Human Development Chapter 3

Overall Physical Growth

Rapid increase in an infant's height and weight; birth weight usually doubles by 4 months, triples by 1 year, and quadruples by age 2.

Body Proportions

The changing relationship between body parts during growth; the head becomes proportionally smaller as the body grows.

Neuron

A nerve cell that stores and transmits information throughout the nervous system.

Dendrites

Branch-like extensions of neurons that receive information from other nerve cells.

Synaptogenesis

The formation of connections (synapses) between neurons.

Synaptic Blooming

A rapid increase in the number of neural connections during infancy.

Synaptic Pruning

The elimination of unused neural connections, making the brain more efficient.

Myelin

A fatty coating around axons that speeds the transmission of nerve impulses.

Myelination

The process of forming myelin around neurons, improving coordination and thinking.

Cortex

The outer layer of the brain responsible for voluntary movement, thinking, memory, and perception.

Frontal Lobe

Brain region responsible for planning, judgment, memory, and problem solving.

Parietal Lobe

Brain region that processes touch and body sensations.

Occipital Lobe

Brain region responsible for vision.

Temporal Lobe

Brain region responsible for hearing, language, and memory.

Prefrontal Cortex

Area of the frontal lobe responsible for self-control, planning, decision-making, and emotional regulation.

Lateralization

The specialization of functions in one hemisphere of the brain.

Neuroplasticity

The brain's ability to reorganize itself and form new neural connections in response to experience or injury.

Polyphasic Sleep

Sleep occurring in multiple periods throughout the day and night.

Rapid Eye Movement (REM) Sleep

The stage of sleep associated with dreaming and rapid brain activity.

Sudden Unexpected Infant Death (SUID

The sudden, unexpected death of an infant under one year of age from any cause.

Sudden Infant Death Syndrome (SIDS

The unexplained death of a healthy infant, usually during sleep, even after investigation.

Unknown Cause

A SUID case where no cause of death can be determined due to insufficient evidence.

Accidental Suffocation and Strangulation in Bed (ASSB

Infant death caused by unsafe sleep conditions such as soft bedding or bed-sharing.

Back to Sleep Campaign

A public health campaign encouraging parents to place babies on their backs to sleep to reduce SIDS.

Co-sleeping

A sleeping arrangement where parents and infants sleep close together; may increase SIDS risk depending on circumstances.

Reflex

An involuntary response to stimulation present at birth.

Rooting Reflex

The infant turns toward a touch on the cheek to find food.

Sucking Reflex

Automatic sucking when something touches the baby's lips.

Grasp Reflex

Automatic closing of the fingers around an object placed in the palm.

Babinski Reflex

The toes fan outward when the sole of the foot is stroked.

Moro Reflex

The startle reflex where infants throw out their arms and then pull them back in.

Tonic Neck Reflex

The "fencer position" where turning the head causes one arm to extend and the other to bend.

Stepping Reflex

The infant makes stepping motions when held upright with feet touching a surface.

Motor Development

The progression from reflexive movements to voluntary movement.

Cephalocaudal Principle

Development proceeds from the head downward.

Proximodistal Principle

Development proceeds from the center of the body outward.

Developmental Milestones

Skills or abilities most children achieve by a certain age.

Fine Motor Skills

Movements involving small muscles, especially in the hands and fingers.

Gross Motor Skills

Movements involving large muscles such as crawling, standing, walking, and running.

Palmar Grasp

Grasping objects using the fingers and palm without the thumb.

Pincer Grasp

Using the thumb and forefinger to pick up small objects.

Visual Acuity

The sharpness or clarity of vision.

Fovea

The center of the retina responsible for sharp central vision.

Binocular Vision

Using both eyes together to judge depth and distance.

Depth Perception

The ability to judge how far away objects are.

Infant-Directed Speech

The exaggerated, high-pitched style adults naturally use when talking to babies.

Circumcision

The surgical removal of the foreskin from the penis.

Intermodality

The ability to combine information from multiple senses.

Habituation

A decrease in response after repeated exposure to the same stimulus.

