperplastic growth reaching up to the xiphoid process by term.
Page 29: Mammary Gland Development
Development stimulated by placental hormones, showing pigmentation changes in areola and nipple.
Page 30: Hormones During Pregnancy
Overview of key hormones involved: hCG, estrogen, and progesterone role during pregnancy.
Page 31: Essential Hormones
Functions of various hormones including placental lactogen, prolactin, relaxin, and corticotropin-releasing hormone in metabolic changes and preparation for parturition.
Page 32: Parturition Overview
General process of labor and birth.
Page 33: Stages of Parturition
Cervical Effacement and Dilation: Involves gradual changes in the cervix.
Fetal and Placental Expulsion: Sequential stages leading to baby's birth.
Page 34: Hormonal Regulation of Parturition
The role of stress and hormonal feedback in triggering labor, involving several hormonal mechanisms that activate uterine contractions and facilitate birth.