Infancy- ch.2 and 3

Alleles

different versions/forms of the same gene.

Example: One allele may contribute to brown eyes, while another contributes to blue eyes in an infant.

behavioral genetics

the field of study that examines how genes and enviornment influence each behavior. Example: Studying how genetics and parenting together affect infant temperament.

chromosomes

the threadlike structure in cells nucleus that contains DNA. structure in cells that contain DNA and genes.

Example: Infants typically have 46 chromosomes inherited from their parents

DNA

the molecule that carries genetic information. molecule that makes up our chromosomes

Example: DNA determines many physical traits such as hair color and growth patterns in infants.

Dominant

a gene that expresses its traits even only one copy is present

Example: If an infant inherits one dominant allele for dimples, they will likely have dimple

epigenetics

changes in gene expression caused by enviornmental factors without changing DNA

Example: Nurturing caregiving can influence how stress-related genes are expressed in infants. if parents are calm it allows for the infant to be less stressed even though he has a high stress gene

experience-dependent plasticity

brain changes that occur as a result of individual experiences. how brain development adapts to experiences

xample: An infant develops stronger language skills by hearing and interacting with caregivers.

experience-expectant plasticity

brain development that depends on experiences most infants naturally recieve. plasticity that reflects the brain adapting to experiences that are common to virtually all memeber of a species

xample: Exposure to sights and sounds helps infants’ brains develop normal vision and hearing.

gene-environment correlations

when genetically influenced traits evoke environmental responses from others so that genes and the environment are similar. when genes influence the enviornments children experience

Example: A naturally calm infant may receive more gentle interactions from caregivers.

gene- environment interactions

when the effect of genes depend on environmental experiences. how the pattern of genes can make one more or less sensitive to environmental factors

Example: A genetic risk for anxiety may only appear if an infant experiences high stress.

genes

segments of DNA that are the basic unit of heredity. units of heredity made of DNA that influence traits and development

genotype

an individual’s unique genetic makeup

Example: An infant’s genotype includes the genes inherited from both parents.

glia

brain cells that support and protect neurons. are non-neuronal cells in the nervous system that support the functioning of nuerons.

xample: Glial cells help nourish neurons during rapid brain growth in infancy.

heredity

the passing of traits from parents to offspring through genes. the tranmission og genetic information across generations and how that genetic information translates to differences in characteristics and behavior

xample: An infant inherits eye color and height potential through heredity.

heterozygous

when each parent contributes a different allele for a particular gene

Example: An infant has one allele for curly hair and one for straight hair.

homozygous

having two indentical alleles for a gene

Example: An infant inherits two alleles for brown eyes.

migration

the movement of newly formed neurons from the ventricular or subventicular zone to their final location. Example: During prenatal development, neurons migrate to form brain structures needed in infancy

myelination

the formation of the fatty sheaths on the axons of neurons during neural development

Example: Myelination helps infants gain better control over movement and coordination.

neuron

a type of cell that is the basic unit of the nervous system.

example: Neurons allow infants to process sensory information and learn.

phenotype

the observable characteristics, or traits of an indiviual, from phsyical like dimples and height to psychological like intelligence and personaility

xample: An infant’s actual height and temperament are part of their phenotype.

plasticity

the adaptive ability of the brain to change or adjust in response to variations in the enviornment and expeience

Example: An infant’s brain reorganizes as they learn to recognize caregivers’ faces.

pruning

the emilination of synapses during neural development

xample: Neural connections not used during infancy are pruned to strengthen important skills

recessive

the non-expressed allele when a child inherits two fidderent alleles from each parents. need to recsive allele for it to seen

Example: An infant must inherit two recessive alleles to have red hair.

synapse

the space between two neurons and through which neural signals are transmitted

Example: Synapses allow information to pass between neurons during learning.

synaptogensis

the creation of synapses during neuronal development

xample: Rapid synaptogenesis occurs in infancy as infants learn new skills.

amniotic sac

thinned walled sac filled with liquid that will fold the fetus and protect it from getting injured during pregnancy

xample: The amniotic sac cushions the fetus and helps maintain a stable temperature.

