Lifespan test 1

Conception

Union of sperm and ovum (gametes) in the fallopian tubes to form a zygote.

Germinal stage (Stage 1 of prenatal development, weeks 0-2)

Cells multiply rapidly to form a blastocyst, which implants into the uterine wall; will later become the embryo.

Embryonic stage (Stage 2 of prenatal development, weeks 3-8)

Rapid organ and system formation (organogenesis) from the three germ layers; the most vulnerable period to teratogens.

Fetal stage (Stage 3 of prenatal development, week 9 to birth)

Rapid growth in size and refinement/maturation of organ systems; the foetus becomes increasingly active, especially in the 8th-9th month.

3 germ layers

Endoderm, mesoderm, and ectoderm.

Endoderm layer

Becomes the digestive system, liver, pancreas, and lungs (inner layers).

Mesoderm layer

Becomes the circulatory system, lungs (epithelial layers), skeletal system, and muscular system.

Ectoderm layer

Becomes hair, nails, skin, and the nervous system.

Chromosomes

Thread-like structures of coiled DNA found in the nucleus of cells; humans typically have 46 chromosomes, arranged in 23 pairs (22 autosomal pairs + 1 sex chromosome pair).

Sex chromosomes

The 23rd chromosome pair; XX determines a female, XY determines a male.

Embryo formation at week 3

About 2cm long, resembles a human form, heart begins beating.

Embryo formation at week 7

Muscles form, cerebral cortex begins to develop.

Embryo formation at week 8

Placenta and amniotic sac have formed.

Length at 12 weeks

7.5cm.

Length at 24 weeks

30cm.

Length at 40 weeks

50cm.

8th and 9th month of foetal development

Foetus becomes active.

How is the birth process initiated?

By the placenta, and contraction of the uterine musculature.

Teratogen definition

Any environmental agent that causes damage during the prenatal period.

Teratogen examples

Prescription and non-prescription drugs, illegal drugs, tobacco, alcohol (Foetal Alcohol Syndrome), radiation, environmental pollution, infectious diseases.

When is the foetus most sensitive to teratogens?

During the embryonic period (weeks 3 to 8).

Growth

Physical change in quantity, such as increases in body size involving height, weight, bone growth, and brain growth, rather than skill acquisition.

Maturation

Progression along a predefined timeframe to a more advanced stage.

Direction of physical growth, 12-24 months

Cephalocaudal and proximodistal.

Cephalocaudal development

A developmental principle where progress proceeds from head to foot; head control develops before leg control.

Proximo-distal development

A developmental principle where progress proceeds from the midline to the extremities, such as the trunk before the arms and legs.

Growth rate from infancy to puberty

Head growth is slow, trunk growth is moderate, limb growth is faster, and hands/feet growth is the most rapid.

WHO Child Growth Standards

Charts used to plot expected weight-for-age, height/length-for-age, and head circumference against percentiles, reflecting genetic and environmental variability.

APGAR

Five physical traits assessed at birth: Activity (muscle tone), Pulse (heart rate), Grimace (irritability/reflex response), Appearance (skin colour & oxygenation), and Respiration (crying/breathing effort).

Apgar score assessment

A physical condition test performed at 1 minute and 5 minutes after birth; a combined score of 7 or higher out of 10 signifies a good condition.

Reciprocal interweaving

Gesell's concept describing three directional shifts in development: gross to fine motor (differentiation), simple to complex (integration), and involuntary to voluntary.

Posture principle

Development moves from stability to mobility; an infant must be stable before becoming mobile (a Gesell principle).

Gallahue's Movement Phases

Reflexive (conception to 6 months), Rudimentary (0-24 months), Fundamental (1-6 years), and Specialised (5 years+).

Gallahue's Functional Tasks

The three categories movement is classified into: Stability, Locomotion, and Manipulation.

Rudimentary movement phase age

0-24 months.

Fundamental movement phase age

1-6 years.

Reflex

An involuntary movement produced in response to a specific sensory stimulus.

Reflex Inhibitory Process

The brain cortex encodes a pattern then decodes/inhibits the reflex as the brain develops, allowing voluntary control to take over.

Two types of reflex

Primitive/neonatal (survival) and postural.

Primitive reflexes

Sucking, rooting, Moro, grasping (palmar & plantar), tonic neck, Babinski.

