Biological Beginnings: Prenatal Development

Unit 2: Biological Development

• Focuses on The Child and Adolescent Learner and Learning Principles

Topic 1: Biological Beginnings

• Explores the concepts of DNA, Prenatal Development, Prenatal Development includes: the development of the zygote, the embryo, and the fetus

Prenatal Development: The Period of the Zygote

• The first phase of Prenatal Development lasts from conception until the developing organism firmly attaches to the wall of the uterus
• By the end of the first stage, the zygote becomes a blastocyst and implants itself into the uterine wall
• The Blastocyst term, is the name given to the ball of cells formed when the fertilized egg begins to divide

Prenatal Development: The Period of the Embryo

• The second phase of prenatal development
• Lasts from the third to the eighth prenatal week
• During this time, the major organs and anatomical structures take shape

Prenatal Development: The Period of the Fetus

• The third phase of prenatal development
• Lasts from the ninth prenatal week until birth
• All major organ systems begin to function, and the fetus grows rapidly

Other Terms from Conception to Birth

• Amnion is a watertight membrane that surrounds the developing embryo and regulates temperature and cushions against injuries
• Chorion is a membrane attached to the uterine tissues to gather nourishment for the embryo
• Placenta is an organ formed from the lining of the uterus and the chorion; provides respiration and nourishment and eliminates metabolic waste
• Umbilical cord is a soft tube connecting blood vessels between the embryo and placenta
• Vernix is a white, cheesy substance covering the fetus to protect the skin from chapping
• Lanugo is a fine hair covering the fetus's body that helps vernix stick to the skin

Potential Problems in Prenatal Development

• Teratogens are diseases, drugs, or environmental agents that can harm a developing embryo or fetus
• These can cause physical deformities, severely retarded growth, blindness, brain damage, or death
• The sensitive period is a timeframe when an organism is most susceptible to environmental influences
• Rubella (German Measles) may cause severe birth defects in developing organisms exposed during the first 3 to 4 months of pregnancy
• Toxoplasmosis is caused by a parasite in raw meat and cat feces; may cause birth defects if transmitted in the first trimester or miscarriage later in pregnancy
• Syphilis is a common sexually transmitted disease
• It crosses the placental barrier in the middle and later stages of pregnancy
• It can cause miscarriage or severe birth defects

Topic 2: Physical Growth in Growing Children and Adolescents

• Explores Growth indicators: weight, height, chest circumference and head circumference

Physical Growth in Growing Children and Adolescents: Weight

• A newborn typically weighs between 2.7 to 4 kg at birth
• Babies normally lose 5%-10% of their weight in the first few days, regaining it by day 10
• By one month, babies gain about 3½ kg
• From 5-8 months, they gain ½ kg per month
• From 9-12 months, they gain ¼ kg per month
• From 5 to 8 months a baby's weight doubles compared to birth weight
• By 9 to 12 months it triples

Calculating Infant's Weight

• For infants from 3 to 12 months calculate based on this formula: Weight = (Age in months + 9)/2
• Ex. 7 month old infant: (7+9)/2 = 16/2 = 8 kg

Physical Growth in Growing Children and Adolescents: Height (Length)

• Boy infants average height is approximately 50 cm
• Girl infants average height is approximately 49 cm
• Normal range for both is 47.5 - 53.75 cm
• Length increases by about 3 cm/month during the first 3 months of age
• Increases 2 cm/month at 4-6 months
• Increases 1½ cm per month at 7 – 12 months

Physical Growth in Growing Children and Adolescents: Chest Conference and Head Circumference

• Chest circumference is 30.5 to 33 cm, usually 2-3 cm less than head circumference
• By the end of the first year, chest circumference equals head circumference
• Head circumference at birth ranges from 33-35 cm, about 1/4 of total body length
• It increases about 2 cm/month during the first 3 months, then 1½ cm/month during the second 9 months

