Unit 5: Prenatal Development

Question 1

Conception

Answer 1

a single sperm cell penetrates the outer coating of the egg and fuses to form one fertilized cell, otherwise known as a zygote

Question 2

Prenatal Development

Answer 2

the period that extends from conception to birth, usually encompassing nine months of pregnancy

Question 3

Overview of prenatal development

Answer 3

zygote: conception to 2 weeks
embryo: 2 weeks to 8 weeks
fetus: 9 weeks to birth

Question 4

Germinal stage (#1)

Answer 4

the phrase encompassing the weeks following conception; zygote moves towards the uterus and begins to implant the lining; placenta and umbilical cord begin to form; cells begin to differentiate

Question 5

Embryonic stage (#2)

Answer 5

the phase lasting from two weeks until the end of the second month; once developing organism firmly attaches to uterus, it is called the embryo; major organs and structures begin to develop; by the end of phase, embryo has heartbeat and features

Question 6

Fetal stage (#3)

Answer 6

the phase lasting from two months through birth; muscles begin to contract and the body moves into position

Question 7

Critical periods

Answer 7

times during which certain environmental influences can have an impact on the development of the infant; in terms of structural development, most critical periods occur during the embryonic stage

Question 8

Teratogens

Answer 8

agents, such as chemicals and viruses, that can reach the embryo or fetus during prenatal development and cause harm

Question 9

Newborn assessment scoring system

Answer 9

scores between 0 and 10
activity: muscle tone dealing with spontaneous movement
pulse: heart rate
grimace: reflex irritability; cries, pulls away, coughs, etc
appearance: skin colour
respiration: breathing - a good, healthy cry

Question 10

Rooting reflex

Answer 10

a newborns tendency, when touched on the cheek, to turn toward the touch, open the mouth and search for the nipple

Question 11

Sucking reflex

Answer 11

a newborns tendency to suck on objects that are placed in mouth

Question 12

Grasping reflex

Answer 12

a newborns tendency to close fist around anything placed in their hand

Question 13

Stepping reflex

Answer 13

a newborns tendency to make stepping motions when held upright

Question 14

Startle (Moro) reflex

Answer 14

a newborns tendency to throw head back, extend arms/legs, cry and bring arms/legs back in when startled

Question 15

Reflexes that are well-to-fully developed at birth

Answer 15

touch (skin-to-womb contact)
smell (mother’s milk vs. imposter’s milk)
taste (preference for sweet)

Question 16

Reflexes that are less developed at birth

Answer 16

hearing (fluids; most responsive to high and low pitches)
vision (rods are well-developed, cones are not)