Postural/locomotor reflexes

Head and body righting, stepping, pull-up, swimming; these evolve as the infant grows, aiding future voluntary movements.

Sucking reflex

An automatic response where the infant sucks when an object touches the mouth; disappears around 4 months as feeding becomes voluntary.

Rooting reflex

A response where the head turns and mouth opens when the cheek or corner of the mouth is touched; disappears around 1 month.

Moro (startle) reflex

A response to sudden stimulation where the infant arches the back, throws the head back, and flings the limbs out before closing them; disappears around 6 months.

Babinski reflex

A response to pressure on the sole of the foot where the toes fan out and the foot twists medially; disappears around 4-5 months.

Palmar grasp reflex

A tight automatic grasp when the palm is touched; weakens around 3-4 months as voluntary grasping develops.

Plantar grasp reflex

A response to pressure under the toes where the toes flex and the legs extend; disappears around 6-9 months as weight-bearing begins.

Asymmetric tonic neck reflex

Also known as the 'fencing posture'; rotating the head to one side causes the limbs on the face side to extend and the limbs on the skull side to flex.

Symmetric tonic neck reflex

A response where the arms and legs extend or flex together to balance the body when the infant is tipped forward or backward; disappears around 4 months.

Stepping reflex

A response where the infant takes 'steps' when held vertically with feet touching a surface; disappears around 2 months.

Pull-up reflex

An involuntary response where the infant grabs a person's hands and attempts to pull themselves into an upright position.

Parachute reflex

A protective postural response where the arms and legs extend outward as if the infant is being dropped; appears around 3 months.

Stereotypies

Normal, repetitive movements of constant form, like leg-kicking or rattle-banging, that decline as voluntary control develops; occur from 1-12 months. (Distinct from reflexes.)

Gross motor development systems

Motor behaviour emerges from interacting systems - nervous, musculoskeletal, perceptual/environmental, and infant motivation - rather than just the CNS.

Static gross motor postures

The four stationary motor positions: prone, supine, sit, and kneel/stand.

Dynamic gross motor postures

The four movement-based motor positions: crawl/creep, roll, pivot, and walk.

Prone (birth-4 weeks)

A position where the infant is tummy down with arms and legs flexed, unable to lift the head.

Supine (birth-4 weeks)

A position on the back where gravity pulls the limbs down and the infant cannot roll or move independently.

Pulled to sit (3.5-5 months)

A milestone where the head stays in line with the trunk, arms flex to assist, and neck flexion (chin-tuck) is maintained.

4-point kneel (7-9 months)

A posture with weight on hands and knees, where the legs are flexed and abducted, often involving rocking back and forth.

Hip dissociation (approx. 7-9 months)

The ability to rotate the trunk separately from the hips, characteristic of the propped side-lying position.

Log roll (approx. 5.5-9 months)

Rolling from supine to prone where the shoulders and pelvis stay in line without trunk rotation.

Pivoting (approx. 6-8 months)

Moving the arms and legs with lateral trunk flexion to turn in a circle on the spot.

Crawling, Australian usage (approx. 7.5-9 months)

A commando crawl where the infant moves forward with the tummy on the ground using the arms and legs.

Creeping, Australian usage (approx. 8.5-13 months)

True reciprocal movement on hands and knees with coordinated arm and leg movement.

Cruising (approx. 9-12 months)

Moving along furniture with rotation, progressing from two-hand to one-hand support while controlling the lowering from standing.

Lumbar lordosis

The curved lower back visible when an infant begins standing alone, between approximately 10.5 and 13 months.

Key physical milestones, 9-15 months

Sitting: able to move in and out of sitting. Creeping: creeps on hands and knees. Pulls to stand: crawls to support and pulls up. Cruises: walks along furniture. Stands alone and walks: without support, wide base, gets up from floor. Squats: able to maintain balance. Eye-hand coordination: fine pincer grasp to use tools.

Progression from rudimentary to fundamental movement

Continues to develop skills learnt in the first 12-15 months: sitting develops variety of posture, stands with less support, climbing skills progress, standing becomes more erect. As progress develops: increased postural stability, decreased base of support, increased propulsion against gravity.

Gross motor skills: locomotion

Walking, then running, then jumping, then one-leg balance.

Climbing up stairs

Becomes easier from 12 months.