Physical Growth in Growing Children and Adolescents: Skull Fontanels

• The skull has two fontanels: anterior & posterior fontanels
• The Anterior fontanel is diamond shaped
• It is located at the junction of the sagittal, coronal, and frontal sutures
• It is between 2 frontal & 2 parietal bones
• It is 3-4 cm in length and 2-3 cm in width
• It closes at 12-18 months old
• Posterior fontanel is triangular
• Located between occipital & 2 parietal bones
• It closes by the end of the 1st month of age

Physical Growth in Growing Children and Adolescents: Physiological Growth

• Infants' body temperatures range from 36.3 to 37.2°C
• Pulse is from 120 to 160 beats/minute
• Respiration is from 35 to 50 cycles/minute

Simulation for Taking Newborn's Vital Signs: Newborn Senses

• Touch is the most highly developed sense in newborns, especially at the lips, tongue, ears, and forehead are very sensitive
• Vision, newborns pupils react to light
• Bright lights are unpleasant to infants and they tend to follow objects in their line of vision
• Newborns respond to sounds from birth
• They hear ordinary sounds well before 10 days of life
• Infants respond to sounds with either cry or eye movement, cessation of activity, and/ or startle reaction
• Taste is well-developed, resisting bitter and sour fluids but accepting sweet fluids
• Smell evidenced in an infant's search for the nipple, identified through breast milk scent

APGAR Scale

• A quick assessment method used to evaluate the health of a newborn immediately after birth
• Used to identify babies who need immediate medical assistance
• Developed by Dr. Virginia Apgar in 1952
• This scoring system helps determine if a baby requires immediate medical care or resuscitation
• Conducted at 1 and 5 minutes after birth, with a possible third evaluation at 10 minutes
• Includes a scale from 0-2 for: Appearance, Pulse, Grimace, Activity and Respiration
• Scores of 7–10 are normal; the baby is in good health
• Scores of 4-6: Moderate difficulty, and may need some medical intervention
• Scores of 0-3: Severe distress, and requires immediate resuscitation or intensive care

Motor Development

• Motor development is categorized into two types of skills
• Fine Motor Skills (FMS) are involve hand control, grasping, holding, writing, painting, or pinching
• Gross Motor Skills (GMS) are abilities of muscles in the torso, legs, and arms allow physical activities from running to raking leaves

Topic 3: Neuroscience and Brain Development

• Technological advances in neuroscience have allowed scientists to research and develop knowledge about the human brain

Nervous System

• The peripheral nervous system handles the central nervous system's input and output, and contains all portions of the nervous system outside of the brain and spinal cord.
• It contains sensory and motor nerves
• It is also divided into the autonomic nervous system and somatic nervous system.
• The sympathetic nervous system activates the fight-or-flight response during a threat or perceived danger
• The parasympathetic nervous system restores the body to a state of calm
• The central nervous system's responsibilities include receiving, processing, and responding to sensory information
• CNS is divided into the Brain and Spinal Cord
• The Spinal Cord is protected by bones, and produces behaviors without the brain
• Spinal reflexes are automatic, and influenced by thoughts/emotions such as touching a hot iron

Central Nervous System: The Brain: The Hind Brain

• The brain is composed of the cerebrum, cerebellum, and the medulla oblongata, which are part of the unconscious brain
• The hind brain includes the medulla, pons, and the reticular activating system
• The Medulla controls breathing and heart rate
• The Pons controls sleeping, walking, and dreaming
• The Reticular Activating System controls alertness and attention

The Brain: Cerebellum and Cerebrum

• The Cerebellum is the second largest part of the brain after the cerebrum
• It functions in muscle coordination, muscle tone and posture and balance
• The Cerebrum is where higher forms of thinking take place and governs intelligence and reasoning, learning, and memory

The forebrain

• Thalamus directs sensory messages to higher centers in the brain
• The only sense that completely bypasses the thalamus is the sense of smell
• Hypothalamus is involved with drives associated with survival, such as hunger, thirst, emotion, sex, and reproduction

The Limbic System: Amygdala and Hippocampus

• The Amygdala is responsible for evaluating sensory information, determines its emotional importance
• The Hippocampus is the gate to memory

