Anatomy and Physiology by Rod R Seeley 6th edition chapter 29 power-point

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Anatomy and Physiology, Sixth Edition
Rod R. SeeleyIdaho State University Trent D.
StephensIdaho State University Philip
TatePhoenix College
Chapter 29 Lecture Outline
See PowerPoint Image Slides for all figures and
tables pre-inserted into PowerPoint without notes.
Copyright The McGraw-Hill Companies, Inc.
Permission required for reproduction or display.
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Chapter 29

• Development, Growth,
• Aging, and Genetics

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Prenatal Development

• From conception to birth
• Three stages
• Germinal period
• First 2 weeks of development during formation of
  primitive germ layers
• Embryonic period
• 2nd to end of 8th week, organ systems develop
• Fetal period
• Last 30 weeks, organ systems grow and mature

• Clinical age
• Mothers LMP to calculate age of unborn child
• Postovulatory age
• Describes timing of developmental events
• Calculated as 14 days less than clinical age

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Fertilization
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Early Cell Division

• Zygote divides to form 2 cells about 18-39 hours
  after fertilization
• 2 cells divide to form 4, 8, and so on
• Pluripotent Ability to develop into wide range
  of tissues
• Morula
• Solid ball of 12 or more cells

• Blastocyst or hollow sphere of cells
• Implantation
• Burrowing into uterine wall
• Placenta develops from trophoblast cells

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Early Stages of Development
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Blastocyst
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Formation of Placenta
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Mature Placenta and Fetus
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Formation of Germ Layers

• Amniotic cavity
• After implantation, new cavity forms inside inner
  mass and separates
• Embryonic disk composed of ectoderm and endoderm

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Primitive Streak
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Neural Tube Formation
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Somite Formation andGut Formation

• Gut formation
• Developing digestive tract pinches off from yolk
  sac as a tube but remain attached by yolk stalk
• Oropharyngeal membrane
• Cloacal membrane
• Evaginations
• Celom or body cavity development

• Somite formation
• As neural tube develops, segments or somites form
  or indistinct somitomeres
• Eventually become part of skull, vertebral
  column, skeletal muscle

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Formation of Digestive Tract
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Limb Bud Development andFace Development

• Face development
• Fusion of 5 embryonic structures
• Frontonasal process
• Maxillary processes
• Mandibular processes
• Nasal placodes
• Cleft lip
• Failure of frontonasal and 2 maxillary processes
  to fuse

• Limb bud development
• Arms and legs appear at about 28 days
• Apical ectodermal ridge develops on lateral
  margin of each limb and stimulates outgrowth
• Limb tissue laid down in proximal-to-distal
  sequence

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Face Development
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Organ Systems Development

• Muscle
• Myoblasts are early embryonic cells that develop
  into skeletal muscle fibers
• Nervous System
• Derived from neural tube and crest cells
• Circulatory System
• Heart develops from 2 endothelial tubes which fuse

• Skin
• Epidermis derived from ectoderm
• Dermis derived form mesoderm or neural crest
  cells as in face
• Skeleton
• Develops from mesoderm or neural crest cells

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Heart Development
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Organ Systems Development

• Respiratory system
• Lungs develop as single midline evagination from
  foregut in region of future esophagus
• Urinary system
• Kidneys develop from mesoderm located between
  somites and lateral part of embryo

• Reproductive system
• Male and female gonads appear as gonadal ridges
• Primordial germ cells are destined to become
  oocytes or sperm cells

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Lung Development
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Kidney and Urinary Bladder Development
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Reproductive System Development
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Fetal Growth

• Fetus
• At 60 days embryo becomes a fetus
• Fetal period
• From day 60 to birth is rapid growth
• Lanugo
• Fine soft hair covering
• Vernix caseosa
• Waxy coat of protection

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Parturition

• Labor
• First stage
• Onset of regular uterine contraction until cervix
  dilates to fetal head diameter
• Second stage
• From maximum cervical dilation until baby exits
  vagina
• Third stage
• Expulsion of placenta from uterus

• Parturition
• Process by which a baby is born
• In mother
• Estrogens overcome inhibitory influence of
  progesterone
• Oxytocin is released
• In fetus
• Adrenal gland is enlarged prior

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Parturition
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Factors Influencing Parturition
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Changes at Birth

• Digestive System
• Meconium (anal discharge) is mixture of cells
  from digestive tract, amniotic fluid, bile, and
  mucus excreted by newborn
• Stomach begin to secrete acid
• Liver does not form adult bilirubin for 1st 2
  weeks
• Lactose can be digested, but other food must be
  gradually introduced

• Respiratory System and Circulatory System
• Foramen ovale closes, two atria separated
• Ductus arteriosus closed, blood no longer flows
  between pulmonary trunk and aorta
• Umbilical vein and arteries degenerate

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Circulatory Conditions in Fetus
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Circulatory Changes at Birth
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Apgar Scores

• Assessment of newborn baby
• Appearance, pulse, grimace, activity, respiratory
  effect
• Rated on scale of 0-2, 2 denotes normal function
• Total Apgar score is sum from five characteristics

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Genetics and Chromosomes

• Genetics
• Study of heredity
• DNA
• Hereditary material of cells and controls cell
  activities
• Chromosomes
• Karyotype or display
• Autosomal and sex (X or Y)
• Contain thousands of genes

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Inheritance of Sex
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Genes
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Genes

• Functional unit of heredity
• Portion of DNA
• Types
• Structural Serve as template for mRNA, code for
  amino acid sequences
• Regulatory Control which structural genes
  transcribed in given tissue

• Dominant and Recessive
• Dominant masks effects of recessive genes
• Sex-linked traits
• Traits affected by genes on sex chromosomes
• Genotype
• Actual set of alleles a person has for a given
  trait
• Phenotype
• Persons appearance

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Traits
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Other Types of Gene Expression

• Incomplete dominance
• Dominant gene doesnt completely mask effects of
  recessive gene
• Sickle-cell disease
• Polygenic traits
• Determined by expression of multiple genes on
  different chromosomes
• Persons height, eye and skin color, intelligence

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Genetic Disorders

• Cancer
• Tumor resulting from uncontrolled cell divisions
• Oncogenes
• Genes associated with cancer
• Tumor suppressor genes
• Carcinogens
• Genetic susceptibility or predisposition

• Genetic disorders
• Abnormalities in DNA
• Congenital disorders
• Birth defects not necessarily genetic
• Teratogens
• Agents that cause birth defects
• Mutation
• Mutagens
• Agents that cause mutations

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Genetic Counseling

• Predicting possible results of matings involving
  carriers of harmful genes
• Talking to prospective parents about possible
  outcomes and treatments of a genetic disorder

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Human Genomic Map