Going down stairs on hands and knees

Harder/more advanced; better at 15-18 months.

manipulation-Prehension

The functional combination of reaching (moving the hand to a target) and grasping (shaping the hand around the object).

Prehension meaning

Reaching for, grasping, or holding an item.

Manipulation meaning

Adjusting or moving that item inside the hand without using the other hand.

Pre-reaching

Hand-to-mouth movements seen as early as approximately 10 weeks gestation, which are likely unintentional.

Proprioception (role in reaching)

The body-position sense that guides early reaching and grasping more than vision does in the initial stages.

Fine motor grasps, infant

Crude palmar grasp, palmar grasp, radial palmar grasp, raking grasp, radial digital grasp, inferior pincer grasp (most advanced, 10-12 months).

Fine pincer grip (approx. 11-12 months)

The most advanced stage of the grasp sequence, involving precise coordination of the thumb and forefinger.

Casting (approx. 9-10 months)

The repeated dropping of objects or food from a height, reinforced by sound and caregiver reaction, coinciding with the development of object permanence.

Fine motor skills: manipulation, under 18 months

Improved attention span leads to development of challenging fine motor skills: hitting pegs into a peg board with a hammer, feeding self with hands, using spoon/fork, hand preference developing, clapping hands together, scribbling with pencil or crayon in fist.

Fine motor skills: manipulation, 18-24 months

Increased confidence: manipulate play dough, stack four or more blocks, dressing/undressing, pincer grasp, feed self with spoon, turn pages of a book (2-3 pages at a time).

Cognition

The process by which sensory inputs are transformed, reduced, elaborated, stored, recovered, and used. Includes attention, reasoning, sequencing, planning, decision making, wayfinding, problem solving, and comprehending/producing language.

Piaget's cognitive developmental theory

Children build schemas through direct interaction with the environment. Change occurs through adaptation: assimilation and accommodation. Schemas are linked internally together to develop the cognitive system.

Sensorimotor stage, birth-8 months

Repeating chance behaviours: actions may be reflexive initially, but the baby starts to volitionally repeat them to get the visual/auditory/tactile response.

Sensorimotor stage, 8-18 months

Intentional behaviour: begins problem solving (e.g. uncovering a hidden toy), imitation of adult actions, trying different actions to achieve an outcome.

Sensorimotor stage, 18-24 months

Mental representation: creates mental pictures/images of objects, people, places, and concepts by grouping together similar objects/events; experiments with actions 'in their heads,' not just trial and error.

Sensory receptors

Interoreceptors, exteroreceptors, and proprioceptors.

Interoreceptors

Internal sensory stimuli (e.g. blood pressure, thirst, pain).

Exteroreceptors

Sensory stimuli from the environment (light, sound, smell, touch, taste).

Proprioceptors

Somatosensory stimuli from the orientation of the body in space (joints, muscles, tendons, inner ear).

Sensory capabilities at birth

Hearing, gustatory (taste), olfactory (smell), tactile (light touch, pressure, temperature, pain), and vestibular (balance).

Anatomical development at 6 months gestation

Eye, ear, nose, and tongue (and their associated neural pathways) are well developed.

Sequence of functional sensory development

1. Touch, 2. Taste, 3. Smell, 4. Hearing, 5. Sight, 6. Balance.

Poorly developed senses at birth

Vision and proprioception.

Vision at birth

Visual acuity and focusing are limited. Some (not a lot of) colour perception.

Vision development, infant

Visual pursuit (following a moving object with the eyes) by 1-2 weeks; depth perception by 2-3 months; eye contact and limb movement to engage adult by 3 months; holds rattle and brings into visual field by 4-6 months; discriminates details by 6-7 months (close to adult capacity); rapid increase in density of visual cortex synapses up to 8 months.

Visual perception

Close objects stimulate reach and grasp. Object permanence develops (6-12 months). Starts to understand that a picture represents an object. Follows the gaze of a parent to an object. Shows an object to a parent. Learns about an object from the parent's response.

Hearing development, infant

At birth, able to discriminate a wide range of sounds (e.g. a 3-day-old newborn prefers mum's voice over a stranger's). Auditory nerve is well myelinated; auditory cortex is less well developed.

Taste, infant

Able to discriminate smells and tastes at birth (sweet, sour, bitter, salty, umami).