Cephalocaudal direction

from head to foot

Example: Infants gain control of their head before their legs.

colic

inconsoable crying for more than 3 hours a day

Example: A baby cries for hours each day despite being fed and changed.

cones

a type of photoreceptors in the retina of the eye; they allow for us to see color

xample: Cones help infants gradually see colors more clearly.

dilation

opening up of the cervix during labor

Example: The cervix dilates to allow the baby to pass through the birth canal.

effacement

thinning of the cervix during labor

Example: Effacement occurs before and during labor

embryonic stage

state of prenatal development that lasts from about 2 to 8 weeks following conception. The prenatal period from weeks 3 to 8 when major organs begin forming.
Example: The heart and brain start developing during the embryonic stage.

fallopian tube

tube that connects the ovaries to the woman’s uterus example. fertilization usually occurs in the fallopian tube.

fetal stage

stage of prenatal development that lasts from about 8 to 38 weeks after conception, of from about the 10th week of pregnancy until birth. The prenatal period from week 9 until birth, marked by growth and maturation.
Example: The fetus gains weight and strengthens organs during this stage.

fovea

he part of the retina responsible for sharp, detailed vision. a region of the retina that is densely packed with cones and is the part of the retina that has the sharpest, clearest vision.
Example: The fovea is immature at birth, which is why newborn vision is blurry.

lens

part of the eyeball that helps to make sure that light is focused on the retina

Example: The lens helps infants gradually focus on objects as vision improves

neural plate

three-layered structure that makes up the spinal cord and brain in prenatal devlopment A flat layer of cells in the embryo that develops into the nervous system.
Example: The neural plate forms early in the embryonic stage.

neural tube

structure that forms the spinal cord in in prenatal development. The structure that develops from the neural plate and becomes the brain and spinal cord.
Example: Problems with neural tube development can lead to conditions like spina bifida.

optic nerve

the nerve that carries messages from the retina to the brain. he nerve that carries visual information from the eye to the brain.
Example: The optic nerve sends images from the retina to the visual cortex.

ovaries

a pair of female glands where eggs form and hormones like estrogen and proestrogen are made. female reproductive organs that produce eggs and hormones.
Example: release eggs that may become fertilized.

papillae

protrusions on the tongue where our taste buds are located . small bumps on the tongue that contain taste buds.
Example: Infants have many papillae, making them sensitive to tastes.

photoreceptors

neurons in the retina that absorb light and send information via the optic nerve to the brain. Cells in the retina that respond to light.
Example: Rods and cones are types of photoreceptors.

placenta

a small organ that filters the exchange of materials between the mother and the fetus, allowing some things like food and antibiotics in and carrying other things like waste out. An organ that connects the fetus to the mother and provides nutrients and oxygen.
Example: The placenta also removes waste from the fetus’s blood.

REM sleep

rapid eyem movement sleep, a deep sycle of sleep where the brain is very active. A stage of sleep characterized by rapid eye movement and brain activity.
Example: Infants spend much of their sleep in REM, which supports brain development.

rods

photoreceptors that function in low light and are not sensitive to color. Photoreceptors responsible for light and dark vision.
Example: Rods help infants see in low-light conditions.

taste buds

gustatory receptors that detect different chemicals in our food. Sensory receptors that detect flavors.
Example: Newborns prefer sweet tastes due to active taste buds.

teratogen

any factors that causes malformation in prenatal development . Any environmental agent that can harm prenatal development.
Example: Alcohol is a teratogen that can cause fetal alcohol spectrum disorders.

umbilical cord

cord that connects the fetus to the placenta. A cord that connects the fetus to the placenta.
Example: The umbilical cord delivers oxygen and nutrients to the fetus.

visual cortex

The part of the brain that processes, represents, and interprets information transmitted from the retinas, by way of the optic nerve. the part of the brain that processes visual information.
Example: As the visual cortex develops, infants’ vision improves.

zygotic stage

the period of prenatal development from conception to implantation, about 2 weeks. the first stage of prenatal development from conception to about two weeks.
Example: The zygote begins dividing rapidly after fertilization.