Fetal and Pediatric Development

Question 1

Gestational Age

Answer 1

Measured from first day of last menstrual period

Question 2

Conception

Answer 2

Fertilization of egg with sperm

Question 3

“embryonic” period

Answer 3

First 8 weeks post conception (all major organs formed)

Question 4

“Fetal” period

Answer 4

remaining 30 weeks (organs grow larger and become more complex)

Question 5

Blastocyst

Answer 5

Two distinct types of cells

1. Inner mass cells: forms the embryo
2. Trophoblast: layer of cells surrounding the cavity which helps form the placenta

Floats for about 3 days –> Implantation on about day 6 post conception: trophoblast erodes uterine wall (takes 1 week to complete)

Question 6

Implantation

Answer 6

1. Adherence of the trophoblast to the uterine wall
2. Inner cell mass divides into epiblast and hypoblast
3. Two fluid filled sacs
   -amniotic sac from
   epiblast
   -Yolk sac from hypoblast

Question 7

Beginning Tissue Formation

Answer 7

Primary Germ layers: Ectoderm, mesoderm, endoderm

Question 8

Endoderm

Answer 8

Epithelium of Gi Tract, liver, pancreas, ureters, urinary bladder

Epithelial portions: pharynx, thyroid, thrachea, bronchi, lungs, tympanic cavity, pharyngotympanic tube, tonsils, parathyroids

Question 9

Ectoderm

Answer 9

• Nervous Tissue: neural tube (CNS, Retina, Post pituitary, pineal gland)
• Neural crest: pigment cells, adrenal medulla, cranial and sensory nn, cranial and sensory ganglia
• Epidermis: hair, nails, mammary glands, cutaneous glands, anterior pituitary, teeth enamel, inner ear, eye lens

Question 10

Mesoderm

Answer 10

Skeleton (head and body), muscle, connective tissue, circulatory system (cardio/lymph), urinary system, spleen, adrenal cortex, genital system: gonads, ducts, accessory glands), Dermis, Dentine of teeth

Question 11

General Overview of Organ System Dev

Answer 11

By month 1, gross characteristics of all different organ systems have already begun to develop

By 4 month, organs are grossly the same as a neonate

By .birth, nervous system, kidneys, and liver are not fully developed

Question 12

Gastrointestinal system development

Answer 12

• Midpregnancy: ingest and absorb large amounts of amniotic fluid
• last 2-3 months - small quantities of meconium formed

Question 13

Kidneys:

Answer 13

Begin to excrete urine during second trimester

Fetal urine = 80

Question 14

Fetal Circulation

Answer 14

Week 3 (heart beings to beat at week 4)

Question 15

Fetal circulation just before birth

Answer 15

1. Ductus venosus
2. High pulmonary vascular resistance
3. Ductus arteriosus
4. Foramen ovale

Question 16

Pediatric growth

Answer 16

Growth: increase in physical size

Question 17

Ped development

Answer 17

• continuous, orderly series
• increase in function and complexity
• increase in capabilities

Question 18

Patterns of Growth and Dev

Answer 18

Pace: rapid from birth to 2 and puberty to ~15 years

• Slower from 2 to puberty and 16-24
• Cepholocaudal: head to toe
• Proximodistal: midline to periphery
• Simple to complex

Question 19

Factors influencing growth and dev

Answer 19

1. Critical/sensitive period
2. Genetics
3. Environment - physical and psychosocial
4. Culture
5. Health Status
6. Family

Question 20

Ectoderm 2

Answer 20

External affairs; interactions with environment

Question 21

Mesoderm 2

Answer 21

Architect and Engineer; structural organization of body

Question 22

Endoderm 2

Answer 22

Chemist, metabolism and homeostasis

Question 23

Fetal Blood

Answer 23

• By 3 month, bone marrow is producing most of RBC
• Even at low PO2 levels, fetal hemoglobin can carry 20-50% more oxygen than maternal hemoglobin
• Hemoglobin concentration of fetal blood is about 50% greater than that of the mother