CHELSEA A. IENNARELLA ANS 536 – PERINATOLOGY SPRING 2014 Central Nervous System Development
ANS Perinatology - CNS Development
Overview: Prenatal CNS Development Period of the Ovum Period of the Embryo Period of the Fetus Post-Natal CNS Development Male vs. Female Brain Lecture 03/26/2014: Epigenetic Changes CNS Abnormalities Species Differences in CNS Development and Physiology ANS Perinatology - CNS Development
Prenatal Growth & Development: ANS Perinatology - CNS Development Period of the Ovum: fertilization through implantation Period of the Embryo: gastrulation through establishment of all major organ systems Period of the Fetus: maturation of organ systems through birth
ANS Perinatology - CNS Development Period of the Ovum:
ANS Perinatology - CNS Development From the time of fertilization until implantation (GW 0-1). Little or no increase in weight of embryo. Characterized by reductive cell divisions; hyperplasia.
ANS Perinatology - CNS Development
Period of the Embryo:
ANS Perinatology - CNS Development From gastrulation through the establishment of all major organ systems (GW 2-15). Formation of specific organs and tissues occurs. All major structures and organ systems are established; heart and circulatory system can be considered functional. Growth mostly resulting from hyperplasia.
ANS Perinatology - CNS Development
Human Development Video: ANS Perinatology - CNS Development
CNS Development: ANS Perinatology - CNS Development CNS development begins during the 3 rd gestational week in humans. Most rapid CNS development occurs during the 24 th gestational week. Brain is not fully developed until adulthood (early 20’s).
ANS Perinatology - CNS Development
Neurulation: ANS Perinatology - CNS Development transformation of the neural plate into the neural tube
Neural Tube Formation: ANS Perinatology - CNS Development neural plate: a thickened plate of ectoderm that gives rise to the neural tube and crests notochord: flexible rod- shaped structure, derived from the mesoderm, that supports the primitive axis of the embryo
Neural Tube Formation: ANS Perinatology - CNS Development neural crest: transient, multipotent, migratory cell population Cells contribute to many different systems including peripheral nervous systems, skin, skeletal, adrenal glands, and GI tract
ANS Perinatology - CNS Development
Period of the Fetus:
ANS Perinatology - CNS Development From maturation of organ systems through birth (GW 16-38). Characterized by a large increase in weight and large increase in nutrient demand. Growth is mostly resulting from hypertrophy.
ANS Perinatology - CNS Development
prosencephalon: forebrain mesencephalon: midbrain rhombencephalon: hindbrain
ANS Perinatology - CNS Development
telencephalon: mature cerebrum diencephalon: thalamus, hypothalamus, pituitary mesencephalon: midbrain metencephalon: pons and the cerebellum myelencephalon: medulla oblongata
Development of the Embryonic Brain: ANS Perinatology - CNS Development
ANS Perinatology - CNS Development Post-Natal CNS Development
Post-Natal Brain Development: ANS Perinatology - CNS Development Infant’s brain is roughly 25% of its adult size at birth. 75% developed by one year of age 80-90% developed by three years of age Full maturation does not occur until adulthood in humans (roughly years old).
ANS Perinatology - CNS Development Developmental Structures of Importance
Limbic System: ANS Perinatology - CNS Development Collection of several structures located in the inner brain beneath the cortex. prefrontal cortex hypothalamus amygdala hippocampus
Prefrontal Cortex: ANS Perinatology - CNS Development Location of most advanced cognitive function Attention, motivation, goal-directed behavior Last area of the brain to mature Undergoes important developmental changes even into adolescence
Hypothalamus: ANS Perinatology - CNS Development Regulation of stress response by signaling the pituitary to secrete ACTH stimulates secretion of stress hormone, cortisol, from adrenal cortex stimulates secretion of adrenaline from the adrenal medulla
Amygdala: ANS Perinatology - CNS Development Evaluates threats and triggers the body’s response to stress Allows for generation of learned emotional responses to a variety of situations
Hippocampus: ANS Perinatology - CNS Development Memory formation and spatial learning. Declarative memory; the memory of facts or events Important in recognition
Synapses & Neurons: ANS Perinatology - CNS Development The brain processes information by forming networks of neurons. Communicate using electrical and chemical signals. Messages are passed between neurons at connections called synapses.
ANS Perinatology - CNS Development
Synaptic Pruning: ANS Perinatology - CNS Development For first three years of life, a child’s brain has roughly twice as many synapses and an adult. Synapses used frequently become stronger. Synapses rarely used are more likely to be eliminated.
Brain Development Video: ANS Perinatology - CNS Development
Continued Brain Development: ANS Perinatology - CNS Development During the second year of life, the brain’s language center develops more synapses and becomes more interconnected Vocabulary often quadrupled during this time. Rapid increase in rate of myelination. Emotional awareness and self awareness develop.
ANS Perinatology - CNS Development
Pinky & the Brain: ANS Perinatology - CNS Development Nature vs. Nurture Genes lay foundation for brain but final wiring is caused by an environmental effect Laboratory mice are virtually genetically identical. Dramatic difference seen in IQ
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Differences Between Male & Female Developing Brain
ANS Perinatology - CNS Development
Differences During Embryonic Development: ANS Perinatology - CNS Development Differences seen as early as GW 26 Thickening of CC in females that remained post birth Males outperformed females on motor and spatial cognitive tasks; females were faster in tasks of emotion identification and nonverbal reasoning (Satterthwaite et al. 2014)
ANS Perinatology - CNS Development
Overview: ANS Perinatology - CNS Development CNS development begins in utero and continues into adulthood. Several transient structures undergo morphological and functional changes to give rise to a more mature system. Interaction between genetics and environment determine final CNS capacity and functionality.
Next Lecture: ANS Perinatology - CNS Development Epigenetic Changes Effecting the CNS CNS Abnormalities Species Differences in CNS Development and Physiology
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