Human Development

Question 1

fertilization

Answer 1

joining of the sperm and the egg cell; chromosomes from each combine to form a new set of 46

Question 2

zygote

Answer 2

newly fertilized egg

Question 3

morula

Answer 3

a ball of cells

Question 4

blastocyst

Answer 4

a hollow ball of cells

Question 5

embryo

Answer 5

the first 10 weeks of development

Question 6

fetus

Answer 6

10 weeks to birth

Question 7

gestation

Answer 7

266 days (38 weeks); three trimesters

Question 8

first trimester

Answer 8

zygote undergos cleavage (splitting into two cells); after further cell division, the morula becomes a blastocyst which has a very large number of cells and a hollow space; cell differentiation has begun to occur

Question 9

three distinct primary germ layers

Answer 9

ectoderm, mesoderm, and endoderm

Question 10

ectoderm

Answer 10

it will form outer tissues such as the skin; eventually it will form an inpocketing that produces the nervous system

Question 11

mesoderm

Answer 11

it will eventually form the middle tissues in the body such as the skeletal system and muscular system

Question 12

endoderm

Answer 12

it forms the inner layer, such as the respiratory system and digestive system

Question 13

implantation

Answer 13

7-10 days after ovulation, the blastocyst will reach the uterus and implant into the endometrium. at first, the blastocyst will release digestive enzymes and eat some of the lining to being growth, and release HCG

Question 14

placenta

Answer 14

the blastocyst and endometrium form together to form this

Question 15

development of the embryo

Answer 15

body systems established in first trimester; end of first trimester the fetus is 12 cm long with a beating heart, a circulatory system legs, arms, and all body organs

Question 16

second trimester

Answer 16

the organ systems mature and grow, by the end the fetus will be 35 cm long and weight 500-800 grams

Question 17

third trimester

Answer 17

most dramatic weight gain, organ systems continue to mature, end around 7 pounds and placenta will increase as well; greatest demand for bulk nutrition, including extra protein, calcium, and iron

Question 18

parturation

Answer 18

also known as birth

Question 19

stages

Answer 19

labor is triggered, estrogen increases, oxytocin increases, cervix begins to dilate, the amniotic sac bursts, abdominal muscles push, delivery, placenta delivers

Question 20

foramen ovale

Answer 20

hole in the fetal heart

Question 21

ductus arteriosus

Answer 21

carries blood from the pulmonary trunk directly to the aorta

Question 22

neonatal

Answer 22

the first month of life after birth; heart rate is very high and metabolism is very high; urinary water losses are high; body temperature is hard to control; nutritional source is entirely milk

Question 23

infancy

Answer 23

one month to 24 months; great amount of growth proportionate to the original body size

Question 24

childhood

Answer 24

from infancy up to the onset of puberty; extensive body tissue growth

Question 25

adolescence

Answer 25

starts at the onset of puberty and continues until growth is completed; boys are slower; hormonal changes involved with puberty and visible development of secondary sexual characteristics

Question 26

maturity

Answer 26

starts where bone growth ends

Question 27

senescense

Answer 27

aging; begins when we are physically mature