Chapter 4 Flashcards
embryonic period
third to eighth week of pregnancy
organogenesis
the process of organ formation in very early development. in humans this is from the first cell divisions until about 10 weeks
prenatal development
the development of human individuals before they are born
foetus
in human prenatal development, the organism 12 weeks after conception until birth
embryo
the developing organism during the period when organs are forming. in humans from first cell divisions until about 10 weeks
neonate
an infant less than a month old
postnatal development
the development of a human individual after he or she is born, particularly during early infancy
axon
the tail-like part of a neuron which transmits impulses (the actual message) away from the cell body
synapses
the connections between neurons which enable them to transmit information
synaptogenesis
the building of connections (synapses) between nerve cells
apoptosis
programmed cell death
neurons
nerve cells within central nervous system which transmit information in the form of electro-chemical impulses
ectoderm
the outermost of the three primary germ layers of an embryo. the central nervous system and skin, among other structures, develop from ectoderm
neural plate
a thickening of endoderm cells that will give rise to the brain
neural tube
a hollow structure in the embryo that gives rise to the brain and the spinal column
cranial-caudal
the direction beginning with the head end and moving toward the opposite end or feet in humans
neurogenesis
the birth of neurons
cerebral cortex
the area of the brain is associated with complex tasks such as memory, language, and thoughts and the control and integration of movement and the senses
sulci
the deep narrow grooves of the outer surface of the brain
gyri
the prominent ridges on the outer surface of the brain
myelin
a fatty insulator which prevents leakage of the messages travelling along the nerves, and increases the speed of neural transmission
myelination
the process by which myelin is formed around the neurons. myelination begins in the sixth month of life in the foetus but continues throughout childhood
term
the end of pregnancy
rooting reflex
the reflex that causes newborn babies to respond to one of their cheeks being touched by turning their head in that direction
chemosensory system
encompasses both the gustatory and olfactory senses
colostrum
the breast fluid that precedes true milk. it is rich in minerals and antibodies, and it helps populate the newborn’s gut with ‘good’ bacteria
vestibular system
the sensory system that contributes to balance and spatial orientation
preterm
born prematurely. human infants are regarded as preterm if they are born before 38 weeks of pregnancy
circadian rhythm
bodily cycles within the body that occur on a 24-hour cycle, such as patterns of sleeping/waking
rods and cones
light-sensitive cells found in the retina of the eye which translate light into electrical signals that are then transferred to the brain so that the image can be interpreted
trimester
a period of three months. the course of human pregnancy is divided into three trimesters
cochlea
the inner ear, a structure encased in bone that contains the receptors for sound
transnatal learning
learning that occurs during the prenatal period which is remembered during the postnatal period
electroencephalogram
a scalp recording done with electrodes that measures electrical activity produced by neurons. the EEG is often measured when it is time-locked to a stimulus event, producing an event-related potential (ERP)
perinatal
the period just before and after birth
meiotic cell division
the type of cell division that occurs in sexually reproducing organisms which halves the number of chromosomes in reproductive cells (sperm and ova)
DNA methylation
a process with an important role in gene regulation, consisting of the addition of methyl groups to DNA
autosomal genetic disorders
disorders resulting from a mutation in a gene in one of the non-sex chromosomes. well-known examples are cystic fibrosis (a receptive type) and achondroplasia (dwarfism, a dominant type)
selective serotonin reuptake inhibitor (SSRI)
a class of drugs typically used to treat depression or anxiety
developmental programming
the hypothesis that prenatal conditions have detrimental effects on health on health into adulthood
ultradian rhythm
rhythms or cycles that repeat in less than a 24-hour period