The Cerebral Cortex

• Occipital Lobes are located at the back of the head and receives visual information
• Parietal Lobe is on the top of the brain
• The Somato-sensory cortex processes information about touch, taste, pressure, pain, heat, and cold
• Temporal Lobes are at the sides of the brain
• They receive auditory signals and process language and the meaning of words
• Frontal Lobes are toward the front of the brain
• Responsible for motor activity and integration of muscle activity, speech, and thought processes

Specialty Functions in Brain Lateralization

• The Left Hemisphere controls Verbal competence, speaking, reading, thinking & reasoning, processing info in sequence, focusing on one piece of data at a time, and is logical
• The Right Hemisphere controls Nonverbal areas, comprehension, spatial relationships, drawing, music, emotion, processes info as a whole, and is intuitive

Language: Broca's Area and Wernicke's Area

• Broca's Area : an area of the frontal lobe, typically in the left hemisphere
• This directs muscle movements in speech
• Wernicke's Area is a brain area in language comprehension and expression and is located in the left temporal lobe

Specialization and Integration in Language

• Visual cortex: receives written words as visual stimulation
• Angular Gyrus transforms visual representations into an auditory code
• Wernicke's area interprets auditory code
• Broca's area controls speech muscles via the motor cortex
• Motor cortex pronounces the word

The Neurons

• Dendrites act like antennas receiving messages
• The Cell Body contains the biochemical machinery to keep the neuron alive
• The Axon transmits messages away from the cell body to other neurons
• Myelin Sheath surrounds the axons, protects signals and speeds neural impulses

Topic 4: Factors Affecting Biological and Physical Development

• Genes and the environment are in constant interaction since birth for biological features, with experiences in the environment
• Early nutrition has impacts the individual's health or sickness and disabilities
• Early attachments affect development through, relationships, which build a healthy/problematic human development
• Learned beliefs and practices from parents or others shape the child's development
• Promoting Child Development is important, however overprotective parents may impede on child development

Topic 5: Developmental Milestone and Ecological System Theory

• Examines Gesell's theory of maturation, developmental principles and Bronfenbrenner's ecological systems theory

Gesell's Concept of Maturation

• Arnold Gesell, a clinical psychologist and pediatrician
• Developed a theory of child development based on observations of both normal and exceptional children
• This research influenced developmental milestones

Gesell's Concept of Maturation and Principles of Development

• Gesell states that there are two major forces influence a child, a product of their environment and also their genes
• Gesell's principles included Reciprocal Interweaving, Functional Asymmetry, and Self-regulation

Principles of Development: Gesell's Observations: Reciprocal Interweaving, Asymmetry and Self Regulation

• Reciprocal Interweaving allows for effective coordination.
• Handedness development, starts with using one hand, then both, preferring another, then both again, to finally reach one-handed dominance
• Functional asymmetry can be seen in the tonic neck reflex
• Where the body lays to have the head turned to one side extending the arm and flexing the other
• Self-regulation involves all children following the same sequences, varying in growth rates, potentially related to temperament and personality.
• Gesell notes can be one who grows slowly, one who grows rapidly, and one who grows irregularly and how each growth style appears in personal dispositions

Ecological Systems Theory

• Urie Bronfenbrenner, first introduced ecological systems theory
• Born in Russia, immigrated to the United States when he was six
• Shaped his ideas about how children adjust to new environments and how factors such as environment, language, and culture influence children
• Views children as developing within a complex system of relationships
• Environmental factors, multiple and complex affect development and it is inseparable from environmental forces

Ecological Systems Theory: Components

• Microsystem is the innermost levels of the environment such as parents, siblings, and daycares
• Mesosystem are interactions between Microsystems such as the home, school and neighborhood affect the child
• Exosystem relates to the social settings in development, such as work of family that can affect children's development
• Macrosystem includes subcultures and cultures in which systems are embedded, and all the factors affect the child
• Chronosystem suggests that time is a factor
• Important life events such as birth, school, parent's divorce modify existing relations
• Changes or life events to the child such aging process affect their development