Dishabituation

A renewed response when a new stimulus is introduced after habituation.

Colostrum

The first nutrient-rich breast milk produced before mature milk.

Breast Milk

The ideal infant food containing nutrients and antibodies that support growth and immunity.

Formula

A manufactured substitute for breast milk.

Exclusive Breastfeeding

Feeding an infant only breast milk without other foods or liquids.

Solid Foods

Foods introduced around 4–6 months when infants show developmental readiness.

Botulism

A serious illness that infants can get from honey due to bacterial spores.

Infantile Marasmus

Severe malnutrition caused by a lack of calories and protein.

Kwashiorkor

Protein-deficiency malnutrition characterized by swelling and a distended abdomen.

Malnutrition

Poor nutrition caused by inadequate intake of nutrients or calories.

Wasting

Severe weight loss due to malnutrition, especially in young children.

Overall Physical Growth

Newborns weigh about 7.5 pounds and are 20 inches long; birth weight doubles by 4 months, triples by 1 year, and quadruples by age 2.

Body Proportions

The head makes up about 25% of body length at birth and becomes proportionally smaller as the body grows.

Neuron

A nerve cell that stores and transmits information.

Dendrites

Branching extensions of neurons that receive information from other neurons.

Synaptogenesis

The formation of connections (synapses) between neurons.

Synaptic Blooming

A rapid increase in neural connections during infancy.

Synaptic Pruning

The elimination of unused neural connections, making the brain more efficient.

Myelin

A fatty coating around axons that speeds nerve impulse transmission.

Myelination

The development of myelin around neurons, improving movement and thinking.

Cortex

The outer layer of the brain responsible for thinking and voluntary activity.

Frontal Lobe

Brain region responsible for planning, thinking, judgment, memory, and decision-making.

Parietal Lobe

Processes touch and body sensations.

Occipital Lobe

Processes visual information.

Temporal Lobe

Responsible for hearing and language.

Prefrontal Cortex

Area behind the forehead involved in planning, self-control, and decision-making; develops slowly.

Lateralization

The specialization of the left and right hemispheres for different functions.

Neuroplasticity

The brain's ability to reorganize itself by forming new neural connections.

Polyphasic Sleep

Sleep that occurs in several periods throughout a 24-hour day.

REM Sleep

Rapid Eye Movement sleep associated with dreaming and brain development.

Sudden Unexpected Infant Death (SUID)

The sudden, unexpected death of an infant under one year old.

Sudden Infant Death Syndrome (SIDS)

The unexplained death of a healthy infant under one year despite investigation.

Unknown Cause (SUID)

An infant death that cannot be explained because sufficient investigation was not completed.

Accidental Suffocation and Strangulation in Bed (ASSB)

Infant death caused by unsafe sleeping environments.

Back to Sleep Campaign

Public health campaign encouraging babies to sleep on their backs to reduce SIDS.

Safe Sleep Recommendations

Place babies on their backs on a firm mattress without loose bedding or pillows.

Bed Sharing

Sleeping in the same bed as an infant; increases the risk of SIDS.

Co-Sleeping

Sleeping near an infant, often in the same room but not necessarily the same bed.

Reflexes

Involuntary responses to stimulation that help newborn survival.

Sucking Reflex

Automatic sucking when something touches the lips.

Rooting Reflex

Turning the head toward something touching the cheek.

Grasp Reflex

Automatic gripping when the palm is touched.

Babinski Reflex

Toes fan outward when the sole of the foot is stroked.

Moro Reflex

Startle reflex where infants spread then pull in their arms and legs.

Tonic Neck Reflex

Fencer-like posture when the infant turns its head.

Stepping Reflex

Stepping motions when the feet touch a surface.

Cephalocaudal Principle

Development occurs from the head downward.

Proximodistal Principle

Development occurs from the center of the body outward.

Developmental Milestones

Typical skills children achieve within expected age ranges.

Motor Skills

Abilities involving body movement.

Fine Motor Skills

Movements involving small muscles, especially hands and fingers.